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1 Relly Victoria Petrescu and Florian Ion Petrescu THE AVIATION HISTORY (NEW AIRCRAFT I) COLOR USA 2013

2 Scientific reviewer: Dr. Veturia CHIROIU Honorific member of Technical Sciences Academy of Romania (ASTR) PhD supervisor in Mechanical Engineering Copyright Title book: The Aviation History (New Aircraft I) Color Author book: Relly Victoria Petrescu, Florian Ion Petrescu , Florian Ion PETRESCU ALL RIGHTS RESERVED. This book contains material protected under International and Federal Copyright Laws and Treaties. Any unauthorized reprint or use of this material is prohibited. No part of this book may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying, recording, or by any information storage and retrieval system without express written permission from the authors / publisher. Manufactured and published by: Books on Demand GmbH, Norderstedt ISBN

3 CONTENT Content Welcome Cap 01 Introduction Cap 02 Some popular models of airplanes Cap 03 Ships STOVL Zeppelins Helicopters Ships STOVL Cap 04 Special Aircraft Cap 05 Invisible Aircraft Cap 06 Planes which have made history Cap 07 Seaplane The Norwegian polar explorer Roald Amundsen Jacques-Yves Cousteau An amphibious aircraft or amphibian A floatplane (or pontoon plane) Tigerfish Aviation Flying boat

4 Cap 08 Aircraft carriers Anti-submarine warfare carrier Helicopter carrier Light aircraft carrier Amphibious assault ship Seaplane tender Supercarrier Escort aircraft carrier Cap 9 The Battle of Midway Cap 10 New Aircraft Bibliography

5 WELCOME According to Aulus Gellius, Archytas, the Ancient Greek philosopher, mathematician, astronomer, statesman, and strategist, was reputed to have designed and built, around 400 BC, the first artificial, selfpropelled flying device, a bird-shaped model propelled by a jet of what was probably steam, said to have actually flown some 200 metres. This machine, which its inventor called The Pigeon, may have been suspended on a wire or pivot for its flight. The 9th century Muslim Berber inventor, Abbas Ibn Firnas's glider is considered by John Harding to be the first attempt at heavier-than-air flight in aviation history. In 1010 AD an English monk, Eilmer of Malmesbury purportedly piloted a primitive gliding craft from the tower of Malmesbury Abbey. Eilmer was said to have flown over 200 yards (180 m) before landing, breaking both his legs. He later remarked that the only reason he did not fly further was because he forgot to give it a tail, and he was about to add one when his concerned Abbot forbade him any further experiments. Bartolomeu de Gusmão, Brazil and Portugal, an experimenter with early airship designs. In 1709 demonstrated a small airship model before the Portuguese court, but never succeeded with a full-scale model. Pilâtre de Rozier, Paris, France, first trip by a human in a free-flying balloon (the Montgolfière), built by Joseph-Michel and Jacques-Étienne Montgolfier,. 9 km covered in 25 minutes on October 15, (see Le Globe below for first unmanned flight, 2 months earlier) Professor Jacques Charles and Les Frères Robert, two French brothers, Anne-Jean and Nicolas-Louis, variously shared three milestones of pioneering flight : Le Globe, the first unmanned hydrogen gas balloon flew on 26 August On 1 December 1783 La Charlière piloted by Jacques Charles and Nicolas-Louis Robert made the first manned hydrogen balloon flight. In 1951, the Lockheed XFV-1 and the Convair XFY tailsitters were both designed around the Allison YT40 turboprop engine driving contra-rotating propellers. The British Hawker P.1127 took off vertically in 1960, and demonstrated conventional take off in By 1964 the first development aircraft, the Hawker Siddeley Kestrel, were flying. These were flown by a tripartite squadron of British, US and West German pilots. The first Hawker Siddeley Harrier flew in In 1962, Lockheed built the XV-4 Hummingbird for the U.S. Army. It sought to "augment" available thrust by injecting the engine exhaust into an ejector pump in the fuselage. First flying vertically in 1963, it suffered a fatal crash in It was converted into the XV-4B Hummingbird for the U.S. Air Force as a testbed for separate, vertically mounted lift engines, similar to those used in the Yak-38 Forger. That plane flew and later crashed in The Ryan XV-5 Vertifan, which was also built for the U.S. Army at the same time as the Hummingbird, experimented with gas driven lift fans. That plane used fans in the nose and each wing, covered by doors which resembled half garbage can lids when raised. However, it crashed twice, and proved to generate a disappointing amount of lift, and was difficult to transition to horizontal flight. Of dozens of VTOL and V/STOL designs tried from the 1950s to 1980s, only the subsonic Hawker Siddeley Harrier and Yak-38 Forger reached operational status, with the Forger being withdrawn after the fall of the Soviet Union. Boeing had studied another odd-looking supersonic fighter in the 1960s which never made it beyond photos in Aviation Week. Rockwell International built, and then abandoned, the Rockwell XFV-12 supersonic fighter which had an unusual wing which opened up like window blinds to create an ejector pump for vertical flight. It never generated enough lift to get off the ground despite developing 20,000 lbf of thrust. The French had a nominally Mach 2 Dassault Mirage IIIV fitted with no less than 8 lift engines that flew (and crashed), but did not have enough space for fuel or payload for combat missions. The German EWR VJ 101 used swiveling engines mounted on the wingtips with fuselage mounted lift engines, and the VJ 101C X1 reached supersonic flight (Mach 1.08) on July 29, The supersonic Hawker Siddeley P.1154 which competed with the Mirage IIIV for NATO use was cancelled even as the aircraft were being built. NASA uses the abbreviation SSTOVL for Supersonic Short Take-Off / Vertical Landing, and as of 2011, the X-35B/F-35B are the only aircraft to conform with this combination within one flight. The experimental Mach 1.7 Yakovlev Yak-141 did not find an operational customer, but its rotating rear nozzle technology found good use with the F-35B. The F-35 Lightning II is expected to enter service by

6 Larger STOVL designs were considered, the Armstrong Whitworth AW.681 cargo aircraft was under development when cancelled in The Dornier Do 31 got as far as three experimental aircraft before cancellation in Although mostly a VTOL design, the V-22 Osprey has increased payload when taking off from a short runway. The Hawker Siddeley Harrier, colloquially the "Harrier Jump Jet", was developed in the 1960s and was the first generation of the Harrier series of aircraft. It was the first operational close-support and reconnaissance fighter aircraft with Vertical/Short Takeoff and Landing (V/STOL) capabilities and the only truly successful V/STOL design of the many that arose in that era. The Harrier was produced directly from the Hawker Siddeley Kestrel prototypes following the cancellation of a more advanced supersonic aircraft, the Hawker Siddeley P The Royal Air Force (RAF) ordered the Harrier GR.1 and GR.3 (fig. 84) variants in the late 1960s. It was exported to the United States as the AV-8A, for use by the US Marine Corps (USMC), in the 1970s. A Zeppelin is a type of rigid airship pioneered by the German Count Ferdinand von Zeppelin in the early 20th century. It was based on designs he had outlined in 1874 and detailed in His plans were reviewed by committee in 1894 and patented in the United States on 14 March Given the outstanding success of the Zeppelin design, the term zeppelin in casual use came to refer to all rigid airships. Zeppelins were operated by the Deutsche Luftschiffahrts-AG (DELAG). DELAG, the first commercial airline, served scheduled flights before World War I. After the outbreak of war, the German military made extensive use of Zeppelins as bombers and scouts. The World War I defeat of Germany in 1918 halted the airship business temporarily. But under the guidance of Hugo Eckener, the deceased Count's successor, civilian zeppelins became popular in the 1920s. Their heyday was during the 1930s when the airships LZ 127 Graf Zeppelin and LZ 129 Hindenburg operated regular transatlantic flights from Germany to North America and Brazil. The Art Deco spire of the Empire State Building was originally if impractically designed to serve as a dirigible terminal for Zeppelins and other airships to dock. The Hindenburg disaster in 1937, along with political and economic issues, hastened the demise of the Zeppelin. An ion thruster is a form of electric propulsion used for spacecraft propulsion that creates thrust by accelerating ions. Ion thrusters are characterized by how they accelerate the ions, using either electrostatic or electromagnetic force. Electrostatic ion thrusters use the Coulomb Force and accelerate the ions in the direction of the electric field. Electromagnetic ion thrusters use the Lorentz Force to accelerate the ions. Note that the term "ion thruster" frequently denotes the electrostatic or gridded ion thrusters, only. The thrust created in ion thrusters is very small compared to conventional chemical rockets, but a very high specific impulse, or propellant efficiency, is obtained. Due to their relatively high power needs, given the specific power of power supplies, and the requirement of an environment void of other ionized particles, ion thrust propulsion currently is only practicable in outer space. The first experiments with ion thrusters were carried out by Robert Goddard at Clark College from The technique was recommended for near-vacuum conditions at high altitude, but thrust was demonstrated with ionized air streams at atmospheric pressure. The idea appeared again in Hermann Oberth's "Wege zur Raumschiffahrt (Ways to Spaceflight), published in Ionic engine (ion thruster, which accelerates the positive ions through a potential difference) is about 10 times more effective than classic system based on combustion. We can still improve the efficiency of times if one uses positive ions accelerated in a cyclotron mounted on the ship; the efficiency can easily grow for 1000 times if the positive ions will be accelerated in a high energy synchrotron, synchrocyclotron or isochronous cyclotron (1-100 GeV). Future (ionic) engine will have mandatory a circular particle accelerator (high or very high energy; see the figure 3). Sure that the difficulties will arise from design, but they need to be resolved step by step. We can thus increase the speed and autonomy of the ship using a less quantity of fuel. One can use synchrotron radiation (synchrotron light, high intensity beams), like high intensity (X-ray or Gamma ray) radiation, as well. In this case will be a beam engine (not an ionic engine). A linear particle accelerator (also called a LINAC) is an electrical device for the acceleration of subatomic particles. This sort of particle accelerator has many applications. It used recently as to an injector into a higher energy synchrotron at a dedicated experimental particle physics laboratory. In this, the big classic synchrotron is reduced to a ring surface (magnetic core). You are welcome to read the full book! The authors. 6

7 1. Introduction According to Aulus Gellius, Archytas, the Ancient Greek philosopher, mathematician, astronomer, statesman, and strategist, was reputed to have designed and built, around 400 BC, the first artificial, selfpropelled flying device, a bird-shaped model propelled by a jet of what was probably steam, said to have actually flown some 200 metres. This machine, which its inventor called The Pigeon, may have been suspended on a wire or pivot for its flight. The 9th century Muslim Berber inventor, Abbas Ibn Firnas's glider is considered by John Harding to be the first attempt at heavier-than-air flight in aviation history. In 1010 AD an English monk, Eilmer of Malmesbury purportedly piloted a primitive gliding craft from the tower of Malmesbury Abbey. Eilmer was said to have flown over 200 yards (180 m) before landing, breaking both his legs. He later remarked that the only reason he did not fly further was because he forgot to give it a tail, and he was about to add one when his concerned Abbot forbade him any further experiments. Bartolomeu de Gusmão, Brazil and Portugal, an experimenter with early airship designs. In 1709 demonstrated a small airship model before the Portuguese court, but never succeeded with a full-scale model. Pilâtre de Rozier, Paris, France, first trip by a human in a free-flying balloon (the Montgolfière), built by Joseph-Michel and Jacques-Étienne Montgolfier,. 9 km covered in 25 minutes on October 15, (see Le Globe below for first unmanned flight, 2 months earlier) Professor Jacques Charles and Les Frères Robert, two French brothers, Anne-Jean and Nicolas-Louis, variously shared three milestones of pioneering flight : Le Globe, the first unmanned hydrogen gas balloon flew on 26 August 1783 (fig. 1). On 1 December 1783 La Charlière piloted by Jacques Charles and Nicolas-Louis Robert made the first manned hydrogen balloon flight. On 19 September 1784, La Caroline, an elongated craft that followed Jean Baptiste Meusnier's proposals for a dirigible balloon, completed the first flight over 100 km from Paris to Beuvry. Fig. 1. Le Globe, the first unmanned hydrogen balloon built by Jacques Charles and the Robert brothers is attacked by terrified villagers in Gonesse near Paris. First real flying was realized by the Montgolfier brothers, in 1786 (fig. 2). First heavier than air powered flight, accomplished by an unmanned free flight steam powered monoplane of 10-foot (3.0 m) wingspan, was realized by John Stringfellow, in 1848 in England. In 1868, he flew a powered monoplane model a few dozen feet, at an exhibition at the Crystal Palace in London. First well-documented Western human glide, was realized by George Cayley, in England year 1853 (fig. 3). Cayley also made the first scientific studies into the aerodynamic forces on a winged flying machine and produced designs incorporating a fuselage, wings, stabilizing tail and control surfaces. He discovered and identified the four aerodynamic forces of flight - weight, lift, drag, and thrust. Modern airplane design is based on those discoveries including cambered wings. Cayley is sometimes called the "Father of aviation". 7

8 Fig. 2. First flying was realized by the Montgolfier brothers. Fig. 3. First well-documented Western human glide, was realized by George Cayley, in England year Matias Perez was a Portuguese pilot, an Cuban resident who, carried away with the ever increasing popularity of aerostatic aircraft, disappeared while attempting an aerostatic flight from Havana's "Plaza de Marte" (currently Parque de la Fraternidad) on June, 1856 (fig. 4). Fig. 4. Matias Perez was a Portuguese pilot, who disappeared while attempting an aerostatic flight from Havana's on June, First airplane able to lift itself under its own power, was made by the French Victor Tatin in 1874 (fig. 5). The Aeroplane was an unmanned plane powered by a compressed-air engine. Fig. 5. First airplane able to lift itself under its own power, was made by the French Victor Tatin in First recorded controlled, powered, sustained heavier than air flight, in Wright Flyer, USA, 1903 (fig. 6). In the day's fourth flight, Wilbur Wright flew 852 ft (260 m) in 59 seconds. First three flights were approximately 120, 175, and 200 ft (61 m), respectively. The Wrights laid particular stress on fully and accurately describing all the requirements for controlled, powered flight and put them into use in an aircraft which took off from a level launching rail, with the aid of a headwind to achieve sufficient airspeed before reaching the end of the rail. 8

9 Modern analysis by Professor Fred E. C. Culick and Henry R. Rex (1985) has demonstrated that the 1903 Wright Flyer was so unstable as to be almost unmanageable by anyone. Fig. 6. In the day's fourth flight, Wilbur Wright flew 852 ft (260 m) in 59 seconds. First recorded controlled, powered, sustained heavier than air flight, in Wright Flyer, USA, Traian Vuia (August 17, September 3, 1950) was a Romanian inventor and aviation pioneer who designed, built and flew an early aircraft. His first flight traveled about 12 m (40 feet) at Montesson, France on March 18, 1906 (fig. 7). This was the first well-documented unassisted takeoff and landing on a level surface by an engine-driven monoplane with a completely-wheeled undercarriage. Fig. 7. The Traian Vuia s plane. This was the first well-documented unassisted takeoff and landing on a level surface by an engine-driven monoplane with a completely-wheeled undercarriage, in 18 March 1906, at Montesson, France. After graduating from high-school in Lugoj, Banat, Romania in 1892, he enrolled in the School of Mechanics at the Polytechnic University of Budapest where he received his engineering diploma. He then joined the Faculty of Law in Budapest - Hungary, where he earned a Ph.D. in law in May 1901 with the thesis "Military and Industry, State and Contract regime". He returned to Lugoj, where he studied the problem of human flight and designed his first flying machine, which he called the "airplane-car". He attempted to build the machine, but due to financial constraints decided to go to Paris in July 1902, hoping to find someone interested in financing his project, possibly balloon enthusiasts. He met with considerable skepticism from people who believed that a heavier-than-air machine could not fly. He then visited Victor Tatin, a well-known theoretician and experimenter who had built an aircraft model which flew in Tatin was interested in the project, but doubted that Vuia had a suitable engine or that his aircraft would be stable. Vuia then presented his plan to the Académie des Sciences in Paris on February 16, 1903 and was rejected with the comment: The problem of flight with a machine which weighs more than air can not be solved and it is only a dream. Undeterred, Vuia applied for a patent which was granted on August 17, 1903 and published on October 16, He began to build his first flying machine in the winter of Overcoming more financial difficulties, he also started construction of an engine of his own design in autumn 1904 and received a patent for it that year in the United Kingdom. 9

10 By December 1905 Vuia has finished construction of his first aircraft, the "Traian Vuia, 1" a high-wing monoplane powered by a carbonic acid gas engine. The liquid carbon dioxide was vaporized in a serpollet boiler, this added heating of the working fluid gave the engine a duration of about three minutes. He chose a site in Montesson, near Paris for testing. At first he used the machine only as a car, without the wings mounted, so he could gather experience driving it. On March 18, 1906 he made his first flight attempt. After accelerating about 50 meters, the plane left the soil and flew about one meter high for about 12 meters distance, then landed. The British aviation historian Charles Harvard Gibbs-Smith described it as "the first man-carrying monoplane of basically modern configuration", and "successful". Newspapers in France, the U.S. and the United Kingdom wrote about the man they believed was the first to fly in a heavier-than-air machine. Romanian enthusiasts emphasize that Vuia's machine was able to take off from a flat surface by on-board means without outside assistance, such as an incline, rails, or catapult. Debate continues over the precise definition of "first" airplane (see First flying machine for more discussion). After his March 18 takeoff, Vuia made several more short flights in 1906 and In August 1906 he built a modified version of his flying machine, the "Vuia I bis." In 1907, his "Vuia II" airplane, with an Antoinette 25 hp (19 kw) internal combustion engine, was exhibited at the first Aeronautical Salon in Paris. Aviation pioneer Alberto Santos Dumont, who made famous short flights in Paris in October and November 1906, recognized Vuia as a "forerunner" of his efforts, as described by Charles Dollfus, the curator of an aeronautical museum in Paris. Between 1918 and 1921 Vuia built two experimental helicopters on the Juvissy and Issy-les-Moulineaux aerodromes, contributing to the development of vertical take-off. Another invention by Vuia was a steam generator with internal combustion that could generate very high pressure of more than 100 atm (10 MPa) that is still used today in thermal power stations. On May 27, 1946 Vuia was named an Honorary Member of the Romanian Academy. Aurel Vlaicu (Romanian pronunciation (November 19, 1882 September 13, 1913) was a Romanian engineer, inventor, airplane constructor and early pilot. Aurel Vlaicu was born in Binţinţi (now renamed Aurel Vlaicu), Geoagiu, Transylvania. He attended Calvinist High School in Orăştie (renamed "Liceul Aurel Vlaicu" in his honour in 1919) and took his Baccalaureate in Sibiu in He furthered his studies at Technical University of Budapest and Technische Hochschule München in Germany, earning his engineer's diploma in After working at Opel car factory in Rüsselsheim, he returned to Binţinţi and built a glider he flew in the summer of Later that year, he moved to Bucharest, in the Kingdom of Romania, where he began the construction of Vlaicu I airplane; it flew for the first time on June 17, Fig. 8. Vlaicu II model, built in With his Vlaicu II model, built in 1911, Aurel Vlaicu won several prizes summing 7,500 Austro- Hungarian krone (for precise landing, projectile throwing and tight flying around a pole) in 1912 at Aspern Air Show near Vienna, where he competed against 42 other aviators of the day, including Roland Garros (fig. 8). Aurel Vlaicu died in 1913 near Câmpina while attempting to cross in flight the Carpathian Mountains in his aged Vlaicu II airplane. 10

11 The Coandă-1910, designed by Romanian inventor Henri Coandă, was the first full-size attempt at a jet aircraft (fig. 9). Built as a sesquiplane, it featured an experimental aircraft engine which Coandă called the "turbo-propulseur," a centrifugal compressor propulsion system with a multi-bladed rotary fan situated in a duct and driven by a conventional piston engine. The unconventional aircraft attracted attention at the Second International Aeronautical Exhibition in Paris in October 1910, being the only plane without propeller. Coandă used a similar mechanism to drive a snow sled, but did not develop it further for aircraft. Fig. 9. The Coandă-1910, designed by Romanian inventor Henri Coandă, was the first full-size attempt at a jet aircraft. Decades later, after the practical demonstration of motorjets and turbojets, Coandă asserted that his turbo-propulseur was the first motorjet engine complete with fuel combustion in the air stream. He also said that he had made a single brief flight in December 1910, crashing just after take-off, the aircraft destroyed by fire. About the Coanda s Effect An early description of this phenomenon (Coanda) was provided by Thomas Young in a lecture given to The Royal Society in 1800: The lateral pressure which urges the flame of a candle towards the stream of air from a blowpipe is probably exactly similar to that pressure which eases the inflexion of a current of air near an obstacle. Mark the dimple which a slender stream of air makes on the surface of water. Bring a convex body into contact with the side of the stream and the place of the dimple will immediately show the current is deflected towards the body; and if the body be at liberty to move in every direction it will be urged towards the current. A hundred years later, Henri Coandă identified an application of the effect during experiments with his Coandă-1910 aircraft which mounted an unusual engine designed by Coandă. The motor-driven turbine pushed hot air rearward, and Coanda noticed that the airflow was attracted to nearby surfaces. He discussed this matter with leading aerodynamicist Theodore von Kármán who named it the Coandă effect. In 1934 Coandă obtained a patent in France for a "Method and apparatus for deviation of a fluid into another fluid". The effect was described as the "Deviation of a plan jet of a fluid that penetrates another fluid in the vicinity of a convex wall." The Coanda effect is a result of entrainment of ambient fluid around the fluid jet. When a nearby wall does not allow the surrounding fluid to be pulled inwards towards the jet (i.e. to be entrained), the jet moves towards the wall instead. The fluid of the jet and the surrounding fluid should be essentially the same substance (a gas jet into a body of gas or a liquid jet into a body of liquid). In one application, a jet of air is blown over the upper surface of an airfoil, which can have a strong influence on the overall lift, especially at high angles of attack when the flow would otherwise separate (stall). The Coanda effect has important applications in various high-lift devices on aircraft, where air moving over the wing can be "bent down" towards the ground using flaps and a jet sheet blowing over the curved surface of the top of the wing. The bending of the flow results in its acceleration and as a result of Bernoulli's principle pressure is decreased; aerodynamic lift is increased. The flow from a high speed jet engine mounted in a pod over the wing produces enhanced lift by dramatically increasing the velocity gradient in the shear flow in the boundary layer. In this velocity gradient particles are blown away from the surface, thus lowering the pressure there. Closely following the work of Coanda on applications of his research, and in particular the work on his "Aerodina Lenticulară," (fig. 10), John Frost of Avro Canada also spent considerable time researching the effect, leading to a series of "inside out" hovercraft-like aircraft where the air exited in a ring around the outside of the aircraft and was directed by being "attached" to a flap-like ring. 11

12 Fig. 10. Coanda Lenticular aerodyne. This is as opposed to a traditional hovercraft design, in which the air is blown into a central area, the plenum, and directed down with the use of a fabric "skirt". Only one of Frost's designs was ever built, the Avrocar. The VZ-9 AV Avrocar (often listed as VZ-9) was a Canadian vertical takeoff and landing (VTOL) aircraft developed by Avro Aircraft Ltd. as part of a secret U.S. military project carried out in the early years of the Cold War. The Avrocar intended to exploit the Coandă effect to provide lift and thrust from a single "turborotor" blowing exhaust out the rim of the disk-shaped aircraft to provide anticipated VTOL-like performance. In the air, it would have resembled a flying saucer. Two prototypes were built as "proof-of-concept" test vehicles for a more advanced USAF fighter and also for a U.S. Army tactical combat aircraft requirement. The effect was also implemented during the U.S. Air Force's AMST project. Several aircraft, notably the Boeing YC-14 (the first modern type to exploit the effect), have been built to take advantage of this effect, by mounting turbofans on the top of wing to provide high-speed air even at low flying speeds, but to date only one aircraft has gone into production using this system to a major degree, the Antonov An-72 'Coaler'. The McDonnell Douglas YC-15 and its successor, the Boeing C-17 Globemaster III, also employ the effect. The NOTAR helicopter replaces the conventional propeller tail rotor with a Coanda effect tail (fig. 11). Fig. 11. The C-17 Globemaster III uses the Coanda effect for a comfortable ride at low flying speeds An important practical use of the Coanda effect is for inclined hydropower screens, which separate debris, fish, etc., otherwise in the input flow to the turbines. Due to the slope, the debris falls from the screens without mechanical clearing, and due to the wires of the screen optimizing the Coanda effect, the water flows though the screen to the penstocks leading the water to the turbines. The Coanda effect is also used to make automotive windshield washers which function without moving parts and to create pneumatic logic circuits. The operation principle of oscillatory flowmeters also relies on the Coanda phenomenon. The incoming liquid enters a chamber that contains 2 "islands". Due to the Coanda effect the main stream splits up and goes under one of the islands. This flow then feeds itself back into the main stream making it split up again, but in the direction of the second isle. This process repeats itself as long as the liquid circulates the chamber, resulting in a self induced oscillation that is directly proportional to the velocity of the liquid and consequently the volume of 12

13 substance flowing through the meter. A sensor picks up the frequency of this oscillations and transforms it into an analog signal yielding volume passing through. In air conditioning the Coanda effect is exploited to increase the throw of a ceiling mounted diffuser. Because the Coanda effect causes air discharged from the diffuser to "stick" to the ceiling, it travels farther before dropping for the same discharge velocity than it would if the diffuser was mounted in free air, without the neighbouring ceiling. Lower discharge velocity means lower noise levels and, in the case of variable air volume (VAV) air conditioning systems, permits greater turn-down ratios. Linear diffusers and slot diffusers that present a greater length of contact with the ceiling exhibit greater Coanda effect. In meteorology, the Coanda effect theory has also been applied to some air streams flowing out of mountain ranges such as the Carpathian Mountains and Transylvanian Alps, where effects on agriculture and vegetation have been noted. It also appears to be an effect in the Rhone Valley in France and near Big Delta in Alaska. Fig. 12. The McDonnell Douglas YC-15 uses the Coanda effect for a comfortable ride at low flying speeds The YC-15 was McDonnell Douglas' entrant into the U.S. Air Force's Advanced Medium STOL Transport (AMST) competition (fig. 12), to replace the C-130 Hercules as the USAF's standard STOL tactical transport. In the end neither the YC-15 nor Boeing YC-14 was ordered into production, although the YC-15's basic design would be used to form the successful C-17 Globemaster III. The feathered propellers of an RAF Hercules C.4. The NOTAR helicopter replaces the conventional propeller tail rotor with a Coanda effect tail (fig. 13). Fig. 13. The NOTAR helicopter replaces the conventional propeller tail rotor with a Coanda effect tail. 13

14 Several aircraft, notably the Boeing YC-14 (the first modern type to exploit the effect), have been built to take advantage of this effect, by mounting turbofans on the top of wing to provide high-speed air even at low flying speeds (fig. 14). Fig. 14. The Boeing YC-14 use the Coanda effect. The Avro Canada VZ-9 Avrocar was a VTOL aircraft developed by Avro Aircraft Ltd. (Canada) as part of a secret U.S. military project carried out in the early years of the Cold War (fig. 15). The Avrocar intended to exploit the Coandă effect to provide lift and thrust from a single "turborotor" blowing exhaust out the rim of the disk-shaped aircraft to provide anticipated VTOL-like performance. In the air, it would have resembled a 14

15 flying saucer. Two prototypes were built as "proof-of-concept" test vehicles for a more advanced USAF fighter and also for a U.S. Army tactical combat aircraft requirement. In flight testing, the Avrocar proved to have unresolved thrust and stability problems that limited it to a degraded, low-performance flight envelope; subsequently, the project was cancelled in September Fig. 15. The Avro Canada VZ-9 Avrocar was a VTOL aircraft developed by Avro Aircraft Ltd. (Canada). The Avrocar intended to exploit the Coanda effect to provide lift and thrust from a single "turborotor" blowing exhaust out the rim of the disk-shaped aircraft to provide anticipated VTOL-like performance. Through the history of the program, the project was referred to by a number of different names. Avro referred to the efforts as Project Y, with individual vehicles known as Spade and Omega. Project Y-2 was later funded by the US Air Force, who referred to it as WS-606A, Project 1794 and Project Silver Bug. When the US Army joined the efforts it took on its final name "Avrocar", and the designation "VZ-9", part of the US Army's VTOL projects in the VZ series. The Avrocar was the ultimate result of a series of blue skies research projects by designer "Jack" Frost, who had joined Avro Canada in June 1947 after working for several British firms. He had been with de Havilland from 1942 and had worked on the de Havilland Hornet, de Havilland Vampire jet fighter and the de Havilland Swallow aircraft, where he had been the chief designer on the supersonic research project. At Avro Canada, he had worked on the Avro CF-100 before creating a research team known as the "Special Projects Group" (more commonly known as SPG). Frost first surrounded himself with a collection of like-minded "maverick" engineers, then arranged for a work site. Initially ensconced in the "Penthouse" (the derisive company nickname for the executive wing) of the Administration Building, the SPG was subsequently relocated to a Second World War-era structure across from the company headquarters, the Schaeffer Building, that was secured with security guards, locked doors and special pass cards. At times, the SPG also operated out of the Experimental Hangar where it shared space with other esoteric Avro project teams. At the time, Frost was particularly interested in jet engine design and ways to improve the efficiency of the compressor without sacrificing the simplicity of the turbine engine. He found Frank Whittle's "reverse flow" design too complex and was interested in ways to "clean up" the layout. This led him to design a new type of engine layout with the flame cans lying directly outside the outer rim of the centrifugal compressor, pointed outwards like the spokes on a wheel. Power for the compressor was drawn from a new type of turbine similar to a centrifugal fan, as opposed to the more typical propeller-like turbine, driving the compressor using gearing rather than a shaft. The resulting engine had no conventional thrust axis, and was arranged in the form of a large disk, which he referred to as a "pancake engine." The jet thrust exited from around the entire rim of the engine, and this presented problems trying to adapt the design to a typical aircraft. At the same time, the aircraft industry as a whole was becoming increasingly interested in VTOL aircraft. It was expected that any future European war would start with a nuclear exchange that would destroy most airbases, so aircraft would need to operate from limited airbases, roads or even unprepared fields. Considerable research effort was put into various solutions to securing a second-strike capability. Some of these solutions included rocket-launched aircraft like the zero-length launch concept, while many companies started work on VTOL aircraft as a more appropriate long-term solution. 15

16 Frost felt the excellent performance of his new engine would be a natural fit for a VTOL aircraft due to its high expected power-to-weight ratio. The problem was how to use the annular thrust to drive the aircraft forward, as well as the problem of fitting the very large engine into a suitable airframe. Frost suggested using a series of vents to redirect the thrust flowing out of the "front" of the engine towards the rear, although it was well known that long channeling leads to a loss of thrust. In order to keep the "piping" as short as possible, the design ported the thrust out along the leading edge of what was essentially a very large delta wing. As the engine was disk-shaped, the triangular shape was "pushed out" near the front, producing a planform shaped roughly like a spade. For this reason the design was also referred to as the "Avro Ace," a likely reference to the Ace of Spades. The compressor inlet was located at the middle of the engine, so the engine air intakes were located just to the front of the centre on the top and bottom of the aircraft. The cockpit was positioned over the main bearing, behind the intakes. A "spine" on the top and bottom ran from the cockpit area to the rear edge of the aircraft. Several other versions of the basic layout were also studied, including the "Omega" which was more disk-like as it cut away the rear portions of the delta wing as well. For VTOL operations the aircraft was expected to sit pointed up, supported by long landing legs that extended out of the spine. Landing would be accomplished at a very high angle, making visibility during the approach very difficult. A number of other VTOL experiments of the era attempted various solutions to this problem, including rotating pilots seats and cockpits, but none proved very effective. Another problem with various VTOL experiments was that stability in a hover was difficult to arrange, although not entirely unexpected. A solution to this problem would require the thrust to be directed downward from a larger area, as it is in a helicopter, where the lift is supplied over the entire area of the rotor disk. Most designers turned to bleeding off air from the engine's compressor, and directing that through pipes arranged around the aircraft. Frost's engine design used such a large number of nozzles that such an arrangement would not be to easy to build. Fig.16. VTOL aircraf project Y was capable to fly with 1,500 miles per hour (2,400 km/h) and climbing vertically. In 1952, the design was advanced enough that the Canadian Defense Research Board funded the effort with a $400,000 contract. By 1953, a wooden mock-up of Project Y was completed, of which only images remain (fig. 16). It appears the project was considered too costly within the military establishment, which was at the time involved in several extremely expensive air defense projects. On 11 February 1953, a story on the project was leaked to the Toronto Star along with images of the Omega design, apparently in order to gain further funding (a strategy widely employed in the U.S. at the time, known as policy by press release). Five days later, the Minister for Defense Production informed the House of Commons that Avro was indeed working on a "mock-up model" of a flying saucer, capable of flying at 1,500 miles per hour (2,400 km/h) and climbing vertically. Nevertheless, further funding was not forthcoming. While Project Y continued, Frost had meanwhile become interested in the Coandă effect, where fluid flows will follow strongly convex shapes, something that might be unexpected at first glance. Frost felt the effect could be used with his engine design to produce a more practical VTOL aircraft, the exhaust flowing outward over the upper surface of the aircraft and then being directed downward over a flap-like arrangement. This would produce a lift force around the entire edge of the aircraft, allowing it to land "flat". He produced a number of small experimental designs using compressed air in place of an engine in order to select a suitable planform shape, and eventually decided that a disk was the best solution. As he continued these experiments, he found that the same thrust-direction system he intended for VTOL operations worked just as well for forward flight. In this case the disk shape was not of itself a good lifting surface, as it was neutral in terms of lift direction that is, it would fly sideways as readily as it would fly forward. However, by modifying the airflow with the application of a small amount of jet thrust, the overall airflow over the craft could be dramatically altered, creating a sort of "virtual airfoil" of any needed configuration. For instance, by directing even a small amount of jet thrust down, a large mass of air would be pulled over the upper surface of the wing and dramatically augment the flow over the wing, creating lift. 16

17 This appeared to offer a solution to one of the most vexing problems of the era, designing an aircraft that was effective at subsonic and supersonic speeds. Subsonic lift is created by the airflow around the wing following streamlines, but supersonic lift is generated by shock waves at points of critical curvature. No single design could offer high performance for both regimes. The blown disk could attack this problem by being laid out for supersonic performance only, and then using jet thrust to modify subsonic airflow into a semblance of a normal wing. The resulting design would be tuned for high supersonic performance, have reasonable subsonic performance, and would also offer VTOL, all in a single design. In late 1953, a group of U.S. defence experts visited Avro Canada to view the new CF-100 fighter jet. Somewhere along the way, Frost co-opted the tour and rerouted it to the Special Projects area where he proceeded to show off the Project Y mock-up and models and drawings (some never before seen by senior company officials) for a completely circular disk-shaped aircraft known as "Project Y-2." The USAF agreed to take over funding for Frost's Special Projects Group, and a contract for $US 750,000 followed in By 1956, Avro management was interested enough to commit $2.5 million to build a "private venture" prototype. In March 1957, the Air Force added additional funding, and the aircraft became Weapons System 606A (fig. 17). Fig. 17. Avro company models of the Y-2 (right) and the Avrocar (left). A wide variety of designs were studied for a VTOL fighter aircraft, all revolved around the disk shape, leading to the Project 1794 involving a supersonic large disk fighter aircraft. The concept proceeded to wind tunnel testing with a variety of scale models. It featured a raised section in the middle over the engine, the intake covered with a series of louvers that would be closed in forward flight. Frost's performance estimates for the concept were for a potential of Mach 3.5 at 100,000 ft (30,000 m) altitudes. There was some debate about the concept within the USAF, as many groups were attempting to gain funding for their own pet projects, like nuclear powered bombers. In a repeat of the earlier Toronto Star release, in 1955 an extensive article appeared in Look Magazine that, among other claims, speculated that current UFO sightings were Soviet-built saucers. The article went on to describe such an aircraft with diagrams that were clearly influenced by the Avro design. A new impeller-driven engine design was proposed as Avro PV-704 (PV stood for Private Venture), powered by six Armstrong Siddeley Viper jet engines blowing across the outer rim of a central rotor. The PV- 704 was a "stop-gap" design built into a bunker-like building behind the Avro Experimental Test facility. It was intended to test various Project 1794 concepts and provide the USAF with test data to show the viability of the concept. The original plan to initially test the "Viper Engine Rig" was to have continued into "free flight" testing. Unfortunately, testing was anything but smooth; the test model suffered from hazardous oil leaks, resulting in three fires. It eventually got to the point that staff were afraid of the machine, even when safely ensconced in a booth constructed of bullet-proof glass and quarter-inch-thick steel. A final, disastrous and nearly lethal engine test in 1956 which involved a Viper jet engine "running wild" convinced Frost that a less dangerous test vehicle was necessary. To gather flight data on the basic concept while the engine development continued, in 1958 Frost proposed building a smaller "proof-of-concept" test vehicle he called the Avrocar. By this point, the US Army 17

18 was involved in a wide variety of experiments on smaller VTOL aircraft that would act as a "flying Jeep," and they became interested in Avro's concept as well. Frost pitched his smaller design both as a prototype of a vehicle suitable for the Army's needs, as well as an aerodynamic testbed for the WS-606. Initial performance requirements for the Avrocar were a ten-minute hover capability in ground effect and 25-mile (40 km) range with a 1,000 lb (450 kg) payload. The new plan appeared to make everybody happy, and a $2 million joint-services contract managed by the Air Force was awarded to Avro to build and test two Avrocars, which the Army referred to as the VZ-9-AV (with AV standing for "Avro," an unusual departure from normal US Army nomenclature), the latest in a series of "VZ" aircraft. Army interest in the Avrocar program was apparently very high. Bernard Lindenbaum recalls a trip to Washington in the late 1950s to request additional funding for a study on helicopter drag reduction. Although the funding was approved, he overheard an Army General remark that the Huey would be the last helicopter the Army would buy since the helicopter would be replaced by the Avrocar. Additional Air Force funding of approximately $700,000 (unexpended from the 606A program) was also moved to the Avrocar project. In March 1959, an additional $1.77 million contract was received for a second prototype. At rollout, projected performance was far in excess of the requirement, with a 225 knots (417 km/h) maximum speed, 10,000 feet (3,000 m) ceiling, 130-mile (209 km) range with 1,000 lb (450 kg) payload, and hover out of ground effect with 2,428 lb (1,101 kg) payload. Maximum takeoff weight with transition to forward flight out of ground effect was calculated to be 5,650 lb (2,560 kg), maximum weight with a transition in ground effect (GETOL) was 6,970 lb (3,160 kg). Just as the first working test models were being manufactured, disaster struck. The Canadian government cancelled the Avro CF-105 Arrow program on "Black Friday," 20 February The ensuing result was the lay-off of almost all Avro Canada employees, including those with the Special Projects Group. However, three days following the announcement of the Arrow cancellation, many of the Special Projects employees were rehired. But it wasn't quite business as usual. The team now included people from the CF-100 and CF-105 teams and the Special Projects Group was moved into the main building, which was nearly empty. As well, company "brass" became more involved in the group s operations. The USAF Project Office devoted to the Avro projects, recommended that the WS-606A and all related work (including the Avrocar) be cancelled. A "stop/go" work order came down and Frost was forced once more to try and rescue the project. In an elaborate effort, Frost made a resounding case for continuation of US military funding. Late in May 1959, the USAF authorized Avro to continue the "flying saucer" programs (fig. 18). Fig. 18. US Army Avrocars depicted as "flying jeeps" in company literature. 18

19 Fig. 19. First Avrocars 1958 (left); the second model 1960 (right). The Avro VZ-9 Avrocar was a "dead end" in VTOL design (fig. 19), according to Russell Lee, curator at the National Air and Space Museum, yet its technological innovations have intrigued other designers. One of the design elements it embodied, the use of ducted fans led to other experimental programs. Dr. Paul Moller, a Canadian expatriate who had worked at Avro Canada as a young engineer, based an initial series of experimental VTOL vehicles on "saucer" technology utilizing the buried ducted fan à la-avrocar. The XM-2, the first of the series looked remarkably like a miniature flying saucer. After successful tether tests, the saucer designs also at one time publicized as "discojet" were abandoned and their latest project, the Moller Skycar, has a flying-car appearance. NASA's Aeronautics Research Mission Directorate (ARMD) works to solve the challenges that still exist in our nation's air transportation system: air traffic congestion, safety and environmental impacts. Solutions to these problems require innovative technical concepts, and dedicated research and development. NASA's ARMD pursues the development of new flight operation concepts, and new tools and technologies that can transition smoothly to industry to become products. Through green aviation, NASA is helping create safer, greener and more effective travel for everyone. Our green aviation goals are to enable fuel-efficient flight planning, and reduce aircraft fuel consumption, emissions and noise. NASA aeronautics' four research programs conduct fundamental, cutting-edge research into new aircraft technologies, as well as systems-level research into the integration of new operations concepts and technologies into the Next Generation Air Transportation System (NextGen). A fifth program manages a portfolio of wind tunnels and other testing facilities (icing, propulsion), flight research and support aircraft, and the evolution of test technologies at NASA centers around the country. The Dryden Flight Research Center is NASA's primary center for atmospheric flight research and operations. NASA Dryden is critical in carrying out the agency's missions of space exploration, space operations, scientific discovery, and aeronautical research and development (R&D). Located at Edwards, California, in the western Mojave Desert, Dryden is uniquely situated to take advantage of the excellent year-round flying weather, remote area, and visibility to test some of the nation's most exciting air vehicles. In support of space exploration, we are managing the launch abort systems testing and integration, in partnership with the Johnson Space Center and Lockheed Martin, for the Crew Exploration Vehicle that will replace the Space Shuttle. Dryden is the primary alternate landing site for the Space Shuttle and orbital support for the International Space Station. In support of scientific discovery, we are managing the Stratospheric Observatory for Infrared Astronomy (SOFIA) program - a flying telescope aboard a Boeing 747 aircraft - in partnership with the Ames Research Center and the German Aerospace Center. In support of aeronautical R&D, we are involved in many aspects of the Fundamental Aeronautics and Aviation Safety programs, including the X-48 Blended Wing Body and Ikhana (Predator B) in support of subsonics and Adaptive Flight Controls in support of the Aviation Safety Program. For 60 years, Projects at Dryden have led to major advancements in the design and capabilities of many state-of-the-art civilian and military aircraft. The newest, the fastest, the highest - all have made their debut in the vast, clear desert skies over Dryden. Dryden Flight Research Center plays a vital role in advancing technology and science through flight. Here, we demonstrate America's leadership in aeronautics and space technology as we continue to push the envelope to revolutionize aviation and pioneer aerospace technology. 19

20 NASA is operating two Lockheed ER-2 Earth resources aircraft as flying laboratories in the Sub-Orbital Science Program under the agency's Science Mission Directorate. The aircraft, based at NASA's Dryden Flight Research Center, Edwards, Calif., collect information about our surroundings, including Earth resources, celestial observations, atmospheric chemistry and dynamics, and oceanic processes. The aircraft also are used for electronic sensor research and development, satellite calibration and satellite data validation (fig. 20). Fig. 20. Lockheed ER-2 The F-15B Research Testbed is a modified twin-engine jet fighter that provides NASA, industry, and universities with long-term capability for the efficient flight test of aerodynamic, instrumentation, propulsion, and other flight research experiments. This aircraft is a unique airborne resource, and is considered by researchers to be a virtual "flying wind tunnel and reliable supersonic testbed. In addition to flying research missions, Dryden's F-15B also is used for crew training, pilot proficiency, and safety chase support for other research aircraft. Bearing NASA tail number 836, the F-15B is about 64 feet long and has a wingspan of just under 43 feet. It is powered by two Pratt and Whitney F100-PW-100 turbofan engines that can produce almost 24,000 pounds of thrust each in full afterburner. It is capable of dash speeds of Mach 2.3, or 2.3 times the speed of sound, at altitudes of 40,000 to 60,000 feet. With an external flight test fixture mounted beneath the fuselage in place of the standard external fuel tank, speeds are limited to Mach 2.0. The aircraft has a full-fuel takeoff weight of about 42,000 pounds and a landing weight of about 32,000 pounds. It has aerial refueling capability for extended-duration research missions. The data acquisition system in the aircraft makes the F-15B one of the most versatile testbed aircraft NASA flies. An on-board video system monitored from the rear seat of the cockpit provides a high-speed airborne video and photo capability that can be downlinked to researchers on the ground. The data system includes a research airdata system for the aircraft, as well as a Global Positioning System (GPS) navigation package; a radome with a nose boom that contains an airdata probe; a digital data recorder; and telemetry antennas. Recent Activity In 2008, 836 hosted several research projects aimed understanding and overcoming the challenges associated with providing civilian overland supersonic transport as well as advanced propulsion system design. Lift and Nozzle Change Effects on Tail Shock (LaNCETS) quantified how changes in lift distribution and nozzle area ratio affect the supersonic shock structure on the aft end of NASA s highly modified F-15 (837) research aircraft. The Propulsion Flight Test Fixture (PFTF) was flown to quantify the flow field surrounding a research inlet (to be flown in early 2009). This project brings the PFTF one step closer to full operational capability, which will allow the F-15B to demonstrate and study advanced propulsion concepts in flight. In 2006, Gulfstream Aerospace and Dryden teamed in a project called Quiet SpikeTM to investigate the suppression of sonic booms. The project centered around a retractable, 24-foot-long lance-like spike mounted on the nose of NASA Dryden's F-15B (#836) research testbed aircraft. The spike, made primarily of composite materials, created three small shock waves that traveled parallel to each other all the way to the ground, producing less noise than typical shock waves that build up at the front of supersonic jets. 20

21 This highly successful project put spike-induced sonic boom suppression theory to the test in the actual flight environment afforded by NASA's supersonic F-15B (fig. 21). Fig. 21. The supersonic F-15B. NASA's Dryden Flight Research Center has acquired two developmental Northrop Grumman autonomously operated Global Hawk aircraft for use in high-altitude, long-duration Earth science missions. Global Hawk measures 44 feet in length, with a wingspan of 116 feet. NASA expects to operate the Global Hawk with payloads up to 2000 pounds and at altitudes up to 65, 000 feet. Its range is greater than 10,000 nautical miles and its endurance is greater than 31 hours (fig. 22). Fig. 22. The Global Hawk. NASA's Ikhana unmanned aircraft completed the fourth in a series of wildfire imaging demonstration flights Thursday over central and southern California. The 10-hour flight departed NASA's Dryden Flight Research Center at Edwards Air Force Base shortly after 6 a.m. PDT Thursday, and returned about 4 p.m. (fig. 23). The flight was part of the Western States Fire Mission being conducted by NASA and the U.S. Forest Service, which is demonstrating improved wildfire imaging and mapping capabilities of a sophisticated thermal- 21

22 infrared imaging sensor and real-time data communications equipment developed at NASA's Ames Research Center. Prior flights lasting as long as 20 hours in August and September took the Ikhana and its imaging payload over a number of wildfires in southern and central California, Oregon, Idaho, Washington, western Wyoming and southwestern Montana. Thursday's flight included imaging previously burned areas in central and southern California for a Burned Area Rehabilitation and Stabilization (BAER) assessment while the Ikhana cruised at about 23,000 feet altitude in the national airspace. The aircraft then re-entered the restricted military test range airspace near Edwards and climbed to over 40,000 feet altitude in an evaluation of the Ikhana's high-altitude performance capabilities with the 420-lb. instrument pod tucked under its left wing. Fig. 23. Ikhana unmanned aircraft. NASA Dryden Pad Abort-1 flight test team technicians Kevin Mount and Jeff Doughty prepare to roll the platform carrying the Orion flight test crew module from the cavernous interior of a C-17 cargo plane following its return to NASA Dryden Flight Research Center on June 15, 2010 (fig. 24). The boilerplate module was undamaged in the PA-1 test of the Launch Abort System at White Sands Missile Range on May 6, The undamaged Pad Abort-1 flight test crew module rests in the desert after a successful Pad Abort-1 flight test May 6 at the White Sands Missile Range in New Mexico. Officials and media representatives watch the launch of an Orion test crew module and its launch abort system during NASA's Pad Abort 1 test on May 6 at White Sands Missile Range, N.M. PA-1 was the first fully integrated flight test of the crew rescue system being developed for the Orion crew capsule. Fig. 24. NASA Dryden Pad Abort-1 flight test team technicians Kevin Mount and Jeff Doughty prepare to roll the platform carrying the Orion flight test crew module from the cavernous interior of a C-17 cargo plane. 22

23 Boeing Phantom Works has partnered with NASA and the Air Force Research Laboratory to study the structural, aerodynamic and operational advantages of the Blended Wing Body concept, a cross between a conventional plane and a flying wing design. The Air Force has designated the prototype the X-48B based on its interest in the design's potential as a multi-role, long-range, high-capacity military transport aircraft. The 8.5 percent scale, remotely piloted X-48B is dynamically scaled to fly much like the full-size aircraft would fly (fig. 25). Following completion of installation of test instrumentation, one of two X-48B Blended Wing Body technology demonstrators began flight tests at NASA's Dryden Flight Research Center in early 2007, and those tests are continuing into Researchers at NASA's Langley Research Center in Hampton, Va., tested the second X-48B prototype aircraft in Langley's historic full-scale wind tunnel in the spring of 2006, and the flight tests are intended in part to validate the results of those wind tunnel tests. Advantages of the blended wing-body concept include high fuel efficiency, low noise and a large payload volume for the size of the aircraft. Flight testing at NASA Dryden will focus on the low-speed, lowaltitude flight characteristics of the blended wing-body configuration, including engine-out control, stall characteristics and handling qualities. The short flight test program is intended to demonstrate that the novel design can be flown as safely as current transports having a traditional fuselage, wings and tail configuration. Fig. 25. X-48B Blended Wing Body. The two X-48B Blended Wing Body technology demonstration aircraft were built by Cranfield Aerospace in the United Kingdom to Boeing's specifications. The subscale prototypes have a wingspan of 20.4 feet, with prominent vertical fins and rudders at the wingtips and elevons along the trailing edges of the wings. The 523-lb. gross weight aircraft are powered by three small model aircraft turbojet engines providing a maximum combined thrust of about 160 lbs. The X-48B has an estimated top airspeed of 118 knots (139 mph), a maximum altitude of about 10,000 feet and a flight duration of about 40 minutes. According to NASA, "ERAST is a multiyear effort to develop the aeronautical and sensor technologies for a new family of remotely piloted aircraft intended for upper atmospheric science missions. Designed to cruise at slow speeds for long durations at altitudes of 60,000 to 100,000 ft, such aircraft could be used to collect, identify, and monitor environmental data to assess global climate change and assist in weather monitoring and forecasting. They also could serve as airborne telecommunications platforms, performing functions similar to communications satellites at a fraction of the cost of lofting a satellite into space." (fig. 26). "The ERAST program is sponsored by the Office of Aeronautics and Space Transportation Technology at NASA Headquarters, and is managed by NASA Dryden Flight Research Center. The NASA Ames Research Center, Moffett Field, California, heads the sensor technology development. The NASA Lewis Research Center, Cleveland, Ohio, and NASA Langley Research Center, Hampton, Virginia, are contributing expertise in the areas of propulsion, structures, and systems analysis. Several small high-technology aeronautical development firms, including ALTUS developer General Atomics Aeronautical Systems, Inc., are teamed with NASA in the ERAST Alliance to work towards common goals of the program." Industry partners in the ERAST Alliance included 23

24 Aurora Flight Systems, AeroVironment, General Atomics, Scaled Composites, Thermo-Mechanical Systems, Hyperspectral Sciences, and Longitude 122 West. The types of science mission which ERAST prepares for can include remote sensing for Earth sciences studies, hyperspectral imaging for agriculture monitoring, tracking of severe storms, and serving as telecommunications relay platforms. A parallel effort headed by Ames developed lightweight, microminiaturized sensors that can be carried by these aircraft for environmental research and Earth monitoring. Additional technologies considered by the ERAST Alliance include lightweight materials, avionics, aerodynamics, and other forms of propulsion suitable for extreme altitudes and duration. Although ERAST Alliance members were responsible for aircraft development and operation, NASA had primary responsibility for overall program leadership, major funding, individual project management, development and coordination of payloads. NASA also worked on long-term issues with the Federal Aviation Administration and developed technology to make operation of these remotely operated aircraft in national airspace practical. Fig. 26. ERAST is a multiyear effort to develop the aeronautical and sensor technologies for a new family of remotely piloted aircraft intended for upper atmospheric science missions. The Lockheed SR-71 "Blackbird" (fig.27) was an advanced, long-range, Mach 3+ strategic reconnaissance aircraft. It was developed as a black project from the Lockheed A-12 reconnaissance aircraft in the 1960s by the Lockheed Skunk Works. Clarence "Kelly" Johnson was responsible for many of the design's innovative concepts. During reconnaissance missions the SR-71 operated at high speeds and altitudes to allow it to outrace threats. If a surface-to-air missile launch was detected, the standard evasive action was simply to accelerate and outrun the missile. The SR-71 served with the U.S. Air Force from 1964 to Although twelve of the 32 aircraft built were destroyed in accidents, none were lost to enemy action. The SR-71 was unofficially named the Blackbird, and called the Habu by its crews, referring to an Okinawan species of pit viper. Since 1976, it has held the world record for the fastest air-breathing manned aircraft, a record previously held by the YF

25 Fig. 27. Lockheed SR-71 Blackbird. Shuttle Carrier Aircraft NASA uses two modified Boeing 747 jetliners, originally manufactured for commercial use, as Space Shuttle Carrier Aircraft (SCA). One is a model, while the other is designated a SR (short range). The two aircraft are identical in appearance and in their performance as Shuttle Carrier Aircraft (Fig. 28). The 747 series of aircraft are four-engine intercontinental-range, swept-wing "jumbo jets" that entered commercial service in The SCAs are used to ferry space shuttle orbiters from landing sites back to the launch complex at the Kennedy Space Center and also to and from other locations too distant for the orbiters to be delivered by ground transportation. The orbiters are placed atop the SCAs by Mate-Demate Devices, large gantry-like structures that hoist the orbiters off the ground for post-flight servicing and then mate them with the SCAs for ferry flights. Fig. 28. NASA uses two modified Boeing 747 jetliners, originally manufactured for commercial use, as Shuttle Carrier Aircraft (SCA). 25

26 NASA 905 NASA 905 was the first SCA. It was obtained from American Airlines in Shortly after acceptance by NASA, the SCA flew a series of wake vortex research flights at the Dryden Flight Research Center, Edwards, Calif., in a study to seek ways of reducing turbulence produced by large aircraft. Pilots flying as much as several miles behind large aircraft have encountered wake turbulence that has caused control problems. The NASA study helped the Federal Aviation Administration modify flight procedures for commercial aircraft during airport approaches and departures. Following the wake vortex studies, NASA 905 was modified by Boeing to its present SCA configuration and the aircraft was returned to Dryden for its role in the 1977 Space Shuttle Approach and Landing Tests (ALT). This series of eight captive and five free flights with the orbiter prototype Enterprise, in addition to ground taxi tests, validated the aircraft's performance as an SCA, in addition to verifying the glide and landing characteristics of the orbiter configuration paving the way for orbital flights. A flight crew escape system, consisting of an exit tunnel extending from the flight deck to a hatch in the bottom of the fuselage, was installed during the modifications. The system also included a pyrotechnic system to activate the hatch release and cabin window release mechanisms. The flight crew escape system was removed from the NASA 905 following the successful completion of the ALT program. NASA 905 was the only SCA used by the space shuttle program until November 1990, when NASA 911 was delivered as an SCA. Along with ferrying Enterprise and the flight rated orbiters between the launch and landing sites and other locations, NASA 905 also ferried Enterprise to Europe for display in England and at the Paris Air Show. NASA 911 The second SCA is designated NASA 911. It was obtained by NASA from Japan Airlines (JAL) in It was also modified by Boeing Corporation. It was delivered to NASA on Nov. 20, The Space Shuttle prototype Enterprise flies free after being released from NASA's 747 Shuttle Carrier Aircraft (SCA) over Rogers Dry Lake during the second of five free flights carried out at the Dryden Flight Research Center, Edwards, California, as part of the Shuttle program's Approach and Landing Tests (ALT) in 1977 (fig. 29). The tests were conducted to verify orbiter aerodynamics and handling characteristics in preparation for orbital flights with the Space Shuttle Columbia. A tail cone over the main engine area of Enterprise smoothed out turbulent airflow during flight. It was removed on the two last free flights to accurately check approach and landing characteristics. A series of test flights during which Enterprise was taken aloft atop the SCA, but was not released, preceded the free flight tests. Fig. 29. The Space Shuttle prototype Enterprise flies free after being released from NASA's 747 Shuttle Carrier Aircraft. The Space Shuttle prototype Enterprise flies free of NASA's 747 Shuttle Carrier Aircraft (SCA) during one of five free flights carried out at the Dryden Flight Research Facility, Edwards, California in 1977 as part of the Shuttle program's Approach and Landing Tests (ALT). The tests were conducted to verify orbiter aerodynamics and handling characteristics in preparation for orbital flights with the Space Shuttle Columbia. A tail cone over the main engine area of Enterprise smoothed out turbulent airflow during flight. It was removed on the two last free flights to accurately check approach and landing characteristics (fig. 30). 26

27 Fig. 30. The Space Shuttle prototype Enterprise flies free. The Boeing B-52 Stratofortress is a long-range, subsonic, jet-powered strategic bomber designed and built by Boeing and operated by the United States Air Force (USAF). Beginning with the successful contract bid on 5 June 1946, the B-52 design evolved from a straightwing aircraft powered by six turboprop engines to the final prototype YB-52 with eight turbojet engines and swept wings. The Stratofortress took its maiden flight in April Built to carry nuclear weapons for Cold War-era deterrence missions, the B-52 Stratofortress replaced the Convair B-36. Although a veteran of a number of wars, the Stratofortress has dropped only conventional munitions in combat. The B-52 carries up to 70,000 pounds (32,000 kg) of weapons. Its Stratofortress name is rarely used outside of official contexts; it has been referred to by Air Force personnel as the BUFF (Big Ugly Fat/Flying Fucker/Fellow). The B-52 has been in active service with the USAF since The bombers flew under the Strategic Air Command (SAC) until it was disestablished in 1992 and its aircraft absorbed into the Air Combat Command (ACC). This remained the case until February 2010 when all B-52 Stratofortress and B-2 Spirit aircraft were transferred from ACC to the recently established Air Force Global Strike Command (AFGSC). Superior performance at high subsonic speeds and relatively low operating costs have kept the B-52 in service despite the advent of later aircraft, including the Mach-3 North American XB-70 Valkyrie, the supersonic Rockwell B-1B Lancer, and the stealthy Northrop Grumman B-2 Spirit. The B-52 marked its 50th anniversary of continuous service with its original primary operator in (Other aircraft with similarly long service include the English Electric Canberra, Tupolev Tu-95, Lockheed C-130 Hercules, Boeing KC-135 Stratotanker, and Lockheed U-2, fig. 31) Fig. 31. A B-52H from Barksdale AFB flying over the desert. In May 1948, AMC asked Boeing to incorporate the previously discarded, but now more fuel-efficient, jet engine into the design. This resulted in Boeing developing yet another revision in July 1948, Model substituted Westinghouse J40 turbojets for the turboprops. Nevertheless, on 21 October 1948, Boeing was told to create an entirely new aircraft using Pratt & Whitney J57 turbojets. On 25 October, Boeing engineers produced a proposal and a hand-carved model of The new design built upon the basic layout of the B-47 Stratojet with 35 swept wings, eight engines paired in four underwing pods, and bicycle landing gear with wingtip outrigger wheels. A notable feature of the landing gear was the ability to pivot the main landing gear up to 20 from the aircraft centerline to increase safety during crosswind landings. The aircraft was projected to exceed all design specifications. Although the full-size mockup inspection in April 1949 was generally favorable, range again became a concern since the J40s and early model J57s had excessive fuel consumption. 27

28 Despite talk of another revision of specifications or even a full design competition among aircraft manufacturers, General LeMay, now in charge of Strategic Air Command, insisted that performance should not be compromised due to delays in engine development. In a final attempt to increase range, Boeing created the larger , stating that once in production, the range could be further increased in subsequent modifications. Following several direct interventions by LeMay, Boeing was awarded a production contract for 13 B- 52As and 17 detachable reconnaissance pods on 14 February The last major design change, also at the insistence of General LeMay, was a switch from the B-47 style tandem seating to a more conventional side-byside cockpit which increased the effectiveness of the copilot and reduced crew fatigue. Both XB-52 (fig. 32) prototypes featured the original tandem seating arrangement with a framed bubble-type canopy. The YB-52, the second XB-52 modified with more operational equipment, first flew on 15 April 1952 with "Tex" Johnston as pilot.[notes 1] A 2 hour, 21-minute proving flight from Boeing Field, King County, near Renton, Washington to Larson AFB was undertaken with Boeing test pilot Alvin M. Johnston and Air Force Lieutenant Colonel Guy M. Townsend. The XB-52 followed on 2 October The thorough development, including 670 days in the wind tunnel and 130 days of aerodynamic and aeroelastic testing, paid off with smooth flight testing. Encouraged, the Air Force increased its order to 282 B-52s. Fig. 32. A XB-52 Prototype on flight line (X-4 in foreground). The YF-17 (fig. 33) was primarily constructed of aluminum, in conventional semi-monocoque stressedskin construction, though over 900 lb (408 kg) of its structure were graphite/epoxy composite. The small nose contained a simple ranging radar. The cockpit sported an ejection seat inclined at 18, a bubble canopy, and a head-up display (HUD). The thin wings carried no fuel, and in areas such as the leading and trailing edge and the LERX, were composed of a Nomex honeycomb core with composite facesheets. The rear of the aircraft featured twin all-moving stabilators of aluminum over a honeycomb core, and twin vertical stabilizers of a conventional construction. Like the wings, the leading and trailing edges were constructed of composite facesheets over honeycomb core. A composite speedbrake was located above and between the engines. The aircraft was powered by a pair of 14,400-pound-force (64 kn) General Electric YJ101-GE-100 turbofans, a development of the GE15, mounted next to each other to minimize thrust asymmetry in the event of an engine loss. For ease of maintenance, the engines are mounted in a steady-rest that allows removal from below the aircraft, without disturbing the empennage controls. Each engine drove an independent hydraulic system. Unlike the P-530, the YF-17 sported a partial flyby-wire control scheme, formally called the electronic control augmentation system (ECAS), utilizing ailerons, rudders, and stabilators for primary flight control. Fig. 33. YF-17 Cobra, operated by NASA. 28

29 Cap. 2. SOME POPULAR MODELS OF AIRPLANES The McDonnell Douglas F-4 Phantom II (fig. 34) started as the prototype McDonnell XF4H-1, which made its first flight on May 27, 1958 with crack test pilot Robert Little at the controls. After five years of strenuous effort, a happy combination of brains, determination, timing, and luck enabled the McDonnell Corporation to deliver an aircraft that leapfrogged a generation of fighter aircraft in development. Fig. 34. F-4 Phantom II. In 1966 the U.S. Air Force formed the Attack Experimental (A-X) program office. On 6 March 1967, the Air Force released a request for information to 21 defense contractors for the A-X. The objective was to create a design study for a low-cost attack aircraft. The officer in charge of the project was Colonel Avery Kay. In 1969, the Secretary of the Air Force asked Pierre Sprey to write the detailed specifications for the proposed A-X project. However, his initial involvement was kept secret because of Sprey's earlier controversial involvement in the F-X project. Sprey's discussions with A-1 Skyraider pilots operating in Vietnam and analysis of the effectiveness of current aircraft used in the role indicated the ideal aircraft should have long loiter time, low-speed maneuverability, massive cannon firepower, and extreme survivability; an aircraft that had the best 29

30 elements of the Ilyushin Il-2, Henschel Hs 129 and Skyraider. The specifications also demanded that each aircraft cost less than $3 million. Sprey required that the biography of World War II attack pilot Hans-Ulrich Rudel be read by people on A-X program. In May 1970, the USAF issued a modified and much more detailed request for proposals (RFP) for the aircraft. The threat of Soviet armored forces and all-weather attack operations had became more serious. Now included in the requirements was that the aircraft would be designed specifically for the 30 mm cannon. The RFP also specified an aircraft with a maximum speed of 460 mph (740 km/h), takeoff distance of 4,000 feet (1,200 m), external load of 16,000 pounds (7,300 kg), 285-mile (460 km) mission radius, and a unit cost of US$1.4 million. During this time, a separate RFP was released for A-X's 30 mm cannon with requirements for a high rate of fire (4,000 round/minute) and a high muzzle velocity. Six companies submitted proposals to the USAF, with Northrop and Fairchild Republic selected to build prototypes: the YA-9A and YA-10A, respectively. General Electric and Philco-Ford were selected to build and test GAU-8 cannon prototypes. The YA-10A first flew on 10 May After trials and a fly-off against the YA-9A, the Air Force announced its selection of Fairchild-Republic's YA-10A on 18 January 1973 for production. General Electric was selected to build the GAU-8 cannon in June The YA-10 had an additional fly-off in 1974 against the Ling-Temco-Vought A-7D Corsair II, the principal Air Force attack aircraft at the time, in order to prove the need to purchase a new attack aircraft. The first production A-10 flew in October 1975, and deliveries to the Air Force commenced in March In total, 715 airplanes were produced, the last delivered in Fig. 35. A-10 Thunderbolt. 30

31 One experimental two-seat A-10 Night Adverse Weather (N/AW) version was built by converting an A-10A. The N/AW was developed by Fairchild from the first Demonstration Testing and Evaluation (DT&E) A-10 (fig. 35) for consideration by the USAF. It included a second seat for a weapons system officer responsible for electronic countermeasures (ECM), navigation and target acquisition. The variant was canceled, and the only two-seat A-10 built now resides at Edwards Air Force Base's Flight Test Center Museum. The N/AW version did not interest the USAF or export customers. The two-seat trainer version was ordered by the Air Force in 1981, but funding was canceled by U.S. Congress and the jet was not produced. The Embraer EMB 314 Super Tucano, also named ALX or A-29 (fig. 36) is a turboprop aircraft designed for light attack, counter insurgency (COIN) and pilot training missions, incorporating modern avionics and weapons systems. It is currently in service with the air forces of Brazil, Dominican Republic and Colombia, and has been ordered by the forces of Chile and Ecuador. Embraer has plans to sell it to other countries in Asia and the Middle East. Besides pilot training, it is heavily employed in monitoring operations within the Amazon basin. Fig. 36. A-29 Super Tucano. The Skyhawk was designed by Douglas Aircraft's Ed Heinemann in response to a U.S. Navy call for a jet-powered attack aircraft to replace the older AD Skyraider. Heinemann opted for a design that would minimize its size, weight, and complexity. The result was an aircraft that weighed only half of the Navy's weight specification. It had a wing so compact that it did not need to be folded for carrier stowage. The diminutive Skyhawk soon received the nicknames "Scooter", "Kiddiecar", "Bantam Bomber", "Tinker Toy Bomber", and, on account of its nimble performance, "Heinemann's Hot-Rod". The aircraft is of conventional post-world War II design, with a low-mounted delta wing, tricycle undercarriage, and a single turbojet engine in the rear fuselage, with two air intakes on the fuselage sides. The tail is of cruciform design, with the horizontal stabilizer mounted above the fuselage. Armament consisted of two 20 mm (.79 in caliber) Colt Mk 12 cannons, one in each wing root, with 200 rpg, plus a large variety of bombs, rockets, and missiles carried on a hardpoint under the fuselage centerline and hardpoints under each wing (originally one per wing, later two). The choice of a delta wing, for example, combined speed and maneuverability with a large fuel capacity and small overall size, thus not requiring folding wings, albeit at the expense of cruising efficiency. The leading edge slats were designed to drop automatically at the appropriate speed by gravity and air pressure, saving weight and space by omitting actuation motors and switches. Similarly the main undercarriage did not penetrate the main wing spar, designed so that when retracted only the wheel itself was inside the wing and the undercarriage struts were housed in a fairing below the wing. The wing structure itself could be lighter with the same overall 31

32 strength and the absence of a wing folding mechanism further reduced weight. This is the opposite of what can often happen in aircraft design where a small weight increase in one area leads to a compounding increase in weight in other areas to compensate, leading to the need for more powerful, heavier engines and so on in a vicious circle. The A-4 pioneered the concept of "buddy" air-to-air refueling. This allows the aircraft to supply others of the same type, eliminating the need of dedicated tanker aircraft a particular advantage for small air arms or when operating in remote locations. This allows for greatly improved operational flexibility and reassurance against the loss or malfunction of tanker aircraft, though this procedure reduces the effective combat force on board the carrier. A designated supply A-4 would mount a center-mounted "buddy store", a large external fuel tank with a hose reel in the aft section and an extensible drogue refueling bucket. This aircraft was fueled up without armament and launched first. Attack aircraft would be armed to the maximum and given as much fuel as was allowable by maximum takeoff weight limits, far less than a full tank. Once airborne, they would then proceed to top off their fuel tanks from the tanker using the A-4's fixed refueling probe on the starboard side of the aircraft nose. They could then sortie with both full armament and fuel loads. While rarely used in U.S. service since the KA-3 Skywarrior tanker became available, the F/A-18E/F Super Hornet includes this capability. The A-4 was also designed to be able to make an emergency landing, in the event of a hydraulic failure, on the two drop tanks nearly always carried by these aircraft. Such landings resulted in only minor damage to the nose of the aircraft which could be repaired in less than an hour. The Navy issued a contract for the type on 12 June 1952, and the first prototype first flew from Edwards Air Force Base, California on 22 June Deliveries to Navy and Marine Corps squadrons (to VA- 72 and VMA-224 respectively) commenced in late The Skyhawk remained in production until 1979, with 2,960 aircraft built, including 555 two-seat trainers. The last production A-4, an A-4M issued to a Marine squadron (VMA-223) had the flags of all nations who had operated the A-4 series aircraft painted on the fuselage sides. The Skyhawk proved to be a relatively common United States Navy aircraft export of the postwar era. Due to its small size, it could be operated from the older, smaller World War II-era aircraft carriers still used by many smaller navies during the 1960s. These older ships were often unable to accommodate newer Navy fighters such as the F-4 Phantom II and F-8 Crusader, which were faster and more capable than the A-4, but significantly larger and heavier than older naval fighters. The Navy operated the A-4 in both Regular Navy and Naval Reserve light attack squadrons (VA). Although the A-4's use as a training and adversary aircraft would continue well into the 1990s, the Navy began removing the aircraft from its front line attack squadrons in 1967, with the last ones (Super Foxes of VA- 55/212/164) being retired in The Marine Corps would not take the U.S. Navy's replacement warplane, the A-7 Corsair II, instead keeping Skyhawks in service with both Regular Marine Corps and Marine Corps Reserve attack squadrons (VMA), and ordering the new A-4M model. The last USMC Skyhawk was delivered in 1979, and they were used until the mid-1980s before they were replaced by the equally small, but more versatile STOVL AV-8 Harrier II. VMA-131, Marine Aircraft Group 49 (the Diamondbacks) retired its last four OA-4Ms on 22 June Lieutenant Colonel George "Eagle" Lake III (CO), Major John "Baja" Rufo (XO), Captain Dave "Yoda" Hurston, and Major Mike "Struts" Volland flew a final official USMC A-4 sortie during the A-4 Standdown Ceremony. Trainer versions of the Skyhawk remained in Navy service, however, finding a new lease on life with the advent of "adversary training", where the nimble A-4 was used as a stand-in for the Mikoyan-Gurevich MiG- 17 in dissimilar air combat training (DACT). It served in that role at "Top Gun" until The A-4's nimble performance also made it suitable to replace the F-4 Phantom II when the Navy downsized its aircraft for the Blue Angels demonstration team, until F/A-18 Hornets were available in the 1980s. The last U.S. Navy Skyhawks, TA-4J models belonging to the composite squadron VC-8, remained in military use for target-towing, and as adversary aircraft, for combat training at Naval Station Roosevelt Roads. These aircraft were officially retired on 3 May Skyhawks were well-loved by their crews for being tough and agile. These attributes, along with their low purchase and operating cost as well as easy maintenance, have contributed to the popularity of the A-4 with American and international armed forces. Besides the United States, at least three other nations have used A-4 Skyhawks in combat (Argentina, Israel, and Kuwait). 32

33 Skyhawks were the Navy's primary light bomber used over North Vietnam during the early years of the Vietnam War while the USAF was flying the supersonic F-105 Thunderchief; they were later supplanted by the A-7 Corsair II in the Navy light bomber role. Skyhawks carried out some of the first air strikes by the US during the conflict, and a Marine Skyhawk is believed to have dropped the last American bombs on the country. Notable naval aviators who flew the Skyhawk included Lieutenant Commanders Everett Alvarez Jr. and John McCain, and Commander James Stockdale. On 1 May 1967, an A-4C Skyhawk piloted by Lieutenant Commander Theodore R. Swartz of VA-76 aboard the carrier USS Bon Homme Richard, shot down a North Vietnamese Air Force MiG-17 with an unguided Zuni rocket as the Skyhawk's only air-to-air victory of the Vietnam war. From 1956 on, Navy Skyhawks were the first aircraft to be deployed outside of the U.S. armed with the AIM-9 Sidewinder. On strike missions, which was the Skyhawk's normal role, the air-to-air armament was for self defensive purposes. In the early-to-mid 1960s, standard US Navy A-4B Skyhawk squadrons were assigned to provide daytime fighter protection for ASW aircraft operating from some Essex class US anti-submarine warfare carriers, these aircraft retained their ground- and sea-attack capabilities. The A-4B model did not have an air-toair radar, and it required visual identification of targets and guidance from either ships in the fleet or an airborne E-1 Tracer AEW aircraft. Lightweight and safer to land on smaller decks, Skyhawks would later also play a similar role flying from Australian, Argentinean, and Brazilian upgraded World War II surplus light ASW carriers, which were also unable to operate most large modern fighters. Primary air-to-air armament consisted of the internal 20 mm (.79 in) Colt cannons and ability to carry an AIM-9 Sidewinder missile on both underwing hardpoints, later additions of two more underwing hardpoints on some aircraft made for a total capacity of four AAMs. The first combat loss of an A-4 occurred on 5 August 1964 (fig. 37), when Lieutenant junior grade Alvarez, of VA-144 aboard the USS Constellation, was shot down while attacking enemy torpedo boats in North Vietnam. Alvarez safely ejected after being hit by anti-aircraft artillery (AAA) fire, and became the first US Naval POW of the war; he was released as a POW on 12 February The last A-4 loss in the Vietnam War occurred on 26 September 1972, when USMC pilot Captain James P. Walsh, USMC of VMA-211, flying from his land base at Bien Hoa Air Base, South Vietnam, was hit by ground fire near An Loc. An Loc was one of the few remaining hotly contested areas during this time period, and Captain Walsh was providing close air support (CAS) for ground troops in contact (land battle/fire fight) when his A-4 was hit, catching fire, forcing him to eject. Rescue units were sent, but the SAR helicopter was damaged by enemy ground fire, and forced to withdraw. Captain Walsh, after safely ejecting, had landed within NVA (North Vietnamese Army) positions, and had become a POW as soon as his feet had touched the ground. Captain Walsh was the last US Marine to be taken prisoner during the war, and was released as a POW on 12 February Although the first A-4Es were flown in Vietnam in early 1965, the A-4Cs continued to be used until late The Seabees of MCB-10 went ashore on 7 May On 1 June 1965, the Chu Lai Short Airfield for Tactical Support (SATS) was officially opened with the arrival of eight A-4 Skyhawks from Cubi Point, Philippine Islands. The group landed with the aid of arresting cables, refueled and took off with the aid of JATO, with fuel and bombs to support Marine combat units. The Skyhawks were from Marine Attack Squadron VMA-223 and VMA-311. On 29 July 1967, the aircraft carrier USS Forrestal was conducting combat operations in the Gulf of Tonkin during the Vietnam War. A Zuni rocket misfired, knocking off an external tank on an A-4. Fuel from the leaking tank caught fire, creating a massive conflagration that burned for hours, killing 134 sailors, and injuring 161. (See 1967 USS Forrestal fire.) During the war, 362 A-4/TA-4F Skyhawks were lost to all causes. The US Navy lost 271 A-4s, the US Marine Corps lost 81 A-4s and 10 TA-4Fs. A total of 32 A-4s were lost to surface-to-air missiles (SAMs), and one A-4 was lost in aerial combat to a MiG-17 on 25 April Fig. 37. A-4C, August

34 During the 1982 Falklands War, Argentina deployed 48 Skyhawk warplanes (26 A-4B, 12 A-4C and 10 A-4 aircraft). Armed with unguided bombs and lacking any electronic or missile self-defense, Argentine Air Force Skyhawks sank the Type 42 Destroyer HMS Coventry and the Type 21 Frigate HMS Antelope as well as inflicting heavy damage on several others: the RFA Sir Galahad (1966) (which was subsequently scuttled as a war grave), the Type 42 HMS Glasgow, the Leander Class Frigate HMS Argonaut, the Type 22 Frigate HMS Broadsword, and the RFA Sir Tristram. Argentine Navy A-4Qs, flying from Río Grande, Tierra del Fuego naval air station, also played a role in the bombing attacks against British ships, destroying the Type 21 HMS Ardent (fig. 38). In all, 22 Skyhawks (10 A-4Ps, nine A-4Cs, and three A-4Qs) were lost to all causes in the six weekslong war (according to other sources, 23 Skyhawks were lost: 10 A-4Bs, 9 A-4Cs and four A-4Qs). These losses included eight to British Sea Harriers, seven to ship-launched surface-to-air missiles, four to ground-launched surface-to-air missiles and anti-aircraft fire (including one to "friendly-fire"), and three to crashes. Fig. 38. A-4C, May 1982, in Argentine. After the war, Argentine Air Force A-4Ps and A-4Cs survivors were upgraded under the Halcon program with 30 mm (1.2 in) DEFA cannons, air-to-air missiles, and other minor details, and merged into the 5th Air Brigade. All of these were withdrawn from service in 1999, and they were replaced with 36 of the much improved OA/A-4AR Fightinghawk. Several TA-4J and A-4E airframes were also delivered under the A-4AR program mainly for spare parts use. In 1983, the United States vetoed the delivery by Israel of 24 A-4Hs for the Argentine Navy as the A-4Q replacement. The A-4Qs were finally retired in More recently, Kuwaiti Air Force Skyhawks fought in 1991 during Operation Desert Storm (fig. 39). When Iraq invaded Kuwait, the available Skyhawks flew attack missions against the advancing Iraqi forces from deserted roads after their bases were overrun. A total of 24 of the 29 A-4KUs that remained in service with Kuwait (from 36 delivered in the 1970s) escaped to Saudi Arabia. The escaped Skyhawks (along with escaped Mirage F1s) operated as the Free Kuwait Air Force, flying 1,361 sorties during the liberation of Kuwait. Twentythree A-4s survived the conflict and the Iraqi invasion, with only one being destroyed in combat. The remaining Kuwaiti Skyhawks were later sold to Brazil, where they currently serve aboard the aircraft carrier NAe São Paulo. Fig. 39. A-4C, 1991, Operation Desert Storm in Kuwait. 34

35 Fig. 40. This is a modern aircraft A-4, Skyhawk. In figure 40 it can see a modern aircraft A-4 Skyhawk. These devices (A-4) have taken the brunt of the fighting over for decades. Fig. 41. Airbus A

36 The Airbus A340 (fig. 41) is a long-range four-engined wide-body commercial passenger jet airliner. Developed by Airbus Industrie,[Nb 1] a consortium of European aerospace companies, which is now fullyowned by EADS, the A340 is manufactured at Toulouse, France. It seats up to 375 passengers in the standard variants and 440 in the stretched 600 series. Depending on the model, it has a range of between 6,700 to 9,000 nautical miles (12,400 to 17,000 km). It is similar in design to the twin-engined A330 with which it was concurrently designed. Its distinguishing features are four high-bypass turbofan engines and three-bogie main landing gear. Airbus manufactured the A340 in four fuselage lengths. The initial variant, A , entered service in 1993, measured metres (194.8 ft), followed by the shorter 200; the stretched A was a metres (52.2 ft) stretch of 200. This particular variant was developed alongside the shorter A , which would become the longest-ranged commercial airliner until the arrival of the Boeing LR. The two initial models were powered by the CFM56-5C, rated at 151 kilonewtons (34,000 lbf), while Rolls-Royce held exclusive powerplant rights to the extended-ranged and heavier 500 and 600 models, through the 267-kilonewton (60,000 lbf) Rolls-Royce Trent 500. Initial A340 versions share the fuselage and wing of the A330 while the 500/-600 models are longer and have larger wings. Launch customers Lufthansa and Air France placed the A340 into service in March As of March 2011, 379 orders have been placed (not including private operators), of which 375 have been delivered, with a backlog of four aircraft. The most common type were the A model, with 218 aircraft delivered. Lufthansa is the biggest operator of the A340, having acquired 59 aircraft. The A340 is used on long-haul, transoceanic routes due to its immunity from ETOPS; however, with reliability in engines improving, airlines are progressively phasing out the type in favour of more economical twinjets such as the Boeing 777. The Airbus A380 (fig. 42) is a double-deck, wide-body, four-engine airliner manufactured by the European corporation Airbus, a subsidiary of EADS. Designed to challenge Boeing's monopoly in the largeaircraft market, the A380, the largest passenger airliner in the world, made its maiden flight on 27 April 2005 from Toulouse, France, and made its first commercial flight on 25 October 2007 from Singapore to Sydney with Singapore Airlines. The aircraft was known as the Airbus A3XX during much of its development phase, but the nickname Superjumbo has since become associated with it. The A380's upper deck extends along the entire length of the fuselage, and its width is equivalent to that of a widebody aircraft. This allows for an A 's cabin with 5,146 square feet (478.1 m2) of floor space; 49% more floor space than the current next-largest airliner, the Boeing with 3,453 square feet (320.8 m2), and provides seating for 525 people in a typical three-class configuration or up to 853 people in alleconomy class configurations. The A has a design range of 15,200 km (8,200 nmi; 9,400 mi), sufficient to fly from New York to Hong Kong for example, and a cruising speed of Mach 0.85 (about 900 km/h or 560 mph at cruising altitude). As of May 2011, 234 firm orders have been placed, of which 49 had been delivered. The largest operator of the type is Emirates, which has 90 aircraft on order. Fig. 42. Airbus A380. In the early 1960s, European air forces began to consider their requirements for the coming decades. One of the results was the emergence of a new generation of jet trainers to replace such aircraft as the Lockheed T-33 and Fouga Magister. The two main rivals in this exercise turned out to be the BAe Hawk and the Franco- German Dassault-Dornier Alpha Jet (fig. 43). 36

37 At the outset, the Alpha Jet had a lead, but the BAe Hawk would prove to be the winner in the race. However, the Alpha Jet has been built in good numbers and served with a number of air forces for several decades. Fig. 43. Alpha Jet. In the early 1960s, the British and French began a collaboration on development of what was supposed to be a supersonic jet trainer/light attack aircraft. The result of this collaboration, the SEPECAT Jaguar, proved to be an excellent aircraft, but its definition had evolved in the interim, and the type emerged as a full-sized strike fighter, with two-seat variants used for operational conversion to the type. This left the original requirement unfulfilled and so the French began discussions with West Germany for collaboration. A joint specification was produced in The trainer was now subsonic, supersonic trainers having proven something of a dead end. A joint development and production agreement was signed in July 1969 which indicated that the two nations would buy 200 machines, each assembled in their own country. The Avro Vulcan (fig. 44), sometimes referred to as the Hawker Siddeley Vulcan, is a delta wing subsonic jet strategic bomber that was operated by the Royal Air Force (RAF) from 1953 until It was developed by Avro in response to a specification released by the Air Ministry. At the time, both jet engines and delta wings were considered cutting-edge and relatively unexplored; thus, the small-scale Avro 707 was produced to test the principles of the design. In flight, the Vulcan was an agile aircraft for its size. The Vulcan B.1 was first delivered to the RAF in In service, the Vulcan was armed with nuclear weapons and was a part of the RAF's V bomber force, the United Kingdom's airborne deterrent against aggression from other powers such as the Soviet Union during the Cold War. In addition to an extensive electronic countermeasures suite, the Vulcan had a small radar cross-section, aiding its deterrent role by evading detection and therefore increasing the likelihood of penetrating Soviet airspace and deploying its weapons load successfully. A second batch of aircraft, the B.2, was produced with new features, including a larger wing and greater fuel capacity, along with more advanced electronics and radar systems. The B.2s were adapted into several other variants, the B.2A carrying the Blue Steel missile, the B.2 (MRR) for Marine Radar Reconnaissance use, and the K.2 tanker for aerial refuelling. The Vulcan was also used in the secondary role of conventional bombing near the end of its service life in the 1982 Falklands War against Argentina during Operation Black Buck. One example, XH558, was recently restored for use in display flights and commemoration of the employment of the aircraft in the Falklands conflict. Fig. 44. Avro Vulcan. 37

38 The Rockwell (now part of Boeing) B-1 Lancer (fig. 45) is a four-engine, variable-sweep wing strategic bomber used by the United States Air Force (USAF). First envisioned in the 1960s as a supersonic bomber with sufficient range and payload to replace the Boeing B-52 Stratofortress, it developed primarily into a low-level penetrator with long range and supersonic speed capability. Fig. 45. B-1 Lancer. Designed by Rockwell International, the bomber's development was delayed multiple times over its history, as the theory of strategic balance changed from flexible response to mutually assured destruction and back again. The initial B-1A version was developed in the early 1970s, but its production was canceled and only four prototypes were built. In 1980, the B-1 resurfaced as the B-1B version with the focus on low-level penetration bombing. The B-1B entered service with the USAF in It began service with the USAF Strategic Air Command as a nuclear bomber. In the 1990s, the B-1B was converted to conventional bombing use. It was first used in combat during Operation Desert Fox in 1998 and during the NATO action in Kosovo the following year. The B-1B continues to support U.S. and NATO military forces in Afghanistan and Iraq. The Lancer is the supersonic component of the USAF's long-range bomber force, along with the subsonic B-52 and Northrop Grumman B-2 Spirit. The bomber is commonly called the "Bone" (originally from "B-One"). With the retirement of the General Dynamics/Grumman EF-111A Raven in 1998 and the Grumman F-14 Tomcat in 2006, the B-1B is the U.S. military's only active variable-sweep wing aircraft. The B-1B is expected to continue to serve into the 2020s, when it is to supplemented by the Next Generation Bomber. The Northrop Grumman B-2 Spirit (fig. 46), (also known as the Stealth Bomber) is an American heavy bomber with low observable stealth technology designed to penetrate dense anti-aircraft defenses and deploy both conventional and nuclear weapons. Because of its considerable capital and operational costs, the project was controversial in the U.S. Congress and among the Joint Chiefs of Staff. During the late 1980s and early 1990s, the Congress slashed initial plans to purchase 132 bombers to 21. Manufactured by Northrop Grumman, the cost of each aircraft averaged US$737 million in 1997 dollars ($1.01 billion today). Total procurement costs averaged US$929 million per aircraft ($1.27 billion today), which includes spare parts, equipment, retrofitting, and software support. The total program cost, which includes development, engineering and testing, averaged US$2.1 billion per aircraft (in 1997 dollars, $2.87 billion today). Twenty B-2s are operated by the United States Air Force. Though originally designed in the 1980s for Cold War operations scenarios, B-2s were first used in combat to drop bombs on Serbia during the Kosovo War 38

39 in 1999, and saw continued use during the wars in Iraq and Afghanistan. One aircraft was lost in 2008 when it crashed just after takeoff; the crew ejected safely. B-2s were also used during the 2011 Libyan uprising. The bomber has a crew of two and can drop up to lb (230 kg)-class JDAM GPS-guided bombs, or 16 2,400 lb (1,100 kg) B83 nuclear bombs in a single pass through extremely dense anti-aircraft defenses. The B-2 is the only aircraft that can carry large air to surface standoff weapons in a stealth configuration. The program has been the subject of espionage and counter-espionage activity and the B-2 has provided prominent public spectacles at air shows since the 1990s. Fig. 46. B-2 Spirit (the Stealth Bomber). The Boeing 787 Dreamliner (fig. 47) is a long-range, mid-size wide-body, twin-engine jet airliner developed by Boeing Commercial Airplanes. It seats 210 to 330 passengers, depending on the variant. Boeing states that it is the company's most fuel-efficient airliner and the world's first major airliner to use composite materials for most of its construction. The 787 consumes 20% less fuel than the similarly-sized Boeing

40 Some of its distinguishing features include a four-panel windshield, noise-reducing chevrons on its engine nacelles, and a smoother nose contour. The aircraft's initial designation was 7E7, prior to its renaming in January The first 787 was unveiled in a roll-out ceremony on July 8, 2007, at Boeing's Everett assembly factory, by which time it had become the fastest-selling wide-body airliner in history with 677 orders. By March 2011, 835 Boeing 787s had been ordered by 56 customers. As of 2011, launch customer All Nippon Airways has the largest number of 787s on order. Fig. 47. Boeing 787 Dreamliner. The 787 development and production has involved a large-scale collaboration with numerous suppliers around the globe. It is being assembled at the Boeing Everett Factory in Everett, Washington. Aircraft will also be assembled at a new factory in North Charleston, South Carolina. Both sites will deliver 787s to airline customers. Originally planned to enter service in May 2008, the project has suffered from repeated delays and is now more than three years behind schedule. The airliner's maiden flight took place on December 15, 2009, and it is currently undergoing flight testing with a goal of receiving certification in mid-2011 and entering service with All Nippon Airways in the third quarter of The Aérospatiale-BAC Concorde (fig. 48) is a turbojet-powered supersonic passenger airliner, a supersonic transport (SST). It was a product of an Anglo-French government treaty, combining the manufacturing efforts of Aérospatiale and the British Aircraft Corporation. First flown in 1969, Concorde entered service in 1976 and continued commercial flights for 27 years. Among other destinations, Concorde flew regular transatlantic flights from London Heathrow (British Airways) and Paris-Charles de Gaulle Airport (Air France) to New York JFK, profitably flying these routes at record speeds, in less than half the time of other airliners. Fig. 48. Concorde (is a turbojet-powered supersonic passenger). With only 20 aircraft built, their development represented a substantial economic loss, in addition to which Air France and British Airways were subsidised by their governments to buy them. As a result of the type s only crash on 25 July 2000 and other factors, its retirement flight was on 26 November

41 Concorde's name reflects the development agreement between the United Kingdom and France. In the UK, any or all of the type unusual for an aircraft are known simply as "Concorde". The aircraft is regarded by many as an aviation icon. The Lockheed F-117 Nighthawk (fig. 49) is a single-seat, twin-engine stealth ground-attack aircraft formerly operated by the United States Air Force (USAF). The F-117A's first flight was in 1981, and it achieved initial operating capability status in October The F-117A was "acknowledged" and revealed to the world in November Fig. 49. The Lockheed F-117 Nighthawk. A product of Lockheed Skunk Works and a development of the Have Blue technology demonstrator, it became the first operational aircraft initially designed around stealth technology. The F-117A was widely publicized during the Persian Gulf War of It was commonly called the "Stealth Fighter" although it was a ground-attack aircraft, making its F-designation misleading. The Air Force retired the F-117 on 22 April 2008, primarily due to the fielding of the F-22 Raptor and the impending introduction of the F-35 Lightning II. Sixty-four F-117s were built, 59 of which were production versions with 5 demonstrators/prototypes. Fig. 50. The Grumman F-14 Tomcat. 41

42 The Grumman F-14 Tomcat (fig. 50) is a supersonic, twin-engine, two-seat, variable-sweep wing fighter aircraft. The Tomcat was developed for United States Navy's Naval Fighter Experimental (VFX) program following the collapse of the F-111B project. The F-14 was the first of the American teen-series fighters which were designed incorporating the experience of air combat against MiGs during the Vietnam War. The F-14 first flew in December It first deployed in 1974 with the U.S. Navy aboard USS Enterprise (CVN-65), replacing the McDonnell Douglas F-4 Phantom II. The F-14 served as the U.S. Navy's primary maritime air superiority fighter, fleet defense interceptor and tactical reconnaissance platform. In the 1990s it added the Low Altitude Navigation and Targeting Infrared for Night (LANTIRN) pod system and began performing precision strike missions. The F-14 was retired from the active U.S. Navy fleet on 22 September 2006, having been replaced by the Boeing F/A-18E/F Super Hornet. As of 2009, the F-14 was only in service with the Islamic Republic of Iran Air Force, having been exported to Iran in 1976 when the US had amicable diplomatic relations with the nation. The General Dynamics F-16 Fighting Falcon (fig. 51) is a multirole jet fighter aircraft originally developed by General Dynamics for the United States Air Force (USAF). Designed as a lightweight day fighter, it evolved into a successful all-weather multirole aircraft. Over 4,400 aircraft have been built since production was approved in Though no longer being purchased by the U.S. Air Force, improved versions are still being built for export customers. In 1993, General Dynamics sold its aircraft manufacturing business to the Lockheed Corporation, which in turn became part of Lockheed Martin after a 1995 merger with Martin Marietta. The Fighting Falcon is a dogfighter with numerous innovations including a frameless bubble canopy for better visibility, side-mounted control stick to ease control while maneuvering, a seat reclined 30 degrees to reduce the effect of g-forces on the pilot, and the first use of a relaxed static stability/fly-by-wire flight control system that makes it a highly nimble aircraft. The F-16 has an internal M61 Vulcan cannon and has 11 hardpoints for mounting weapons, and other mission equipment. Although the F-16's official name is "Fighting Falcon", it is known to its pilots as the "Viper", due to it resembling a viper snake and after the Battlestar Galactica Colonial Viper starfighter. In addition to USAF active, reserve, and air national guard units, the aircraft is used by the USAF aerial demonstration team, the U.S. Air Force Thunderbirds, and as an adversary/aggressor aircraft by the United States Navy. The F-16 has also been procured to serve in the air forces of 25 other nations. Fig. 51. The F-16 Fighting Falcon over Iraq. 42

43 The Boeing F/A-18E/F Super Hornet (fig. 52) is a twin-engine carrier-based multirole fighter aircraft. The F/A-18E single-seat variant and F/A-18F tandem-seat variant are larger and more advanced derivatives of the F/A-18C and D Hornet. The Super Hornet has an internal 20 mm gun and can carry air-to-air missiles and air-to-surface weapons. Additional fuel can be carried with up to five external fuel tanks and the aircraft can be configured as an airborne tanker by adding an external air refueling system. Fig. 52. The F-18 Super Hornet. Designed and initially produced by McDonnell Douglas, the Super Hornet first flew in Full-rate production began in September 1997, after the merger of McDonnell Douglas and Boeing the previous month. The Super Hornet entered service with the United States Navy in 1999, replacing the Grumman F-14 Tomcat since 2006, and serves alongside the original Hornet. The Royal Australian Air Force (RAAF), which has operated the F/A-18A as its main fighter since 1984, ordered the F/A-18F in 2007 to replace its aging F-111 fleet. RAAF Super Hornets entered service in December The Lockheed Martin/Boeing F-22 Raptor (fig. 53) is a single-seat, twin-engine fifth-generation supermaneuverable fighter aircraft that uses stealth technology. It was designed primarily as an air superiority fighter, but has additional capabilities that include ground attack, electronic warfare, and signals intelligence roles. Lockheed Martin Aeronautics is the prime contractor and is responsible for the majority of the airframe, weapon systems and final assembly of the F-22. Program partner Boeing Defense, Space & Security provides the wings, aft fuselage, avionics integration, and all of the pilot and maintenance training systems. Fig. 53. The Lockheed Martin/Boeing F-22 Raptor. 43

44 The aircraft was variously designated F-22 and F/A-22 during the years prior to formally entering USAF service in December 2005 as the F-22A. Despite a protracted and costly development period, the United States Air Force considers the F-22 a critical component for the future of US tactical air power, and claims that the aircraft is unmatched by any known or projected fighter, while Lockheed Martin claims that the Raptor's combination of stealth, speed, agility, precision and situational awareness, combined with air-to-air and air-toground combat capabilities, makes it the best overall fighter in the world today. Air Chief Marshal Angus Houston, Chief of the Australian Defence Force, said in 2004 that the "F-22 will be the most outstanding fighter plane ever built." The high cost of the aircraft, a lack of clear air-to-air combat missions because of delays in the Russian and Chinese fifth generation fighter programs, a US ban on Raptor exports, and the ongoing development of the supposedly cheaper and more versatile F-35 resulted in calls to end F-22 production. In April 2009 the US Department of Defense proposed to cease placing new orders, subject to Congressional approval, for a final procurement tally of 187 Raptors. The National Defense Authorization Act for Fiscal Year 2010 was signed into law in October 2009 without funding for further F-22 production. The Lockheed Martin F-35 Lightning II (fig. 54) is a family of single-seat, single-engine, fifth generation multirole fighters under development to perform ground attack, reconnaissance, and air defense missions with stealth capability. The F-35 has three main models; one is a conventional takeoff and landing variant, the second is a short take off and vertical-landing variant, and the third is a carrier-based variant. The F-35 is descended from the X-35, the product of the Joint Strike Fighter (JSF) program. JSF development is being principally funded by the United States, with the United Kingdom and other partner governments providing additional funding. It is being designed and built by an aerospace industry team led by Lockheed Martin. The F-35 took its first flight on 15 December The United States intends to buy a total of 2,443 aircraft for an estimated US$323 billion, making it the most expensive defense program ever. The United States Air Force (USAF) budget data in 2010, along with other sources, projects the F-35 to have a flyaway cost from US$89 million to US$200 million over the planned production of F-35s. Cost estimates have risen to $382 billion for 2,443 aircraft, at an average of $156 million each. The rising program cost estimates have cast doubt on the actual number to be produced for the U.S. In January 2011, the F-35B variant was placed on "probation" for two years because of development issues. In February 2011, the Pentagon put a price of $207.6 million for each of the 32 aircraft to be acquired in FY2012, rising to $ million ($9,732.8/32) if its share of RDT&E spending is included. Fig. 54. The Lockheed Martin F-35 Lightning II. Beginning with the Vietnam War doubts began to be raised about the ability of the 700+ KC-135 fleet to meet the needs of the United States' global commitments. The aerial refueling fleet was deployed to Southeast Asia in support of tactical aircraft and strategic bombers, while maintaining the US-based support of the nuclear bomber fleet. The United States Air Force as a result sought an air-to-air tanker with a greater capability than the KC-135. In 1972 two DC-10s were flown in trials at Edwards Air Force Base, simulating air refuelings to check for possible wake issues. Boeing performed similar tests with a

45 The 1973 Yom Kippur War and the US Operation Nickel Grass demonstrated the necessity of adequate air-refueling capabilities. Denied landing rights in Europe, USAF C-5 Galaxies were forced to carry a fraction of their maximum payload on direct flights from the continental United States to Israel. As a result C-5 crews were soon trained in aerial refueling and the U.S. Department of Defense concluded that a more advanced tanker was needed. In 1975, under the Advance Tanker Cargo Aircraft program, four aircraft were evaluated: the C-5 itself, the Boeing 747, the McDonnell Douglas DC-10, and the Lockheed L The U.S Air Force selected McDonnell Douglas's DC-10 over Boeing's 747 in December The design for the KC-10 involved only modifications from the DC-10-30CF design. The major changes were the addition of a boom control station in the rear of the fuselage and extra fuel tanks below the main deck. The KC-10 has both a centerline refueling boom and a drogue/hose system on the right side of the rear fuselage. Other changes from the DC-10-30CF include the removal of most cargo doors and windows. The KC-10 first flew on 12 July Early aircraft featured a paint scheme with light gray on the airplane's belly and white on the upper portion with blue around the cockpit. A gray-green camouflage scheme was used on later tankers. Aircraft have since been switched to a medium gray color. The KC-10 boom operator is located in the rear of the airplane with wide window for monitoring refueling. The operator controls refueling operations through a digital, fly-by wire system. The final 20 KC-10s produced included wing-mounted pods for added refueling locations. In addition to the USAF refueling boom, the KC-10's hose and drogue system allows refueling of U.S. Navy, Marine Corps, and most NATO allied aircraft. This gives the KC-10 the ability to refuel US and other NATO aircraft, all in one mission. A need for new transport aircraft for the Royal Netherlands Air Force was first identified in In 1991 four categories of transport requirements were established. Category A required a large cargo aircraft with a range of at least 4500 km and the capability to refuel F-16s. In 1992, 2 DC-10-30CFs were acquired from Martinair in a buy/leaseback contract. When one of the bought aircraft was lost in the Martinair Flight 495 crash, a third aircraft was bought from Martinair. The conversion was handled via the United States foreign military sales program, which in turn contracted McDonnell Douglas, the designer of both the DC-10 and the KC-10 tanker. Costs for the conversion were initially estimated at $89.5 million (FY 1994). The aircraft was to be equipped with both a boom and a probe and drogue system. However, because McDonnell Douglas did not have any experience with the requested Remote Aerial Refueling Operator (RARO) system, and because the third aircraft differed from the original two, the program could not be completed at budget. By omitting the probe and drogue system and a fixed partition wall between the cargo and passenger, the cost could be limited at $96 million. To make up for the cost increase McDonnell Douglas hired Dutch companies to do part of the work. The actual converting of the aircraft for instance was done by KLM. Conversion of the aircraft was done from October 1994 to September 1995 for the first aircraft and from February to December 1995 for the second. This was much longer than planned, mostly because McDonnell Douglas did not deliver the parts in time. This would have again increased the cost, but in the contract for the AH-64 Apaches which the Royal Netherlands Air Force also bought from McDonnell Douglas, the price was agreed to be kept at $96 million. In 2005 Fokker Services (NL) was awarded with a contract to update the avionics on the two KDC-10 and one DC-10 aircraft of the Royal Netherlands Air Force to a common standard. The aircraft will be updated with digital cockpits, Link 16 and satellite communications. This design is now offered by Boeing to the US Air Force to update their KC-10s. The KC-10 was delivered to the USAF Strategic Air Command (SAC), then in control of air refueling assets from 1981 to SAC had KC-10 Extenders (fig. 55) in service from 1981 until 1992, when they were re-assigned to the newly established Air Mobility Command. In the air-to-air refueling (AAR) role, the KC-10s have been operated largely in the strategic refueling of large number of tactical aircraft on ferry flights and the refueling of other strategic transport aircraft. Conversely, the KC-135 fleet has operated largely in the in-theater tactical role. There are 59 KC-10 Extenders (fig. 55) in service with the United States Air Force (USAF) as of The KC-10 has a significantly larger fuel capacity than the Air Force's other main tanker, the KC-135. with over 440 in service in The USAF's KC-10s are stationed primarily at Travis AFB, California and McGuire AFB, New Jersey. 45

46 When faced with refusals of basing and overflight rights from continental European countries during Operation El Dorado Canyon, the U.S. was forced to use the UK-based F-111s in the 1986 air-strikes against Libya. The KC-10s allowed 29 F-111s to reach their targets. The KC-10 fleet also facilitated the deployment of tactical, strategic, and transport aircraft to Saudi Arabia during Operation Desert Shield. In recent times, USAF KC-10s have seen use in supporting military operations in Iraq and Afghanistan through In addition to offering in-flight refueling capabilities, USAF KC-10s also undertake cargo and personnel transport operations. In an attempt to modernize the platform, the USAF has awarded Boeing a US$216 million contract to upgrade its fleet of 59 aircraft with new communication, navigation, surveillance and air traffic management (CNS/ATM) system. Boeing claims that this will allow the aircraft to fly in civil airspace after 2015 as new ICAO and FAA standards take effect. Fig. 55. The KC-10 Extenders. The Lockheed C-5 Galaxy (fig. 56) is a large military transport aircraft built by Lockheed. It was designed to provide strategic heavy airlift over intercontinental distances and to carry outsize and oversize cargo. The C-5 Galaxy has been operated by the United States Air Force (USAF) since 1969 and is among the largest military aircraft in the world. The C-5M Super Galaxy is an upgraded version with new engines and modernized avionics designed to extend its service life beyond Fig. 56. The Lockheed C-5 Galaxy. In 1961, several aircraft companies began studying heavy jet transport designs that would replace the Douglas C-133 Cargomaster transport and complement Lockheed C-141 Starlifters. In addition to higher overall performance, the United States Army wanted a transport with a larger cargo bay than the C-141, whose interior was too small to carry a variety of their outsized equipment. These studies led to the "CX-4" design concept, but 46

47 in 1962 the proposed six-engine design was rejected, because it was not viewed as a significant advance over the C-141. By late 1963, the next conceptual design was named CX-X. It was equipped with four engines, instead of six engines in the earlier CX-4 concept. The CX-X had a gross weight of 550,000 pounds (249,000 kg), a maximum payload of 180,000 lb (81,600 kg) and a speed of Mach 0.75 (500 mph/805 km/h). The cargo compartment was 17.2 ft (5.24 m) wide by 13.5 feet (4.11 m) high and 100 ft (30.5 m) long with front and rear access doors. To provide required power and range with only four engines required a new engine with dramatically improved fuel efficiency. The criteria were finalized and an official Request for Proposal was sent out in April 1964 for the "Heavy Logistics System" (CX-HLS) (previously CX-X). In May 1964, proposals for aircraft were received from Boeing, Douglas, General Dynamics, Lockheed, and Martin Marietta. Proposals for engines were received from General Electric, Curtiss-Wright, and Pratt & Whitney. After a downselect, Boeing, Douglas and Lockheed were given one-year study contracts for the airframe, along with General Electric and Pratt & Whitney for the engines. All three of the designs shared a number of features. In particular, all three placed the cockpit well above the cargo area to allow for cargo loading through a nose door. The Boeing and Douglas designs used a pod on the top of the fuselage containing the cockpit, while the Lockheed design extended the cockpit profile down the length of the fuselage, giving it an egg-shaped cross section. All of the designs featured swept wings and front and rear cargo doors allowing simultaneous loading and unloading. Lockheed's design featured a T- tail, while the designs by Boeing and Douglas had conventional tails. The Air Force considered Boeing's design better than the Lockheed design, although Lockheed's proposal was the lowest total cost bid. Lockheed was selected the winner in September 1965, then awarded a contract in December General Electric's engine design was selected in August 1965 for the new transport; the Pratt & Whitney engine design was developed and later used on the Boeing 747. The first C-5A Galaxy (number ) was rolled out of the manufacturing plant in Marietta, Georgia on 2 March On 20 June 1968, Lockheed-Georgia Co. began flight testing its new Galaxy C-5A heavy transport with the aircraft's first flight taking to the air under the call-sign "eight-three-oh-three heavy" (8303H). Cost overruns and technical problems of the C-5A were the subject of a congressional investigation in 1968 and The Lockheed C-5 program holds the dubious distinction of being the first program to produce a one billion dollar overrun. Upon completion of testing the first C-5A was transferred to the Transitional Training Unit at Altus Air Force Base, OK, in December Lockheed then delivered the first operational Galaxy to the 437th Airlift Wing, Charleston Air Force Base, SC, in June Due to the higher than expected development costs, there were calls within the military as early as in June 1970 for the government to split the losses that Lockheed were experiencing. Production was nearly brought to a halt in 1971 due to Lockheed going through financial difficulties, brought on in part due to the C-5 Galaxy but also by the civilian jet liner, the Lockheed L The U.S. government loaned Lockheed money so they could keep running. In 1969 Henry Durham raised concerns about the C-5 production process with his employer, Lockheed. He was transferred and subjected to abuse until he resigned from the company. The GAO substantiated some of his charges against Lockheed and the American Ethical Union honored him with the Elliott-Black Award. In the early 1970s, NASA considered the C-5 for the Shuttle Carrier Aircraft role, to transport the Space Shuttle to Kennedy Space Center. However, they rejected it in favor of the Boeing 747, in part due to the 747's low-wing design. In contrast, the Soviet Union chose to transport its shuttles using the high-winged An-225, which derives from the An-124, which is similar in design and function to the C-5. During static and fatigue testing cracks were noticed in the wings of several aircraft, and as a consequence the C-5A fleet was restricted to 80% of maximum design loads. To reduce wing loading, load alleviation systems were added to the aircraft. By 1980, payloads were restricted to as low as 50,000 lb (23,000 kg) for general cargo during peacetime operations. To restore full payload capability and service life, a $1.5 billion program to re-wing the 76 completed C-5As began in After design and testing of the new wing design, the C-5As received their new wings from 1980 to During 1976, numerous cracks were also found in the fuselage along the upper fuselage on the centerline, aft of the refueling port, extending back to the wing. The cracks required a redesign to the hydraulic system for the visor, the front cargo entry point. In 1974, Iran, then a monarchy which maintained good relations with the United States, offered $160 million to restart the production of the C-5 to enable them to make their own procurements of the Galaxy; in a 47

48 similar climate as to their acquisition of F-14 Tomcat fighters. However no C-5 aircraft were ever ordered by Iran, as the prospect was firmly halted by the Iranian Revolution in As part of President Ronald Reagan's military planning, a new version of the C-5, the C-5B, was approved by Congress for purchase in July The first C-5B was delivered to Altus Air Force Base in January In April 1989, the last of 50 C-5B aircraft was added to the 77 C-5As in the Air Force's airlift force structure. The C-5B includes all C-5A improvements and numerous additional system modifications to improve reliability and maintainability. In 1998, the Avionics Modernization Program (AMP) began upgrading the C-5's avionics to include a glass cockpit, navigation equipment, and a new autopilot system. Another part of the C-5 modernization effort is the Reliability Enhancement and Re-engining Program (RERP). The program will mainly replace the engines with newer, more powerful ones. Three C-5s are to undergo RERP as a test with full production planned to begin in May The C-5 is a large high-wing cargo aircraft. It has a distinctive high T-tail, 25 degree wing sweep, and four TF39 turbofan engines mounted on pylons beneath the wings. The C-5 is similar in layout to its smaller predecessor, the C-141 Starlifter. The C-5 has 12 internal wing tanks and is equipped for aerial refueling. It has both nose and aft doors for "drive-through" loading and unloading of cargo. The C-5 features a cargo compartment 121 ft (37 m) long, 13.5 ft (4.1 m) high, and 19 ft (5.8 m) wide, or just over 31,000 cu ft (880 m3). The compartment can accommodate up to L master pallets or a mix of palletized cargo and vehicles. The cargo hold of the C-5 is actually a foot longer than the length of the first powered flight by the Wright Brothers' Flyer at Kitty Hawk. The nose and aft doors open the full width and height of the cargo compartment to permit faster and easier loading. Ramps are full width at each end for loading double rows of vehicles. It has an upper deck seating area for 73 passengers. The passengers face the rear of the aircraft, rather than forward. Its takeoff and landing distances, at maximum gross weight, are 8,300 ft (2,500 m) and 4,900 ft (1,500 m) respectively. Its high flotation main landing gear has 28 wheels to share the weight. The rear main landing gear is steerable for a smaller turning radius and it rotates 90 degrees horizontally before it is retracted after takeoff. The "kneeling" landing gear system permits lowering of the parked aircraft so the cargo floor is at truck-bed height to facilitate vehicle loading and unloading. The C-5 has a Malfunction Detection Analysis and Recording (MADAR) system, which records and analyzes information and detects malfunctions in more than 800 test points. The C-5 requires an average of 16 hours of maintenance for each flight hour based on 1996 data. The Galaxy has a Low Pressure Pneumatic System (LPPS) that utilizes a turbo compressor driven by bleed air to provide 150 psi pressure for inflating aircraft's tires on the ground. The LPPS is no longer used on C-5s. The Galaxy is capable of carrying nearly every type of the Army's combat equipment, including bulky items such as the 74 short tons (67 t) armored vehicle launched bridge (AVLB), from the United States to any location on the globe. One of the unique features was the crosswind landing system that allows the landing gear to be offset up to 20 degrees either side of centerline. When the main landing gear was down (MLG) all the other 28 wheels would be slaved to the MLG and driven by hydraulic actuators to the same offset. The first C-5A was delivered to the USAF on 17 December Wings were built up in the early 1970s at Altus AFB, Oklahoma, Charleston AFB, Dover AFB, Delaware, and Travis AFB, California. 9 July 1970 marked the C-5's first mission in Southeast Asia during the Vietnam War. Through the rest of the war, C- 5s were used to transport equipment and troops, including Army tanks and various smaller aircraft. C-5s have also been used to deliver support and reinforce various U.S. allies over the years, critically delivered weapons and supplies to Israel as part of Operation Nickel Grass in 1973, in which the aircraft performed to such a high degree that the Pentagon considered further purchases. The C-5 was also made available to support British-led peacekeeping efforts in Zimbabwe in The C-5 is the largest aircraft to ever operate in the Antarctic. Williams Field near McMurdo Station is capable of handling C-5 aircraft and the first C-5 landed there in The C-5 Galaxy was a core part of the extensive airlift operations supplying troops involved in the First Gulf War, and in delivering relief aid to Rwanda in The wings on the C-5As were replaced during the 1980s to restore full design capability. The U.S. Air Force took delivery of the first C-5B on 28 December 1985 and the final one in April The reliability of the 48

49 C-5 fleet has been a continued issue throughout its lifetime, however the C-5M upgrade program seeks in part to address this issue. In response to Air Force motions towards the retirement of the C-5 Galaxy, Congress implemented legislation that placed set limits upon retirement plans for C-5A models in By 2005, 14 C-5As were retired. One was sent to the Warner Robins Air Logistics Center (WR-ALC) for tear down and inspection to evaluate structural integrity and estimate the remaining life for the fleet. Thirteen C-5As were sent to the Air Force's Aerospace Maintenance and Regeneration Group (AMARG) for inspection of levels of corrosion and fatigue. In 2007 the Air Force requested information on the Airbus A380 freighter for possible use as a military transport to supplement the U.S. strategic airlift fleet. The U.S. Air Force began to receive refitted C-5M aircraft in December 2008; full production of C-5Ms began in the summer of In 2009, the Congressional ban on the retirement of C-5s was overturned. The Air Force seeks to retire one C-5A for each 10 new C-17s ordered. The C-5A is the original version of the C-5. From 1969 to 1973, 81 C-5As were delivered to U.S. Air Forces bases. Due to cracks found in the wings in the mid-1970s, the cargo weight was restricted. To restore the plane's full capability, the wing structure was redesigned. A program to install new strengthened wings on 77 C- 5As was conducted from 1981 to The redesigned wing made use of a new aluminum alloy that did not exist during the original production. The C-5B is an improved version of the C-5A. It incorporated all modifications and improvements made to the C-5A with improved wings, upgraded TF-39-GE-1C turbofan engines and updated avionics. From 1986 to 1989, 50 of the new variant were delivered to the U.S. Air Force. The C-5C is a specially modified variant for transporting large cargo. Two C-5s ( and ) were modified to have a larger internal cargo capacity to accommodate large payloads, such as satellites for use by NASA. The major modifications were the removal of the rear passenger compartment floor, splitting the rear cargo door in the middle, and installing a new movable aft bulkhead further to the rear. Modifications also included adding a second inlet for ground power, which can feed any power-dependent equipment that may form part of the cargo. The two C-5Cs are operated by U.S. Air Force crews on the behalf of NASA, and are stationed at Travis AFB, California completed the Avionics Modernization Program in January Based on a recent study showing 80% of the C-5 airframe service life remaining, AMC began an aggressive program to modernize all remaining C-5Bs and C-5Cs and many of the C-5As. The C-5 Avionics Modernization Program (AMP) began in 1998 and includes upgrading avionics to Global Air Traffic Management compliance, improving communications, new flat panel displays, improving navigation and safety equipment, and installing a new autopilot system. The first flight of the first modified C-5 with AMP ( ) occurred on 21 December Another part of the plan is a comprehensive Reliability Enhancement and Re-engining Program (RERP), which includes new General Electric CF6-80C2 engines, pylons and auxiliary power units, with upgrades to aircraft skin and frame, landing gear, cockpit and the pressurization system. The CF6 engine produces 22% more thrust (for 50,000 lbf/220 kn total from each engine) than existing C-5 engines, which will result in a 30% shorter takeoff roll, a 38% higher climb rate to initial altitude, a significantly increased cargo load, and a longer range between refueling. The C-5s that complete these upgrades are designated C-5M Super Galaxy. The C-5 AMP and RERP modernization programs plan to raise mission-capable rate to a minimum goal of 75%. Over the next 40 years, the U.S. Air Force estimates the C-5M will save over $20 billion. The first C-5M conversion was completed on 16 May 2006, and performed its first flight on 19 June C-5Ms have been in flight testing out of Dobbins Air Reserve Base since June Test aircraft include a distinctively colored nose boom to acquire flight data. The USAF decided to convert remaining C-5Bs and C-5Cs into C-5Ms with avionics upgrades and reengining in February The C-5As will receive only the avionics upgrades. The three test C-5Ms successfully completed developmental flight testing in August The test aircraft will begin Operational Test and Evaluation in September The RERP upgrade program is to be completed in Lockheed Martin announced that a C-5M test flight on 13 September 2009, set 41 new records. The flight's data have been submitted to the National Aeronautic Association for formal acceptance. The C-5M carried a payload of 176,610 lb (80,110 kg) to over 41,100 ft (12,500 m) in 23 minutes, 59 seconds. The flight set 33 time to climb records at various payload classes, and broke the world record for greatest payload to 6,562 feet 49

50 (2,000 meters). The aircraft used for this flight had a takeoff weight of 649,680 lb (294,690 kg), which included payload, fuel and crew. A total of 52 C-5s are contracted to be modernized, consisting of 49 B-, two C- and one A-model aircraft through the Reliability Enhancement and Re-Engining Program (RERP). Over 70 changes and upgrades are incorporated in the program, including newer, quieter, General Electric engines which increase reliability and make the Super Galaxy 10 percent more fuel efficient than legacy C-5s. Five C-5M Super Galaxies have been produced. Lockheed also planned a civilian version of the C-5 Galaxy, the L-500, the company designation also used for the C-5 itself. Both passenger and cargo versions of the L-500 were designed. The all-passenger version would have been able to carry up to 1,000 travelers, while the all-cargo version was predicted to be able to carry typical C-5 volume for as little as 2 cents per ton-mile (in 1967 dollars). Although some interest was expressed by carriers, no orders were placed for either L-500 version, due to operational costs caused by low fuel efficiency, a significant concern for a profit-making carrier, even before the oil crises of the 1970s, keen competition from Boeing's 747, and high costs incurred by Lockheed in developing the C-5 and later, the L which led to the governmental rescue of the company. There have been five C-5 Galaxy aircraft lost in crashes along with two class-a losses resulting from ground fire and one loss resulting from damage sustained on the ground. There have been at least two other C-5 crashes that resulted in major airframe damage, but the aircraft were repaired and returned to service. On 27 May 1970, C-5A serial number was destroyed during a ground fire at Palmdale, California after an Air Turbine Motor (ATM) started backwards and quickly overheated, setting the hydraulic system on fire and quickly consuming the aircraft. The engines were not running at the time of the fire. Five crew escaped, but seven firefighters suffered minor injuries fighting the blaze. On 17 October 1970, C-5A S/N was destroyed during a ground fire at Marietta, Georgia. The fire started during maintenance in one of the aircraft's 12 fuel cells. One worker was killed and another injured. This was the first C-5 aircraft produced. On 27 September 1974, C-5A crashed after over-running the runway at Clinton, Oklahoma Municipal Airport during an emergency landing following a serious landing gear fire. The crew mistakenly aligned the aircraft for the visual approach into the wrong airport, landing at Clinton Municipal Airport, which has a 4,400 ft (1,300 m) runway instead of Clinton-Sherman airfield, which has a 13,500 ft (4,100 m) runway. This was the first operational loss of a C-5 Galaxy. On 4 April 1975, C-5A crashed while carrying orphans out of Vietnam (Operation Baby Lift). This crash, known as Tan Son Nhut C-5 accident, is one of the most well known C-5 accidents to date. The crash occurred while trying to make an emergency landing at Tan Son Nhut Air Base Saigon, following a door lock failure in flight. 144 adults and children (including 76 babies) were killed out of the 305 aboard (243 children, 44 escorts, 16 crewmen and two flight nurses). Use of the C-5 was heavily restricted for several months due to this high profile incident. On 31 July 1983, C-5A crashed on landing at Shemya, Alaska. The C-5 approached below the glide slope, hit an embankment short of the runway and bounced back into the air before coming to rest on the runway. Structural damage was extensive and the two aft main landing gear bogies were sheared from the airplane. There were no fatalities. A joint USAF/Lockheed team made repairs enabling a one-time ferry flight from Shemya to the Lockheed plant in Marietta, Georgia. There, the airplane was quickly christened Phoenix II and permanent repair efforts got underway. In addition to the structural repairs, Phoenix II also received an improved landing gear system (common to the then-new C-5B), wing modification, and a color weather radar upgrade. The airplane was returned to service, and was transferred to the Texas Air National Guard. In July 1985, C-5A landed wheels (gear) up at Travis Air Force Base, California. There were no injuries. The accident occurred while the crew was performing touch-and-go landings, and did not lower the landing gear during the final approach of the day. The aircraft received significant damage to the lower fuselage and main landing gear pods. The C-5A was later flown to Marietta for repairs. While there, the aircraft was selected to be the first C-5A converted to the C-5C configuration. On 29 August 1990, C-5A crashed following an engine failure shortly after take-off. The aircraft took off from Ramstein Air Base in Germany in support of Operation Desert Shield. It was flown by a nine-member reserve crew from the 68th Airlift Squadron, 433rd Airlift Wing based at Kelly AFB, Texas. As the aircraft started to climb off the runway, one of the thrust reversers suddenly deployed. This resulted in loss of control of the aircraft and the subsequent crash. Of the 17 people on board, only four survived the crash. All 50

51 four were in the rear troop compartment. The sole crew member to survive, Staff Sgt. Lorenzo Galvan, Jr., was awarded the Airman's Medal for his actions in evacuating the survivors from the wreckage. On 3 April 2006, C-5B crashed after an in-flight emergency involving an indication that a thrust reverser was not locked. The C-5B assigned to the 436th Airlift Wing and flown by a reserve crew from the 709th Airlift Squadron, 512th Airlift Wing crashed about 2,000 ft (610 m) short of runway 32, while attempting a heavyweight emergency landing at Dover Air Force Base, Delaware. The airplane, carrying 17 people, had taken off from Dover about 21 minutes earlier and reported an in-flight emergency (number two engine thrust reverser not locked indication) 10 minutes into the flight. All 17 aboard survived, but two received serious injures. The Air Force's accident investigation concluded the crash was a result of human error, most notably that the crew kept one of the functioning engines in flight idle while manipulating the throttle of the (dead) number two engine as if it was still running, while having the number three engine at idle, an error that was further amplified by the crew's decision to use a high flap setting that increased drag beyond normal two engine performance capabilities. The forward fuselage will be converted into a C-5 AMP avionics test bed, and the rest of the airframe has been scrapped. The Saab 37 Viggen (Fig. 57), (English: Thunderbolt) was a Swedish single-seat, single-engine, shortmedium range fighter and attack aircraft, manufactured between 1970 and Several variants were produced to perform the roles of all-weather fighter-interceptor, ground-attack and photo-reconnaissance, as well as a two-seat trainer. Fig. 57. The SAAB JA 37 Viggen. The Viggen was initially developed as a replacement for the Saab 32 Lansen in the attack role and later the Saab 35 Draken as a fighter. The first studies were carried out between 1952 and 1957 involving the Finnish aircraft designer Aarne Lakomaa. Several different concepts were studied involving both single- and twin engines and also with separate lift engines, both simple and double delta wings and also with canard wings. Even VTOL designs were considered. The aim was to produce a robust aircraft with good short-runway performance that could be operated from numerous specially prepared roads and highways to reduce the vulnerability to attack in the event of war. Other requirements included supersonic ability at low level, Mach 2 performance at altitude, and the ability to make short landings at low angles of attack (to avoid damaging improvised runways). The aircraft was also designed from the beginning to be easy to repair and service, even for personnel without much training. To meet these design goals, Saab selected a radical configuration: a conventional delta wing with small, high-set canard wings. Canards have since become common in fighter aircraft, notably with the Eurofighter Typhoon, Dassault Rafale, Saab JAS 39 Gripen and the IAI Kfir, but mainly for agility reasons rather than STOL capabilities. The final proposal was presented and accepted on 28 September Construction started in 1964, with a first prototype maiden flight on 8 February In 1960, the U.S. National Security Council, led by President Eisenhower, formulated a military security guarantee for Sweden. The U.S. promised to help the Swedish militarily in the event of a Soviet attack against Sweden; both countries signed a military-technology agreement. In what was known as the "37-annex", Sweden was allowed access to advanced U.S. aeronautical technology which made it possible to design and produce the Saab 37 Viggen much faster and cheaper than would otherwise have been possible. According to the doctoral research of Nils Bruzelius at the Swedish National Defence College, the reason for this officially unexplained U.S. support was the need to protect U.S. Polaris submarines deployed just outside the Swedish west coast against the threat of Soviet anti-submarine aircraft. However, Bruzelius' theory have been thoroughly debunked by Simon Moores and Jerker Widén. 51

52 The Viggen was powered by a single Volvo RM8 turbofan. This was essentially a licence-built variant of the Pratt & Whitney JT8D engine that powered commercial airliners of the 1960s, with an afterburner added for the Viggen. The airframe also incorporated a thrust-reverser to use during landings and land manoeuvres, which, combined with the aircraft having flight capabilities approaching a limited STOL-like performance, enabled operations from 500 m airstrips with minimal support. The thrust reverser could be pre-selected in the air to engage when the nose-wheel strut was compressed after touchdown. The Viggen was the first aircraft to feature both afterburners and thrust-reversers. Only the Viggen, Concorde and the Panavia Tornado featured both afterburners and thrust-reversers. The requirements from the Swedish Air Force dictated Mach 2 capability at high altitude and Mach 1 at low altitude. At the same time, short-field takeoff and landing performance was also required. Since the Viggen was developed initially as an attack aircraft instead of an interceptor (the Saab 35 Draken fulfilled this role), some emphasis was given to low fuel consumption at high subsonic speeds at low level for good range. With turbofan engines just emerging and indicating better fuel economy for cruise than turbojet engines, the former was favoured, since the latter were mainly limited by metallurgy development resulting from limitations in turbine temperature. Mechanical simplicity was also favoured, so the air intakes were simple D-section types with boundary layer splitter plates, while the fixed inlet had no adjustable geometry for improved pressure recovery. The disadvantage was that the required engine would be very large. In fact, at the time of introduction, it was the second largest fighter engine, with a length of 6.1 m and 1.35 m diameter; only the Tumansky R-15 was bigger. Saab had originally wanted the Pratt & Whitney TF30 as the Viggen's powerplant. Since the engine design had not been completed in 1962 when the airframe vs. engine design size needed to be frozen, the JT8D was chosen as the basis for modification instead. The RM8 became the second operational afterburning turbofan in the world, and also the first equipped with a thrust reverser. It had a bypass ratio of around 1.07:1 in the RM8A, which reduced to 0.97:1 in the RM8B. The AJ, SF, SH and SK 37 models of the Viggen had the first version of the RM8A engine with uprated internal components from the JT8D that it was based on. Thrust was 65.6 kn dry and kn with afterburner. For the JA 37, the RM8A was modified to an 8B by replacing one LP compressor stage with a fan stage and improved combustor, turbine and afterburner. Thrust is 72.1 kn dry and kn with afterburner. The engine was started via a small gas turbine, itself started by an electric motor. Standby power and cooling air for onboard avionics were supplied via an external cart. An internal battery permitted start of the starter turbine and main engine in absence of the standby power cart. With the performance requirements to a large extent dictating the choice of the engine, the airframe turned out to be quite bulky compared to contemporary slimmer designs with turbojet engines. The first prototypes had a straight midsection fuselage that was later improved with a "hump" on the dorsal spine for reduced drag according to the area rule. The wing had the shape of a double delta with a dogtooth added to improve longitudinal stability when carrying external stores. Each dogtooth was also used as a fairing for a radar warning receiver (RWR) antenna. A consequence of a tailless delta design, such as in the Viggen, is that the elevons, which replace more conventional control surfaces, operate with a small effective moment arm; their use adds substantial weight to the aircraft at takeoff and landing. Hinged leading edge surfaces can help counteract this, but an even more effective tool is the canard. The canards were positioned behind the inlets and placed slightly higher than the main wing, but were not movable as control surfaces (however, they were equipped with flaps). The purpose of the canard wings were to act as vortex generators for the main wing and therefore provide more lift. An added benefit was that they also improved roll stability in the transonic region around Mach 0.9. The canard flaps were deployed in conjunction with the landing gear to provide even more lift for takeoff and landing. To withstand the stresses of no-flare landings, Saab made extensive use of titanium in the construction of the Viggen, especially in the fuselage, and incorporated an unusual arrangement for the main landing gear, in which the two wheels on each leg were placed in tandem. While such a layout is common in airliners and cargo aircraft, it is rare in fighters, but allows stowage in a thinner wing. The tall single vertical stabilizer (45 degrees sweepback on the leading edge) was foldable to make it easier to store in hangars. After prototype testing of the SK variant, reduced longitudinal stability was discovered. To correct this, the vertical stabilizer was extended 10 cm (4 in) and the pitot tube was moved from the top of the fin leading edge to about midpoint where a sawtooth was also incorporated. The JA model later used the same improvements. 52

53 The six tanks in the fuselage and wings held approximately 5,000 litres of fuel with an additional 1,500 litres in an external drop tank. The specific fuel consumption was only 0.63 for cruise speeds (fuel consumption was rated 18 mg/ns dry and 71 with afterburner). The Viggen's consumption was around 15 kg/sec at maximum afterburner, which meant that the internal fuel was exhausted in just seven minutes due to the relative inefficiency of the turbofan over a turbojet at full afterburner. Performance comparisons with other aircraft from the same age are however slightly difficult, since no other fighter or attack aircraft aside from the Harrier and Yak-38 were designed for STOL or VTOL capability. In the early 1960s, it was decided that the Viggen should be a single seat aircraft. A digital central computer and a head-up display replaced the human navigator. This computer, called CK 37 (centralkalkylator 37), was the world's first airborne computer to use integrated circuits. It utilized the STRIL 60 system to be linked with the Swedish defence systems. The main sensor was an Ericsson PS 37 X-band monopulse radar with several functions: air-to-ground and air-to-air telemetry and cartography. A Honeywell radar altimeter with transmitter and receiver in the canard wings was used to assist low altitude flight. A Decca Type 72 doppler navigation radar and a series of other electronic sub-systems were also provided. A novel landing-aid device, the TILS (Tactical Instrument Landing System), made by Cutler-Hammer AIL, was used to improve landing accuracy down to 30 m from the threshold on the short highway airbase system. ECM consisted of a Satt Elektronik radar warning receiver system in the wings and the tail, an optional Ericsson Erijammer pod and BOZ-100 chaff/flare pod. In total, the electronics weighed 600 kg which was a substantial amount for a singleengine, late 1960s fighter. The SK 37 trainer omitted the radar and CK 37 navigational computer, navigating only using the Decca system and later DME. The radar warning receiver electronics were also removed. Initially, only a single reconnaissance (S) variant was considered, but fitting cameras as well as a radar proved to be impossible. The SH 37 maritime strike and reconnaissance variant was very similar to the AJ 37 and differed mainly in a maritime optimized PS 371/A radar with longer range and cockpit camera and tape recorder for mission analysis. "Red Baron" and LOROP camera pods were usually carried on the fuselage pylons. The centerline fuel tank was converted for a short period of time to a camera pod with two Recon/Optical CA mm cameras. In addition to the reconnaissance equipment, the SH 37 could also use all weapons for the AJ 37. For the photographic SF version, the radar in the nose was omitted in favour of one SKa mm, three SKa 24C 120 mm and two SKa mm photographic cameras as well as one VKa 702 Infrared linescan camera. The "Red Baron" and LOROP camera pods could also be carried on the fuselage pylons. The avionics suite of the JA was a major improvement over the other variants designed a decade earlier. The onboard computer was a Singer-Kearfott SKC-2037 built under license by Saab as CD 107, a Garrett AiResearch LD-5 air data computer (also used in the F-14 Tomcat), a Saab-Honeywell SA07 automatic flight control systems (which was the first digital variant to enter production) and a KTL-70L inertial navigation system. In the cockpit, several dial-indicator instruments were replaced by two CRT displays; one target indicator MI (sw: MålIndikator) in the center and one tactical moving- and rotating map indicator TI (sw: Taktisk Indikator) to the right while the head-up display SI (sw: SiktlinjesIndikator - line-of-sight indicator) was retained. The radar on the JA 37 was upgraded to a multi-mode, pulse-doppler Ericsson PS 46/A unit more optimized for the fighter/interceptor role. It sported lookdown/shootdown capability, range up to 48 km (30 mi), continuous-wave illumination for the Skyflash missiles as well as the ability to track two targets while scanning. The MTBF was reported as 100 hours, a very high reliability level for that generation of avionics systems. In 1992, an upgrade program of some of the AJ/SF/SH (with least hours on the airframe) to AJS/AJSF/AJSH was initiated because of delays of the new JAS 39 Gripen. The modifications were not too extensive and consisted to the major part of a new Ericsson computer processor system, MIL-STD-1553B databus and MIL-STD-1760 stores interface system to carry the Rb 15F anti-ship missile and DWS 39 Mjölner submunitions dispenser. An upgraded radar warning receiver system with recording capability as well as a Mission planning system via a portable cartridge were also implemented. The original PS 37/A radar from the AJ 37 was upgraded to the PS 371/A (from the SH 37) allowing the new AJS 37 to perform radar reconnaissance missions. No airframe- and very minor cockpit modifications were made. The JA 37 was continuously upgraded throughout its lifetime. In 1985, the "fighter link" went into service, permitting encrypted data communication between four fighters and ground radar based fighter command. This enabled one fighter to "paint" an airborne enemy with guidance radar for the Skyflash missiles of the three other fighters in a group while they had their search and guidance radar switched off. This system 53

54 was operational ten years before any other country's. The autopilot was also slaved to the radar control to obtain better precision firing the cannon. In 1990, the PS 46/A was upgraded with higher resistance to jamming and the ability to track several targets at the same time. In 1993, the ability to generate virtual targets in the radar reduced the cost of flying aggressors for training. Between 1992 and 1997, a major avionics upgrade program to the JA was implemented, given the new designation JA 37D. It consisted of an Ericsson CD207 mission computer, an ANP-37 stores management computer, linked via dual MIL-STD-1553B databuses permitting use of the Rb 99 AMRAAM. In the cockpit, a TI 327 color tactical moving-map display (originally intended for the Gripen) and a Synthetic Attitude Heading Reference System were installed. The ECM and ECCM suite were enhanced with improved electronics, upgraded radar warning receivers, a new Ericsson U95 jammer pod as well as the ability to carry BOY-401 chaff/flare dispensers on a separate location from the weapon pylons. Between 1998 and 2000, the conversion of ten Sk 37 trainers to Sk 37E electronic aggressors was completed. The fairly substantial upgrade package consisted of the nose-radome mounted G24 jammer inherited from the decommissioned J 32E Lansen, U22/A jammer- and KB chaff/flare pods and radar warning receivers from the AJS 37 and a new U95 jammer pod all linked together with the MIL-STD-1553B databus. The rear cockpit for the Electronic Warfare Officer was improved with new displays and controls while retaining the ability to convert back to the original flight training role. A weapons load of up to 7,000 kg could be accommodated on seven hardpoints; one centerline pylon, two fuselage pylons, two inner and two outer wing pylons. The centerline pylon was the only wet pylon and was usually occupied by an external fuel tank. The outboard wing pylons were never used in peacetime since aerodynamic flutter loads would structurally fatigue the wing. The AJ 37 was designed to carry two RB 04E anti-ship missiles on the inboard wing pylons with an optional third missile on the centerline pylon. An optional load consisted of two RB 05A air-to-surface missiles on the fuselage pylons. The RB 05A was later replaced by Rb 75 TV-guided missiles. In a ground-attack role, a combination of unguided 135 mm rockets in sextuple pods and 120 kg fragmentation bombs on quadruplemounts could be used. Self-defense was provided with either ECM or 30 mm ADEN cannon pods with 150 rounds of ammunition on the inboard wing pylons. Rockets had warheads of several types: the 50 mm M56GP 4 kg armour-piercing, the M56B with 6.9 kg of HE, and the M70 with a 4.7 kg HEAT warhead. For the secondary air-to-air role and self defence, the Rb 28 IR-missile was initially selected, but was never used due to poor performance. This left the outboard wing pylons unutilised as the Rb 28 was the only missile integrated there up until the AJS modernisation. Instead, Rb 24/Rb 24J were used on the fuselage pylons and inboard wing pylons or in combination with optional 30 mm underwing ADEN cannon pods. AJ 37 was under consideration as a carrier of both nuclear and chemical weapons, although no nuclear or chemical weapons were adopted by Sweden. The SH 37 was capable of carrying the same configuration of weapons as the AJ 37. However, since it was only used in the maritime role, only the RB 04E in combination with Rb 24/Rb 24J for self defense were employed. The chaff and jammer-pods was the most commonly used load. Both the SF and SK variants lacked the radar and could not carry the guided air-to-surface missiles as the AJ and SH. The SF could carry Rb 24/Rb 24J for self defense though. The unguided cannon and rocket pods were also an option. With the introduction of the JA 37 in 1979 came the Ericsson PS 46/A radar capable of guiding the two semi-active radar homing Rb 71 missiles on the fuselage pylons simultaneously in combination with Rb 24J/Rb 24J air-to-air missiles. Unlike the strike variant a KCA 30mm Oerlikon internal cannon was carried as well as 126 rounds, in a conformal pod under the fuselage. The firing rate was selectable at 22 or 11 rounds. The KCA cannon fired 50% heavier shells at higher velocity than the older ADENs, giving a much higher kinetic energy. This, in conjunction with the fire control system, allowed air-to-air engagements at longer range than other fighters. The unguided cannon and rocket pods were available in the secondary ground-attack role. The centerline pylon was almost exclusively carried a semi-permanent fuel tank, which was jettisonable in the event of a dogfight. In 1987, the more advanced all-aspect Rb 74 air-to-air missile was introduced for the JA 37. With the major upgrade of the JA to JA 37D in 1997 came the ability to carry four Rb 99 on the fuselage- and inner wing 54

55 pylons. In addition, a U95 ECM pod could now be carried under the right wing in place of an AMRAAM as well as chaff and flare dispensers on a pair of hitherto unused pylons just behind the main landing gear on each wing. With the extensive electronics upgrade of the old AJ/SF/SH in 1992 came the ability to carry the new Rb 74 on all weapons pylons. The AJS and AJSH also received the Rb 15F anti-ship missile and BK 90 stand-off cluster bomb originally intended for the delayed JAS 39 Gripen. One hundred and ten of the original, ground-attack optimized variant, AJ 37 were built, with the first operational squadron established in 1972 at F 7 Såtenäs. A two-seat trainer was not initially planned since it was considered that new pilots could get enough experience with delta-winged aircraft on the SK 35 Draken trainer. Eventually, however, 18 SK 37 two-seat trainers were ordered and delivered in To make room for the second cockpit, one fuel tank and some avionics were removed. The radar was also omitted limiting the weapons load to gun pods and unguided rockets. A total of 26 of the SH 37 maritime reconnaissance and strike variant were built in 1974, replacing the S 32C Lansen. Although fitted with radar and weaponry, the SH 37 Viggen could also undertake photographic missions with its single long-range camera, while external pods could carry a photographic day-set, a "Red Baron" IR set, an ELINT set, and AQ series ECM (made by SATT). A further 26 of the SF 37 reconnaissance variant were also delivered to replace the S 35 Draken in These were recognizable by having an elongated nose, equipped with six cameras and a VKa 702 infrared linescanner for night reconnaissance. Also, the "Red Baron" pod, with three IR cameras was widely used, as well as an ELINT set. Although the Viggen was offered for sale worldwide, and regarded as a very competent aircraft, no export sales occurred. Reasons to explain Saab's failure to sell a competitively priced, highly advanced and wellrespected aircraft include the Swedish government's relatively strict controls on arms exports to undemocratic countries, potential customers' doubts about continuity of support and supply of spare parts in the event of a conflict disapproved of by Sweden, and strong diplomatic pressure of larger nations. The United States blocked an export of Viggens to India in 1978 by not issuing an export license for the RM8/JT8D engine, forcing India to choose the SEPECAT Jaguar instead. The Viggen saw initial service in natural metal, later receiving an extremely elaborate disruptive camouflage scheme for the AJ/SF/SH/SK variants and the first 27 JA aircraft. The 28th JA was painted in a gray tone that turned out too close to white. All latter JA aircraft were painted in a darker light/dark gray, appropriate for a high altitude fighter. The final Viggen production variant was the JA 37 interceptor entering service in The last of 149 JA 37s was delivered in Differences from the previous models included an improved and more powerful RM8B engine, a new PS 46/A interception radar, new computers, HUD, ECM and some other subsystems. Unusually for a 1970s fighter, three multi-purpose CRT display screens were fitted within the cockpit, in a system called AP-12, that also included a new model of HUD. The new radar was compatible with the Skyflash medium-range missiles, for the first time in a Swedish fighter. Two Skyflash missiles could be carried under the wings on hardpoints, as well as four Sidewinder J or L models. Another improvement was the addition of an Oerlikon KCA 30 mm cannon mounted internally, with 126 rounds of 360 g ammunition. The structural strength was also improved, especially for the multi-sparred wings (initially Viggens had a high loss rate, with 21 aircraft lost in the early years). Various upgrades have been performed over the years, mainly to cockpit equipment, weapons and sensor fit. Between 1998 and 2000, ten SK 37 trainers were converted to SK 37E electronic warfare trainers to replace the aging J 32E Lansen. The SEPECAT Jaguar (fig. 58) is an Anglo-French jet ground attack aircraft, originally used by the British Royal Air Force and the French Armée de l'air in the close air support and nuclear strike role, and still in service with several export customers, notably the Indian Air Force and the Royal Air Force of Oman. Originally conceived in the 1960s as jet trainer with a light ground attack capability, the requirement for the aircraft soon changed to include supersonic performance, reconnaissance and tactical nuclear strike roles. A carrier-based variant was also planned for French service, but this was cancelled in favour of the cheaper Dassault Super Étendard. The airframes were manufactured by SEPECAT, a joint venture between Breguet and the British Aircraft Corporation, one of the first major joint-anglo-french military aircraft programs. The Jaguar was successfully exported to India, Oman, Ecuador and Nigeria. With various airforces, the Jaguar was used in numerous conflicts and military operations in Mauritania, Chad, Iraq, Bosnia, and Pakistan, as well as providing a ready nuclear delivery platform for Britain, France, and India throughout the latter half of the 55

56 Cold War and beyond. In the Gulf War, the Jaguar was praised for its reliability and was a valuable coalition resource. The aircraft served with the Armée de l'air as the main strike/attack aircraft until 1 July 2005, and with the Royal Air Force until the end of April It was replaced by the Panavia Tornado and the Eurofighter Typhoon in the RAF and the Dassault Rafale in the Armée de l'air. India plans in the long term to replace its Jaguar fleet with the developing Advanced Medium Combat Aircraft (AMCA). Fig. 58. The SEPECAT Jaguar. The T-45 Goshawk (fig. 59) is a highly modified version of the BAE Hawk land-based training jet aircraft. Manufactured by McDonnell Douglas (now Boeing) and British Aerospace (now BAE Systems), the T- 45 is used by the United States Navy as an aircraft carrier-capable trainer. Fig. 59. The T-45 Goshawk. The T-45 Goshawk is a fully carrier-capable version of the Hawk Mk.60. It was developed for the United States Navy (USN) and United States Marine Corps (USMC) jet flight training. The Goshawk's origins began in the mid-1970s, when the US Navy began looking for replacement for its T-2 and TA-4 trainers. The US Navy started the VTXTS advanced trainer program in British Aerospace and McDonnell Douglas proposed a version of the Hawk and were awarded the T-45 contract in The Hawk had not been designed for carrier operations and numerous modifications were required for Navy carrier use. These included improvements to the low-speed handling characteristics and a reduction in the approach speed. Other changes were strengthened airframe, more robust and wider landing gear with catapult tow bar attachment and an arresting hook. It features a two-wheel nose landing gear. The Goshawk first flew in 1988 and became operational in BAE Systems manufactures the fuselage aft of the cockpit, the air inlets, the vertical stabilizer of the T-45 at Samlesbury, and the wings at 56

57 Brough, England. Boeing, which merged with McDonnell Douglas in 1997, manufactures the remainder of the aircraft and assembles them in St. Louis, Missouri. On 16 March 2007 the 200th airframe was delivered to the US Navy. Their requirements call for 223 aircraft, and the T-45 is slated to continue in service until at least The T-45 has been used for intermediate and advanced portions of the Navy/Marine Corps Student Naval Aviator strike pilot training program with Training Air Wing One at Naval Air Station Meridian, Mississippi and Training Air Wing Two at Naval Air Station Kingsville, Texas. The T-45 replaced the T-2C Buckeye intermediate jet trainer and the TA-4J Skyhawk II advanced jet trainer with an integrated training system that includes the T-45 Goshawk aircraft, operational and instrument flight simulators (OFT/IFT), academics, and training integration system support. In 2008, the T-45C also began operation in the advanced portion of Navy/Marine Corps Student Naval Flight Officer (NFO) training with Training Air Wing Six at Naval Air Station Pensacola, Florida. The T-45's A and C models are currently in operational use. The T-45A, which became operational in 1991, contains an analog cockpit design while the newer T-45C, which was first delivered in December 1997, features a new digital "glass cockpit" design. All T-45A aircraft will eventually be converted to a T-45C configuration under the T-45 Required Avionics Modernization Program (T-45 RAMP). The Panavia Tornado (fig. 60) is a family of twin-engine, variable-sweep wing combat aircraft, which was jointly developed by the United Kingdom, West Germany and Italy. There are three primary versions of the Tornado; the Tornado IDS (interdictor/strike) fighter-bomber, the suppression of enemy air defences Tornado ECR (electronic combat/reconnaissance) and the Tornado ADV (air defence variant) interceptor. Developed and built by Panavia, a tri-national consortium consisting of British Aerospace (previously British Aircraft Corporation), MBB of West Germany, and Aeritalia of Italy, the Tornado first flew on 14 August 1974, and saw action with the Royal Air Force (RAF), Italian Air Force and Royal Saudi Air Force in the Gulf War. International co-operation continued after its entry into service within the Tri-National Tornado Training Establishment, a tri-nation training and evaluation unit operating from RAF Cottesmore, UK. Including all variants, 992 aircraft were built for the three partner nations and Saudi Arabia. Fig. 60. The Panavia Tornado. The Northrop/McDonnell Douglas YF-23 (fig. 61) was a prototype fighter aircraft designed for the United States Air Force. The YF-23 was a finalist in the U.S. Air Force's Advanced Tactical Fighter competition. Two YF-23s were built and were nicknamed "Black Widow II" and "Gray Ghost". The YF-23 lost the contest to the Lockheed YF-22, which entered production as the Lockheed Martin F-22 Raptor. Fig. 61. The Northrop/McDonnell Douglas YF-23 Black Widow II. 57

58 The YF-22 and YF-23 were competing in the USAF's Advanced Tactical Fighter (ATF) program, conceived in the early 1980s, to provide a replacement for the F-15 Eagle. Contracts for the two most promising designs were awarded in The YF-23 was designed to meet USAF requirements for survivability, supersonic cruise (supercruise), stealth, and ease of maintenance. Designed with all-aspect stealth as a high priority, Northrop drew on the company's experience with the B-2 Spirit and F/A-18 Hornet. The YF-23 was an unconventional-looking aircraft with trapezoidal wings, substantial area-ruling, and a V-tail. Similar to the B-2, the exhaust from the YF-23's engines flows through troughs lined with heat ablating tiles, which shields the exhaust from infrared (IR) missile detection from below. The vehicle management system coordinates movements of the control surfaces for maneuvers and for stable flight, along with other aircraft functions. The wing flaps and ailerons deflect inversely on either side to provide roll. Pitch was provided by movement of both V-tails, and yaw was supplied by opposite movement. Deflecting the wing flaps down and ailerons up on both sides simultaneously provided for aerodynamic braking. Although possessing an advanced design, in order to reduce costs and development, a number of F-15 Eagle components were utilized including the standard F-15 nose wheel unit and the forward cockpit of the F-15E Strike Eagle. Two aircraft were built. YF-23 I (PAV-1) was fitted with Pratt & Whitney YF119 engines, while YF-23 II (PAV-2) was fitted with General Electric YF120 engines. The YF-23 featured fixed nozzles. The first YF-23 was rolled out on 22 June 1990, and first flew on 27 August YF-23 II first flew on 26 October The black YF-23 (PAV-1) was nicknamed "Black Widow II", after the Northrop P-61 Black Widow of World War II and had a red hourglass marking resembling the underbelly marking of the black widow spider. The black widow marking was briefly seen under PAV-1 before being removed at the insistence of Northrop management. The gray colored YF-23 (PAV-2) was nicknamed "Gray Ghost". Both YF-23s were furnished in the configuration specified before the requirement for thrust reversing was dropped. The weapons bay was configured for weapons launch but no missiles were fired, unlike Lockheed's demonstration aircraft. The YF-23s flew 50 times for a total of 65.2 hours. The first YF-23 with P&W engines supercruised at Mach 1.43 on 18 September 1990 and the second YF-23 with GE engines reached Mach 1.6 on 29 November For comparison, the YF-22 achieved Mach 1.58 in supercruise. The flight testing demonstrated Northrop's predicted performance values for the YF-23. The YF-22 won the competition in April The YF-23 design was more stealthy and faster, but the YF-22 was more agile. It has been speculated in the aviation press that the YF-22 was also seen as more adaptable to the Navy's Navalized Advanced Tactical Fighter (NATF), though as it turned out the US Navy abandoned NATF a few months later. After losing the competition, both YF-23s were transferred to NASA's Dryden Flight Research Center, at Edwards AFB, California without the engines. NASA planned to use one of the aircraft to study strain gauge loads calibration techniques, but this did not occur. In late 2004, Northrop Grumman proposed a YF-23 based design for the USAF's interim bomber requirement, a role for which the FB-22 and B-1R are also competing. Aircraft PAV-2 was modified by Northrop as a full size model of its proposed interim bomber. The interim bomber requirement has since been canceled in favor of a more long-term, bomber replacement requirement. The same YF-23-derived design could possibly be adapted to fulfill this role as well. However, it appears the possibility of a YF-23-based interim bomber was ended with the 2006 Quadrennial Defense Review, in favor of a long range bomber with a much greater range. 58

59 Cap. 3. SHIPS STOVL ZEPPELINS A Zeppelin is a type of rigid airship pioneered by the German Count Ferdinand von Zeppelin in the early 20th century. It was based on designs he had outlined in 1874 and detailed in His plans were reviewed by committee in 1894 and patented in the United States on 14 March Given the outstanding success of the Zeppelin design, the term zeppelin in casual use came to refer to all rigid airships. Zeppelins were operated by the Deutsche Luftschiffahrts-AG (DELAG). DELAG, the first commercial airline, served scheduled flights before World War I. After the outbreak of war, the German military made extensive use of Zeppelins as bombers and scouts. The World War I defeat of Germany in 1918 halted the airship business temporarily. But under the guidance of Hugo Eckener, the deceased Count's successor, civilian zeppelins became popular in the 1920s. Their heyday was during the 1930s when the airships LZ 127 Graf Zeppelin and LZ 129 Hindenburg operated regular transatlantic flights from Germany to North America and Brazil. The Art Deco spire of the Empire State Building was originally if impractically designed to serve as a dirigible terminal for Zeppelins and other airships to dock. The Hindenburg disaster in 1937, along with political and economic issues, hastened the demise of the Zeppelin. The most important feature of Zeppelin's design (fig. 62) was a rigid metal alloy skeleton, made of rings and longitudinal girders. The advantage of this design was that the aircraft could be much larger than non-rigid airships (which relied on a slight overpressure within the single gasbag to maintain their shape). This enabled Zeppelins to lift heavier loads and be fitted with more and more powerful engines. The basic form of the first Zeppelins was a long cylinder with tapered ends and complex multi-plane fins. During World War I, as a result of improvements by the rival firm Schütte-Lanz Luftschiffbau, the design was changed to the more familiar streamlined shape and empennage of cruciform fins used by almost all airships ever since. Within this outer envelope, several separate balloons, also known as "cells" or "gasbags", contained the lighter-than-air gas hydrogen or helium. For most rigid airships the gasbags were made of many sheets of goldbeater's skin from the intestines of cows. About 200,000 were needed for a typical World War I Zeppelin. The sheets were joined together and folded into impermeable layers. Non-rigid airships do not have multiple gas cells. Fig. 62. Zeppelin's design. Forward thrust was provided by several internal combustion engines, mounted in nacelles (cowlings) connected to the skeleton. The R101 airship used diesel engines, which were then an untried technology for powering aircraft; they were unsuccessful. The Graf Zeppelin used spark-ignition engines, but fuelled with a natural gas called Blaugas, which was stored uncompressed. It was similar to propane and was named after its inventor rather than its colour (Blau is German for "blue"). The advantage of Blaugas for airships was that it weighed more or less the same as air and so as the fuel was used up, it did not affect the trim of the airship. Apart from the fins, zeppelins were also steered by adjusting and selectively reversing engine thrust. A comparatively small compartment for passengers and crew was built into the bottom of the frame, but in large Zeppelins this was not the entire habitable space; they often carried crew or cargo internally for aerodynamic reasons. Count Ferdinand von Zeppelin became interested in constructing a "Zeppelin balloon" after the Franco-Prussian War of , where he witnessed the French use of balloons to transport mail during the early part of the war. He had also encountered Union Army balloons in 1863, during the American Civil War, where he was a military observer. He first wrote of his dirigible interest in 1874 and began to seriously pursue his project after his early retirement from the military in 1890 at the age of

60 Convinced of the potential importance of aircraft designs, he started working on various designs shortly after leaving the military in He had already outlined an overall system in 1874, and detailed designs in 1893 that were reviewed by committee in 1894, and that he patented on 31 August 1895, with Theodor Kober producing the technical plans. After hearing about the rigid airship constructed by David Schwarz and witnessing its trial flight at the Tempelhof Airfield near Berlin on November 3, 1897, he proceeded to buy the patent rights from the widow of the prematurely deceased Schwarz, in order to allow Carl Berg to supply aluminium. However, Schwarz's design was "radically different from Zeppelin's" and in December 1897 Zeppelin admitted the Schwarz design could not be developed. Sean Dooley speculates on the indirect benefits Zeppelin gained from Carl Berg and Schwarz's work. In 1899, Zeppelin started constructing his first airship from his own designs. One unusual idea, which never saw service, was the ability to connect several independent airship elements like train wagons; indeed, the patent title called the design Lenkbarer Luftfahrzug (steerable air train). An expert committee to whom he had presented his plans in 1894 showed little interest, so the count was on his own in realizing his idea. In 1898 he founded the Gesellschaft zur Förderung der Luftschiffahrt (Society for the promotion of airship flight), contributing more than half of its 800,000 Mark share capital himself. He assigned the technical implementation to the engineer Theodor Kober and later to Ludwig Dürr. Construction of the first Zeppelin began in 1899 in a floating assembly hall on Lake Constance in the Bay of Manzell, Friedrichshafen. This location was intended to facilitate the difficult launching procedure, as the hall could easily be aligned with the wind. The prototype airship LZ 1 (LZ for Luftschiff Zeppelin, or "Airship Zeppelin") had a length of 128 metres (420 ft), was driven by two 14.2 horsepower (10.6 kw) Daimler engines and was controlled in pitch by moving a weight between its two nacelles. The first Zeppelin (fig. 63) flight occurred on 2 July 1900 over Lake Constance (the Bodensee). It lasted only 18 minutes before LZ 1 was forced to land on the lake after the winding mechanism for the balancing weight failed. After it was placed back in the hangar an apparatus used to suspend it broke. Upon repair, rigid airship technology proved its potential in subsequent flights (the second and third flights were on 17 October 1900 and 24 October 1900) beating the 6 m/s velocity record of the French airship La France by 3 m/s. Despite this performance, the shareholders declined to invest more money, and so the company was liquidated, with Count von Zeppelin purchasing the ship and equipment. The Count wished to continue experimenting, but he eventually dismantled the ship in It was largely due to support by aviation enthusiasts that von Zeppelin's idea got a second (and third) chance and would be developed into a reasonably reliable technology. Only then could the airships be profitably used for civilian aviation and sold to the military. Fig. 63. First Zeppelin. 60

61 Donations, the profits of a special lottery, some public funding, a mortgage of Count von Zeppelin's wife's estate and a 100,000 Mark contribution by Count von Zeppelin himself allowed the construction of LZ 2, which took off for the only time on 17 January After both engines failed, it made a forced landing in the Allgäu mountains, where the anchored ship was subsequently damaged beyond repair by a storm. Incorporating all usable parts of LZ 2, the successor LZ 3 became the first truly successful Zeppelin, which by 1908 had travelled a total of 4,398 kilometres (2,733 mi) in the course of 45 flights. The technology then interested the German military, who bought LZ 3 and redesignated it Z 1. She served as a school ship until 1913, when she was decommissioned as obsolescent. The army was also willing to buy LZ 4, but requested a demonstration of her ability to make a 24-hour trip. While attempting to fulfill this requirement, the crew of LZ 4 had to make an intermediate landing in Echterdingen near Stuttgart. During the stop, a storm tore the airship away from its anchorage in the afternoon of 5 August She crashed into a tree, caught fire, and quickly burnt out. No one was seriously injured, although two technicians repairing the engines escaped only by making a hazardous jump. This accident would have certainly knocked out the Zeppelin project economically had not one of the spectators in the crowd spontaneously initiated a collection of donations, yielding an impressive total of 6,096,555 Mark. This enabled the Count to found the Luftschiffbau Zeppelin GmbH (Airship Construction Zeppelin Ltd.) and a Zeppelin Foundation. Before World War I, a total of 21 Zeppelin airships (LZ 5 to LZ 25) were manufactured. In 1909 LZ 6 became the first Zeppelin used for commercial passenger transport. The world's first airline, the newly founded DELAG, bought seven Zeppelins by The airships were given names in addition to their production numbers, four of which were LZ 8 Deutschland II (1911), LZ 11 Viktoria Luise (1912), LZ 13 Hansa (1912) and LZ 17 Sachsen (1913). Seven of the twenty-seven were destroyed in accidents, mostly while being moved into their halls. There were no casualties. One of them was LZ 7 Deutschland which made its maiden voyage on 19 June On 28 June it began a pleasure trip to make Zeppelins more popular. Among those aboard were 19 journalists, two of whom were reporters of well known British newspapers. LZ 7 crashed in bad weather at Mount Limberg near Bad Iburg in Lower Saxony, its hull getting stuck in trees. The crew then let down a ladder to allow all the passengers to leave the ship. One crew member was slightly injured on leaving the craft. All together, the several airships[clarification needed] traveled approximately 200,000 kilometres (120,000 mi) and transported about 40,000 passengers. The German Army and Navy purchased 14 Zeppelins, who labeled their airships Z 1/2/... and L 1/2/..., respectively. During the war, the Army changed their scheme twice: following Z XII, they switched to using LZ numbers, later adding 30 to obscure the total production. When World War I broke out, the military also took over the three remaining DELAG ships. By this time, it had already decommissioned three other Zeppelins (LZ 3 "Z 1" included). Before the war the Army had lost three zeppelins to accidents, in which two people had died. The Navy lost two, both in 1913: a storm forced Navy Zeppelin LZ 14 or "L 1" down into the North Sea, drowning 14; LZ 18 or "L 2" burst into flames following an engine explosion, killing the entire crew. These accidents deprived the Navy of a large number of experienced personnel. By 1914, state-of-the-art Zeppelins had lengths of 150 to 160 metres (490 to 520 ft) and volumes of 22,000 25,000 m3, enabling them to carry loads of around 9,000 kilograms (20,000 lb). They were typically powered by three Maybach engines of around 140 to 210 horsepower (100 to 160 kw) each, reaching speeds of up to 80 kilometres per hour (50 mph). The German airships were operated by both the Army and Navy as two entirely separate divisions. Over the course of World War I, the Zeppelins were mainly used in reconnaissance missions for the Navy. Bombing missions, especially those targeting London, captured the public's imagination, but in the end proved to have only psychological value, and were not a military success. These were executed by both Navy and Army aircraft. The main use of the craft was in reconnaissance over the North Sea and the Baltic, where the endurance of the craft led German warships to a number of Allied vessels. Zeppelin patrolling had priority over any other airship activity. The majority of airships manufactured were commissioned by the Navy. During the war almost 1,000 patrols were made over the North Sea alone, compared to about 50 strategic bombing raids. The German Navy had some 15 Zeppelins in commission in 1915 and was able to have two or more patrolling continuously at any one time, almost regardless of weather. They prevented British ships from approaching Germany, spotted when and where the British were laying mines and later aided in the destruction of those mines. Zeppelins would sometimes land on the sea next to a minesweeper, bring aboard an officer and show him the mines' locations. Before the widespread availability of incendiary ammunition made commerce raiding too risky, they would also 61

62 land or hover close to a merchant ship suspected of carrying contraband, order all ship's hands to leave in boats, then inspect the ship, and either destroy it or take it back to Germany as a prize. At the beginning of the conflict the German command had high hopes for the aircraft, which were almighty comparing to the contemporary light fixed-wing machines they were almost as fast, could carry machine guns (even multiple ones), had a greater bomb-load and enormously greater range and endurance. Contrary to the previous beliefs, it was not easy to ignite the hydrogen using standard bullets and shrapnels. Later in the war, only with the invention of incendiary ammunition Allies started to exploit the Zeppelin's great weakness of flammability. At the beginning of the war, Captain Ernst A. Lehmann and Baron Gemmingen, Count Zeppelin's nephew, developed an observation car for use by Zeppelin dirigibles. The car was equipped with a wicker chair, chart table, electric lamp, compass, telephone, and a lightning conductor. With the Zeppelin sometimes within, sometimes above the clouds and unable to see the ground, the observer in the hanging basket would relay orders on navigation and when and which bombs to drop. Defenders could hear the engines but their searchlights and artillery fire could not reach the airship. The LZ26's basket was lowered from the airship on a specially constructed tether 1000 metres long; other airships may have used one approximately 750 metres long. The tether was high-grade steel with a brass core insulated with rubber to act as the telephone cable. From 1915, a number of Zeppelin raids was conducted. The majority were against Britain, leading the way in bombing techniques and also forcing the British military to bolster its air defences. The possibility of airship raids was approved by the Kaiser on 19 January 1915, although he excluded London as a target and further demanded that no attacks be made on historic, government buildings, or museums. The night-time raids were intended to target only military sites on the east coast and around the Thames estuary, but after blackouts became widespread, many bombs fell at random on East Anglia. The first attack was planned for 13 January Four Zeppelins were launched but bad weather forced all the craft to abandon the raid. The first successful raid was on the night of January 19 20, 1915, in which two Zeppelins, L.3 and L.4, were directed towards the Humber but, diverted by strong winds, dropped twenty-four 50 kg high explosive bombs and ineffective 3 kg incendiaries on Great Yarmouth, Sheringham, King's Lynn and the surrounding villages. In all 4 people were killed and 16 were injured. Monetary damage was estimated at 7,740. The Kaiser allowed the bombing of London docks from February 1915, but no raids took place on London until May. The first two London raids failed owing to poor weather L.8 crashed near Ghent on 26 February and a four airship raid by the Army ran into fog on 17 March and was abandoned. One Army airship was damaged on landing and three more were lost in the next few weeks. With two Navy raids failing due to bad weather on 14 April and 15, it was decided to hold off further action until the more capable P-class Zeppelins were in service. The Army received its P-class Zeppelins first and undertook the first raids. Erich Linnarz commanded LZ.38 on a raid over Ipswich on April and again on May 9 10, attacking Southend; it also attacked Dover and Ramsgate on May 16 17, before returning to bomb Southend on May These four raids killed 6 people and injured 6, causing property damage estimated at 17,000. Twice Royal Naval Air Service (RNAS) aircraft tried to intercept LZ 38 but on both occasions the zeppelin was either able to outclimb the aircraft or was already at too great an altitude for the aircraft to intercept the BE2 took some fifty minutes to climb to 10,000 feet (3,000 m). The Kaiser extended the, so far theoretical, ambit of the London raids in May 1915, allowing attacks anywhere east of the Tower of London. On 31 May Captain Linnarz again commanded LZ.38 on the first London raid; LZ.37 was also to be part of the raid but suffered structural damage early on and returned to Namur. Flying from Evere LZ.38 crossed the English coast near Margate at 21:42 before turning west once over Southend. London police were warned of an incoming raid around 23:00; a few minutes later small incendiaries began to fall. The devices were a simple metal canister filed with a mix of thermite, tar, and benzol; the exterior was wrapped in tarred rope and a simple fuse was fitted. The first device fell on a house at 16 Alkham Road, others were scattered around residential streets as the Zeppelin flew south over Stoke Newington and then Hoxton. Two incendiaries fell on Shoreditch Empire Music Hall and as LZ.38 turned southeast explosive bombs were dropped on Spitalfields and a whiskey distillery in Commercial Road. Turning northeast the remaining load was dropped on Stepney, Stratford and finally, around 23:30, five bombs fell on Leytonstone. LZ.38 then headed back towards Southend, crossing the coast near Foulness. In total some 120 devices were dropped, totalling 3,000 pounds (1,400 kg), including 91 incendiaries, 28 bombs and two 'grenades'. 7 people were killed, 35 were injured; forty-one fires were started, burning out seven properties, damage was priced at 18,596. The RNAS had fifteen aircraft in the air, but only one even sighted the Zeppelin; no ground-based 62

63 guns fired and no searchlights found the airship. This marked failure by the capital's defences led to the British government implementing strong press restrictions on the reporting of air-raids. The Naval airships also tried to raid London. L.10 attempted to reach the city on 4 June, strong winds led the commander to misjudge his position and the bombs were dropped on Gravesend. L.9 was also diverted by the weather on June 6 7, attacking Hull instead of London and causing considerable damage. On the same night an Army raid of three Zeppelins also failed because of the weather; in an added blow, as the craft returned to Evere they coincided with a pre-planned raid by RNAS aircraft flying from Furnes, France. LZ.38 was destroyed on the ground while LZ.37 was intercepted in the air by R. A. J. Warneford in his Morane Parasol, he dropped six 20 pounds (9.1 kg) Hales bombs on the zeppelin which caught fire and crashed into the convent school of Sint-Amandsberg. Two nuns were killed and the entire crew of the Zeppelin also died except for one man. Flight S/L Warneford was awarded the Victoria Cross for his achievement. As a further consequence of the raid both the Army and Navy withdrew from all bases in Belgium; the vulnerability of such sites was now clear. The short summer nights discouraged further raids for some months, after an ineffective attack by L.10 on Tyneside on June In the same period the remaining Army Zeppelins were re-assigned to the Russian Front. The Navy returned to raids on Britain in August. On August 9 10 four Zeppelins were directed against London; none reached their target and one, L.12, was damaged by ground fire while near Dover and ditched into the sea off Zeebrugge. Despite eight attacks by RNAS aircraft the craft was towed into Ostend where it was abandoned and later dismantled. The four-zeppelin raid was repeated on August 12 13; again only one craft made landfall, L.10 dropped its bombs on Harwich. A third four-zeppelin raid again tried to reach London on August 17 18, two turned back with mechanical problems, one bombed Ashford, Kent on 10 August in the belief it was Woolwich, but L.10 became the first Navy airship to reach London. L.10 was also misnavigated, mistaking the reservoirs of the Lea Valley for the Thames, and consequently dropping the bombs on Walthamstow and Leytonstone. 10 people were killed, 48 injured, property damage was estimated at 30,750 by the London Fire Brigade. A number of guns fired at L.10 and a few aircraft were launched (two Caudron G.3s crashed on landing after their search), but the Zeppelin suffered no damage in the raid (L.10 was destroyed a little over two weeks later in a thunderstorm over the North Sea; it crashed off Cuxhaven and the whole crew was killed). Two Army Zeppelins successfully bombed London on September 7 8, SL.2 dropped bombs on the Isle of Dogs, Deptford, Greenwich and Woolwich. LZ.74 was forced to drop weight on its approach and scattered 39 bombs over Cheshunt, before heading on to London and dropped devices on Bermondsey, Rotherhithe and New Cross. 18 people were killed and 28 injured, property damage totalled 9,616. Fog and mist prevented any aircraft being launched but a number of anti-aircraft guns fired at LZ.74 with no effect. The Navy attempted to follow up the Army's success the following night. Three Zeppelins were directed against London and one against an ironworks at Skinningrove. L.11 turned back early with engine trouble; L.14 suffered the same problem while over Norfolk, its bombs were dropped on East Dereham and the Zeppelin returned home. L.13 reached London, approaching over Golders Green, Kapitänleutnant Heinrich Mathy began bombing around 22:40. Amongst the bomb-load was a 300 kilograms (660 lb) device, the largest yet carried by a significant margin. It exploded on Bartholomew Close, did much property damage, gouged a crater eight feet deep and killed two men. The Zeppelin was repeatedly caught by searchlights and all twelve anti-aircraft emplacements in London were active but every shell exploded too low and the falling shrapnel caused both damage and alarm on the ground. Three aircraft were in the air. None even saw the Zeppelin; one crashed on landing killing the pilot. The raid took 22 lives and injured 87. The wavering line of destruction through central London caused damage estimated at 530,787. After three more raids were scattered by the weather a five-zeppelin raid was launched by the Navy on 13 October, the "Theatreland Raid." Arriving over the Norfolk coast around 18:30 the Zeppelins encountered new ground defences installed since the September raid under the guidance of Sir Percy Scott. These new gun sites proved ineffectual. Indeed a 13-pounder near Broxbourne was actually put out of action by three bombs dropped from L.15. L.15 continued on to London and began bombing over Charing Cross, the first bombs striking the Lyceum Theatre and the corner of Exeter and Wellington Streets, killing 17 and injuring 20. Further bombs were dropped on Holborn, as the airship neared Moorgate it was engaged by a new 75 mm gun sited at the Honourable Artillery Company. L.15 quickly recognised this new threat and dumped ballast, dropped only three more bombs (one landing on Aldgate High Street causing much damage) before departing, having suffered some engine damage from the shells. L.13 dropped its bombs around Guildford and later near Woolwich. L.14 dropped bombs on Otterpool Army Camp, killing 14 soldiers and injuring 12, and later bombed Tonbridge and East Croydon, on its return path it almost collided with L.13 over Bromley. Both the other Zeppelins, L.16 and L.11, were even further off course, L.16 dropped up to fifty bombs on Hertford and L.11 scattered a few bombs 63

64 over Norfolk before heading home. In total 71 people were killed and 128 injured. This was the last raid of 1915, as bad weather coincided with the new moon in both November and December 1915, and continued into January There were twenty raids in 1915, in which 37 tons of bombs were dropped, killing 181 people and injuring 455. Italy was the only country other than Germany to use lighter-than-air craft for bombing purposes, against tagets in the Austro-Hungarian Empire. Italian airships were "semi-rigid dirigibles," they were different from the "rigid" Zeppelins in that they had a keel only, as opposed to the entire frame favoured by the Germans. Their first bombing raid was on 26 May 1915, three days after entering the war, when they crossed the Adriatic to attack Sebenico, which was attacked by a dirigible again the following day. On 8 June 1915, the Città di Ferrara took off from an airfield in Pordenone to bomb the Whitehead torpedo factory and the oil refinery at Fiume (later Rijeka, Croatia), killing one civilian, injuring several other people, but only causing slight damage. After Città di Ferrara turned for home, it was intercepted and shot down by a Lohner L flying boat (pennant number L-48) of the Austro-Hungarian Navy, over Kvarner Gulf, near the island of Lussino. This was the first time that an airship had been destroyed in air combat. British ground defences were divided between the Royal Navy and the British Army at first, before the Army took full control in February 1916, and a variety of sub 4-inch (less than 102 mm) calibre guns were converted to anti-aircraft use. Searchlights were introduced, initially manned by police, whose inexperience led to a number of illuminated clouds being mistaken for attacking airships. In January 1916 a set of two defensive rings was proposed for London with 490 guns and 490 searchlights divided between them. This grand scheme was soon reduced, and by mid-1916 there were nationally 271 anti-aircraft guns and 258 searchlights. Aerial defences against Zeppelins were haphazard, and divided between the RNAS and the Royal Flying Corps (RFC), with the Navy engaging enemy craft approaching the coast while the RFC took responsibility once the enemy had crossed the coastline. The lack of an interrupter gear in early fighters meant the basic technique of downing them was to drop bombs on them (a technique which was to resurface in World War II). Initially the War Office also believed that the Zeppelins used a layer of inert gas to protect themselves from incendiary bullets, and discouraged the use of such ammunition in favour of bombs. The initial trials of incendiary bullets in mid-1915 were unimpressive. Incendiary ammunition also underwent several separate development tracks. The first bullet was designed by John Pomery, but by mid-1916 the RFC also had Brock, Buckingham and 'Sparklet' incendiary cartridges. Ten 'home defence' squadrons were organised from February 1916, with London's defences assigned to No. 19 RAS at Sutton's Farm and Hainault Farm (renamed No. 39 (Home Defence) Squadron in April 1916, who were also allocated North Weald Bassett airfield in August 1916). The actual number of aircraft varied: in February there were only eight squadrons and less than half the number of aircraft expected, and by June the number of squadrons had been cut to six and only No. 39 Squadron was at full strength and equipped with newer aircraft BE12s with interrupter gear and Lewis guns firing a mix of explosive, incendiary and tracer rounds. Raids continued in In December 1915 new Q-class airships were delivered to both the German Army and Navy as well as additional P-class Zeppelins. The Q-class simply added two more gas cells to the P- class, lengthening the craft to 585 feet (178 m), adding 100,000 cubic feet (2,800 m3) of gas, and improving both ceiling and bomb-load. The first raid of 1916 was organised by the Navy. Nine Zeppelins were sent to Liverpool over the night of 31 January 1 February. A combination of poor weather, difficult navigation and mechanical problems scattered the aircraft across the English Midlands and several towns were bombed. A total of 61 people were reported killed and 101 injured by the raid. Despite ground fog, twenty-two aircraft were launched to find the Zeppelins but none succeeded. In attempting to land in the poor conditions, sixteen aircraft suffered various degrees of damage and two pilots were killed. One airship, the L.19, crashed in the North Sea because of engine failure and damage from Dutch ground fire; all 16 crew were lost. Further raids were curtailed by an extended period of poor weather and also by the withdrawal of the majority of Naval Zeppelins in an attempt to identify and remove the recurrent mechanical failures. Three P-class Zeppelins did attack Hull on March 5 6, causing significant property damage. On July the first 'Super Zeppelin', the 650 ft M-class L.31, appeared in English skies. Powered by six engines and capable of operating at 13,000 ft (4,000 m), (with another 5,000 ft (1,500 m) to its maximum ceiling), while carrying up to four tonnes of bombs. Part of a ten-zeppelin raid that achieved very little, four returned home early and the rest wandered over a fog-shrouded landscape before giving up. Adverse weather dispersed the next raid on July and again on August 2 3. On August 8 9 two M-class Zeppelins were part of a nine craft raid that did much damage to Hull. The sixth successful London raid was on August 24 25, 64

65 thirteen Navy Zeppelins were launched and Heinrich Mathy's L.31 reached London, flying above low cloud, thirty-six bombs were dropped in ten minutes on West Ferry Road, Deptford Dry Dock, the station at Norway Street and homes in Greenwich, Eltham and Plumstead. 9 people were killed, 40 injured and 130,000 of damage was caused. L.31 suffered no damage in the attack but several weeks of repair-work was needed following a rough landing. The biggest raid so far was launched on September 2 3, twelve Navy craft and four Zeppelins from the Army took part. A combination of rain and snowstorms scattered the craft while they were still over the North Sea. None of the Naval craft reached London. Only the Army's LZ.98 and the newly commissioned SL.11 achieved their objective. SL.11 came in over Foulness with the intention of looping around and attacking the capital from the north-west. The craft dropped a few bombs over London Colney and South Mimms. At about 01:50 it was picked up by a searchlight over Hornsey and subjected to an intense but ineffective barrage. Sl.11 was lost in cloud over Wood Green but rediscovered by the searchlights at Waltham Abbey as it bombed Ponders End. At around 02:15 one of the three aircraft in the sky that night finally came into range a BE2c piloted by Lt. William Leefe Robinson flying from Suttons Farm. Robinson fired three drums of ammunition from his Lewis gun, one on each of three passes. After emptying the third drum the airship began burning from the stern and was quickly enveloped in flames. It fell to the ground near Cuffley. There were no survivors. Four Naval Zeppelins which had regrouped over Hertfordshire saw the fate of SL.11 and quietly slipped away. For the first Zeppelin downed on British soil and the first 'night fighter' victory Leefe Robinson received the Victoria Cross. The pieces of SL.11 were gathered up and sold by the Red Cross to raise money for wounded soldiers. The loss of SL.11 ended the Army's interest in raids on Britain. The Navy remained aggressive and a twelve Zeppelin raid was launched on September 23 24, eight older craft bombing targets in the Midlands and four M-class Zeppelins (L.30, L.31, L.32, and L.33) attacking London. L.30 did not even cross the coast, dropping its bombs at sea. L.31 approached London from the south, dropped a few bombs on Kenley and Mitcham and was picked up by a number of searchlights. Forty-one devices were then dropped in rapid succession over Streatham, killing 7 and wounding 27. More bombs were dropped on Brixton before crossing the river and dropping ten bombs on Leyton, killing another 8 people and injuring 30. L.31 then headed home. Also coming in from the south was L.32, running late due to engine problems, it dropped a few bombs on Sevenoaks and Swanley before crossing Purfleet at about 01:00. The Zeppelin then came under anti-aircraft fire as it dropped bombs on Aveley and South Ockendon. Shortly thereafter, at 01:10, a BE2c piloted by 2nd Lieutenant Frederick Sowrey engaged L.32. He fired three drums of incendiaries and succeeded in starting a blaze which quickly covered the entire craft. The Zeppelin crashed to earth at Snail's Hall Farm, Great Burstead. The entire crew was killed, with some, including the commander Oberleutnant-zur-See Werner Peterson, chosing to jump rather than burn. L.33 dropped a few incendiaries over Upminster before losing its way and making a number of turns, heading over London and dropping bombs on Bromley at around midnight. As the bombs began to explode, the Zeppelin was hit by an anti-aircraft shell fired from the guns at either Beckton, Wanstead, or Victoria Park despite being at 13,000 feet (4,000 m). Dropping bombs now to shed weight, a large number fell on homes in Botolph Road and Bow Road. As the craft headed towards Chelmsford it continued to lose height, coming under fire at Kelvedon Hatch and briefly exchanging fire with a BE2c. Despite the efforts of the crew, L.33 was forced to the ground at around 01:15 in a field close to New Hall Cottages, Little Wigborough. The Zeppelin was set alight and the crew headed south before being arrested at Peldon by the police. A close inspection of the wreckage enabled the British to understand where their own rigid airship designs had been deficient. Furthermore, one 250 hp (190 kw) engine recovered from the wreck subsequently substituted for two (of four) 180 hp (130 kw) engines on a Vickers-built machine, the hitherto underpowered R.9. The next raid came on 1 October Eleven Zeppelins were launched at targets in the Midlands and at London. As usual weather played a major role and only L.31 under the experienced Heinrich Mathy, on his fifteenth raid, reached London. Approaching from Suffolk, L.31 was picked up by the searchlights at Kelvedon Hatch around 21:45; turning away, the craft detoured over Harlow, Stevenage and Hatfield before cutting its engines and drifting with the wind over Hertford. As the airship neared Cheshunt at about 23:20 the engines were restarted and the craft was quickly picked up by six searchlights. Three aircraft of No. 39 Squadron were in the air and closed on L.31. Mathy ordered the dumping of bombs, (fifty fell on Cheshunt), in order to gain altitude. A BE2c piloted by 2nd lieutenant Wulstan Tempest engaged the Zeppelin around 23:50; three bursts were sufficient to set L.31 ablaze and it crashed near Potters Bar with all nineteen crew dying although again many decided to jump rather than burn (including Mathy, whose body was found near the wreckage, embedded some four inches in the softened earth). Tempest had had to dive out of the way of the stricken craft and, overwrought, had crashed on landing, suffering minor injuries. 65

66 With the next raid on November 27 28, the Zeppelins avoided London for targets in the Midlands. But again the aircraft and the incendiary bullet proved lethal L.34 was shot down over the mouth of the Tees and L.21 was attacked by two aircraft and crashed into the sea off Lowestoft. There were no further raids in 1916 although the Navy lost three more craft, all on 28 December SL.12 was destroyed at Ahlhorn by strong winds after sustaining damage on a poor landing, and at Tondern L.24 crashed into the shed while landing and the resulting fire destroyed both L.24 and the adjacent L.17. There were 23 airship raids in 1916 in which 125 tons of ordnance were dropped, killing 293 people and injuring 691. Anti-aircraft defences were becoming tougher and new Zeppelins were introduced with an increased operating altitude of 16,500 feet (5,000 m) and a maximum ceiling of 21,000 feet (6,400 m). The first S-class Zeppelins entered service in February They were largely a modification of the M-class, sacrificing weight for improved altitude. The surviving M-class Zeppelins were converted to S-class, notably by reducing the number of engines from six to five. To avoid searchlights, they flew above the clouds whenever possible, lowering an observer through them in a Spähkorb (observation gondola) to direct the bombing. The improved safety was counteracted by the extra strain on the airship crews who became more prone to altitude sickness and exposure to extreme cold and high altitude winds. The first raid of 1917 did not occur until March and the five high flying Zeppelins encountered very strong winds and none reached their targets. This experience was repeated on May Two days later twenty-one Gotha bombers attempted a daylight raid on London. They were halted by heavy cloud but the effort led the Kaiser to announce that airship raids on London were past; under pressure he later relented to allow Zeppelin attacks to continue under "favourable circumstances". On June another Zeppelin raid was attempted, only two out of six Zeppelins reached England in the face of strong winds. L.42 bombed Ramsgate, hitting a munitions store. The month-old L.48, commanded by Korvettenkapitän Franz Eichler, but with Korvettenkapitän Viktor Schutze also on board, suffered from both engine problems and compass malfunction. It was forced to drop to 13,000 feet (4,000 m) where it was caught by four aircraft and destroyed, crashing near Theberton, Suffolk. This was the last Zeppelin raid to explicitly target London. After ineffectual raids on the Midlands and other targets in the north of England on August and September the last major Zeppelin raid was launched on October with thirteen airships headed for Sheffield, Manchester and Liverpool. Two Zeppelins did not launch and the remainder quickly found themselves badly affected by powerful headwinds which made navigation extremely difficult. L.45 was trying to reach Sheffield, instead it dropped bombs on Northampton and London. Undetected and with no warning its bombs did great damage the first few fell on Hendon Aerodrome but the rest, dropped at random from 16,000 feet (4,900 m), struck in Piccadilly, Camberwell and Hither Green. L.45 then reduced altitude to try and escape the winds but was forced back into the higher air currents by a BE2e. The craft then had mechanical failure in three engines and was pushed by the wind out over France, eventually coming down near Sisteron; it was set ablaze and the crew surrendered. L.44, L.49, and L.50 were also lost to anti-aircraft fire or the weather over France. L.55 was badly damaged on landing and later scrapped. There were no more raids in 1917, although the airships were not abandoned but refitted with new, more powerful engines. There were only four raids in 1918, all against targets in the Midlands and northern England. The final raid on 5 August 1918 resulted in the loss of L.70 and the death of its entire crew under the command of Frigattenkapitän Peter Strasser, head of the Imperial German Naval Airship Service and the Führer der Luftschiffe. Crossing the North Sea during daylight, the airship was intercepted by a Royal Air Force DH.4 biplane piloted by Major Egbert Cadbury, and shot down in flames. On 5 January 1918 a fire at Ahlhorn destroyed four of the specialised double sheds along with four Zeppelins and one Schütte-Lanz. The British had begun bombing the Zeppelin production lines and their sheds in Cologne and Düsseldorf as early as September/October This was followed by the Cuxhaven Raid, which included Zeppelins as its targets, on Christmas Day In July 1918, the Tondern Raid conducted by the RNAS, destroyed two Zeppelins in their sheds. In 1917, the German High Command made an attempt to deliver much needed supplies using a dirigible to Lettow-Vorbeck's East African Campaign in German East Africa. L.59 Zeppelin travelled over 6,400 km (4,000 miles) in 95 hours, but in the end failed to deliver the supplies. The craft had been purpose-built and was intended to be broken up and used on arrival. It never attempted the mission again, and was converted into a bomber. 66

67 Strategic issues aside, Zeppelin technology improved considerably as a result of the increasing demands of warfare. The pre-war M-class designs were quickly enlarged, first to the 530 feet (160 m) long duralumin P-class, which increased gas capacity from 880,000 cubic feet (25,000 m3) to 1,130,000 cubic feet (32,000 m3), introduced a fully enclosed gondola, and extra engines. these modifications added 2,000 feet (610 m) to the maximum ceiling, over 10 mph to the top speed, and greatly increased crew comfort and hence endurance. Twenty-two P-class craft were ordered and the first, LZ.38, was delivered to the Army on 3 April In 1916 the Zeppelin Company, having spawned several dependencies around Germany with shipyards closer to the fronts than Friedrichshafen, delivered airships of around 200 m (660 ft) in length (some even more) and with volumes of 56,000 69,000 m3. These M-class dirigibles could carry loads of 3 4 tons of bombs and reach speeds of up to 100 to 130 kilometres per hour (62 to 81 mph) using six Maybach engines of 260 hp (190 kw) each. To avoid enemy defences such as British aircraft, guns and searchlights, Zeppelins became capable of much higher altitudes (up to 7,600 metres (24,900 ft)) and they also proved capable of long-range flights. For example, LZ.104 L.59, based in Yambol, Bulgaria, was sent to reinforce troops in German East Africa (today Tanzania) in November The ship did not arrive in time and had to return following reports of a German defeat by British troops, but it had traveled 6,757 kilometres (4,199 mi) in 95 hours and thus had broken a longdistance flight record. A considerable, frequently overlooked, contribution to these technological advancements originated from Zeppelin's only serious competitor, the Mannheim-based Schütte-Lanz airship construction company. While their dirigibles never became comparably successful, Professor Schütte's more scientific approach to airship design led to a number of important innovations copied, over time, by the Zeppelin company. These included the streamlined hull shape, the simple yet functional cruciform fins (replacing the more complicated box-like arrangements of older Zeppelins), individual direct-drive engine cars, anti-aircraft machine-gun positions, and gas ventilation shafts which removed excess hydrogen. The German defeat in the war also marked the end of German military dirigibles, as the victorious Allies demanded a complete disarmament of German air forces and delivery of the remaining airships as reparations. Specifically, the Treaty of Versailles contained the following articles dealing explicitly with dirigibles: be kept. Article 198 The armed forces of Germany must not include any military or naval air forces. [...] No dirigible shall Article 202 On the coming into force of the present Treaty, all military and naval aeronautical material [...] must be delivered to the Governments of the Principal Allied and Associated Powers. [...] In particular, this material will include all items under the following heads which are or have been in use or were designed for warlike purposes: [...] Dirigibles able to take to the air, being manufactured, repaired or assembled. Plant for the manufacture of hydrogen. Dirigible sheds and shelters of every kind for aircraft. Pending their delivery, dirigibles will, at the expense of Germany, be maintained inflated with hydrogen; the plant for the manufacture of hydrogen, as well as the sheds for dirigibles may at the discretion of the said Powers, be left to Germany until the time when the dirigibles are handed over. [...] On 23 June 1919, a week before the treaty was signed, many war Zeppelin crews destroyed their airships in their halls in order to avoid delivery. In doing so, they followed the example of the German fleet which had been scuttled two days before in Scapa Flow. The remaining dirigibles were transferred to France, Italy, Britain, and Belgium in A total of 84 Zeppelins were built during the war. Over 60 were lost, roughly evenly divided between accident and enemy action. 51 raids had been undertaken, in which 5,806 bombs were dropped, killing 557 people and injuring 1,358 while causing damaged estimated at 1.5 million. It has been argued the raids were effective far beyond material damage in diverting and hampering wartime production, one estimate was that the 67

68 due to the raids "one sixth of the total normal output of munitions was entirely lost," and diverting 12 fighter squadrons and over 10,000 personnel to air defences. Count von Zeppelin had died in 1917, before the end of the war. Dr. Hugo Eckener, a man who had long envisioned dirigibles as vessels of peace rather than of war, took command of the Zeppelin business. With the Treaty of Versailles having knocked out their competitor Schütte-Lanz, the Zeppelin company and DELAG hoped to resume civilian flights quickly. In fact, despite considerable difficulties, they completed two small Zeppelins: LZ 120 Bodensee, which first flew in August 1919 and in the following two years actually transported some 4,000 passengers; and LZ 121 Nordstern, which was envisaged being used on a regular route to Stockholm. However, in 1921, the Allied Powers demanded these two Zeppelins be delivered as war reparations, as compensation for the dirigibles destroyed by their crews in Further Zeppelin projects could not be realized, partly because of Allied interdiction. This temporarily halted German Zeppelin aviation. Eckener and his co-workers refused to give up and kept looking for investors and a way to circumvent Allied restrictions. Their opportunity came in The United States had started to experiment with rigid airships, constructing one of their own, the ZR-1 USS Shenandoah (see below), and ordering another from the UK when the British R38 (ZR-2) was cancelled. However, the R38 (based on the Zeppelin L70, ordered as ZR- 2) broke apart and exploded during a test flight above the Humber on 23 August 1921, killing 44 crewmen. Under these circumstances, Eckener managed to acquire an order for the next American dirigible. Of course, Germany had to pay the costs for this airship itself, as they were calculated against the war reparation accounts, but for the Zeppelin company, this was secondary. So engineer Dr. Dürr designed LZ 126, and using all the expertise accumulated over the years, the company finally achieved its best Zeppelin so far, which took off for a first test flight on 27 August No insurance company was willing to issue a policy for the delivery to Lakehurst, which, of course, involved a transatlantic flight. Eckener, however, was so confident of the new ship that he was ready to risk the entire business capital, and on 12 October 07:30 local time, the Zeppelin took off for the US under his command. His faith was not disappointed, and the ship completed her 8,050 kilometres (5,000 mi) voyage without any difficulties in 81 hours and two minutes. American crowds enthusiastically celebrated the arrival, and President Calvin Coolidge invited Dr. Eckener and his crew to the White House, calling the new Zeppelin an "angel of peace". Under its new designation the ZR-3 USS Los Angeles (the former LZ 126), became the most successful American airship. She operated reliably for eight years until she was retired in 1932 for economic reasons. She was dismantled in August With the delivery of LZ 126, the Zeppelin company had reasserted its lead in rigid airship construction, but it was not yet quite back in business. Acquiring the necessary funds for the next project proved a problem in the difficult economic situation of post-world-war-i Germany, and it took Eckener two years of lobbying and publicity work to secure the realization of LZ 127. Another two years passed before 18 September 1928, when the new dirigible, christened Graf Zeppelin in honor of the Count, flew for the first time. With a total length of metres (776 ft) and a volume of 105,000 m3, she was the largest dirigible yet. Eckener's initial concept was to use Graf Zeppelin for experimental and demonstration purposes to prepare the way for regular airship traveling, by carrying passengers and mail to cover the costs. In October 1928 the first long-range voyage brought her to Lakehurst, where Eckener and his crew were once more welcomed enthusiastically with confetti parades in New York and another invitation to the White House. Graf Zeppelin toured Germany and visited Italy, Palestine, and Spain. A second trip to the United States was aborted in France due to engine failure in May In August 1929 LZ 127 departed for another daring enterprise: a circumnavigation of the globe. The growing popularity of the "giant of the air" made it easy for Eckener to find sponsors. One of these was the American press tycoon William Randolph Hearst, who requested the tour officially start in Lakehurst. As with the October 1928 flight to New York, Hearst had placed a reporter, Grace Marguerite Hay Drummond-Hay, on board who therefore became the first woman to circumnavigate the globe by air. From there, Graf Zeppelin flew to Friedrichshafen, then Tokyo, Los Angeles, and back to Lakehurst, in 21 days 5 hours and 31 minutes. Including the initial and final trips Friedrichshafen Lakehurst and back, the dirigible traveled 49,618 kilometres (30,831 mi). 68

69 In the following year, Graf Zeppelin undertook a number of trips around Europe, and following a successful tour to Recife, Brazil in May 1930, it was decided to open the first regular transatlantic airship line. This line operated between Frankfurt and Recife in 68 hours, and later, between Frankfurt and Rio de Janeiro, with a stop in Recife. Despite the beginning of the Great Depression and growing competition from fixed-wing aircraft, LZ 127 would transport an increasing volume of passengers and mail across the ocean every year until The ship pursued another spectacular venue in July 1931 with a research trip to the Arctic. This had already been a dream of Count von Zeppelin twenty years earlier, which could, however, not be realized at the time due to the outbreak of war. Eckener intended to supplement the successful craft by another, similar Zeppelin, projected as LZ 128. However the disastrous accident of the British passenger airship R101 on 5 October 1930 led the Zeppelin company to reconsider the safety of hydrogen-filled vessels, and the design was abandoned in favour of a new project. LZ 129 would advance Zeppelin technology considerably, and was intended to be filled with inert helium. Following 1933, the establishment of the Third Reich in Germany began to overshadow the Zeppelin business. The Nazis knew very well dirigibles would be useless in combat and thus chose to focus on heavierthan-air technology. On the other hand, they were eager to exploit the popularity of the airships for propaganda. As Eckener refused to cooperate, Hermann Göring, the German Air minister, formed a new airline in 1935, the Deutsche Zeppelin-Reederei (DZR), which took over operation of airship flights. Zeppelins would now display the Nazi swastika on their fins and occasionally tour Germany to play march music and propaganda speeches for the people from the air. On 4 March 1936, LZ 129 Hindenburg (named after former President of Germany Paul von Hindenburg by Eckener) made her first flight. The Hindenburg was the largest airship ever built. However, in the new political situation, Eckener had not obtained the helium to inflate it due to a military embargo; only the United States possessed the rare gas in usable quantities. So, in what ultimately proved a fatal decision, the Hindenburg was filled with flammable hydrogen. Apart from the propaganda missions, LZ 129 began to serve the transatlantic lines together with Graf Zeppelin. On 6 May 1937, while landing in Lakehurst after a transatlantic flight, in front of thousands of spectators, the tail of the ship caught fire, and within seconds, the Hindenburg burst into flames, killing 35 of the 97 people on board and one member of the ground crew. The actual cause of the fire has not been definitively determined; it is likely that a combination of leaking hydrogen from a torn gas bag, the vibrations caused by a swift rotation for a quicker landing to have started static electricity in the duralumin alloy skeleton and a flammable outer coating similar to rocket fuel accounted for the fact that the fire spread from its starting point in the tail to engulf the entire airship so rapidly (34 seconds). Whatever caused the disaster, the end of the dirigible era was due to politics and the upcoming war, not the wreck itself, though it surely led to some public misgivings. Despite everything, there remained a list of 400 people who still wanted to fly as Zeppelin passengers and had paid for the trip. Their money was refunded in Graf Zeppelin completed more flights, though not for overseas commercial flights to the U.S., and was retired one month after the Hindenburg wreck and turned into a museum. Dr. Eckener kept trying to obtain helium gas for Hindenburg's sister ship, Graf Zeppelin II, but due to political bias against the airship's commercial use by the Nazi leadership, coupled with the inability to obtain helium gas in sufficient quantities due to an embargo by the United States, his efforts were in vain. The intended new flagship Zeppelin was completed in 1938 and, inflated with hydrogen, made some test flights (the first on 14 September), but never carried passengers. Another project, LZ 131, designed to be even larger than Hindenburg and Graf Zeppelin II, never progressed beyond the production of some single skeleton rings. The career of Graf Zeppelin II was not over. She was assigned to the Luftwaffe and performed about 30 test flights prior to the beginning of World War II. Most of those test flights were carried out near the Polish border, first in the Sudeten mountains region of Silesia, then in the Baltic Sea region. During one such flight LZ 130 crossed the Polish border near the Hel Peninsula, where she was intercepted by a Polish Lublin R-XIII aircraft from Puck naval airbase and forced to leave Polish airspace. During this time, LZ 130 was used as an electronic scouting airframe and was equipped with various telemetric equipment. From May to August 1939, she performed flights near the coastline of Great Britain in an attempt to determine whether the 100-metre towers erected from Portsmouth to Scapa Flow were used for aircraft radio localization. Photography, radio wave interception, magnetic and radio frequency analysis were unable to detect operational British Chain Home radar due to searching in the wrong frequency range. The frequencies searched were too high, an assumption 69

70 based on the Germans' own radar systems. The mistaken conclusion was the British towers were not connected with radar operations, but formed a network of naval radio communications and rescue. After the German invasion of Poland started the Second World War on 1 September, the Luftwaffe ordered LZ 127 and LZ 130 moved to a large Zeppelin hangar in Frankfurt, where the skeleton of LZ 131 was also located. In March 1940 Göring ordered the destruction of the remaining airships and the Duralumin fed into the Nazi war industry. In May a fire broke out in the Zeppelin facility, which destroyed most of the remaining parts. The rest of the parts and materials were soon scrapped, with almost no trace of the German "giants of the air" remaining by the end of the year. Airships using the Zeppelin construction method are sometimes referred to as zeppelins even if they had no connection with the Zeppelin business. Several airships of this kind were built in the USA and Britain in the 1920s and 1930s, mostly imitating original Zeppelin designs derived from crashed or captured German World War I airships. The British R33 and R34, for example, were near identical copies of the German L-33, which crashed virtually intact in Essex on 24 September Despite being almost three years out of date by the time they were launched in 1919, these sister ships were two of the most successful in British service. On 2 July 1919, R34 began the first return crossing of the Atlantic by aircraft. She landed at Mineola, Long Island on 6 July 1919 after 108 hours in the air. The return crossing commenced on 8 July because of concerns about mooring the ship in the open, and took 75 hours. Their success led to proposals for a fleet of airships to link far-flung British colonies, but unfortunately post-war economic conditions resulted in most airships being scrapped and trained personnel dispersed, until design and construction of the R-100 and R-101 commenced in 1925, see Imperial Airship Scheme. Another example was the first American-built rigid dirigible ZR-1 USS Shenandoah, launched in September, 1923, while the USS Los Angeles (ZR-3) was still under construction. The ship was christened on 20 August in Lakehurst, New Jersey and was the first to be inflated with helium, which was still so rare at the time that Shenandoah contained most of the world's reserves. When Los Angeles was delivered, she was at first filled with helium borrowed from ZR-1. Other airships were the USS Akron (ZRS-4) and the USS Macon (ZRS-5), (fig. 64). Fig. 64. U.S. Navy Zeppelin ZRS-5 "USS Macon" over Moffett Field in Since the 1990s Zeppelin Luftschifftechnik, a daughter enterprise of the Zeppelin conglomerate that built the original German Zeppelins, has been developing Zeppelin "New Technology" (NT) airships. These vessels are semi-rigids and not strictly zeppelins because their shape is based partly on internal pressure, partly on a frame. The Airship Ventures company recently re-introduced zeppelin passenger travel to California with one of these Zeppelin NT airships (fig. 65). 70

71 Fig. 65. Some modern Zeppelins. HELICOPTERS A helicopter is a type of rotorcraft in which lift and thrust are supplied by one or more engine driven rotors. In contrast with fixed-wing aircraft, this allows the helicopter to take off and land vertically, to hover, and to fly forwards, backwards, and laterally. These attributes allow helicopters to be used in congested or isolated areas where fixed-wing aircraft would not be able to take off or land. The capability to efficiently hover for extended periods of time allows a helicopter to accomplish tasks that fixed-wing aircraft and other forms of vertical takeoff and landing aircraft cannot perform. The word 'helicopter' is adapted from the French hélicoptère, coined by Gustave de Ponton d'amecourt in 1861, which originates from the Greek helix/helik = "twisted, curved" and pteron = "wing". Helicopters were developed and built during the first half-century of flight, with the Focke-Wulf Fw 61 being the first operational helicopter in Some helicopters reached limited production, but it was not until 1942 that a helicopter designed by Igor Sikorsky reached full-scale production, with 131 aircraft built. Though most earlier designs used more than one main rotor, it was the single main rotor with antitorque tail rotor configuration of this design that would come to be recognized worldwide as the helicopter. 71

72 The earliest references for vertical flight have come from China. Since around 400 BC, Chinese children have played with bamboo flying toys, and the 4th-century AD Daoist book Baopuzi ("Master who Embraces Simplicity") reportedly describes some of the ideas inherent to rotary wing aircraft: Someone asked the master about the principles of mounting to dangerous heights and traveling into the vast inane. The Master said, "Some have made flying cars with wood from the inner part of the jujube tree, using ox-leather [straps] fastened to returning blades so as to set the machine in motion." It was not until the early 1480s, when Leonardo da Vinci created a design for a machine that could be described as an "aerial screw" (fig ), that any recorded advancement was made towards vertical flight. His notes suggested that he built small flying models, but there were no indications for any provision to stop the rotor from making the whole craft rotate. As scientific knowledge increased and became more accepted, men continued to pursue the idea of vertical flight. Many of these later models and machines would more closely resemble the ancient bamboo flying top with spinning wings, rather than Da Vinci's screw. Fig. 66. First helicopter designed by Leonardo da Vinci (1480). Fig. 67. First helicopter designed by Leonardo da Vinci (1480). In July 1754, Mikhail Lomonosov demonstrated a small tandem rotor to the Russian Academy of Sciences. It was powered by a spring and suggested as a method to lift meteorological instruments. In 1783, Christian de Launoy, and his mechanic, Bienvenu, made a model with a pair of counter-rotating rotors, using turkey flight feathers as rotor blades, and in 1784, demonstrated it to the French Academy of Sciences. Sir George Cayley, influenced by a childhood fascination with the Chinese flying top, grew up to develop a model of feathers, similar to Launoy and Bienvenu, but powered by rubber bands. By the end of the century, he had progressed to using sheets of tin for rotor blades and springs for power. His writings on his experiments and models would become influential on future aviation pioneers. Alphonse Pénaud would later develop coaxial rotor model helicopter toys in 1870, also powered by rubber bands. One of these toys, given as a gift by their father, would inspire the Wright brothers to pursue the dream of flight. In 1861, the word "helicopter" was coined by Gustave de Ponton d'amécourt, a French inventor who demonstrated a small, steam-powered model. While celebrated as an innovative use of a new metal, aluminum, the model never lifted off the ground. D'Amecourt's linguistic contribution would survive to eventually describe the vertical flight he had envisioned. Steam power was popular with other inventors as well. In 1878 Enrico 72

73 Forlanini's unmanned helicopter was also powered by a steam engine. It was the first of its type that rose to a height of 12 meters (40 ft), where it hovered for some 20 seconds after a vertical take-off. Emmanuel Dieuaide's steam-powered design featured counter-rotating rotors powered through a hose from a boiler on the ground. In 1885, Thomas Edison was given US$1,000 by James Gordon Bennett, Jr., to conduct experiments towards developing flight. Edison built a helicopter and used the paper for a stock ticker to create guncotton, with which he attempted to power an internal combustion engine. The helicopter was damaged by explosions and one of his workers was badly burned. Edison reported that it would take a motor with a ratio of three to four pounds per horsepower produced to be successful, based on his experiments. Ján Bahýľ, a Slovak inventor, adapted the internal combustion engine to power his helicopter model that reached a height of 0.5 meters (1.6 ft) in On 5 May 1905, his helicopter reached four meters (13 ft) in altitude and flew for over 1,500 meters (4,900 ft). In 1908, Edison patented his own design for a helicopter powered by a gasoline engine with box kites attached to a mast by cables for a rotor, but it never flew. In 1906, two French brothers, Jacques and Louis Breguet, began experimenting with airfoils for helicopters and in 1907, those experiments resulted in the Gyroplane No.1. Although there is some uncertainty about the dates, sometime between 14 August and 29 September 1907, the Gyroplane No. 1 lifted its pilot up into the air about two feet (0.6 m) for a minute. However, the Gyroplane No. 1 proved to be extremely unsteady and required a man at each corner of the airframe to hold it steady. For this reason, the flights of the Gyroplane No. 1 are considered to be the first manned flight of a helicopter, but not a free or untethered flight. Fig. 68. First helicopter made by the French inventor Paul Cornu (1907). That same year, fellow French inventor Paul Cornu (Romanian-born French) designed and built a Cornu helicopter that used two 20-foot (6 m) counter-rotating rotors driven by a 24-hp (18-kW) Antoinette engine (fig. 68). On 13 November 1907, it lifted its inventor to 1 foot (0.3 m) and remained aloft for 20 seconds. Even though this flight did not surpass the flight of the Gyroplane No. 1, it was reported to be the first truly free flight with a pilot.[n 1] Cornu's helicopter would complete a few more flights and achieve a height of nearly 6.5 feet (2 m), but it proved to be unstable and was abandoned. The Danish inventor Jacob Ellehammer built the Ellehammer helicopter in It consisted of a frame equipped with two contra-rotating discs, each of which was fitted with six vanes around its circumference. After a number of indoor tests, the aircraft was demonstrated outdoors and made a number of free take-offs. Experiments with the helicopter continued until September 1916, when it tipped over during take-off, destroying its rotors. In the early 1920s, Argentine Raúl Pateras Pescara, while working in Europe, demonstrated one of the first successful applications of cyclic pitch. Coaxial, contra-rotating, biplane rotors could be warped to cyclically increase and decrease the lift they produced. The rotor hub could also be tilted forward a few degrees, allowing the aircraft to move forward without a separate propeller to push or pull it. Pescara was also able to demonstrate the principle of autorotation, by which helicopters safely land after engine failure. By January 1924, Pescara's helicopter No. 3 could fly for up to ten minutes. One of Pescara's contemporaries, Frenchman Etienne Oehmichen, set the first helicopter world record recognized by the Fédération Aéronautique Internationale (FAI) on 14 April 1924, flying his helicopter 360 meters (1,181 ft), (fig. 69). On 18 April 1924, Pescara beat Oemichen's record, flying for a distance of 736 meters (nearly a half mile) in 4 minutes and 11 seconds (about 8 mph, 13 km/h) maintaining a height of six feet (2 m). Not to be outdone, Oehmichen reclaimed the world record on 4 May when he flew his No. 2 machine again for a 14-minute flight covering 5,550 feet (1.05 mi, 1.69 km) while climbing to a height of 50 feet (15 m). Oehmichen also set the 1 km closed-circuit record at 7 minutes 40 seconds. 73

74 Fig. 69. A helicopter made by the Frenchman Etienne Oehmichen (1922). In the USA, George de Bothezat built the quadrotor De Bothezat helicopter for the United States Army Air Service but the Army cancelled the program in 1924, and the aircraft was scrapped. Meanwhile, Juan de la Cierva was developing the first practical rotorcraft in Spain. In 1923, the aircraft that would become the basis for the modern helicopter rotor began to take shape in the form of an autogyro, Cierva's C.4. Cierva had discovered aerodynamic and structural deficiencies in his early designs that could cause his autogyros to flip over after takeoff. The flapping hinges that Cierva designed for the C.4 allowed the rotor to develop lift equally on the left and right halves of the rotor disk. A crash in 1927, led to the development of a drag hinge to relieve further stress on the rotor from its flapping motion. These two developments allowed for a stable rotor system, not only in a hover, but in forward flight. Albert Gillis von Baumhauer, a Dutch aeronautical engineer, began studying rotorcraft design in His first prototype "flew" ("hopped" and hovered in reality) on 24 September 1925, with Dutch Army-Air arm Captain Floris Albert van Heijst at the controls. The controls that Captain van Heijst used were Von Baumhauer's inventions, the cyclic and collective. Patents were granted to von Baumhauer for his cyclic and collective controls by the British ministry of aviation on 31 January 1927, under patent number 265,272. In 1928, Hungarian aviation engineer Oszkár Asbóth constructed a helicopter prototype that took off and landed at least 182 times, with a maximum single flight duration of 53 minutes. In 1930, the Italian engineer Corradino D'Ascanio built his D'AT3, a coaxial helicopter. His relatively large machine had two, two-bladed, counter-rotating rotors. Control was achieved by using auxiliary wings or servo-tabs on the trailing edges of the blades, a concept that was later adopted by other helicopter designers, including Bleeker and Kaman. Three small propellers mounted to the airframe were used for additional pitch, roll, and yaw control. The D'AT3 held modest FAI speed and altitude records for the time, including altitude (18 m or 59 ft), duration (8 minutes 45 seconds) and distance flown (1,078 m or 3,540 ft). In the Soviet Union, Boris N. Yuriev and Alexei M. Cheremukhin, two aeronautical engineers working at the Tsentralniy Aerogidrodinamicheskiy Institut (English: Central Aerohydrodynamic Institute), constructed and flew the TsAGI 1-EA single rotor helicopter, which used an open tubing framework, a four blade main rotor, and twin sets of 1.8-meter (6-foot) diameter anti-torque rotors; one set of two at the nose and one set of two at the tail. Powered by two M-2 powerplants, up-rated copies of the Gnome Monosoupape rotary radial engine of World War I, the TsAGI 1-EA made several successful low altitude flights. By 14 August 1932, Cheremukhin managed to get the 1-EA up to an unofficial altitude of 605 meters (1,985 ft), shattering d'ascanio's earlier achievement. As the Soviet Union was not yet a member of the FAI, however, Cheremukhin's record remained unrecognized. Nicolas Florine, a Russian engineer, built the first twin tandem rotor machine to perform a free flight. It flew in Sint-Genesius-Rode, at the Laboratoire Aérotechnique de Belgique (now von Karman Institute) in April 1933, and attained an altitude of six meters (20 ft) and an endurance of eight minutes. Florine chose a corotating configuration because the gyroscopic stability of the rotors would not cancel. Therefore the rotors had to be tilted slightly in opposite directions to counter torque. Using hingeless rotors and co-rotation also minimised the stress on the hull. At the time, it was one of the most stable helicopter in existence. The Bréguet-Dorand Gyroplane Laboratoire was built in After many ground tests and an accident, it first took flight on 26 June Within a short time, the aircraft was setting records with pilot Maurice Claisse at the controls. On 14 December 1935, he set a record for closed-circuit flight with a 500-meter (1,600 ft) diameter. The next year, on 26 September 1936, Claisse set a height record of 158 meters (520 ft). And, finally, on 24 November 1936, he set a flight duration record of one hour, two minutes and 5 seconds over a 44 kilometer (27 mi) closed circuit at 44.7 kilometers per hour (27.8 mph). The aircraft was destroyed in 1943 by an Allied airstrike at Villacoublay airport. 74

75 Despite the success of the Gyroplane Laboratoire, the German Focke-Wulf Fw 61, first flown in 1936, would eclipse its accomplishments. The Fw 61 broke all of the helicopter world records in 1937, demonstrating a flight envelope that had only previously been achieved by the autogyro. Nazi Germany would use helicopters in small numbers during World War II for observation, transport, and medical evacuation. The Flettner Fl 282 Kolibri synchropter was used in the Mediterranean, while the Focke Achgelis Fa 223 Drache was used in Europe. Extensive bombing by the Allied forces prevented Germany from producing any helicopters in large quantities during the war. In the United States, Igor Sikorsky and W. Lawrence LePage were competing to produce the United States military's first helicopter. Prior to the war, LePage had received the patent rights to develop helicopters patterned after the Fw 61, and built the XR-1. Meanwhile, Sikorsky had settled on a simpler, single rotor design, the VS-300. After experimenting with configurations to counteract the torque produced by the single main rotor, he settled on a single, smaller rotor mounted vertically on the tailboom. Developed from the VS-300, Sikorsky's R-4 became the first mass produced helicopter with a production order for 100 aircraft. The R-4 was the only Allied helicopter to see service in World War II, primarily being used for rescue in Burma, Alaska, and other areas with harsh terrain. Total production would reach 131 helicopters before the R-4 was replaced by other Sikorsky helicopters such as the R-5 and the R-6. In all, Sikorsky would produce over 400 helicopters before the end of World War II. As LePage and Sikorsky were building their helicopters for the military, Bell Aircraft hired Arthur Young to help build a helicopter using Young's two-blade teetering rotor design which used a weighted stabilizing bar placed at a 90º angle to the rotor blades. The subsequent Model 30 helicopter showed the design's simplicity and ease of use. The Model 30 was developed into the Bell 47, which became the first helicopter certificated for civilian use in the United States. Produced in several countries, the Bell 47 would stand as the most popular helicopter model for nearly 30 years (fig. 70). Fig. 70. First modern helicopter made by Igor Sikorsky (1947). In 1951, at the urging of his contacts at the Department of the Navy, Charles Kaman modified his K- 225 helicopter with a new kind of engine, the turboshaft engine. This adaptation of the turbine engine provided a large amount of power to the helicopter with a lower weight penalty than piston engines, with their heavy engine blocks and auxiliary components. On 11 December 1951, the Kaman K-225 became the first turbinepowered helicopter in the world. Two years later, on 26 March 1954, a modified Navy HTK-1, another Kaman helicopter, became the first twin-turbine helicopter to fly. However, it was the Sud Aviation Alouette II that would become the first helicopter to be produced with a turbine-engine. Reliable helicopters capable of stable hover flight were developed decades after fixed-wing aircraft. This is largely due to higher engine power density requirements than fixed-wing aircraft. Improvements in fuels and engines during the first half of the 20th century were a critical factor in helicopter development. The availability of lightweight turboshaft engines in the second half of the 20th century led to the development of larger, faster, and higher-performance helicopters. While smaller and less expensive helicopters still use piston engines, turboshaft engines are the preferred powerplant for helicopters today. Due to the operating characteristics of the helicopter its ability to takeoff and land vertically, and to hover for extended periods of time, as well as the aircraft's handling properties under low airspeed conditions it has been chosen to conduct tasks that were previously not possible with other aircraft, or were time- or work- 75

76 intensive to accomplish on the ground. Today, helicopter uses include transportation, construction, firefighting, search and rescue, and military uses. A helicopter used to carry loads connected to long cables or slings is called an aerial crane. Aerial cranes are used to place heavy equipment, like radio transmission towers and large air conditioning units, on the tops of tall buildings, or when an item must be raised up in a remote area, such as a radio tower raised on the top of a hill or mountain. Helicopters are used as aerial cranes in the logging industry to lift trees out of terrain where vehicles cannot travel and where environmental concerns prohibit the building of roads. These operations are referred to as longline because of the long, single sling line used to carry the load. Helitack is the use of helicopters to combat wildland fires. The helicopters are used for aerial firefighting (or water bombing) and may be fitted with tanks or carry helibuckets. Helibuckets, such as the Bambi bucket, are usually filled by submerging the bucket into lakes, rivers, reservoirs, or portable tanks. Tanks fitted onto helicopters are filled from a hose while the helicopter is on the ground or water is siphoned from lakes or reservoirs through a hanging snorkel as the helicopter hovers over the water source. Helitack helicopters are also used to deliver firefighters, who rappel down to inaccessible areas, and to resupply firefighters. Common firefighting helicopters include variants of the Bell 205 and the Erickson S-64 Aircrane helitanker. Helicopters are used as air ambulances for emergency medical assistance in situations when an ambulance cannot easily or quickly reach the scene. Helicopters are also used when a patient needs to be transported between medical facilities and air transportation is the most practical method for the safety of the patient. Air ambulance helicopters are equipped to provide medical treatment to a patient while in flight. The use of helicopters as an air ambulance is often referred to as MEDEVAC, and patients are referred to as being "airlifted", or "medevaced". Police departments and other law enforcement agencies use helicopters to pursue suspects. Since helicopters can achieve a unique aerial view, they are often used in conjunction with police on the ground to report on suspects' locations and movements. They are often mounted with lighting and heat-sensing equipment for night pursuits. Military forces use attack helicopters to conduct aerial attacks on ground targets. Such helicopters are mounted with missile launchers and miniguns. Transport helicopters are used to ferry troops and supplies where the lack of an airstrip would make transport via fixed-wing aircraft impossible. The use of transport helicopters to deliver troops as an attack force on an objective is referred to as Air Assault. Unmanned Aerial Systems (UAS) helicopter systems of varying sizes are being developed by companies for military reconnaissance and surveillance duties. Naval forces also use helicopters equipped with dipping sonar for anti-submarine warfare, since they can operate from small ships. Oil companies charter helicopters to move workers and parts quickly to remote drilling sites located out to sea or in remote locations. The speed over boats makes the high operating cost of helicopters cost effective to ensure that oil platforms continue to flow. Various companies specialize in this type of operation. The rotor system, or more simply rotor, is the rotating part of a helicopter which generates lift. A rotor system may be mounted horizontally as main rotors are, providing lift vertically, or it may be mounted vertically, such as a tail rotor, to provide lift horizontally as thrust to counteract torque effect. The rotor consists of a mast, hub and rotor blades. The mast is a cylindrical metal shaft which extends upwards from and is driven by the transmission. At the top of the mast is the attachment point for the rotor blades called the hub. The rotor blades are then attached to the hub by a number of different methods. Main rotor systems are classified according to how the main rotor blades are attached and move relative to the main rotor hub. There are three basic classifications: hingeless, fully articulated, and teetering, although some modern rotor systems use an engineered combination of these types. Most helicopters have a single main rotor, but torque created as the engine turns the rotor against its air drag causes the body of the helicopter to turn in the opposite direction to the rotor. To eliminate this effect, some sort of antitorque control must be used. The design that Igor Sikorsky settled on for his VS-300 was a smaller rotor mounted vertically on the tail. The tail rotor pushes or pulls against the tail to counter the torque effect, and has become the recognized convention for helicopter design. Some helicopters utilize alternate antitorque controls in place of the tail rotor, such as the ducted fan (called Fenestron or FANTAIL), and NOTAR. NOTAR provides antitorque similar to the way a wing develops lift, through the use of a Coandă effect on the tailboom (fig. 71). 76

77 Fig. 71. MD Helicopters 520N NOTAR. The use of two or more horizontal rotors turning in opposite directions is another configuration used to counteract the effects of torque on the aircraft without relying on an antitorque tail rotor. This allows the power normally required to drive the tail rotor to be applied to the main rotors, increasing the aircraft's lifting capacity. Primarily, there are three common configurations that use the counterrotating effect to benefit the rotorcraft. Tandem rotors are two rotors with one mounted behind the other. Coaxial rotors are two rotors that are mounted one above the other with the same axis. Intermeshing rotors are two rotors that are mounted close to each other at a sufficient angle to allow the rotors to intermesh over the top of the aircraft. Transverse rotors is another configuration found on tiltrotors and some earlier helicopters, where the pair of rotors are mounted at each end of the wings or outrigger structures. Tip jet designs permit the rotor to push itself through the air, and avoid generating torque (fig. 72). Fig. 72. The Piasecki H-21 employed tandem rotors. The number, size and type of engine used on a helicopter determines the size, function and capability of that helicopter design. The earliest helicopter engines were simple mechanical devices, such as rubber bands or spindles, which relegated the size of helicopters to toys and small models. For a half century before the first airplane flight, steam engines were used to forward the development of the understanding of helicopter aerodynamics, but the limited power did not allow for manned flight. The introduction of the internal combustion engine at the end of the 19th century became the watershed for helicopter development as engines began to be developed and produced that were powerful enough to allow for helicopters able to lift humans. Early helicopter designs utilized custom-built engines or rotary engines designed for airplanes, but these were soon replaced by more powerful automobile engines and radial engines. The single, most-limiting factor of helicopter development during the first half of the 20th century was that the amount of power produced by an engine was not able to overcome the engine's weight in vertical flight. This was overcome in early successful helicopters by using the smallest engines available. When the compact, flat engine was developed, the helicopter industry found a lighter-weight powerplant easily adapted to small helicopters, although radial engines continued to be used for larger helicopters. 77

78 Turbine engines revolutionized the aviation industry, and the turboshaft engine finally gave helicopters an engine with a large amount of power and a low weight penalty. The turboshaft engine was able to be scaled to the size of the helicopter being designed, so that all but the lightest of helicopter models are powered by turbine engines today. Special jet engines developed to drive the rotor from the rotor tips are referred to as tip jets. Tip jets powered by a remote compressor are referred to as cold tip jets, while those powered by combustion exhaust are referred to as hot tip jets. An example of a cold jet helicopter is the Sud-Ouest Djinn, and an example of the hot tip jet helicopter is the YH-32 Hornet. Some radio-controlled helicopters and smaller, helicopter-type unmanned aerial vehicles, use electric motors. Radio-controlled helicopters may also have piston engines that use fuels other than gasoline, such as Nitromethane. Some turbine engines commonly used in helicopters can also use biodiesel instead of jet fuel. A helicopter has four flight control inputs. These are the cyclic, the collective, the anti-torque pedals, and the throttle. The cyclic control is usually located between the pilot's legs and is commonly called the cyclic stick or just cyclic. On most helicopters, the cyclic is similar to a joystick. However, the Robinson R22 and Robinson R44 have a unique teetering bar cyclic control system and a few helicopters have a cyclic control that descends into the cockpit from overhead. The control is called the cyclic because it changes the pitch of the rotor blades cyclically. The result is to tilt the rotor disk in a particular direction, resulting in the helicopter moving in that direction. If the pilot pushes the cyclic forward, the rotor disk tilts forward, and the rotor produces a thrust in the forward direction. If the pilot pushes the cyclic to the side, the rotor disk tilts to that side and produces thrust in that direction, causing the helicopter to hover sideways. The collective pitch control or collective is located on the left side of the pilot's seat with a settable friction control to prevent inadvertent movement. The collective changes the pitch angle of all the main rotor blades collectively (i.e. all at the same time) and independently of their position. Therefore, if a collective input is made, all the blades change equally, and the result is the helicopter increasing or decreasing in altitude. The anti-torque pedals are located in the same position as the rudder pedals in a fixed-wing aircraft, and serve a similar purpose, namely to control the direction in which the nose of the aircraft is pointed. Application of the pedal in a given direction changes the pitch of the tail rotor blades, increasing or reducing the thrust produced by the tail rotor and causing the nose to yaw in the direction of the applied pedal. The pedals mechanically change the pitch of the tail rotor altering the amount of thrust produced. Helicopter rotors are designed to operate in a narrow range of RPM. The throttle controls the power produced by the engine, which is connected to the rotor by a fixed ratio transmission. The purpose of the throttle is to maintain enough engine power to keep the rotor RPM within allowable limits in order to keep the rotor producing enough lift for flight. In single-engine helicopters, the throttle control is a motorcycle-style twist grip mounted on the collective control, while dual-engine helicopters have a power lever for each engine. A Swashplate transmits the pilot commands to the main rotor blades for articulated rotors. There are three basic flight conditions for a helicopter; hover and forward flight, and the transition between the two.. Hover Hovering is the most challenging part of flying a helicopter. This is because a helicopter generates its own gusty air while in a hover, which acts against the fuselage and flight control surfaces. The end result is constant control inputs and corrections by the pilot to keep the helicopter where it is required to be. Despite the complexity of the task, the control inputs in a hover are simple. The cyclic is used to eliminate drift in the horizontal plane, that is to control forward and back, right and left. The collective is used to maintain altitude. The pedals are used to control nose direction or heading. It is the interaction of these controls that makes hovering so difficult, since an adjustment in any one control requires an adjustment of the other two, creating a cycle of constant correction. Transition from hover to forward flights As a helicopter moves from hover to forward flight it enters a state called Translational lift which provides extra lift without increasing power. This state, most typically, occurs when the airspeed reaches approximately knots, and may be necessary for a helicopter to obtain flight. Forward flight 78

79 In forward flight a helicopter's flight controls behave more like that in a fixed-wing aircraft. Displacing the cyclic forward will cause the nose to pitch down, with a resultant increase in airspeed and loss of altitude. Aft cyclic will cause the nose to pitch up, slowing the helicopter and causing it to climb. Increasing collective (power) while maintaining a constant airspeed will induce a climb while decreasing collective will cause a descent. Coordinating these two inputs, down collective plus aft cyclic or up collective plus forward cyclic, will result in airspeed changes while maintaining a constant altitude. The pedals serve the same function in both a helicopter and a fixed-wing aircraft, to maintain balanced flight. This is done by applying a pedal input in whichever direction is necessary to center the ball in the turn and bank indicator. The main limitation of the helicopter is its low speed. There are several reasons a helicopter cannot fly as fast as a fixed wing aircraft. When the helicopter is hovering, the outer tips of the rotor travel at a speed determined by the length of the blade and the RPM. In a moving helicopter, however, the speed of the blades relative to the air depends on the speed of the helicopter as well as on their rotational velocity. The airspeed of the advancing rotor blade is much higher than that of the helicopter itself. It is possible for this blade to exceed the speed of sound, and thus produce vastly increased drag and vibration. See Wave drag. Because the advancing blade has higher airspeed than the retreating blade and generates a dissymmetry of lift, rotor blades are designed to "flap" lift and twist in such a way that the advancing blade flaps up and develops a smaller angle of attack. Conversely, the retreating blade flaps down, develops a higher angle of attack, and generates more lift. At high speeds, the force on the rotors is such that they "flap" excessively and the retreating blade can reach too high an angle and stall. For this reason, the maximum safe forward airspeed of a helicopter is given a design rating called VNE, Velocity, Never Exceed. In addition it is possible for the helicopter to fly at an airspeed where an excessive amount of the retreating blade stalls which results in high vibration, pitch -up, and roll into the retreating blade. During the closing years of the 20th century designers began working on helicopter noise reduction. Urban communities have often expressed great dislike of noisy aircraft, and police and passenger helicopters can be unpopular. The redesigns followed the closure of some city heliports and government action to constrain flight paths in national parks and other places of natural beauty. Helicopters also vibrate; an unadjusted helicopter can easily vibrate so much that it will shake itself apart. To reduce vibration, all helicopters have rotor adjustments for height and weight. Blade height is adjusted by changing the pitch of the blade. Weight is adjusted by adding or removing weights on the rotor head and/or at the blade end caps. Most also have vibration dampers for height and pitch. Some also use mechanical feedback systems to sense and counter vibration. Usually the feedback system uses a mass as a "stable reference" and a linkage from the mass operates a flap to adjust the rotor's angle of attack to counter the vibration. Adjustment is difficult in part because measurement of the vibration is hard, usually requiring sophisticated accelerometers mounted throughout the airframe and gearboxes. The most common blade vibration adjustment measurement system is to use a stroboscopic flash lamp, and observe painted markings or coloured reflectors on the underside of the rotor blades. The traditional low-tech system is to mount coloured chalk on the rotor tips, and see how they mark a linen sheet. Gearbox vibration most often requires a gearbox overhaul or replacement. Gearbox or drive train vibrations can be extremely harmful to a pilot. The most severe being pain, numbness, loss of tactile discrimination and dexterity. Canada Receives First CH-148 Maritime Helicopter. The first interim maritime helicopter, the CH-148 Cyclone, arrived at 12 Wing Shearwater, Nova Scotia, last week to support training of Canadian Forces (CF) aircrew and technicians for the Maritime Helicopter Project (fig. 73). The arrival of this helicopter in Shearwater demonstrates progress with this project and brings us one step closer towards the delivery of a Maritime Helicopter capability that provides the Canadian Forces with a modern, flexible helicopter to assist in the defence of Canada and Canadian interests well into the future, said the Honourable Peter MacKay, Minister of National Defence. On May 13, 2011, Sikorsky Operations International Inc. flew the helicopter to Shearwater as part of its contractual obligation under the Maritime Helicopter Project to deliver initial cadre training to the Canadian Forces. The helicopter will be used as a ground-based training aid for technicians. The arrival of this helicopter does not mark formal delivery at this time as Sikorsky has not yet met all of the contractual delivery requirements. The helicopter will remain under Sikorsky title and control until all requirements are met. The CF will take formal delivery and assume ownership of the helicopter once a Canadian military airworthiness certificate is granted and once initial aircrew flight training is conducted. 79

80 Sikorsky continues to make steady progress. Formal delivery of the first interim maritime helicopter is expected later this summer. The new Cyclone, in its final configuration, will be at the forefront of modern technology and will be one of the most capable maritime helicopters in the world. Fig. 73. CH-148 Cyclone. Fig. 74. Agusta A129 Mangusta. The Agusta A129 Mangusta (English: Mongoose) is an attack helicopter originally designed and produced by Agusta in Italy (fig. 74). It was the first attack helicopter to be designed and produced wholly in Western Europe. The TAI/AgustaWestland T-129 ATAK is an enhanced version of the A129, and its development is now the responsibility of Turkish Aerospace Industries (TAI), with AgustaWestland as the primary partner. The Bell AH-1 SuperCobra is a twin-engine attack helicopter based on the US Army's AH-1 Cobra. The twin Cobra family includes the AH-1J SeaCobra, the AH-1T Improved SeaCobra, and the AH-1W SuperCobra. The AH-1W is the backbone of the United States Marine Corps's attack helicopter fleet, but will be replaced in service by the Bell AH-1Z Viper upgrade in the next decade (fig. 75). Fig. 75. The Bell AH-1W Super Cobra is the backbone of the United States Marine Corps's attack helicopter fleet. 80

81 The AH-1 Cobra was developed in the mid-1960s as an interim gunship for the U.S. Army for use in Vietnam. The Cobra shared the proven transmission, rotor system, and the T53 turboshaft engine of the UH-1 "Huey". By June 1967, the first AH-1G HueyCobras had been delivered. Bell built 1,116 AH-1Gs for the U.S. Army between 1967 and 1973, and the Cobras chalked up over a million operational hours in Vietnam. The U.S. Marine Corps was very interested in the AH-1G Cobra, but preferred a twin-engined version for improved safety in over-water operations, and also wanted a more potent turret-mounted weapon. At first, the Department of Defense had balked at providing the Marines with a twin-engined version of the Cobra, in the belief that commonality with Army AH-1Gs outweighed the advantages of a different engine fit. However, the Marines won out and awarded Bell a contract for 49 twin-engined AH-1J SeaCobras in May As an interim measure, the U.S. Army passed on 38 AH-1Gs to the Marines in The AH-1J also received a more powerful gun turret. It featured a three barrel 20 mm XM197 cannon that was based on the six barrel M61 Vulcan cannon. The Marine Corps requested greater load carrying capability in high temperatures for the Cobra in the 1970s. Bell used systems from its Model 309 to develop the AH-1T. This version had a lengthened tailboom and fuselage with an upgraded transmission and engines from the 309. Bell designed the AH-1T to be more reliable and easier to maintain in the field. The version was given full TOW missile capability with targeting system and other sensors. An advanced version, known as the AH-1T+ with more powerful T700-GE-700 engines and advanced avionics was proposed to Iran in the late 1970s, but the overthrow of the Shah of Iran resulted in the sale being canceled. In the early 1980s, the U.S. Marine Corps sought a new navalized helicopter, but was denied funding to buy the AH-64 Apache by Congress in The Marines in turn pursued a more powerful version of the AH- 1T. Other changes included modified fire control systems to carry and fire AIM-9 Sidewinder and AGM-114 Hellfire missiles. The new version was funded by Congress and received the AH-1W designation. Deliveries of AH-1W SuperCobras totaled 179 new-built helicopters plus 43 upgrades of AH-1Ts. The AH-1T+ demonstrator and AH-1W prototype was later tested with a new experimental composite four blade main rotor system. The new system offered better performance, reduced noise and improved battle damage tolerance. Lacking a USMC contract, Bell developed this new design into the AH-1Z with its own funds. By 1996, the Marines were again not allowed to order the AH-64. Developing a marine version of the Apache would have been expensive and it was likely that the Marine Corps would be its only customer. They instead signed a contract for upgrading 180 AH-1Ws into AH-1Zs. The AH-1Z Viper features several design changes. The AH-1Z's two redesigned wing stubs are longer with each adding a wing-tip station for a missile such as the AIM-9 Sidewinder. Each wing has two other stations for 70 mm (2.75 in) Hydra rocket pods, or AGM-114 Hellfire quad missile launcher. The Longbow radar can be mounted on a wing tip station. During the closing months of the United States' involvement in the Vietnam War, the Marine Corps embarked the AH-1J SeaCobra assigned to HMA-369 (now HMLA-369) aboard the USS Denver (LPD-9), USS Cleveland (LPD-7), and later the USS Dubuque (LPD-8), for sea-based interdiction of the Ho Chi Minh Trail in North Vietnam in the vicinity of Hon La (Tiger) Island. These were termed Marine Hunter-Killer (MARHUK) Operations and lasted from June to December Marine Cobras took part in the invasion of Grenada, during Operation Urgent Fury in 1983, flying close-support and helicopter escort missions. Two Marine AH-1Ts were shot down and three crew members killed. The Marines also deployed the AH-1 off the coast of Beirut, Lebanon in 1983, during that nation's civil war. The AH-1s were armed with Sidewinder missiles and guns as an emergency air defense measure against the threat of light civil aircraft employed by suicide bombers. USMC Cobras provided escort in the Persian Gulf in the late 1980s while the Iran Iraq War was ongoing. The Cobras sank three Iranian patrol boats while losing one AH-1T to Iranian anti-aircraft fire. USMC Cobras from the USS Saipan (LHA-2) flew "top cover" during an evacuation of American and other foreign nationals from Liberia in During the Gulf War, 78 Marine SuperCobras deployed, and flew a total of 1,273 sorties in Iraq with no combat losses. However, three AH-1s were lost to accidents during and after the combat operations. The AH- 1W units were credited with destroying 97 tanks, 104 armored personal carriers and vehicles, and two antiaircraft artillery sites during the 100-hour ground campaign. Marine Cobras provided support for the US humanitarian intervention in Somalia, during Operation Restore Hope in They were also employed during the U.S. invasion of Haiti in USMC Cobras 81

82 were used in U.S. military interventions in the former Yugoslavia in the 1990s, and assisted in the rescue of USAF Captain Scott O'Grady, after his F-16 was shot down by a SAM in June AH-1 Cobras continue to operate with the U.S. Marine Corps. USMC Cobras were also used in operations throughout the 1990s. USMC Cobras have also served in Operation Enduring Freedom in Afghanistan and in Operation Iraqi Freedom in the ongoing conflict in Iraq. While new replacement aircraft were considered as an alternative to major upgrades of the AH-1 fleet, Marine Corps studies showed that an upgrade was the most affordable, most supportable and most effective solution for the Marine Corps light attack helicopter mission. In 1971, Iran purchased 202 improved AH-1J Cobras, with the name "AH-IJ International", from the United States. This improved Cobra, known as the AH-1J International, resulted from this contract featured an uprated P&WC T400-WV-402 engine and stronger drivetrain. Recoil damping gear was fitted to the 20mm gun turret, and the gunner was given a stabilized sight and even a stabilized chair. 62 of the International AH-1Js delivered to the Shah's forces were TOW-capable, while the rest were not. They participated in the Iran Iraq War. Iranian AH-1J SeaCobras engaged in air combat with Iraqi Mi- 24s on several separate occasions during the war. The results of these engagements are disputed. One document cited that "Iranian AH-1Js engaged Iraqi MI-8 Hip and MI-24 Hind helicopters. Unclassified sources report that the Iranian AH-1 pilots achieved a 10:1 kill ratio over the Iraqi helicopter pilots during these engagements (1:5). Additionally, Iranian AH-1 and Iraqi fixed-wing aircraft engagements also occurred. Others claim that in the entire eight-year conflict, ten Iranian AH-1Js were lost in combat, compared to six Iraqi Mi-24s. The skirmishes are described as fairly evenly matched in another source. Iranian AH-1Js are still operating today and have undergone indigenous upgrade programs. In 1988, two Soviet MiG-23s shot down a pair of Iranian AH-1Js that had strayed into western Afghan airspace. Turkey bought ten AH-1W SuperCobras in the early 1990s, and supplemented this fleet with 32 ex-us Army AH-1 Cobras. The US Army Cobras included some TAH-1P trainers, while the rest were brought up to AH-1F standard. AH-1Ws have been used in the war against the Kurdistan Workers Party, or PKK. Turkey seeks to purchase nine additional AH-1Ws, but the US seems unwilling to sell them. However, Turkey is to obtain two AH-1Ws from the USMC inventory in The Bell AH-1Z Viper (fig. 76) is a twin-engine attack helicopter based on the AH-1W SuperCobra, that was developed for the United States Marine Corps. The AH-1Z features a four-blade, bearingless, composite main rotor system, uprated transmission, and a new target sighting system. The AH-1Z is part of the H-1 upgrade program. It is also called "Zulu Cobra" in reference to its variant letter. Fig. 76. The Bell AH-1Z Viper. The MH-6 Little Bird (also known as Killer Egg) and its attack variant, the AH-6 (fig. 77), are singleengine light helicopters used for special operations aviation in the United States Army. Originally based on a modified OH-6A, it was later based on the MD 500E, with a single five-bladed main rotor. The newest version, the MH-6M, is based on the MD 530F and has a single, six-bladed main rotor and four-bladed tail rotor. 82

83 Fig. 77. The AH-6 Little Bird. The Boeing AH-64 Apache (fig. 78) is a four-blade, twin-engine attack helicopter with a tailwheel-type landing gear arrangement, and a tandem cockpit for a crew of two. The Apache was developed as Model 77 by Hughes Helicopters for the United States Army's Advanced Attack Helicopter program to replace the AH-1 Cobra. First flown on 30 September 1975, the AH-64 features a nose-mounted sensor suite for target acquisition and night vision systems. The Apache is armed with a 30-millimeter (1.2 in) M230 Chain Gun carried between the main landing gear, under the aircraft's forward fuselage. It has four hardpoints mounted on stub-wing pylons, typically carrying a mixture of AGM-114 Hellfire and Hydra 70 rocket pods. The AH-64 also features double- and triple-redundant aircraft systems to improve survivability for the aircraft and crew in combat, as well as improved crash survivability for the pilots. Fig. 78. The AH-64 Apache. The U.S. Army selected the AH-64 over the Bell YAH-63 in 1976, awarding Hughes Helicopters a preproduction contract for two more aircraft. In 1982, the Army approved full production. McDonnell Douglas continued production and development after purchasing Hughes Helicopters from Summa Corporation in The first production AH-64D Apache Longbow, a greatly upgraded version of the original Apache, was delivered to the Army in March AH-64 production is continued by the Boeing Defense, Space & Security division; over one thousand AH-64s have been produced to date. The U.S. Army is the primary operator of the AH-64, however it has also become the primary attack helicopter of several nations it has been exported to, including Greece, Japan, Israel, the Netherlands and Singapore; as well as being produced under license in the United Kingdom as the AgustaWestland Apache. U.S. AH-64s have served in conflicts in Panama, Persian Gulf War, Kosovo War, Afghanistan, and Iraq. Israel has made active use of the Apache in its military conflicts in Lebanon and Gaza Strip; while two coalition allies have deployed their AH-64s in Afghanistan and Iraq. Following the cancellation of the AH-56 Cheyenne in 1972, in favor of United States Air Force and Marine Corps projects like the A-10 Thunderbolt II and Harrier, the United States Army sought an aircraft to fill an anti-armor attack role that would still be under Army command; the 1948 Key West Agreement forbade the Army from owning fixed-wing aircraft. The Army wanted an aircraft better than the AH-1 Cobra in firepower, performance and range. It would have the maneuverability for terrain following nap-of-the-earth (NoE) flying. To this end, the US Army issued a Request For Proposals (RFP) for an Advanced Attack Helicopter (AAH) on 83

84 15 November As a sign of the importance of this project, in September 1973 the Army designated their five most important projects, the "Big Five" with AAH included. Proposals were submitted by Bell, Boeing Vertol/Grumman team, Hughes, Lockheed, and Sikorsky. In July 1973, the U.S. Department of Defense selected finalists Bell and Hughes Aircraft's Toolco Aircraft Division (later Hughes Helicopters). This began the phase 1 of the competition. Each company built prototype helicopters and went through a flight test program. Hughes' Model 77/YAH-64A prototype first flew on 30 September 1975, while Bell's Model 409/YAH-63A prototype first flew on 1 October. After evaluating test results, the Army selected Hughes' YAH-64A over Bell's YAH-63A in Reasons for selecting the YAH- 64A included its more damage tolerant four-blade main rotor and the instability of the YAH-63's tricycle landing gear arrangement. The AH-64A then entered phase 2 of the AAH program. This called for building three pre-production AH-64s, and upgrading the two YAH-64A flight prototypes and the ground test unit up to the same standard. Weapons and sensor systems were integrated and tested during this time, including the new Hellfire missile. In 1981, three pre-production AH-64As were handed over to the US Army for Operational Test II. The Army testing was successful, but afterward it was decided to upgrade to the more powerful T700-GE-701 version of engine, rated at 1,690 shp (1,259 kw). The AH-64 was named the Apache in late 1981, keeping with the Army's traditional use of American Indian tribal names for its helicopters and it was approved for full scale production in In 1983, the first production helicopter was rolled out at Hughes Helicopter's facility at Mesa, Arizona. Hughes Helicopters was purchased by McDonnell Douglas for $470 million in The helicopter unit later became part of The Boeing Company with the merger of Boeing and McDonnell Douglas in August In 1986, the incremental or flyaway cost for the AH-64A was US$7.03 million and the average unit cost was approximately US$13.9 million based on total costs. In the mid-1980s, McDonnell Douglas studied an improved "AH-64B" design with an updated cockpit, new fire control system and other upgrades. In 1988 funding was approved for a multi-stage upgrade program to improve sensor and weapon avionic systems and incorporate some digital systems. However, improved technology was becoming available. It was decided to cancel the upgrade program for more ambitious changes. This would lead to the more advanced AH-64D Apache Longbow. Development of the AH-64D was approved by the Defense Acquisition Board in August The first AH-64D Apache Longbow prototype was flown on 15 April 1992, and testing of the prototypes ended in April 1995 after they had significantly outperformed the AH-64A model. On 13 October 1995 full-scale production of the Apache Longbow was approved and a $1.9 billion five year contract was signed in August 1996 to upgrade and rebuild 232 existing AH-64 Apaches. The first production AH-64D flew on 17 March 1997 and was delivered on 31 March The cost of the AH-64D program totaled US$11 billion through The Apache has a four-blade main rotor and a four-blade tail rotor. The crew sits in tandem, with the pilot sitting behind and above the copilot/gunner. The crew compartment and fuel tanks are armored such that the aircraft will remain flyable even after sustaining hits from 23-millimeter (0.91 in) gunfire. The AH-64 is powered by two General Electric T700 turboshaft engines with high-mounted exhausts on either side of the fuselage. Various models of engines have been used on the Apache, those in British service use engines from Rolls-Royce instead of General Electric. In 2004, General Electric Aviation began producing more powerful T700-GE-701D engines, rated at 2,000 shp (1,500 kw) for AH-64Ds. One of the revolutionary features at the introduction of the Apache was its helmet mounted display, the Integrated Helmet and Display Sighting System (IHADSS); among other abilities the pilot or gunner can slave the helicopter's 30 mm automatic M230 Chain Gun to his helmet, making the gun track head movements to point at where he looks. The M230E1 can be alternatively fixed to a locked forward firing position, or controlled via the Target Acquisition and Designation System (TADS). The AH-64 is designed to endure front-line environments and to operate during the day or night and in adverse weather using avionics, such as the Target Acquisition and Designation System, Pilot Night Vision System (TADS/PNVS), passive infrared countermeasures, GPS, and the IHADSS. A newer system that is replacing TADS/PNVS is Arrowhead (MTADS); it is manufactured by Lockheed Martin, a contract was made on 17 February 2005 to begin equipping all models of American Apaches. The AH-64 is adaptable to numerous different roles within its context as Close Combat Attack (CCA), and has a customizable weapons loadout for the role desired. In addition to the 30-mm M230E1 Chain Gun, the Apache carries a range of external stores on its stub-wing pylons, typically a mixture of AGM-114 Hellfire anti-tank missiles, and Hydra 70 general-purpose unguided 70 mm (2.76 in) rockets. The Stinger and AIM-9 Sidewinder air-to-air missiles and the AGM-122 Sidearm anti-radiation missile were evaluated beginning in the late 1980s. The Stinger was initially selected over the AIM-9, but the US Army is considering the Starstreak air-to-air missile instead. The stub-wing pylons also 84

85 have mounting points for use during ground helicopter maintenance; though in case of emergency the mount points can be used for harnessing personnel to the wings during transport. External fuel tanks can also be carried by the pylons to increase range and mission time. The U.S. Army formally accepted its first production AH-64A in January 1984 and training of the first pilots began later that year. The first operational Apache unit, 7th Battalion, 17th Cavalry Brigade, began training on the AH-64A in April 1986 at Fort Hood, Texas. Two operational units with 68 AH-64s first deployed to Europe in September 1987 and took part in large military exercises there. The helicopter was first used in combat in 1989, during Operation Just Cause, the invasion of Panama. The AH-64 participated in over 240 hours of combat attacking various targets, mostly at night. During Operation Desert Storm on 17 January 1991, eight AH-64As guided by four MH-53 Pave Low IIIs, were used to destroy a portion of the Iraqi radar network. This was the first attack of Desert Storm and it allowed attack aircraft into Iraq without detection. The Apaches carried an asymmetric load of Hydra 70 flechette rockets, Hellfires, and one auxiliary fuel tank each. During the 100-hour ground war a total of 277 AH- 64s took part, destroying over 500 tanks, numerous armored personnel carriers and other Iraqi vehicles. Only one AH-64 was lost in the war. It was hit by an RPG at close range and crashed, but the crew survived. The AH-64 played roles in the Balkans during separate conflicts in Bosnia and Kosovo in the 1990s. During these deployments the Apache encountered problems such as deficiencies in training, night vision equipment, fuel tanks, and survivability. On 27 April 1999 an Apache crashed during training in Albania due to a failure with the tail rotor, causing the entire fleet in the Balkans to be grounded in December Major General Dick Cody, commanding officer of the 101st Airborne at the time, wrote a strongly worded memo to the US Army Chief of Staff about the failures in training and equipment. The AH-64 took part in invasion of Iraq in 2003 during Operation Iraqi Freedom. In one engagement on 24 March 2003, 31 Apaches were damaged, and one Apache was shot down and captured by Iraqi troops near Karbala. The intended attack against an armored brigade of the Iraqi Republican Guard's Medina Division was unsuccessful. The tank crews had set up a "flak trap" amongst terrain and employed their guns to good effect. Iraqi officials claimed a farmer with a Brno rifle shot down the Apache, however the farmer denied involvement. The helicopter came down intact, and both the pilot and co-pilot were captured. The AH-64D was destroyed via air strike the following day. The U.S. Apaches have been serving in Operation Enduring Freedom in Afghanistan from American AH-64Ds are flying in Iraq and Afghanistan without the Longbow Fire Control Radar as there are no armored threats to be dealt with. Most Apache helicopters that have taken heavy combat damage have been able to continue their missions and return safely. In 2006, an Apache helicopter was downed by a Soviet-made Strela 2 (SA-7) in Iraq. The Apache is typically able to avoid hits by such missiles; however, in this instance it did not. As of 2009, 12 Apache helicopters were shot down by enemy fire during the Iraq War. According to Boeing the U.S. Army Apache fleet has accumulated more than 2 million flight hours since the first prototype aircraft flew in The UK operates a modified version of the Apache Longbow initially called the Westland WAH-64 Apache, and is designated Apache AH1 by the British Army. Westland built 67 WAH-64 Apaches under license from Boeing, following a competition between the Eurocopter Tiger and the Apache for the British Army's new Attack Helicopter in Important deviations made by AgustaWestland from the US variants of the Apache include replacing the engines with more powerful Rolls-Royce units, and the addition of a folding blade assembly for naval use; allowing British Apaches to operate from Royal Navy warships and auxiliaries. The Eurocopter AS332 Super Puma (fig. 79) is a four-bladed, twin-engine, medium-size utility helicopter marketed for both civil and military use. Originally designed and built by Aérospatiale, it is an enlarged and re-engined version of the original Aérospatiale Puma. The Super Puma first flew on 13 September Fig. 79. The Eurocopter AS332 Super Puma. 85

86 In 1974, Aérospatiale commenced development of a new medium transport helicopter based on its SA 330 Puma, announcing the project at the 1975 Paris Air Show. While the new design was of similar layout to the AS 330, it was powered by two of the new and more powerful Turbomeca Makila turboshaft engines powering a four-bladed composite main rotor, and was designed to be withstand damage better, with a more robust fuselage structure, a new crashworthy undercarriage and the ability to withstand battle damage to the rotor blades and other key mechanical systems. It was fitted with a ventral fin under the tail a more streamlined nose compared with the SA 330, while from the start was planned to be available with two fuselage lengths, with a short fuselage version offering similar capacity to the SA 330, which gives better performance in "hot and high" conditions and a stretched version allowing more passengers to be carried when weight is less critical. A pre-production prototype, the SA 331, modified from a SA 330 airframe with Makila engines and a new gearbox, flew on 5 September The first prototype of the full Super Puma made its maiden flight on 13 September 1978, being followed by a further five prototypes. The type has proved immensely successful, chosen by 37 military forces around the world, and some 1,000 civil operators. The Super Puma has proved especially well-suited to the North Sea oil industry, where it is used to ferry personnel and equipment to and from oil platforms. In civilian configuration it can seat approximately 18 passengers and two crew, though since the early 2000s most oil companies have banned use of the middle-rear seat reducing effective capacity to This down-rating is due to difficulties encountered in evacuating through the rear-most windows in crashes at sea. A wide variety of specialised military variants are in use, including dedicated Search and rescue (SAR) and Anti-submarine warfare (ASW) versions. Since 1990, military Super Pumas have been marketed as the AS532 Cougar. Fig. 80. The Boeing CH-47 Chinook. The Boeing CH-47 Chinook (fig. 80) is a twin-engine, tandem rotor heavy-lift helicopter. Its top speed of 170 knots (196 mph, 315 km/h) was faster than contemporary utility and attack helicopters of the 1960s. It is one of the few aircraft of that era, such as the C-130 Hercules and the UH-1 Iroquois, that is still in production and front line service with over 1,179 built to date. Its primary roles include troop movement, artillery 86

87 emplacement and battlefield resupply. It has a wide loading ramp at the rear of the fuselage and three externalcargo hooks. The Chinook was designed and initially produced by Boeing Vertol in the early 1960s. The helicopter is now produced by Boeing Rotorcraft Systems. Chinooks have been sold to 16 nations with the US Army and the Royal Air Force (see Boeing Chinook (UK variants)) being the largest users. The CH-47 is among the heaviest lifting Western helicopters. In late 1956, the Department of the Army announced plans to replace the CH-37 Mojave, which was powered by piston engines, with a new, turbine-powered helicopter. Turbine engines were also a key design feature of the smaller UH-1 "Huey" utility helicopter. Following a design competition, in September 1958, a joint Army-Air Force source selection board recommended that the Army procure the Vertol medium transport helicopter. However, funding for full-scale development was not then available, and the Army vacillated on its design requirements. Some in the Army aviation corps thought that the new helicopter should be a light tactical transport aimed at taking over the missions of the old piston-engined H-21 and H-34 helicopters, and consequently capable of carrying about fifteen troops (one squad). Another faction in the Army aviation corps thought that the new helicopter should be much larger to be able to airlift a large artillery piece, and have enough internal space to carry the new MGM-31 "Pershing" Missile System. Vertol began work on a new tandem-rotor helicopter designated Vertol Model 107 or V-107 in In June 1958, the US Army awarded a contract to Vertol for the aircraft under the YHC-1A designation. The YHC-1A had a capacity for 20 troops. Three were tested by the Army to derive engineering and operational data. However, the YHC-1A was considered by most of the Army users to be too heavy for the assault role and too light for the transport role. The decision was made to procure a heavier transport helicopter and at the same time upgrade the UH-1 "Huey" as a tactical troop transport. The YHC-1A would be improved and adopted by the Marines as the CH-46 Sea Knight in The Army then ordered the larger Model 114 under the designation HC-1B. The pre-production Boeing Vertol YCH-1B made its initial hovering flight on 21 September In 1962 the HC-1B was redesignated the CH-47A under the 1962 United States Tri-Service aircraft designation system. The name "Chinook" alludes to the Chinook people of the Pacific Northwest. The CH-47 is powered by two turboshaft engines, mounted on each side of the helicopter's rear end and connected to the rotors by driveshafts. Initial models were fitted with engines of 2,200 horsepower. The counter-rotating rotors eliminate the need for an anti-torque vertical rotor, allowing all power to be used for lift and thrust. The ability to adjust lift in either rotor makes it less sensitive to changes in the center of gravity, important for the cargo lifting role. If one engine fails, the other can drive both rotors. The "sizing" of the Chinook was directly related to the growth of the Huey and the Army's tacticians' insistence that initial air assaults be built around the squad. The Army pushed for both the Huey and the Chinook, and this focus was responsible for the acceleration of its air mobility effort. Improved and more powerful versions of the CH-47 have been developed since the helicopter entered service. The US Army's first major design leap was the now-common CH-47D, which entered service in Improvements from the CH-47C included upgraded engines, composite rotor blades, a redesigned cockpit to reduce pilot workload, improved and redundant electrical systems, an advanced flight control system and improved avionics. The latest mainstream generation is the CH-47F, which features several major upgrades to reduce maintenance, digitized flight controls, and is powered by two 4,733-horsepower Honeywell engines. A commercial model of the Chinook, the Boeing-Vertol Model 234, is used worldwide for logging, construction, fighting forest fires, and supporting petroleum extraction operations. On 15 December 2006, the Columbia Helicopters company of the Salem, Oregon, metropolitan area, purchased the Type Certificate of the Model 234 from Boeing. The Chinook has also been licensed to be built by companies outside of the United States, such as Elicotteri Meridionali (now AgustaWestland) in Italy, Kawasaki in Japan, and a company in the United Kingdom. The Army finally settled on the larger Chinook as its standard medium transport helicopter and as of February 1966, 161 aircraft had been delivered to the Army. The 1st Cavalry Division had brought their organic Chinook battalion with them when they arrived in 1965 and a separate aviation medium helicopter company, the 147th, had arrived in Vietnam on 29 November This latter company was initially placed in direct support of the 1st Infantry Division. The most spectacular mission in Vietnam for the Chinook was the placing of artillery batteries in perilous mountain positions inaccessible by any other means, and then keeping them resupplied with large quantities of ammunition. The 1st Cavalry Division found that its Chinooks were limited to 7,000 pounds payload when operating in the mountains, but could carry an additional 1,000 pounds when operating near the 87

88 coast. The early Chinook design was limited by its rotor system which did not permit full use of the installed power, and users were anxious for an improved version which would upgrade this system. As with any new piece of equipment, the Chinook presented a major problem of "customer education". Commanders and crew chiefs had to be constantly alert that eager soldiers did not overload the temptingly large cargo compartment. It would be some time before troops would be experts at using sling loads. The Chinook soon proved to be such an invaluable aircraft for artillery movement and heavy logistics that it was seldom used as an assault troop carrier. Some of the Chinook fleet were used for casualty evacuation, due to the very heavy demand for the helicopters they were usually overburdened with wounded. Perhaps the most cost effective use of the Chinook was the recovery of other downed aircraft. The Chinooks were generally armed with a single 7.62 millimeter M60 machine gun on a pintle mount on either side of the machine for self-defense, with stops fitted to keep the gunners from firing into the rotor blades. Dust filters were also added to improve engine reliability. At its peak employment in Vietnam, there were 22 Chinook units in operation. Of the nearly 750 Chinooks in the US and Republic of Vietnam fleets, about 200 were lost in combat or wartime operational accidents. US Army supplied Chinooks to the Australian Task Force as required. During the 1970s, the United States and Iran had a strong relationship, in which the Iranian armed forces began to use many American military aircraft, most notably the F-14 Tomcat, as part of a modernisation programme. After an agreement signed between Boeing and Elicotteri Meridionali, the Imperial Iranian Air Force purchased 20 Elicotteri Meridionali-built CH-47Cs in The Imperial Iranian Army Aviation purchased 70 CH-47Cs from Elicotteri Meridionali during the period of In late 1978, Iran placed an order for an additional 50 helicopters with Elicotteri Meridionali, but that order was canceled immediately after the revolution. Despite the arms embargo on place upon Iran, they have managed to keep their fleet operational. In the 1978 Iranian Chinook shootdown, four Iranian CH-47C Chinooks penetrated km into Soviet airspace in the Turkimenistan Military District. They were intercepted by a MiG-23M which shot down one Chinook, killing eight crew members, and forced a second one to land. Chinooks were used in efforts by the Imperial Iranian loyalist forces to resist the 1979 Iranian revolution. During the war with Iraq, Iran made heavy use of its US-bought equipment, and lost at least 8 Chinooks during the period; most notably during a clash on 15 July 1983, where an Iraqi Mirage F-1 destroyed three Iranian CH-47s transporting troops to the front line. The Chinook was used both by Argentina and the United Kingdom during the Falklands War in The Argentine Air Force and the Argentine Army deployed four CH-47C (two each) which were widely used in general transport duties. Of the Army's airframes one was destroyed on ground by a Harrier while the other was captured (and reused after the war) by the British. Both Air Force helicopters returned to Argentina and remained in service until Approximately 163 CH-47Ds served in Kuwait and Iraq during Operations Desert Shield and Desert Storm in The CH-47D has been seen wide use in Operation Enduring Freedom in Afghanistan and Operation Iraqi Freedom in Iraq. The Chinook is being used in air assault missions, inserting troops into fire bases and later bringing food, water, and ammunition. It is also the casualty evacuation (casevac) aircraft of choice in the British Army. In today's usage it is typically escorted by attack helicopters such as the AH-64 Apache for protection. Its tandem rotor design and lift capacity have been found to be particularly useful in the mountainous terrain of Afghanistan where high altitudes and temperatures limit the use of the UH-60 Black Hawk. The CH-47F is being fielded by more units such as the 101st Combat Aviation Brigade and 4th Combat Aviation Brigade in the U.S. Army as it continues to operate in Afghanistan. The Chinooks of several nations have participated in the Afghanistan War, including aircraft from Britain, Italy, the Netherlands, Spain, Canada, and Australia. Despite the age of the Chinook, it is still in heavy demand, in part due its proven versatility and ability to operate in demanding environments such as Afghanistan. Three CH-47 Chinooks were used to cool Reactors 3 and 4 of the Fukushima Nuclear powerplant with sea water after the 9.0 earthquake in To protect the crew from the heightened radiation levels, lead plates were attached to the floor. The Sikorsky CH-53E Super Stallion (fig. 81) is the largest and heaviest helicopter in the United States military. It was developed from the CH-53 Sea Stallion, mainly by adding a third engine. Sailors commonly refer to the Super Stallion as the "Hurricane Maker" because of the downwash the helicopter generates. It was built by Sikorsky Aircraft for the United States Marine Corps. The less common MH-53E Sea Dragon fills the United 88

89 States Navy's need for long range mine sweeping or Airborne Mine Countermeasures (AMCM) missions, and perform heavy-lift duties for the Navy. The CH-53E/MH-53E are designated "S-80" by Sikorsky. Currently under development is the CH-53K, which will be equipped with new engines, new composite rotor blades, and a wider cabin. Fig. 81. The Sikorsky CH-53E Super Stallion. The Eurocopter Tiger (company designation EC 665), (fig. 82), is an attack helicopter manufactured by Eurocopter. In Germany it is known as the Tiger; in France and Spain it is called the Tigre. 89

90 Fig. 82. The Eurocopter Tiger EC 665. The Sikorsky X2 (fig. 83) is an experimental compound helicopter with coaxial rotors under development by the American aircraft manufacturer Sikorsky Aircraft. Fig. 83. The Sikorsky X2. Sikorsky has incorporated decades of company research and development into X2 Technology helicopters. The S-69/XH-59A Advancing Blade Concept Demonstrator showed high speed was possible with a coaxial helicopter and auxiliary propulsion; the Cypher UAV expanded company knowledge of the unique aspects of flight control laws in a fly by wire aircraft with coaxial rotors; and the RAH-66 Comanche, which developed expertise in composite rotors and advanced transmission design. On 4 May 2009, Sikorsky unveiled a mock-up of a Light Tactical Helicopter derivative of the X2. The X2 first flew on 27 August 2008 from Schweizer Aircraft's (a division of Sikorsky Aircraft Corporation) facility at Horseheads, New York. The flight lasted 30 minutes. This began a 4-phase flight test program, to culminate with reaching a planned 250-knot top speed. The X2 completed flights with its pusher propeller fully engaged in July Sikorsky completed phase 3 of the testing with the X2 hitting 181 knots in test flight in late May On 26 July 2010, Sikorsky announced that the X2 exceeded 225 knots (259 mph; 417 km/h) during flight testing in West Palm Beach Florida, unofficially surpassing the current FAI rotorcraft world speed record of 216 knots (249 mph) set by a modified Westland Lynx in The X2 flight was purposefully made 37 years to the date of the S-69's first flight. On 15 September 2010, test pilot Kevin Bredenbeck achieved Sikorsky's design goal for the X2 when he flew it at a speed of 250 knots (290 mph; 460 km/h) in level flight, an unofficial speed record for a helicopter. The demonstrator also reached a speed of 260 knots (300 mph; 480 km/h) in a shallow 2 to 3 dive. 90

91 SHIPS STOVL STOVL is an acronym for short take off and vertical landing. This is the ability of some aircraft to take off from a short runway or take off vertically if it does not have a very heavy payload and land vertically (i.e. with no runway). The formal NATO definition (since 1991) is: A Short Take-Off and Vertical Landing aircraft (aéronef à décollage court et atterrissage vertical) is a fixed-wing aircraft capable of clearing a 15 m (50 ft) obstacle within 450 m (1,500 ft) of commencing take-off run, and capable of landing vertically. This is often accomplished on aircraft carriers through the use of "ski-jump" runways, instead of the conventional catapult system. STOVL use tends to allow aircraft to carry a larger payload as compared to during VTOL use, while still only requiring a short runway. The most famous example is probably the Hawker Siddeley Harrier, which though technically a VTOL aircraft, is operationally a STOVL aircraft due to the extra weight it carries at take off for fuel and armaments. The same is true of the F-35B Lightning II, which demonstrated VTOL capability in test flights but is operationally STOVL. In 1951, the Lockheed XFV-1 and the Convair XFY tailsitters were both designed around the Allison YT40 turboprop engine driving contra-rotating propellers. The British Hawker P.1127 took off vertically in 1960, and demonstrated conventional take off in By 1964 the first development aircraft, the Hawker Siddeley Kestrel, were flying. These were flown by a tripartite squadron of British, US and West German pilots. The first Hawker Siddeley Harrier flew in In 1962, Lockheed built the XV-4 Hummingbird for the U.S. Army. It sought to "augment" available thrust by injecting the engine exhaust into an ejector pump in the fuselage. First flying vertically in 1963, it suffered a fatal crash in It was converted into the XV-4B Hummingbird for the U.S. Air Force as a testbed for separate, vertically mounted lift engines, similar to those used in the Yak-38 Forger. That plane flew and later crashed in The Ryan XV-5 Vertifan, which was also built for the U.S. Army at the same time as the Hummingbird, experimented with gas driven lift fans. That plane used fans in the nose and each wing, covered by doors which resembled half garbage can lids when raised. However, it crashed twice, and proved to generate a disappointing amount of lift, and was difficult to transition to horizontal flight. Of dozens of VTOL and V/STOL designs tried from the 1950s to 1980s, only the subsonic Hawker Siddeley Harrier and Yak-38 Forger reached operational status, with the Forger being withdrawn after the fall of the Soviet Union. Boeing had studied another odd-looking supersonic fighter in the 1960s which never made it beyond photos in Aviation Week. Rockwell International built, and then abandoned, the Rockwell XFV-12 supersonic fighter which had an unusual wing which opened up like window blinds to create an ejector pump for vertical flight. It never generated enough lift to get off the ground despite developing 20,000 lbf of thrust. The French had a nominally Mach 2 Dassault Mirage IIIV fitted with no less than 8 lift engines that flew (and crashed), but did not have enough space for fuel or payload for combat missions. The German EWR VJ 101 used swiveling engines mounted on the wingtips with fuselage mounted lift engines, and the VJ 101C X1 reached supersonic flight (Mach 1.08) on July 29, The supersonic Hawker Siddeley P.1154 which competed with the Mirage IIIV for NATO use was cancelled even as the aircraft were being built. NASA uses the abbreviation SSTOVL for Supersonic Short Take-Off / Vertical Landing, and as of 2011, the X-35B/F-35B are the only aircraft to conform with this combination within one flight. The experimental Mach 1.7 Yakovlev Yak-141 did not find an operational customer, but its rotating rear nozzle technology found good use with the F-35B. The F-35 Lightning II is expected to enter service by Larger STOVL designs were considered, the Armstrong Whitworth AW.681 cargo aircraft was under development when cancelled in The Dornier Do 31 got as far as three experimental aircraft before cancellation in Although mostly a VTOL design, the V-22 Osprey has increased payload when taking off from a short runway. The Hawker Siddeley Harrier, colloquially the "Harrier Jump Jet", was developed in the 1960s and was the first generation of the Harrier series of aircraft. It was the first operational close-support and reconnaissance fighter aircraft with Vertical/Short Takeoff and Landing (V/STOL) capabilities and the only truly successful V/STOL design of the many that arose in that era. The Harrier was produced directly from the Hawker Siddeley Kestrel prototypes following the cancellation of a more advanced supersonic aircraft, the Hawker Siddeley 91

92 P The Royal Air Force (RAF) ordered the Harrier GR.1 and GR.3 (fig. 84) variants in the late 1960s. It was exported to the United States as the AV-8A, for use by the US Marine Corps (USMC), in the 1970s. Fig. 84. The Hawker Siddeley Harrier; this is an RAF Harrier GR.3. The RAF positioned the bulk of their Harriers in West Germany to defend against a potential invasion of Western Europe by the Soviet Union; the unique abilities of the Harrier allowed the RAF to disperse their forces away from vulnerable and well-known airbases. The USMC used their Harriers primarily for close air support, operating from amphibious assault ships, and if needed forward operating bases. Harrier squadrons saw several deployments overseas. The Harrier's ability to operate with minimal ground facilities and very short runways allowed it to be used at locations unavailable to other fixed-wing aircraft. In the 1970s the British Aerospace Sea Harrier was developed from the Harrier for use by the Royal Navy (RN) on Invincible class aircraft carriers. The Sea Harrier and the Harrier were crucial during the 1982 Falklands War, in which the aircraft proved to be flexible and versatile. The RN Sea Harriers provided fixed-wing air defence while the RAF Harriers focused on ground-attack missions in support of the advancing British land force. The Harrier was also extensively redesigned as the AV-8B Harrier II and British Aerospace Harrier II by the team of McDonnell Douglas and British Aerospace. The innovative Harrier family and its Rolls-Royce Pegasus engines with thrust vectoring have generated long-term interest in V/STOL aircraft. Similar V/STOL operational aircraft include the contemporary Soviet Yakovlev Yak-38 as well as one variant of the Lockheed Martin F-35 Lightning II, which is currently under development. The F-35 Lightning II joint strike fighter (JSF), is being developed by Lockheed Martin Aeronautics Company for the US Air Force, Navy and Marine Corps and the UK Royal Navy. The stealthy, supersonic multirole fighter was designated the F-35 Lightning II in July The JSF is being built in three variants: a conventional take-off and landing aircraft (CTOL) for the US Air Force; a carrier variant (CV) for the US Navy; and a short take-off and vertical landing (STOVL) aircraft for the US Marine Corps and the Royal Navy (fig. 85). Fig. 85. The F-35B short take-off and vertical landing (STOVL) variant for the US Marine Corps and the Royal Navy. 92

93 The Lockheed Martin F-35 Joint Strike Fighter short takeoff/vertical landing (STOVL) variant flew faster than the speed of sound for the first time June 10, achieving a significant milestone. The aircraft accelerated to Mach 1.07 (727 miles per hour) on the first in a long series of planned supersonic flights. "For the first time in military aviation history, supersonic, radar-evading stealth comes with short takeoff/vertical landing capability," said Bob Price, Lockheed Martin's F-35 U.S. Marine Corps program manager. "The supersonic F-35B can deploy from small ships and austere bases near front-line combat zones, greatly enhancing combat air support with higher sortie-generation rates." The F-35B will enter service for the Marines, the United Kingdom's Royal Air Force and Royal Navy, and the Italian Air Force and Navy. The F-35B is the short takeoff and vertical landing (STOVL) variant of the aircraft. Similar in size to the A variant, the B sacrifices about a third of the other versions fuel volume to make room for the vertical flight system. Takeoffs and landing with vertical flight systems are by far the riskiest, and in the end, a decisive factor in design. Like the AV-8B Harrier II, the B s guns will be carried in a ventral pod. Whereas the F-35A is stressed to 9 g, the F-35B is stressed to 7 g. The F-35B was unveiled at Lockheed Martin's Fort Worth plant on 18 December 2007, and the first test flight was on 11 June The three-bearing swivel nozzle that directs the full thrust of the afterburning jet engine is moved by a fueldraulic actuator, using pressurized jet fuel. Unlike the other variants, because it can land vertically the F-35B has no landing hook. The "STOVL/HOOK" button in the cockpit initiates conversion instead of dropping the hook. The F-35B sends jet thrust directly downwards during vertical takeoffs and landing and the nozzle is being redesigned to spread the output out in an oval rather than a small circle so as to limit damage to asphalt and ship decks. The United States Marine Corps plans to purchase 340 F-35Bs, to replace all current inventories of the F/A-18 Hornet (A, B, C and D-models), and AV-8B Harrier II in the fighter, and attack roles. The Royal Air Force and Royal Navy had planned to use the F-35B to replace their Harrier GR9s. One of the Royal Navy requirements was that the F-35B design should have a Shipborne Rolling and Vertical Landing (SRVL) mode so that wing lift could be added to powered lift to increase the maximum landing weight of carried weapons. This method of landing is slower than wire arrested landing and could disrupt regular carrier operations, as the landing method uses the same pattern of approach as wire arrested. With SRVL, the aircraft is able to "bring back" 2 1K JDAM, 2 AIM-120 and reserve fuel. However, in October 2010, Prime Minister David Cameron announced that the UK would change their F-35 order to the CATOBAR F-35C variant. Commandant of the Marine Corps, General James Amos has said that, in spite of its increasing costs and schedule delays, there is no plan B to substitute for the F-35B. The F-35B is larger than the aircraft it replaces, which required the USS America (LHA-6) to be designed without needed well deck capabilities. In 2011, the USMC and USN signed an agreement that the USMC will purchase 340 F-35B and 80 F-35C while the USN will purchase 260 F-35C. The five squadrons of Marine Corps F-35Cs will be assigned to the Navy carriers while the Marine Corps F-35Bs will be used on Amphibious ships and ashore. On 6 January 2011, Gates said that the 2012 budget would call for a two year pause in F-35B production during which the aircraft may be redesigned, or canceled if unsuccessful. Gates stated, "If we cannot fix this variant during this time frame, and get it back on track in terms of performance, cost and schedule, then I believe it should be canceled." Lockheed Martin executive vice president Tom Burbage and former Pentagon director of operational testing Tom Christie have said that most of the delays in the total program have been due to issues with the F- 35B, which forced massive redesigns on the other versions. The USMC intends to declare Initial Operational Capability with about 50 F-35s running interim Block 2B software in the 2014 to 2015 timeframe. The Bell-Boeing V-22 Osprey (fig. 86) is an American multi-mission, military, tiltrotor aircraft with both a vertical takeoff and landing (VTOL), and short takeoff and landing (STOL) capability. It is designed to combine the functionality of a conventional helicopter with the long-range, high-speed cruise performance of a turboprop aircraft. The V-22 originated from the United States Department of Defense Joint-service Vertical takeoff/landing Experimental (JVX) aircraft program started in The team of Bell Helicopter, and Boeing Helicopters was awarded a development contract in 1983 for the tiltrotor aircraft. The Bell Boeing team jointly produce the aircraft. The V-22 first flew in 1989, and began flight testing and design alterations; the complexity and difficulties of being the first tiltrotor intended for military service in the world led to many years of development. 93

94 Fig. 86. The Bell-Boeing V-22 Osprey. The United States Marine Corps began crew training for the Osprey in 2000, and fielded it in 2007; it is supplementing and will eventually replace their CH-46 Sea Knights. The Osprey's other operator, the U.S. Air Force fielded their version of the tiltrotor in Since entering service with the U.S. Marine Corps and Air Force, the Osprey has been deployed in both combat and rescue operations over Iraq, Afghanistan and Libya (fig. 87). Fig. 87. The Bell-Boeing MV-22B Osprey, (M from Marine). 94

95 Cap. 4. SPECIAL AIRCRAFT The PA-23 was the first twin-engine design from Piper and was developed from a proposed "Twin Stinson" design inherited when Piper bought the Stinson Division of the Consolidated Vultee Aircraft Corporation (fig. 88). The prototype PA-23 was a four-seater low-wing all-metal monoplane with a twin tail, powered by a two 125 hp Lycoming O-290-D piston engines the prototype first flew 2 March The aircraft performed badly and it was redesigned with a single vertical stabilizer and an all-metal rear fuselage and more powerful 150 hp Lycoming O-320-A engines. Two new prototype of re-designed aircraft now named Apache were built in 1953 and entered production in 1954; 1,231 were built. In 1958, the Apache 160 was produced by upgrading the engines to 160 hp (119 kw), and 816 were built before being superseded by the Apache 235, which went to 235 hp (175 kw) engines and swept tail surfaces (119 built). In 1958 an upgraded version with 250 hp (186 kw) Lycoming O-540 engines and adding a swept vertical tail was produced as the PA and was named Aztec. These first models came in a five-seat configuration which became available in In 1961 a longer nosed variant the Aztec B entered production. The later models of the Aztec were equipped with IO-540 fuel-injected engines and six-seat capacity, and continued in production until There were also turbocharged versions of the later models, which were able to fly at higher altitudes. The US Navy acquired 20 Aztecs, designating them UO-1, which changed to U-11A when unified designations were adopted in In 1974, Piper produced a single experimental PA-41P Pressurized Aztec concept. This concept was short-lived, however, as the aspects of the Aztec that made it so popular for its spacious interior and ability to haul large loads did not lend themselves well to supporting the sealed pressure vessel required for a pressurized aircraft. The project was scrapped, and the one pressurized Aztec produced, N9941P, was donated to Mississippi State University, where it was used for testing purposes. In 2000, N9941P was donated to the Piper Aviation Museum in Lock Haven, PA, on the condition that it never be flown again. It now sits there on display. Fig. 88. The Piper PA Aztec F aircraft. The DHC-6 Twin Otter is a Canadian 19-passenger STOL (Short Takeoff and Landing) utility aircraft developed by de Havilland Canada and currently produced by Viking Air. The aircraft's fixed tricycle undercarriage, STOL abilities and high rate of climb have made it a successful cargo, regional passenger airliner and MEDEVAC aircraft. In addition, the Twin Otter has been popular with commercial skydiving operations, and it is used by the United States Army Parachute Team (fig. 89). Development of the aircraft began in 1964, with the first flight on May 20, A twin-engined replacement for the single-engined Otter had been planned by de Havilland Canada. Twin engines not only provided improved safety but also allowed for an increase in payload while retaining the renowned STOL qualities. Design features included double slotted trailing edge flaps and ailerons that work in unison with the flaps to boost STOL performance. The availability of the 550 shp (410 kw) Pratt and Whitney Canada PT6A-20 propeller turbine engine in the early 1960s made the concept of a twin more feasible. To bush operators, the improved reliability of turboprop power and the improved performance of a twin-engined configuration made it an immediately popular alternative to the single engine, piston-powered Otter which had been flying since

96 The first six aircraft produced were designated Series 1, indicating that they were prototype aircraft. The initial production run consisted of Series 100 aircraft, serial number seven to 115 inclusive. In 1968, Series 200 production began with serial number 116. Changes made at the beginning of Series 200 production included improving the STOL performance, adding a longer nose that was equipped with a larger baggage compartment (except to aircraft fitted with floats) and fitting a larger door to the rear baggage compartment. All Series 1, 100 and 200 aircraft and their variants (110, 210) were fitted with the 550 shaft horsepower PT6A-20 engines. In 1969, the Series 300 was introduced, beginning with serial number 231. Both aircraft performance and payload were improved by fitting more powerful PT6A-27 engines. This was a 680 hp (510 kw) engine that was flat-rated to 620 hp (460 kw) for use in the Series 300 Twin Otter. The Series 300 proved to be the most successful variant by far, with 614 Series 300 aircraft and their sub-variants (Series 310 for United Kingdom operators, Series 320 for Australian operators, etc.) sold before production ended in Fig. 89. De Havilland Canada DHC Twin Otter aircraft. After Series 300 production ended, the remaining tooling was purchased by Viking Air of Victoria, British Columbia, who manufacture replacement parts for all of the out of production de Havilland Canada aircraft. On February 24, 2006 Viking purchased the type certificates from Bombardier Aerospace for all the out of production de Havilland DHC-1 through DHC-7 aircraft. The ownership of the certificates gives Viking the exclusive right to manufacture new aircraft. On July 17, 2006, at the Farnborough Air Show, Viking Air announced its intention to offer a Series 400 Twin Otter. On April 2, 2007 Viking announced that with 27 orders and options in hand, it was restarting production of the Twin Otter, equipped with a more powerful Pratt & Whitney Canada PT6A-34/35 engine. As of November 2007, 40 firm orders and 10 options had been taken and a new assembly plant established in Calgary, Alberta. Zimex Aviation of Switzerland received the first new production aircraft, serial number 845, in July Major changes introduced with the Series 400 include Honeywell Primus Apex fully integrated avionics, deletion of the AC electrical system, deletion of the beta backup system, modernization of the electrical and lighting system, and use of composites for non-load-bearing structures such as doors. The Edgley EA-7 Optica (fig. 90) was a British light aircraft designed for observation work, intended as a low-cost alternative to helicopters, retailing originally at around US$200,000. The Optica, designed by John Edgley and built by Brooklands Aerospace, had an unusual configuration with a fully-glazed forward cabin seating three across, reminiscent of an Alouette helicopter. Behind it was situated a Lycoming flat-six engine powering a ducted fan, twin boom cantilever tailplane with twin rudders and a high-mounted single elevator. The fixed tricycle undercarriage had the nosewheel offset to the left. The wings were unswept and untapered, and the aircraft was of a fairly standard all-metal construction with stressed aluminium skin. The aircraft's distinctive appearance led to it being known as the "bug-eye" in some popular reports. It first flew on 14 December 1979, powered by a 150 hp (112 kw) Lycoming O-320 engine and flown by the chief pilot of the Cranfield College of Aeronautics. The Optica, now powered by a more powerful Lycoming O-540, entered production in 1983, achieving certification on 8 February A crash of police Optica G-KATY on 15 May 1985 killed two members of the Hampshire Constabulary. The cause was suspected to be a stall: insufficient airspeed during a turn causing instability. The reason for the low speed was never 96

97 established. This led to the bankruptcy of Edgley, with Optica Industries being formed in October 1985 to continue production and 25 were built before a fire caused by arson destroyed the factory and all but one flying Optica. The company was reformed again as Brooklands Aircraft, and the Optica returned to production, production ceasing in March 1990, when Brooklands Aircraft went bankrupt. The Design of the Optica has now been bought by John Edgley once more (along with the design for the FLS Sprint 160). Edgley hopes to put both types into production and further to that goal the Optica 300 Series s/n 021 G-BOPO is being restored as a UK type demonstrator. Fig. 90. Edgley EA-7 Optica aircraft. The P-791 is an experimental aerostatic/aerodynamic hybrid airship developed by Lockheed-Martin corporation (fig. 91). The first flight of the P-791 was on 31 January 2006 at the company's flight test facility on the Palmdale Air Force Plant 42. It has a unique tri-hull shape, with disk-shaped cushions on the bottom for landing. A very similar design can be seen in the Long-Endurance Multi-intelligence Vehicle (LEMV). Fig. 91. Lockheed Martin P-791 aircraft. The P-791 is an example of a hybrid airship. In such designs, part of the weight of the craft and its payload are supported by aerostatic (buoyant) lift and the remainder is supported by aerodynamic lift. The combination of aerodynamic and aerostatic lift is an attempt to benefit from both the high speed of aerodynamic craft and the lifting capacity of aerostatic craft. Critics of the hybrid approach have labeled it as being the "worst of both worlds" in that such craft require a runway for take-off and landing, are difficult to control and protect on the ground, and have relatively poor aerodynamic performance. Proponents of hybrid designs claim that these shortcomings can be overcome through advanced technologies. In particular, it has been proposed that buoyancy control mechanisms can minimize or eliminate the need for a runway. Recently, Worldwide Aeros Corporation has successfully tested its COSH system which will regulate its upcoming ML866's static heaviness. No other hybrid airship design has been developed past the initial experimental stages. Although many such designs have been proposed, very few have flown. One hybrid airship design that did take flight was the Aereon 26. The development of this aircraft was documented in the book "The Deltoid Pumpkinseed" by John McPhee. 97

98 Although Lockheed-Martin is developing a design for the DARPA project WALRUS, the company claims that the P-791 is unrelated to WALRUS. Nonetheless, the design represents an approach that may well be applicable to WALRUS. Some believe that Lockheed-Martin has used the secret P-791 program as a way to get a head-start on Worldwide Aeros Corp, the other Phase I WALRUS competitor. The company has released no details about the design of the aircraft. However, from a distance, the P- 791 appears to be essentially identical in design to the SkyCat design unsuccessfully promoted by the now defunct British company Advanced Technologies Group (ATG). SkyCat technologies are once again being developed and promoted in the US by the Hybrid Aircraft Corporation (HAC) located in New Mexico. Press reports have also confirmed that the P-791 incorporates some of the most distinctive design features of the SkyCat, specifically the use of hover/suction skirts as "landing gear." Industry observers have noted that engineering individuals closely associated with HAC later worked on the WALRUS project and P-791 at Lockheed-Martin. A plane of high overall gauge is Airbus A300B4-608ST Super Transporter (fig. 92). Fig. 92. Airbus A300B4-608ST Super Transporter aircraft. It can carry even and an aircraft (fig. 93). 98

99 Fig. 93. Airbus A300B4-608ST Super Transporter aircraft. The BD-5 Micro (fig. 94) is a series of small, single-seat homebuilt aircraft created in the late 1960s by US aircraft designer Jim Bede and introduced to the market primarily in "kit" form by the now-defunct Bede Aircraft Corporation in the early 1970s. The BD-5 has a small, streamlined fuselage holding its semi-reclined pilot under a large canopy, with the engine installed in a compartment in the middle of the fuselage, and a propeller or jet engine in the BD-5J variant, mounted immediately to the rear of the cockpit. The combination of fighter-like looks and relatively low cost led to the BD-5 selling over 5,000 kits or plans, with approximately 12,000 orders being taken for a proposed factory-built FAA certified version. However, few of the kit versions were actually completed due to the company's bankruptcy in the mid-1970s, and none of the factory built "D" models produced, brought on by the failure to deliver a reliable engine for the design. In total, only a few hundred BD-5 kits were completed, although many of these are still being flown today. The BD-5J version holds the record for the world's lightest jet aircraft, weighing only lb (162.7 kg). Fig. 94. Bede BD-5B aircraft. Development of the "Micro" dates back as early as 1967, when Jim Bede was inspired by the Schleicher ASW 15. At the time, however, Bede was working on the Bede BD-4 design. The BD-4 was a fairly conventional looking high-wing four-seater, but it offered good performance and was fairly inexpensive. Over the lifetime of the company about 600 BD-4s were sold, a success by any measure. Serious work on the Micro started in 1970, with construction of the prototype starting in earnest late that year. While the BD-4 was fairly conventional looking, the Micro was a radical design. It is an extremely 99

100 small one-seat design that looked more like a jet fighter than a "prop plane," with the pilot sitting in a semireclined position under a large fighter-like plexiglas canopy only inches above the pilot's head. Behind the cockpit was a compartment housing a two-cylinder air-cooled 40 hp engine driving a pusher propeller. Two versions were planned, the BD-5A with "short" 14' 3" (4.34 m) wings tuned for high speeds and acrobatics, and the BD-5B with a 21' 6" (6.55 m) wings for longer range and powered glider use. Builders could optionally buy both wings, switching them in about 10 minutes. For improved performance the aircraft featured both a V-tail and retractable landing gear in order to reduce drag. Calculated drag was so low that spoilers were added to the wing in order to improve deceleration for landing. This was apparently the first application of spoilers on a light aircraft. The low drag implied excellent performance; with the short wings it would reach 210 mph (340 km/h) in cruise, while the long-wing BD-5B would be only slightly slower and have an extended range of 1,215 miles. In addition to being easy to fly, the BD-5 was also intended to be easy to build and own. The fuselage was constructed primarily from fiberglass panels over an aluminum frame, reducing construction time to only a few hundred hours. Although the early designs required some welding in the landing gear area, it was planned that this would be removed in the kit versions, so construction would require no special tooling or skills. Even the cost of operation would be extremely low, offering fuel efficiency of almost 40 mpg. With the wings removed the aircraft could be packed into a small custom trailer, allowing it to be towed away by car for storage in a garage, and from there to any suitable flat area for takeoff. Bede published an information booklet about the BD-5 in November Several very positive magazine articles appeared at this point. The October 1971 issue of Science & Mechanics had the BD-5 on the cover, listing the price as $1,950 and a top speed of 215 MPH. The associated article showed the construction of the original prototype, with numerous claims about how easy it was to construct. The August 1973 issue of Popular Science also covered the aircraft, although it listed the price at $2,965. A feeding frenzy followed as the "mini fighter" generated intense demand. As one author put it, "Even before the plane first left the ground, thoughts of flying the sleek, bullet-shaped aircraft with its pusher prop stimulated the imagination of nearly everyone who had heard of the program." On February 24, 1971, the first $200 deposit to reserve a "place in line" to receive a kit was accepted, with the target shipping date being May 24, By August 1971, 800 deposits had been taken, even though the first BD-5 prototype had yet to complete high-speed taxi tests. By the end of the year, they had over 4,300 orders, making it one of the most popular general aircraft projects in modern history. The prototype, N500BD, flew briefly on September 12, 1971, powered by a 36 hp Polaris Industries snowmobile engine. The stability of the aircraft with the original V-tail was marginal at best, and clearly needed a redesign. With the original fiberglass fuselage this was a time consuming process, so the decision was made to switch to an all-metal fuselage with the components incorporating compound curves produced using hydroformed aircraft-grade aluminum alloy. These could be modified with relative ease during the testing cycle. It also made economic sense as the orders rolled in, as assembly line production of stamped metal parts is expensive to set up but less expensive in the long run. By December 1971 the tooling for the new fuselage was in development. The aircraft now featured a longer, more pointed nose, whereas the more ovoid N500BD had been patterned on the ASW 15. While this work was in progress, Bede continued to experiment with modifications to the tail, eventually abandoning the V- tail and changing to a more conventional vertical rudder and horizontal elevator layout with highly swept surfaces. Further testing on N500BD showed flow interference between the horizontal surfaces and the propeller, and the elevator was raised six inches to correct it, placing it about mid-way up the rear fuselage. The first example of the new fuselage arrived in March 1972, and was fitted with a new Kiekhaefer Aeromarine engine Bede had seen at the Oshkosh Airshow in Finished as N501BD, numerous small delays prevented it from flying until July 11, These flights demonstrated continued problems with the tail design, which was again redesigned, losing the sweep and becoming much more conventional. The program was now far too large for Bede to handle alone. In March 1972, he hired Burt Rutan to head the flight test department, who was soon followed by Les Berven as chief test pilot. They took over development, giving Bede more time to work on business issues. This was proving difficult enough, as Kiekhaefer and Bede could not reach an agreement about deliveries, forcing him to change to a similar 440 cc 40 hp Hirth Motoren design, but then selecting a larger 650 cc 55 hp Hirth engine instead. Several additional problems turned up during testing. Stick forces were very low, but this was easily addressed by making the servo tabs larger. A more worrying development was that the engines all had problems with mixture due to changes in engine speed or load, which led to rough engine operation. In August Bede was 100

101 demonstrating the BD-5 to the FAA in order to receive permission to fly at Oshkosh, when the engine seized. On its deadstick landing, the aircraft overran the runway, buckling the nose gear. The air-fuel mixture was identified as the cause of the crash of N501BD in September 1972 when the mixture control broke and Berven had to execute a forced landing. Since N502BD would be ready in two months, N501BD was not repaired. However, N502BD ran into problems of its own. The earlier models used a variable speed belt drive system to transfer power from the engine to the propeller shaft, but this was removed from N502BD and it suddenly began exhibiting a serious vibration problem. Experts were called in, and additional bearings corrected the problem, but it was not until March 26, 1973 that N502BD flew. From then on the test program seemed to go more smoothly. By the time the test program neared its conclusion the aircraft had undergone major changes. One victim of the program was the shorter "A" wing, which calculations showed would only improve performance at speeds very close to Vmax (the highest available speed). Flight testing also showed the landing speed with the smaller wing was decidedly fast. Split flaps and spoilers had also disappeared. The canopy and cockpit dimensions had changed and the aircraft had new landing gear systems and a completely new tail section. More ominous was the fact that the engines had already been changed twice. What remained, however, was the basic concept of the fighter-like pusher aircraft which, if anything, had improved in looks. By this point it seemed the basic design was complete, and Bede turned his attention to other projects. One was a jet-powered BD-5, the BD-5J, which is detailed below. Another was the Bede BD-6, a single-seat version of the BD-4 based on the same Hirth engine being used in the BD-5. Still another was the "new" Bede BD-7, a two-seat side-by-side version of the BD-5 of which a prototype was built. There was even an attempt to sidestep the engine problem with the BD-5S, a glider (S for Sailplane) version with lengthened wings and no engine, which prompted Air Progress magazine to sarcastically note, "At last, a BD-5 with no engine problems". This glider version did not fly well and the project was scrapped. Bede also decided to seek FAA certification of the BD-5D as a production aircraft and sell it complete, and began taking $600 deposits for this model. By the middle of 1973 the basic design was complete and the tooling set up for production. The engines were the only part holding up deliveries, so Bede offered to ship the kit with the engine to follow. This was a fairly attractive option; it meant the builder could "get to work" and hopefully complete the airframe by the time the engine arrived, at that point expected in September Many builders took the company up on the offer, only to receive incomplete kits and plans. All three Hirth engines were offered; builders could keep the 40 hp design, or "trade up" to the larger 55 hp or 70 hp engines. The latter, which Bede had developed with Hirth, was now considered the baseline engine for the aircraft as the original 40 hp proved to be of insufficient power. In a late 1973 newsletter to prospective owners, Bede suggested the 70 hp model and discouraged use of the smaller engines. Prices had risen throughout the 30 months since the deposits were first taken. Originally priced at $1,799, the base price was raised to $2,599 with the 55 hp, and owners were offered a "trade up" for the difference in price if they had ordered the aircraft with the original 40 hp engine. When 1974 came around, the engines were still not being delivered in quantity, although some started to arrive early that year. At that point, unexpectedly, Hirth went bankrupt after about 500 of the engines had shipped. Once again the design lacked a suitable engine, but this time the search for a replacement ended with a Xenoah design from Japan. Development of this engine was lengthy, and in the end it would not be certified for export until 1978, although this was not expected at the time. In the meantime, Bede came up with another novel solution to the problems of converting pilots to the new aircraft. They took an engine-less example and bolted it to the front of a pickup truck on a trapeze, attaching the pilot's throttle control to the truck's. Pilots could test fly the aircraft without danger - if a problem developed the driver of the truck simply hit the brakes. After more than 5,100 kits had been delivered to prospective builders, the kits stopped shipping as well. Although the company was effectively bankrupt at this point, work on the BD-5D continued for some time. The bankruptcy became official in 1979, by which point the BD-5 project was long dead. During the bankruptcy proceedings it was learned that the money ostensibly being used to build kits was instead being spent on a variety of projects. As a result, Bede entered a consent decree with the FTC to no longer accept deposits on aircraft for a period of 10 years. Many owners stored, abandoned, or sold their incomplete kits, but a few hundred diehard builders finished them with a variety of engine solutions designed by third parties and former Bede Aircraft dealers. Having to hunt for an engine was only one problem. The time to build the aircraft was much longer than quoted, as much as 3,000 to 3,500 hours. Some of this was due to the need to fit their selected engine into an airframe designed for the Hirth, which was no longer available. Additionally, some of the kits were shipped with missing parts, adding to the confusion. All of this led to a rash of kits being sold for fire sale prices, although this 101

102 did allow the builders that were looking to complete their kits to do so at bargain prices. While Bede claimed the aircraft could be put together by anyone in a garage, builders generally agree that doing so without proper construction techniques could result in a potentially dangerous aircraft. One way to overcome that issue is to use a set of properly laid-out jigs to align and drill the pilot holes for the airframe, wings and other components. For all of these reasons, it was some time before completed BD-5s started to appear. Over the next few years the aircraft garnered a terrible safety record. Although Bede had suggested using the B wings, the earliest kits shipped only with the short "A" wings. All four examples completed with these wings crashed on their first flight, three on takeoff and one lasted long enough to crash on landing, three of the four causing fatalities. Of the first 25 completed, with both the "A" and "B" wings, 14 crashed with 9 fatalities. Even when examples with the "B" wings were completed, the safety record did not improve greatly. Several crashes in the -5B models were found to have taken place due to engine failure on takeoff, both due to the mix of "oddball" engines as well as endemic cooling problems. The reason this is such an issue with the BD- 5 is twofold the high line of thrust means an engine failure immediately results in an unexpected (for most pilots) nose-up attitude change. Pilots who fail to fly the aircraft first and then attempt to restart the engine inevitably stall, with the associated consequences. This was aggravated by the fact the original wing had a very sharp stall with little warning and a nasty tendency to "snap roll." To make matters worse, a documented manufacturing error in some wing skins delivered to kit builders exacerbated the problem. A rather small center of gravity range also added to the problems of properly trimming the aircraft. With the demise of the Bede Aircraft Company, the BD-5 entered a sort of limbo while builders completed their kits. The early safety problems and the challenge of adapting a suitable engine exacerbated delays. Over the next few years, however, solutions to most of these problems arrived in one form or another. Many other changes have also been incorporated to improve the original design. Today the BD-5 is a rewarding, if demanding aircraft. For instance, the problem of finding a suitable engine with 60 to 70 hp yet still weighing under 100 lbs was a serious problem in the 1970s, but today there are a number of "off the shelf" designs in this class. The widely available Rotax 582 is a 65 hp engine of 80 lbs in standard configuration, almost tailor-made for the BD-5. Other engines successfully used in BD-5s include the Subaru EA-81, Honda EB-1 and EB-2 (with and without turbocharging), Hirth 2706, AMW and 2SI 808. The current record holder of the FAI C-1a/0 (300 kg or less takeoff weight) class speed record over a 3 km (1.9 mi) course at restricted altitude is a BD-5A (listed as BD-5B but used -5A wings for the record attempt) with a Rotax 618UL 74 hp two-stroke, two-cylinder water-cooled engine. Problems with the abrupt stall were mostly addressed by Harry Riblett, an airfoil designer who documented a procedure to apply a slight reprofile of the wing root airfoil which softened the stall response of the aircraft without any significant performance degradation. The reprofile presents other unique problems associated with the way it is applied to the wing upper surface, essentially gluing foam to the aluminum skin and covering with fiberglass. Similarly, the small center-of-gravity range has since been addressed with 5.5- to 13- inch stretch kits for the fuselage. Several companies were formed to help builders complete their kits, and many of the aftermarket modifications were worked into these services. Today, BD Micro Technologies of Siletz, Oregon continues to offer kit building support, including new-build kits featuring (optionally) all of these modifications, and even the BD-5T, a turboprop version of the BD-5 using a modified Solar T62 turbine powering a mechanicallycontrolled variable-pitch propeller. Alturair, Inc. of San Diego, California also offers extensive parts and construction assistance services. An unusual adaptation of the BD-5, the Acapella 100, appeared in the early 1980s. Designer Carl D. Barlow of Option Air Reno mated a BD-5 fuselage with a distinctive twin-boom empennage and fitted it with a 100 hp Continental O-200 engine. Later, a 200 hp Lycoming IO-360 was fitted, and the wings shortened from 26.5 feet to 19.5 feet, becoming the Acapella 200-S model. The prototype of this aircraft was first flown on June 6, 1980, with pilot Bill Skiliar at the controls. Nonetheless, it flew poorly and was difficult to control. Only the one prototype was built and it was donated to the Experimental Aircraft Association's Airventure Museum in Oshkosh, Wisconsin, USA, where it is occasionally placed on display. Bede Aircraft Company has since re-formed and has been working on several new designs. Bede has hinted at a two-seat tandem version of the aircraft called the "Super BD-5" using a certified aircraft engine and a number of modifications and improvements, but to date nothing other than a preliminary design drawing has been made available. While the new Hirth engine was being tested, Bede decided to create an unconventional variant of the BD-5 with a small jet engine. The result was the sleek BD-5J, a 300 mph (480 km/h) aircraft. The design used the Sermel TRS turbojet (now Microturbo, a division of Turbomeca), which produced 225 lbs of thrust 102

103 and was used on a Caproni certified motorglider design. The original engines were produced under license by Ames Industrial in the USA. The wing was modified to an "intermediate" size between the original A and B wings, with a 17 ft span. Bob Bishop had purchased 20 BD-5J kits as soon as they had appeared, and many of the flying examples started life in this batch of twenty. Versions from the original batch became a popular airshow fixture. Throughout the 1980s and until 1991, Coors flew two of them as the "Silver Bullets." Budweiser also had a BD- 5J called the "Bud Light Jet", but that contract has long expired and the aircraft was lost as a result of an engine compartment fire from which Bob Bishop successfully bailed out. The aircraft also appeared in the opening sequence of the James Bond film, Octopussy. Many of these aircraft have since been involved in crashes. The loss of the Bud Light Jet was caused by an incorrectly specified fuel flow sending unit which burst in mid-flight and caused fuel to be sprayed directly into the engine compartment. The fuel ignited when it came in contact with the hot components of the turbojet engine, forcing the pilot to trade speed for altitude, climb and bail out. The aircraft then went into a flat spin and pancaked into the ground, but was sufficiently intact to allow the cause of the fire to be determined relatively quickly. On June 16, 2006, while practicing for an air show at Carp Airport in Ottawa, Canada, Scott Manning fatally crashed in his "Stinger Jet," the last BD-5J that remained on the airshow circuit. The Transportation Safety Board of Canada investigated the accident and issued a report assigning the probable cause to the incorrect installation of the right wing, which caused the flap on that wing to suddenly retract in flight and create a "split flap" condition. The aircraft rolled to the right and Manning was unable to recover in time. Recently, the BD-5J operates in the national security arena. The aircraft is certified by the United States Department of Defense as a cruise missile surrogate, with Bishop's Aerial Productions offering a version known as the Smart-1 (Small Manned Aerial Radar Target, Model 1). The radar return and general performance characteristics make it a useful aid in training. On June 27, 2006, while flying one of these aircraft, pilot Chuck Lischer, a highly experienced professional air show pilot, impacted trees on final approach to the Ocean City Municipal Airport in Ocean City, Maryland in a fatal accident. The BD-5J has also held the Guinness record for the World's Smallest Jet for more than 25 years. Bob Bishop originally garnered the record with one of his jets, and in November 2004 the record changed hands to Juan Jiménez,who purchased the aircraft from the original builder whose BD-5J weighed in at lb (162.7 kg) empty weight, 80 lb (36 kg) lighter than Bishop's jet and the lightest documented weight for a BD-5. The jet has not yet flown due to significant mechanical issues, turbine starting and safety concerns. Another monster is Boeing C Phalcon aircraft (fig. 95). Fig. 95. Boeing C Phalcon aircraft. 103

104 Cap. 5. INVISIBLE AIRCRAFT Stealth aircraft are aircraft that use stealth technology to avoid detection by employing a combination of features to interfere with radar as well as reduce visibility in the infrared, visual, audio, and radio frequency (RF) spectrum. Development of stealth technology likely began in Germany during World War II. Well-known modern examples of stealth aircraft include the United States' F-117 Nighthawk ( , fig. 96), the B-2 Spirit (fig. 97), the F-22 Raptor (fig. 98), and the F-35 Lightning II (fig. 99). Fig. 96. A F-117 Nighthawk stealth strike aircraft. While no aircraft is totally invisible to radar, stealth aircraft prevent conventional radar from detecting or tracking the aircraft effectively, reducing the odds of a successful attack. Stealth is the combination of passive low observable (LO) features and active emitters such as Low Probability of Intercept Radars, radios and laser designators. These are usually combined with active defenses such as chaff, flares, and ECM. It is accomplished by using a complex design philosophy to reduce the ability of an opponent's sensors to detect, track, or attack the stealth aircraft. This philosophy also takes into account the heat, sound, and other emissions of the aircraft as these can also be used to locate it. Fig. 97. A B-2 Spirit stealth bomber of the U.S Air Force. Fig. 98. A F-22 Raptor fifth generation stealth air superiority fighter. 104

105 Fig. 99. A prototype of the F-35 Lightning II fifth generation stealth multi-role fighter. Full-size stealth combat aircraft demonstrators have been flown by the United States (in 1977), Russia (in 2010) and China (in 2011), while the US Military has already adopted three stealth designs, and is preparing to adopt another. Most recent fighter designs will at least claim to have some sort of stealth, low observable, reduced RCS or radar jamming capability, but as of yet there has been no actual air to air combat experience against stealth aircraft. During World War I, an attempt to reduce the visibility of military aircraft resulted in the German heavy bomber, the Linke-Hofmann R.I; this had a wooden structure covered with transparent material. The first true "stealth" aircraft may have been the Horten Ho 229 flying wing fighter-bomber, developed in Germany during the last years of World War II. In addition to the aircraft's shape, which may not have been a deliberate attempt to affect radar deflection, the majority of the Ho 229's wooden skin was bonded together using carbonimpregnated plywood resins designed with the purported intention of absorbing radar waves. Testing performed in early 2009 by the Northrop-Grumman Corporation established that this compound, along with the aircraft's shape, would have rendered the Ho 229 virtually invisible to Britain's Chain Home early warning radar, provided the aircraft was traveling at high speed (approximately 550 mph (890 km/h)) at extremely low altitude ( feet). In the closing weeks of WWII the US military initiated "Operation Paperclip", an effort by the US Army to capture as much advanced German weapons research as possible, and also to deny that research to advancing Soviet troops. A Horton glider and the Ho 229 number V3 were secured and sent to Northrop Aviation for evaluation in the United States, who much later used a flying wing design for the B-2 stealth bomber. During WWII Northrop had been commissioned to develop a large wing-only long-range bomber (XB-35) based on photographs of the Horton's record-setting glider from the 1930s, but their initial designs suffered controllability issues that were not resolved until after the war. Northrop's small one-man prototype (N9M-B) and a Horton wing-only glider are located in the Chino Air Museum in Southern California. Modern stealth aircraft first became possible when Denys Overholser, a mathematician working for Lockheed Aircraft during the 1970s, adopted a mathematical model developed by Petr Ufimtsev, a Russian scientist, to develop a computer program called Echo 1. Echo made it possible to predict the radar signature an aircraft made with flat panels, called facets. In 1975, engineers at Lockheed Skunk Works found that an aircraft made with faceted surfaces could have a very low radar signature because the surfaces would radiate almost all of the radar energy away from the receiver. Lockheed built a model called "the Hopeless Diamond", so-called because it resembled a squat diamond, and looked too hopeless to ever fly. Because advanced computers were available to control the flight of even a Hopeless Diamond, for the first time designers realized that it might be possible to make an aircraft that was virtually invisible to radar. Reduced radar cross section is only one of five factors the designers addressed to create a truly stealthy design such as the F-22. The F-22 has also been designed to disguise its infrared emissions to make it harder to detect by infrared homing ("heat seeking") surface-to-air or air-to-air missiles. Designers also addressed making the aircraft less visible to the naked eye, controlling radio transmissions, and noise abatement. 105

106 The first combat use of purpose-designed stealth aircraft was in December 1989 during Operation Just Cause in Panama. On December 20, 1989, two USAF F-117s bombed a Panamanian Defense Force barracks in Rio Hato, Panama. In 1991, F-117s were tasked with attacking the most heavily fortified targets in Iraq in the opening phase of Operation Desert Storm and were the only jets allowed to operate inside Baghdad's city limits. Early stealth aircraft were designed with a focus on minimal radar cross section (RCS) rather than aerodynamic performance. Highly-stealth aircraft like the F-117 Nighthawk are aerodynamically unstable in all three axes and require constant flight corrections from a fly-by-wire (FBW) flight system to maintain controlled flight. Most modern non-stealth fighter aircraft are unstable on one or two axes only. However, in the pursuit of increased maneuverability, most 4th and 5th-generation fighter aircraft have been designed with some degree of inherent instability that must be controlled by fly-by-wire computers. As for the B2 Spirit, based on the development of the all-wing aircraft by Jack Northrop since 1940, design allowed creating stable aircraft with sufficient yaw control, even without vertical surfaces such as rudders. Earlier stealth aircraft (such as the F-117 and B-2) lack afterburners, because the hot exhaust would increase their infrared footprint, and breaking the sound barrier would produce an obvious sonic boom, as well as surface heating of the aircraft skin which also increased the infrared footprint. As a result their performance in air combat maneuvering required in a dogfight would never match that of a dedicated fighter aircraft. This was unimportant in the case of these two aircraft since both were designed to be bombers. More recent design techniques allow for stealthy designs such as the F-22 without compromising aerodynamic performance. Newer stealth aircraft, like the F-22 and F-35, have performance characteristics that meet or exceed those of current front-line jet fighters due to advances in other technologies such as flight control systems, engines, airframe construction and materials. The high level of computerization and large amount of electronic equipment found inside stealth aircraft are often claimed to make them vulnerable to passive detection. This is highly unlikely and certainly systems such as Tamara and Kolchuga, which are often described as counter-stealth radars, are not designed to detect stray electromagnetic fields of this type. Such systems are designed to detect intentional, higher power emissions such as radar and communication signals. Stealth aircraft are deliberately operated to avoid or reduce such emissions. Current Radar Warning Receivers look for the regular pings of energy from mechanically swept radars while fifth generation jet fighters use Low Probability of Intercept Radars with no regular repeat pattern. Stealth aircraft are still vulnerable to detection during, and immediately after using their weaponry. Since stealth payload (reduced RCS bombs and cruise missiles) are not yet generally available, and ordnance mount points create a significant radar return, stealth aircraft carry all armament internally. As soon as weapons bay doors are opened, the plane's RCS will be multiplied and even older generation radar systems will be able to locate the stealth aircraft. While the aircraft will reacquire its stealth as soon as the bay doors are closed, a fast response defensive weapons system has a short opportunity to engage the aircraft. This vulnerability is addressed by operating in a manner that reduces the risk and consequences of temporary acquisition. The B-2's operational altitude imposes a flight time for defensive weapons that makes it virtually impossible to engage the aircraft during its weapons deployment. All stealthy aircraft carry weapons in internal weapons bays. New stealth aircraft designs such as the F-22 and F-35 can open their bays, release munitions and return to stealthy flight in less than a second. Some weapons require that the weapon's guidance system acquire the target while the weapon is still attached to the aircraft. This forces relatively extended operations with the bay doors open. Also, such aircraft as the F-22 Raptor and F-35 Lighting II Joint Strike Fighter can also carry additional weapons and fuel on hardpoints below their wings. When operating in this mode the planes will not be nearly as stealthy, as the hardpoints and the weapons mounted on those hardpoints will show up on radar systems. This option therefore represents a trade off between stealth or range and payload. External stores allow those aircraft to attack more targets further away, but will not allow for stealth during that mission as compared to a shorter range mission flying on just internal fuel and using only the more limited space of the internal weapon bays for armaments. Fully stealth aircraft carry all fuel and armament internally, which limits the payload. By way of comparison, the F-117 carries only two laser or GPS guided bombs, while a non-stealth attack aircraft can carry several times more. This requires the deployment of additional aircraft to engage targets that would normally require a single non-stealth attack aircraft. This apparent disadvantage however is offset by the reduction in fewer supporting aircraft that are required to provide air cover, air-defense suppression and electronic counter measures, making stealth aircraft "force multipliers". 106

107 The B-2 has a skin made with highly specialized materials such as Polygraphite. Stealth aircraft are typically more expensive to develop and manufacture. An example is the B-2 Spirit that is many times more expensive to manufacture and support than conventional bomber aircraft. The B-2 program cost the U.S. Air Force almost $45 billion. Theoretically there are a number of methods to detect stealth aircraft at long range. Passive (multistatic) radar, bistatic radar and especially multistatic radar systems are believed to detect some stealth aircraft better than conventional monostatic radars, since first-generation stealth technology (such as the F117) reflects energy away from the transmitter's line of sight, effectively increasing the radar cross section (RCS) in other directions, which the passive radars monitor. Such a system typically uses either low frequency broadcast TV and FM radio signals (at which frequencies controlling the aircraft's signature is more difficult). Later stealth approaches do not rely on controlling the specular reflections of radar energy and so the geometrical benefits are unlikely to be significant. Researchers at the University of Illinois at Urbana-Champaign with support of DARPA, have shown that it is possible to build a synthetic aperture radar image of an aircraft target using passive multistatic radar, possibly detailed enough to enable automatic target recognition (ATR). In December 2007, SAAB researchers also revealed details for a system called Associative Aperture Synthesis Radar (AASR) that would employ a large array of inexpensive and redundant transmitters and a few intelligent receivers to exploit forward scatter to detect low observable targets. The system was originally designed to detect stealthy cruise missiles and should be just as effective against aircraft. The large array of inexpensive transmitters also provides a degree of protection against anti-radar (or anti-radiation) missiles or attacks. Some analysts claim Infra-red search and track systems (IRSTs) can be deployed against stealth aircraft, because any aircraft surface heats up due to air friction and with a two channel IRST is a CO2 (4.3 µm absorption maxima) detection possible, through difference comparing between the low and high channel. These analysts also point to the resurgence in such systems in several Russian designs in the 1980s, such as those fitted to the MiG-29 and Su-27. The latest version of the MiG-29, the MiG-35, is equipped with a new Optical Locator System that includes even more advanced IRST capabilities. In air combat, the optronic suite allows: Detection of non-afterburning targets at 45-kilometre (28 mi) range and more; Identification of those targets at 8-to-10-kilometre (5.0 to 6.2 mi) range; and Estimates of aerial target range at up to 15 kilometres (9.3 mi). For ground targets, the suite allows: A tank-effective detection range up to 15 kilometres (9.3 mi), and aircraft carrier detection at 60 to 80 kilometres (37 to 50 mi); Identification of the tank type on the 8-to-10-kilometre (5.0 to 6.2 mi) range, and of an aircraft carrier at 40 to 60 kilometres (25 to 37 mi); and Estimates of ground target range of up to 20 kilometres (12 mi). The Dutch company Thales Nederland, formerly known as Holland Signaal, have developed a naval phased-array radar called SMART-L, which also is operated at L-Band and is claimed to offer counter stealth benefits. However, as with most claims of counter-stealth capability, these are unproven and untested. True resonant effects might be expected with HF sky wave radar systems, which have wavelengths of tens of metres. However, in this case, the accuracy of the radar systems is such that the detection is of limited value for engagement. Any radar which can successfully match the resonant frequency of a type of stealth aircraft should be able to detect its direction. In practice this is difficult because the resonant frequency changes depending on how the stealth aircraft is oriented with respect to the radar system. Over-the-horizon radar is a design concept that increases radar's effective range over conventional radar. It is claimed that the Australian JORN Jindalee Operational Radar Network can overcome certain stealth characteristics. It is claimed that the HF frequency used and the method of bouncing radar from ionosphere overcomes the stealth characteristics of the F-117A. In other words, stealth aircraft are optimized for defeating much higher-frequency radar from front-on rather than low-frequency radars from above. 107

108 Stealth aircraft have been used in several conflicts: the United States invasion of Panama, the Gulf War, the Kosovo Conflict, the War in Afghanistan the War in Iraq and the 2011 military intervention in Libya. To date, the United States of America is the only country to have used stealth aircraft in combat. The first use of stealth aircraft was in the United States invasion of Panama, where F-117 Nighthawk stealth attack aircraft were used to drop bombs on enemy airfields and positions while evading enemy radars. The successful first deployment of stealth aircraft to a combat zone marks a milestone in military aviation. In 1990 the F-117 Nighthawk was used again in the Gulf War, where F-117s flew approximately 1,300 sorties and scored direct hits on 1,600 high-value targets in Iraq while accumulating over 6,905 flight hours. Only 2.5% of the American aircraft in Iraq were F-117s, yet they struck more than 40% of the strategic targets, dropping over 2,000 tons of precision-guided munitions and striking their targets with over an 80% success rate. In the 1999 NATO bombing of Yugoslavia two stealth aircraft were used by the United States, the veteran F-117 Nighthawk, and the newly introduced B-2 Spirit strategic stealth bomber. The F-117 performed its usual role of striking precision high-value targets and performed well, although one F-117 was shot down by a Serbian Isayev S-125 'Neva-M' missile. The new B-2 Spirit was highly successful, destroying 33% of selected Serbian bombing targets in the first eight weeks of U.S. involvement in the War. During this war, B-2s flew non-stop to Kosovo from their home base in Missouri and back. In the 2003 invasion of Iraq, F-117 Nighthawks and B-2 Spirits were again used, and this was the last time the F-117 would see combat. F-117s dropped satellite-guided strike munitions on selected targets, with high success. B-2s conducted 49 sorties in the invasion, releasing more than 1.5 million pounds of munitions. The most recent use of stealth aircraft was in the 2011 military intervention in Libya, where B-2 Spirits dropped 40 bombs on a Libyan airfield with concentrated air defenses in support of the UN no-fly zone. In the future, it is likely that stealth aircraft will continue to play a valuable role in air combat. In future conflicts the United States is likely to use the F-22 Raptor, B-2 Spirit, and the F-35 Lightning II to perform a variety of operations. In Russia, the Sukhoi PAK FA stealth multi-role fighter is scheduled to be introduced from 2015, to perform a wide variety of missions. In India, the Sukhoi/HAL FGFA, the Indian version of the PAK FA is scheduled to be introduced from 2017 in higher numbers, also to perform a wide variety of missions. In the People's Republic of China, the Chengdu J-20 stealth multi-role fighter is planned to be introduced around A prototype was flown in early The only time that a stealth aircraft has been shot down was on 27 March 1999, during Operation Allied Force. An American F-117 Nighthawk's bomb bay had malfunctioned causing it to remain open for an unusually long time, allowing a Serbian Air Defense crew who were operating their radars on unusually long wavelengths to launch a Isayev S-125 'Neva-M' missile at it which brought it down. The pilot ejected and was rescued and the aircraft itself remained relatively intact due to striking the ground at a slow speed in an inverted position. A B-2 crashed on 23 February 2008 shortly after takeoff from Andersen Air Force Base in Guam. The findings of the investigation stated that the B-2 crashed after "heavy, lashing rains" caused water to enter skinflush air-data sensors, which feed angle of attack and yaw data to the computerized flight-control system. The water distorted preflight readings in three of the plane's 24 sensors, causing the flight-control system to send an erroneous correction to the B-2 on takeoff. The B-2 quickly stalled, became unrecoverable, and crashed. The sensors in question measure numerous environmental factors, including air pressure and density, for data to calculate airspeed, altitude and attitude. Because of the faulty readings, the flight computers determined inaccurate airspeed readings and incorrectly indicated a downward angle for the aircraft, which contributed to an early rotation and an un-commanded 30-degree pitch up and left yaw, resulting in the stall. The Sukhoi PAK FA (fig. 101), (Perspektivny aviatsionny kompleks frontovoy aviatsii, literally "Prospective Airborne Complex of Frontline Aviation") is a twin-engine jet fighter being developed by Sukhoi OKB for the Russian Air Force. 108

109 The current prototype is Sukhoi's T-50 (fig. 100). The PAK FA, when fully developed, is intended to be the successor to the MiG-29 and Su-27 in the Russian inventory and serve as the basis of the Sukhoi/HAL FGFA being developed with India. A fifth generation jet fighter, the T-50 performed its first flight 29 January Its second flight was on 6 February and its third on 12 February As of 31 August 2010, it had made 17 flights and by mid-november, 40 in total. The second prototype was to start its flight test by the end of 2010, but this was delayed until March Fig A Sukhoi T-50 during a test flight. Fig PAK FA T-50 prototype on the day of its first flight. Sukhoi director Mikhail Pogosyan has projected a market for 1,000 aircraft over the next four decades, which will be produced in a joint venture with India, 200 each for Russia and India and 600 for other countries. He has also said that the Indian contribution would be in the form of joint work under the current agreement rather than as a joint venture. The Indian Air Force will "acquire 50 single-seater fighters of the Russian version" before the two seat FGFA is developed. The Russian Defense Ministry will purchase the first 10 aircraft after 2012 and then 60 after The first batch of fighters will be delivered with current technology engines. Ruslan Pukhov, director of the Centre for Analysis of Strategies and Technologies, has projected that Vietnam will be the second export customer for the fighter. The PAK-FA is expected to have a service life of about years. In the late 1980s, the Soviet Union outlined a need for a next-generation aircraft to replace its MiG-29 and Su-27 in frontline service. Two projects were proposed to meet this need, the Sukhoi Su-47 and the Mikoyan Project In 2002, Sukhoi was chosen to lead the design for the new combat aircraft. The Tekhnokompleks Scientific and Production Center, Ramenskoye Instrument Building Design Bureau, the Tikhomirov Scientific Research Institute of Instrument Design, the Ural Optical and Mechanical Plant (Yekaterinburg), the Polet firm (Nizhniy Novgorod) and the Central Scientific Research Radio Engineering Institute (Moscow) were pronounced winners in the competition held in the beginning of 2003 for the development of the avionics suite for the fifth-generation airplane. NPO Saturn has been determined the lead executor for work on the engines for this airplane. The Novosibirsk Chkalov Aviation Production Association (NAPO Chkalov) has begun construction of the fifth-generation multirole fighter. This work is being performed at Komsomol'sk-on-Amur together with Komsomolsk-on-Amur Aircraft Production Association; the enterprise's general director, Fedor Zhdanov reported during a visit to NAPO by Novosibirsk Oblast's governor Viktor Tolokonskiy on 6 March "Final assembly will take place at Komsomol'sk-on-Amur, and we will be carrying out assembly of the fore body of this airplane", Zhdanov specified. On 8 August 2007, Russian Air Force Commander Alexander Zelin was quoted by Russian news agencies that the development stage of the PAK FA program is now complete and construction of the first aircraft for flight testing will now begin. Alexander Zelin also said that by 2009 there will be three fifthgeneration aircraft ready. "All of them are currently undergoing tests and are more or less ready", he said. In the summer of 2009 the design was approved. On 11 September 2010, it was reported that Indian and Russian negotiators had agreed on a preliminary design contract that would then be subject to Cabinet approval. The joint development deal would have each country invest $6 billion and take 8 to 10 years to develop the FGFA fighter. The agreement on the pre-design of the fighter was to be signed in December The preliminary design will cost $295 million and will be complete within 18 months. 109

110 On 28 February 2009, Mikhail Pogosyan announced that the airframe for the aircraft was almost finished and that the first prototype should be ready by August On 20 August 2009, Sukhoi General Director Mikhail Pogosyan said that the first flight would be by year end. Konstantin Makiyenko, deputy head of the Moscow-based Centre for Analysis of Strategies and Technologies said that "even with delays", the aircraft would likely make its first flight by January or February, adding that it would take 5 to 10 years for commercial production. The maiden flight had been repeatedly postponed since early 2007 as the T-50 encountered unspecified technical problems. Air Force chief Alexander Zelin admitted as recently as August 2009 that problems with the engine and in technical research remained unsolved. On 8 December 2009, Deputy Prime Minister Sergei Ivanov announced that the first trials with the fifth-generation aircraft would begin in The testing, however, has commenced earlier than stated, with the first successful taxiing test taking place on 24 December The aircraft's maiden flight took place on 29 January 2010 at KnAAPO's Komsomolsk-on-Amur Dzemgi Airport; the aircraft was piloted by Sergey Bogdan (Сергей Богдан) and the flight lasted for 47 minutes. A second airframe was first planned to join the flight testing in the fourth quarter of 2010 but was postponed. On 3 March 2011 a second prototype was reported to have made a successful 44 minutes test flight. These first two aircraft will lack radar and weapon control systems, while the third and fourth aircraft, to be added in 2011, will be fully functional test aircraft. Siberia. On 14 March 2011, the aircraft achieved supersonic flight at a test range near Komsomolsk-on-Amur in The T-50 is expected to be on display at the 2011 MAKS Airshow. Navalized Sukhoi T-50 PAK FAs will be deployed on the Russian aircraft carrier Admiral Kuznetsov and future Russian aircraft carriers. There will be a competition between the Sukhoi, Mikoyan and Yakovlev design bureaus to choose the new naval aircraft. Alexei Fedorov has said that any decision on applying fifth generation technologies to produce a smaller fighter (in the F-35 range) must wait until after the heavy fighter, based on the T-50, is completed. Although most of information about the PAK FA is classified, it is believed from interviews with people in the Russian Air Force and Defense Ministry that it will be stealthy, have the ability to supercruise, be outfitted with the next generation of air-to-air, air-to-surface, and air-to-ship missiles, incorporate a fix-mounted AESA radar with a 1,500-element array and have an "artificial intellect". According to Sukhoi, the new radar will reduce pilot load and the aircraft will have a new data link to share information between aircraft. Composites are used extensively on the T-50 and comprise 25% of its weight and almost 70% of the outer surface. It is estimated that titanium alloy content of the fuselage is 75%. Sukhoi's concern for minimizing radar cross-section (RCS) and drag is also shown by the provision of two tandem main weapons bays in the centre fuselage, between the engine nacelles. Each is estimated to be between m long. The main bays are augmented by bulged, triangular-section bays at the wing root. The Moskovsky Komsomolets reported that the T-50 has been designed to be more maneuverable than the F-22 Raptor at the cost of making it less stealthy than the F-22. One of the design elements that have such an effect is the Leading Edge Vortex Controller (LEVCON). The PAK FA SH121 radar complex includes three X-Band AESA radars located on the front and sides of the aircraft. These will be accompanied by L-Band radars on the wing leading edges. L-Band radars are proven to have increased effectiveness against very low observable (VLO) targets which are optimized only against X-Band frequencies, but their longer wavelengths reduce their resolution. The PAK FA will feature an IRST optical/ir search and tracking system, based on the OLS-35M which is currently in service with the Su-35S. Hindustan Aeronautics Limited will reportedly provide the navigation system and the mission computer. The PAK FA was expected to use a pair of Saturn 117S engines on its first flights. The 117S (AL- 41F1A) is a major upgrade of the AL-31F based on the AL-41F intended to power the Su-35BM, producing 142 kn (32,000 lb) of thrust in afterburner and 86.3 kn (19,400 lb) dry. In fact, PAK FA already used a completely new engine in its first flight, as stated by NPO Saturn. The engine is not based on the Saturn 117S and is 110

111 rumoured to be called "127 engine". The engine generates a larger thrust and has a complex automation system, to facilitate flight modes such as maneuverability. Exact specifications of the new engine are still secret. It is expected that each engine will be able to independently vector its thrust upwards, downward or side to side. Vectoring one engine up with the other one down can produce a twisting force. Therefore the PAK FA would be the first fifth generation fighter with full 3-D thrust vectoring along all three aircraft axes: pitch, yaw and roll. These engines will incorporate infrared and RCS reduction measures. The PAK FA has a reported maximum weapons load of 7,500 kg. It has an apparent provision for a cannon (most likely GSh-301). It could possibly carry as many as two 30 mm cannons. It has two internal bays estimated at metres by metres. Some sources suggest two auxiliary internal bays for short range AAMS and six external hardpoints. Two Izdeliye 810 Extended beyond visual range missiles per weapons bay. Multiple Izdeliye 180 / K77M beyond visual range missiles. K74 and K30 within visual range missiles can also be carried. Two KH38M or KH58 USHK air-to-ground missiles per weapons bay. Multiple kg precision guided bombs per weapons bay, with a maximum of 10 bombs in internal bays. Other possible loads include one 1,500 kg bomb per weapons bay or two 400 km+ range anti-awacs weapons on external hardpoints. The first flight video shows that PAK FA has no conventional rudders, its vertical tails are fully movable. This special tail fin design is mechanically similar to V-tails used by the Northrop YF-23 in 1990s, but is supplemented by dedicated horizontal stabilators (as on the F-22). The T-50 has wing leading-edge devices above the jet engine intakes that have been called a challenge for signature control. The Chengdu J-20 (literally "Fighter aircraft Twenty", fig. 102) is a fifth generation stealth, twin-engine fighter aircraft prototype developed by Chengdu Aircraft Industry Group for the Chinese People's Liberation Army Air Force. In late 2010, the J-20 underwent high speed taxiing tests. The J-20 made its first flight on 11 January General He Weirong, Deputy Commander of the People's Liberation Army Air Force said in November 2009 that he expected the J-20 to be operational in Fig A Chengdu J-20. The J-20 was one of the stealth fighter programs under the codename J-XX that was launched in the late 1990s. It was designated Project 718, and won the PLAAF endorsement in a 2008 competition against a Shenyang proposal that was reportedly even larger than J-20. Two prototypes ( & ) have been built as of the end of On 22 December 2010, the J-20 was under-going high speed taxiing tests outside the Chengdu Aircraft Design Institute with no confirmed flight tests. The J-20 made its first flight, which lasted about 20 minutes, on 11 January Director of National Intelligence James R. Clapper has testified that the United States has known about the program for a "long time" and that the test flight was not a surprise. The J-20 made its first flight, lasting about 15 minutes, on 11 January A Chengdu J-10S served as the escort aircraft. After the successful first flight, a ceremony was held. The test pilot of the J-20, Li Gang, Chief designer Yang Wei and General Li Andong (Deputy-Director of General Armaments Department, and Director of Science and Technology Commission of General Armaments Department of the PLA since 2000) attended the ceremony. China thus became the third nation in the world to "develop and test-fly a full-size stealth combat aircraft demonstrator", after the United States and Russia. The Guardian reported that experts, on the one hand, expressed "surprise" at the speed with which the aircraft was developed, but on the other hand "said the country's military prowess was still relatively backward and way behind that of the US" and that its military interests were limited to its region. 111

112 The first test flight coincided with a visit of United States Secretary of Defense Robert Gates to China, and was initially interpreted by Pentagon officials and media pundits[who?] as a possible signal to the visiting delegation from the U.S. However, after meeting with senior Chinese officials including Chinese President Hu Jintao, Secretary Gates remarked, "The civilian leadership seemed surprised by the test and assured me it had nothing to do with my visit." Jin Canrong, a professor at Renmin University in Beijing who specializes in China- U.S. relations, suggested that President Hu's ignorance of the test raises questions about the nature of civilian control of the Chinese military. However, as Michael Swaine, an expert on the PLA and United States China military relations, explained, although it's possible and even likely that "senior officials in the [Chinese] leadership did not know that this flight test would occur on this precise day," this is not necessarily evidence of a military-backed effort to insult Secretary Gates' delegation or embarrass President Hu. Rather, decisions regarding the production, development and testing of such military aircraft are routinely managed by engineers and low-level officials more than by senior civilian or military leadership. Coupled with the fact that there was relatively limited coverage of the event in Chinese media initially, it is likely that the test may not have been considered a significant enough event to warrant notification to President Hu. Moreover, the Chinese military has conducted important tests (including the 2007 anti-satellite missile test) on 11 January in the past; thus, the test may have been related to this. A second test flight of an hour and twenty minutes took place on 17 April On 5 May 2011, a 55 minute test flight included retraction of the landing gear. 112 The full initial test program of 10 to 20 test flights is expected to take years to complete. states that China probably declined to participate in joint development and production of new fifth generation fighter with Russia given the belief that Russia stood to gain more from Chinese participation. Chinese leaders may have determined that their design was superior to the Russian PAK FA. United States House Committee on Armed Services chairman Howard McKeon said on the J-20 "my understanding is that they built it on information that they received from Russia, from a Russian plane, that they were able to copy". Balkan military officials told the Associated Press that China and Russia may have adopted some stealth technology from a Lockheed F-117 Nighthawk, which was shot down by the Serbian military in 1999 during the Kosovo war. If Chinese experts used the F-117 stealth coatings, the result would be decades behind current American state-of-the-art. However, Chinese test pilot Xu Yongling said that the J-20 was a "masterpiece" of home-grown innovation, he also said the F-117 technology was already "outdated" even at the time it was shot down, and could not be applied to a next-generation stealth jet. Janes editor James Hardy agrees that it was unlikely China would have learned much from the wreckage. Retired USAF General Thomas G. McInerney has suggested that the J-20 design may have been based on cyber-espionage of the Lockheed Martin FB-22 project. A federal prosecutor has suggested that China may have used technology from the Northrop Grumman B-2 Spirit for their stealth aircraft which was supplied by Noshir Gowadia. Chief of the Air Staff of the Indian Air Force Pradeep Vasant Naik has suggested that the J-20 is entirely reverse engineered with no Chinese R&D involved, and questioned if the practice was ethical. The Deccan Chronicle has called Naik's comment an "unusual outburst of helplessness" as China surpasses Indian airpower. Russian military commentator Ilya Kramnik conjectures that China is still 10 to 15 years behind the United States and Russia in fighter technology and may not be able to manufacture all the advanced composite materials, avionics and sensor packages needed for such aircraft, and could instead turn to foreign suppliers. However, he speculates that China may be able to produce the J-20 at a cost 50% to 80% lower than US and Russian fifth-generation jet fighters, and that potential customers may include Pakistan, the Middle East, Latin America, Southeast Asia and the richest countries in Africa. Konstantin Sivkov of the Academy for Geopolitical Issues argued that the US is correct to be alarmed at the progress of Chinese military technology. Bill Sweetman speculates that China will have problems meeting its production requirements, as it has several other jet fighter projects in production. Aviation Week raised the question of whether the aircraft is a prototype, like the Sukhoi T-50, or a technology demonstrator similar to the Lockheed YF-22. The J-20 is a single-seat, twin-engine aircraft which appears to be somewhat larger and heavier than the comparable Sukhoi T-50 and Lockheed Martin F-22 Raptor. Bill Sweetman estimates that it is approximately 75 feet (23 m) in length, has a wingspan of 45 feet (14 m) or more, and is expected to have a takeoff weight of 75,000 to 80,000 pounds (34,000 to 36,000 kg) with internal stores only. The prototype could be powered by twin 32,000 pounds (15,000 kg) thrust Saturn 117S engines provided by Russia, a sign of problems in the

113 development of the aircraft, according to Pentagon spokesman Col. David Lapan. Chinese sources have claimed that production aircraft will be powered by two 13,200 kilograms (29,000 lb)/ws-10 class high thrust turbofan engines fitted with Thrust Vector Controlled (TVC) nozzles, both made in China. However Richard Aboulafia has said that the WS-10 engine has suffered catastrophic failures in flight. The J-20 may have lower supercruise speed (yet greater range) and less agility than a Lockheed Martin F-22 Raptor or PAK FA, but might also have larger weapons bays and carry more fuel. The J-20 has a long and wide fuselage and low jet engine intakes with a forward chine, a main delta wing, forward canards, a bubble canopy, conventional round engine exhausts and canted all-moving fins. The front section of the J-20 is similarly chiseled as the F-22 Raptor and the body and tail resemble those of the Sukhoi T-50 prototype. As early photographs of the prototype surfaced, Bill Sweetman commented that the design may suggest a large, long range ground attack aircraft, not unlike a "stealth version" of the General Dynamics F-111 Aardvark. Douglas Barrie has noted that the canard-delta configuration with canted vertical fins appears to resemble the MiG Yet, Barrie notes that key differences include greater forward fuselage shaping as the basis for low observable characteristics, along with the different engine intake configuration. It is suspected that cyberespionage may have assisted the development of the J-20, with information used by subcontractors of Lockheed Martin for the F-35 project in particular having been significantly compromised during development of the J-20. The J-20 has a pair of all-moving tailfins that are swept back in the F-35 style instead of being trapezoid like the F-22 and PAK-FA tails and ventral stabilizing fins. It also has an F-22 style nose section, but with F-35 style dropped nose, forward swept intake cowls with diverterless supersonic inlet (DSI) bumps and a one-piece canopy. It was reported in November 2006 that a T/W=10 17,000 kilograms (37,000 lb) class turbofan (WS- 15/"large thrust") was being developed for the J-20. One ( ) prototype is fitted with AL-31F, the other ( ) is fitted with the improved WS-10G with a new "stealth" nozzle possibly to reduce RCS and IR emission. The J-20 may become the first operational combat aircraft that carries sufficient fuel to supercruise throughout its missions, doubling its sortie rate. Pentagon spokesman Geoff Morrell has said that it was premature to call the J-20 a stealth fighter or to judge if it had any other fifth generation characteristics. The production J-20 may incorporate an advanced fly-by-wire (FBW) system fully integrated with the fire-control and the engine systems. Its fire-control radar is expected to be Active Electronically Scanned Array (AESA) (Type 1475/KLJ5?). According to recent pictures from the internet, two small dark diamond shaped windows can be seen on both sides of the nose, which could house certain EO sensors, such as MAWS and/or IRST. Two additional windows are seen underneath the rear fuselage, plus two more on top of the forward fuselage above the canard wings, suggesting a distributed situational awareness system similar to the EODAS onboard American F-35 was installed providing a full 360 coverage. The aircraft features a "pure" glass cockpit (two large color liquid crystal display (LCD) and several smaller ones and a wide-angle holographic head-up display (HUD)). Many of these subsystems have been tested onboard J-10Bs to speed up the development. The J-20 has a large belly weapon bay for short/long-range air-to-air missiles (AAM) (PL-10, PL- 12C/D & PL-21) and two smaller lateral weapon bays behind the air inlets for short-range AAMs (PL-10). Carlo Kopp has suggested that the J-20's overall stealth shaping is "without doubt considerably better" than the F-35 and PAK FA, but he agrees with others, such as Shih Hiao-wei of Defense International monthly and Bill Sweetman of Aviation Week, that some parts on the J-20 will challenge its ability to remain stealthy from all directions: "The aft fuselage, tailbooms, fins/strakes and axi-symmetric nozzles are not compatible with high stealth performance, but may only be stop-gap measures to expedite flight testing of a prototype." As of January 2011 the engine nozzles were clearly non-stealthy; this may be due to the fact that the final "fifth generation" engines had not been completed yet. However, one of the prototypes uses WS-10G engines with stealthy jagged-edge nozzles and tiles, however without the reduced RCS afterburners of the F119 and F135 this would have limited impact. Robert Gates has also questioned how stealthy the J-20 might be although he did say the development of the J-20 had the potential to "put some of our capabilities at risk, and we have to pay attention to them, we have to respond appropriately with our own programs. Kopp and Goon have further speculated that the J-20 is designed to operate as a heavy interceptor, destroying opposing AWACS and tanker aircraft. If true, this would make it more similar to a MiG-25 with stealth capability. Sweetman agrees that this is the most likely role for such a large aircraft with low thrust to weight ratio and limited agility that is optimized for range and speed. 113

114 Lewis Page has said that it is unlikely that the Chinese will soon have an American style Low Probability of Intercept Radar and so the J-20 would be limited to attacking ground targets like previous generations of American stealth aircraft such as the Lockheed F-117 Nighthawk. In that case the J-20 would carry a radar, but using it would instantly give away its location. However, the J-20 is expected to use a AESA radar, which should have Low Probability of Intercept modes. Given that the F-35 can already track and jam even the F-22's radar, this might not be sufficient. Loren B. Thompson has said that this combination of forward sector only stealth and long range will allow the J-20 to make attacks on surface targets while the United States lacks sufficient bases for F-22s in the area to counter these attacks and American allies have no comparable aircraft. Thompson has also said that a long-range maritime strike aircraft may cause the United States more trouble than a shorter range air-superiority fighter like the F-22. A canard delta offers greater efficiency in both subsonic and supersonic flight (which may help supercruise range), but it is unknown if the Chinese have the same software used on the Eurofighter Typhoon to control the otherwise non-stealthy canards. Teal Group analyst Richard Aboulafia has also raised doubts about the use of canards on a design that is intended to be low-observable: There s no better way of guaranteeing a radar reflection and compromise of stealth. Aboulafia has also called the J-20 a kludge made of mismatched parts and questioned if the Chinese have the skills or technology to produce a true fifth generation fighter. Nevertheless, canards greatly boost the aircraft's maneuverability over that of a pure delta wing without canards. Sweetman notes that the canard delta works with the Whitcomb area rule for a large-volume mid-body section supersonic aircraft. Also, while the DSI intakes are easier to maintain than more complex stealth-compatible intakes, such as on the F-22, their fixed form limits the aircraft to around Mach 2.0. J.D. McFarlan of Lockheed Martin has said that the J-20 DSI inlets resemble those of the F-35, but it is unclear if the Chinese have perfected their own design. The Advanced Medium Combat Aircraft (AMCA), formerly known as the Medium Combat Aircraft (MCA), is a single-seat, twin-engine fifth-generation stealth multirole fighter being developed by India. It will complement the HAL Tejas, the Sukhoi/HAL FGFA, the Sukhoi Su-30MKI and the as yet undecided MRCA in the Indian Air Force. The main purpose of this aircraft is to replace the aging SEPECAT Jaguar & Dassault Mirage Unofficial design work on the MCA has been started. A naval version is confirmed as Indian Navy also contributed to the funding. $2 billion funding is set to be allocated over the next three years.number of AMCA orders are expected to reach 250 units. In August 2006, India's then defence minister Mr. Pranab Mukherjee announced in Parliament that the government is evaluating experiences gained from the Tejas programme for the MCA. In October 2008, the Indian Air Force asked the Aeronautical Development Agency (ADA) to prepare a detailed project report on the development of a Medium Combat Aircraft (MCA) incorporating stealth features. In February 2009, ADA director P.S Subramanyam said at a Aero-India 2009 seminar, that they are working closely with Indian Air Force to develop a Medium Combat Aircraft. He added that according to the specification provided by the Indian Air Force, it would likely be a twenty ton aircraft powered by two GTX Kaveri engines. In April 2010, the Indian Air Force issued the Air Staff requirements (ASR) for the AMCA which placed the aircraft in the twenty five ton category. The AMCA will be designed with a very small radar cross-section and will also feature serpentine shaped air-intakes, internal weapons and the use of composites and other materials. It will be a twin-engined design using the GTX Kaveri engine with thrust vectoring with the possibility of giving the aircraft supercruise capabilities. A wind-tunnel testing model of the MCA airframe was seen at Aero-India As well as advanced sensors the aircraft will be equipped with missiles like DRDO Astra and other advanced missiles, stand-off weapons and precision weapons. The aircraft will have the capability to deploy JDAM's. The aircraft will feature Extended detection range and targeting range with the ability to release weapons at supersonic speeds. The aircraft's avionics suite will include AESA radar IRST and appropriate Electronic warfare systems and all aspect missile warning suite. DARE, Bangalore has appointed a special team to begin identifying avionics and cockpit packages for the first prototype vehicle, and will supply this in published form to the ADA by July This will include cockpit electronics, cockpit configuration, man-machine interface, mission console systems and 114

115 computers/software with a focus on data fusion and modular architecture. The LRDE will, in about the same time frame, provide a separate project proposal for an all new radar, to be re-designated for the AMCA, as a derivative of the MMR currently being completed with technology from Israel's ELTA. LRDE will independently look in the market for a partner for active array technology, though it communicated to ADA in June 2009 that it had sufficient R&D available to build a reliable AESA prototype with assistance from Bharat Electronics Ltd and two private firms based in Hyderabad. The Next-Generation Bomber program (formerly called the 2018 Bomber) is a medium bomber under development by the United States Air Force. It was originally projected to enter service around 2018 as a super stealthy, subsonic, medium range, medium payload "B-3" type system to augment and possibly to a limited degree replace the U.S. Air Force's aging bomber fleet. On 24 June 2010 Lt. Gen. Philip M. Breedlove said that the term "next-generation bomber" was dead and that the Air Force was working on a long-range strike "family" that would draw on the capabilities of systems like the F-35 and F-22 to help a more affordable and versatile bomber complete its missions. On 13 September 2010 Air Force Secretary Michael Donley said that long range strike would continue cautiously with proven technologies and that the plan to be submitted with the 2012 budget could call for either a missile or an aircraft. General Norton Schwartz clarified that the bomber will not itself be nuclear capable, but will be the basis of a future nuclear capable aircraft. USAF Air Combat Command in studied alternatives for a new bomber type aircraft to augment the current bomber fleet which now consists of largely 1970s era airframes, with a goal of having a fully operational aircraft on the ramp by Speculation that the next generation bomber would be hypersonic and unmanned were laid to rest when Air Force Major General Mark T. Matthews, head of ACC Plans and Programs said "Our belief is that the bomber should be manned" at a 1 May 2007 Air Force Association sponsored event. He later cited that the bomber would also likely be subsonic due to the higher cost of development and maintenance of a supersonic or hypersonic bomber. The 2018 bomber is expected to serve as a stop-gap until the more advanced "2037 Bomber" enters service. USAF officials expect the new bomber to have top end low observability characteristics with the ability to loiter for hours over the battlefield area and respond to threats as they appear. Major General David E. Clary, ACC vice-commander, summed it up by saying the new bomber will be expected to "penetrate and persist". Deployment of cruise missiles is another issue for the new bomber. The B-52 is the only aircraft currently in the Air Force inventory allowed under treaty to carry and fire the cruise missiles. Major consideration was paid to operation readiness and flexibility. In 2006, the program expected that a prototype could be flying as early as In September 2007, Air Force generals stated that even though the development schedule for the bomber is short, it could be fielded by On 25 January 2008, Boeing and Lockheed Martin announced an agreement to embark on a joint effort to develop a new U.S. Air Force strategic bomber, with plans for the new airplane to be in service by This collaborative effort for a long-range strike program will include work in advanced sensors and future electronic warfare solutions, including advancements in network-enabled battle management, command and control, and virtual warfare simulation and experimentation. Under the Boeing-Lockheed arrangement, Boeing, the No. 2 Pentagon supplier, would be the primary contractor with about 60% of the deal, said sources familiar with the companies' plans. Lockheed, the world's largest defense contractor, would have around 40%. However on March 1, 2010 Boeing said that the joint project had been suspended. Northrop Grumman received $2 billion in funding in 2008 for "restricted programs" also called black programs for a demonstrator which could fly in The Air Force was expected to announce late in 2009 its precise requirements for a new bomber that would be operating by In May 2009 testimony before Congress, U.S. Secretary of Defense Robert Gates mentioned that the Pentagon is considering a pilotless aircraft for the next-generation bomber role. Then in April 2009, Defense Secretary Gates announced a delay in the new generation bomber project that would push it past the 2018 date. This was caused not only by budget considerations, but also by nuclear arms treaty considerations. On 19 May 2009, Air Force Chief of Staff General Norton Schwartz said that the USAF's focus in the 2010 budget was on Long-range strike, not next-generation bomber and will push for this in the QDR. In June 2009, the two teams working on NGB proposals were told to "close up shop". On 16 September 2009, Defense Secretary Gates endorsed the concept of a new bomber but insisted that it must be affordable. He said, "I am committed to seeing that the United States has an airborne long-range strike capability one of several areas being examined in the ongoing Quadrennial Defense Review. What we 115

116 must not do is repeat what happened with our last manned bomber. By the time the research, development, and requirements processes ran their course, the aircraft, despite its great capability, turned out to be so expensive $2 billion each in the case of the B-2 that less than one-sixth of the planned fleet of 132 was ever built." On 5 October 2009, Ashton Carter said that the DoD was still deciding if the Air Force really needed a new bomber and that if the program was approved the aircraft would need to handle reconnaissance as well as strike. And in July 2010 he said he intended to make affordability a requirement" for the next-generation intelligence and strike platform. On 11 December 2009, Gates said that the QDR had shown the need for both manned and unmanned long range strike and that the 2011 budget would most likely include funding for the future bomber. The Air Force plans for the new bomber to be multi-role with intelligence, surveillance, and reconnaissance (ISR) capabilities. Andrew Krepinevich has questioned the reliance on a short range aircraft like the F-35 to 'manage' China in a future conflict and has called on reducing the F-35 buy in favor of a longer range platform like the Next-Generation Bomber, but then-united States Secretary of the Air Force Michael Wynne rejected this plan of action back in During the debate on the New START treaty in December 2010, several senators used the stalled bomber project as a reason to oppose or delay the ratification of the treaty. US Secretary of Defense Robert Gates in a 6 January 2011 speech on the U.S. defense budget for FY 2012, announced that major investments will be made in developing a new, long-range, nuclear-capable penetrating bomber that has the option of being remotely piloted. He also said the aircraft will be designed and developed using proven technologies, an approach that should make it possible to deliver this capability on schedule and in quantity. It is important that we begin this project now to ensure that a new bomber can be ready before the current aging fleet goes out of service. The follow on bomber represents a key component of a joint portfolio of conventional deep-strike capabilities an area that should be a high priority for future defense investment given the anti-access challenges our military faces. In addition to the strategic bombing, tactical bombing, and prompt global strike roles that one might expect for a long-range bomber, the new next generation bomber will be a part of a family of systems also responsible for ground surveillance and electronic attack. The Air Force intends to purchase from 80 to 100 of the aircraft. Global Strike Command has indicated that one of the objectives for the bomber is for it to carry a weapon with the effects of the Massive Ordnance Penetrator. This would either be with the same weapon or a smaller weapon designed to match the penetrating power of the larger weapon. The Obama administration in its 2012 budget request asked for $197 million and a total of $3.7 billion over five years to develop the bomber which would include modular payload options for Intelligence, Surveillance, Reconnaissance (ISR), Electronic Attack (EA), and communications. In 2011 the House Armed Services Committee added language that would require two engine programs for the bomber, but Ashton Carter objected that this would interfere with plans to reuse an existing engine. In May 2011 Air Force undersecretary Erin Conaton announced that a program office for the bomber was being stood up. The PAK DA (or PAK-DA), is a next generation strategic bomber which is being developed by Kazan Aircraft Production Association for Russia. It stands for Perspektivnyi Aviatsionnyi Kompleks Dalney Aviatsyi, which means Prospective Air Complex for Long Range Aviation. The PAK DA will be a new, stealthy, strategic bomber and is expected to enter service in the timeframe. The Russian Air Force has tactical and technical requirements for a new generation of strategic bombers, as reported by Interfax. According to some sources, the PAK DA will be based on the supersonic Tu- 160 bomber. Later references to the new bomber, including a televised address from Prime Minister Vladimir Putin, seem to imply the aircraft will be an entirely new design. Some speculation suggests that it might follow the stealthy design of the America B-2 Spirit bomber, but there is little public evidence to support that. Russian Maj. Gen. Anatoly Zhikharev has stated that the new bomber will replace both the turboproppowered Tupolev Tu-95 and the supersonic Tupolev Tu-160. The 2037 Bomber is the unofficial name given to a heavy strategic bomber planned by the United States Air Force. It is projected to enter service in 2037 as a stealthy, supersonic, long-range, heavy-payload, possibly unmanned aircraft to potentially replace the B-52 Stratofortress, which is scheduled to be retired in

117 With the ending of B-2 production in the early 1990s, the U.S. Air Force was left with a gap in its bomber development. A new bomber would be needed in the 2037 time frame to replace retiring B-52s and B- 1s according to the Air Force's Bomber Roadmap, released in This was considered too long to wait, as the Air Force needed an interim bomber before the 2030s. This left the aircraft proposed for 2037 as more of a heavy bomber than a medium bomber. The McDonnell Douglas/General Dynamics A-12 Avenger II (fig. 103) was a proposed American ground-attack aircraft from McDonnell Douglas and General Dynamics. It was to be an all-weather, carrierbased stealth bomber replacement for the Grumman A-6 Intruder in the United States Navy and Marine Corps. Its Avenger II name was taken from the Grumman TBF Avenger of World War II. The development of the A-12 was troubled by cost overruns and several delays, causing questions of the program's ability to deliver upon its objectives; these doubts led to the development program being canceled in The manner of its cancellation has been contested through litigation to this day. Fig A concept of the A-12 Avenger II. The US Navy began the Advanced Tactical Aircraft (ATA) program in The program was to develop and field a replacement for the A-6 Intruder by Stealth technology developed for the US Air Force would be used heavily in the program. Concept design contracts were awarded to the industry teams of McDonnell Douglas/General Dynamics, and Northrop/Grumman/Vought in November The teams were awarded contracts for further concept development in The McDonnell Douglas/General Dynamics team was selected as the winner on 13 January 1988, the rival team lead by Grumman surprisingly failed to submit a final bid. The McDonnell Douglas/General Dynamics team was awarded a development contract and the ATA aircraft was designated A-12. The first flight was initially planned for December The A-12 was named Avenger II in homage to the World War II-era Navy torpedo-bomber Grumman TBF Avenger. The Navy initially sought to buy 620 A-12s and Marines wanted 238. In addition, the Air Force briefly considered ordering some 400 of an A-12 derivative. The A-12 was promoted as as possible replacement for the Air Force's General Dynamics F-111 Aardvark, and for the United Kingdom's Panavia Tornado fighterbombers. The craft was a flying wing design in the shape of an isosceles triangle, with the cockpit situated near the apex of the triangle. The A-12 gained the nickname "Flying Dorito". The aircraft was to be powered by two General Electric F412-D5F2 turbofan engines, each producing about 13,000 pounds-force (58 kn) of thrust. It was designed to carry precision guided weapons internally, up to two AIM-120 AMRAAM air-to-air missiles, two AGM-88 HARM air-to-ground missiles and a complement of air-to-ground ordnance, including unguided or precision-guided bombs, could be carried in an internal weapons bay. It has been claimed that the A-12 was to be capable of delivering nuclear weapons held in its internal weapons bay as well. The A-12 was to have a weapons load of 5,160 pounds (2,300 kg). Beginning in early 1990 McDonnell Douglas and General Dynamics revealed delays and projected cost increases. The weight of the aircraft had significantly increased due to complications with the composite materials used, the weight being 30% over design specification, this was a significantly negative factor for carrierbased operations. Technical difficulties with the complexity of the radar system to be used also caused costs to increase; by one estimate the A-12 was to consume up to 70% of the Navy's budget for aircraft. After delays, its critical design review was successfully completed in October 1990; the A-12's maiden flight was rescheduled to early In December 1990, it was planned for 14 Navy aircraft carriers to equipped with a wing of 20 A-12s each. A government report released in November 1990 documented serious problems with the A-12 development program. In December 1990 Secretary of Defense Dick Cheney told the Navy to justify the program and deliver reasons why it should not be canceled. The response given by the Navy and the contractors 117

118 failed to persuade the Secretary of Defense, as he canceled the program in the following month, on 7 January 1991, for breach of contract. The government felt the contractors could not complete the program and instructed them to repay most of the $2 billion that had been spent on A-12 development. McDonnell Douglas and General Dynamics disputed this in Federal Claims court; the reasons and causes for the cancellation have been debated and remain an issue of controversy, with suggestions of political expediency and scheming mooted to be behind the action. After the cancellation of the A-12, the Navy elected to purchase the F/A-18E/F Super Hornet, which went on to replace the A-6 Intruder and the F-14 Tomcat. The Super Hornet uses the General Electric F414 turbofan engine, which is a modified variant of the upgraded F404 version developed for the A-12. The full-size A-12 mockup was revealed to the public at the former Carswell Air Force Base in June The cancellation of the A-12 is seen as one of the major losses in the 1990s that weakened McDonnell Douglas and led to its merger with rival Boeing in The manner in which the program was canceled led to years of litigation between the contractors and the Department of Defense over breach of contract. On 1 June 2009, the U.S. Court of Appeals for the Federal Circuit ruled that the U.S. Navy was justified in canceling the contract. The ruling also required the two contractors to repay the U.S. government more than US$1.35 billion, plus interest charges of US$1.45 billion. Boeing, which had merged with McDonnell Douglas, vowed to appeal the decision, as has General Dynamics. In September 2010, the U.S. Supreme Court said it would hear the two companies' arguments, that the government canceled the project improperly and that the use of a state secrets claim by the U.S. prevented them from mounting an effective defense. In May 2011, the Supreme Court set aside the Appeals Court decision and returned the case to federal circuit court. The Lockheed Martin F-35 Lightning II, an in-development carrier-capable fighter featuring stealth technology and oriented toward ground-attack operations, is in effect a successor to the A-12 in both role and industrial origins. Comparisons have been drawn between the role of the future Next-Generation Bomber and the A-12; the two aircraft both being stealthy sub-sonic bombers designed to carry comparative bomb loads and fly similar ranges. The Mitsubishi ATD-X Shinshin is a state of the art prototype fifth-generation jet fighter that uses advanced stealth technology. Being developed by the Japanese Ministry of Defense Technical Research and Development Institute (TRDI) for research purposes. The main contractor of the project is Mitsubishi Heavy Industries. Many consider this aircraft to be Japan's first domestically made stealth fighter. ATD-X is an acronym meaning "Advanced Technology Demonstrator X". The aircraft's Japanese name is 心神 (shin-shin) which means one's mind. The aircraft's first flight is scheduled for At the beginning of the 21st century, Japan sought to replace its aging fleet of fighter aircraft, began making overtures to the United States on the topic of purchasing several Lockheed Martin F-22 Raptor fighters for their own forces. However the U.S. Congress had banned the exporting of the aircraft in order to safeguard secrets of the aircraft's technology such as its extensive use of stealth; this rejection necessitated Japan to develop its own modern fighter, to be equipped with stealth features and other advanced systems. A mock-up of the ATD-X was constructed and used to study the radar cross section in France in A radio-controlled 1/5 scale model made its first flight in 2006 to gain data on performance at high angles of attack and to test new sensory equipment and self-repairing flight control systems. Following these preliminary steps, the decision was taken in 2007 to push ahead with the multi billionyen project. At the time of this decision, production was forecast to start roughly 10 years later, around As of 2007, the ATD-X is expected to conduct its maiden flight in The ATD-X will be used as a technology demonstrator and research prototype to determine whether domestic advanced technologies for a fifth generation fighter aircraft are viable, and is a 1/3 size model of a possible full-production aircraft. The aircraft also features 3D thrust vectoring capability. Thrust is controlled in the ATD-X by the use of 3 paddles on each engine nozzle similar to the system used on the Rockwell X-31, while an axis-symmetric thrust vectoring engine is also being developed for the full scale production model. The nozzles on the prototype appear to be uncovered and might have a slight adverse effect on the aircraft's stealth characteristics. Among the features the ATD-X is to have is a fly-by-optics flight control system, which by substituting optical fibers for wires, allows data to be transferred faster and with immunity to electromagnetic disturbance. 118

119 Its radar will be an active electronically scanned array (AESA) radar called the 'Multifunction RF Sensor', which is intended to have broad spectrum agility, capabilities for electronic countermeasures (ECM), electronic support measures (ESM), communications functions, and possibly even microwave weapon functions. A further feature will be a so-called 'Self Repairing Flight Control Capability', which will allow the aircraft to automatically detect failures or damage in its flight control surfaces, and using the remaining control surfaces, calibrate accordingly to retain controlled flight. The JASDF is reported to have issued a request for information for engines in the 10 to 20 thousand pound thrust range to power the prototypes while Ishikawajima-Harima Heavy Industries is to provide the engines for the completed fighter. The Lockheed Have Blue was the code name for Lockheed's "proof of concept" (i.e., prototype) stealth aircraft that preceded the F-117 Nighthawk production stealth aircraft program. Have Blue was designed by Lockheed's Skunk Works division, and tested at the top-secret Groom Lake base, Nevada. The Have Blue was the first fixed-wing aircraft designed from an electrical engineering (rather than an aerospace engineering) perspective. The aircraft's plate-like, faceted shape was designed to deflect electromagnetic waves, greatly reducing its radar signature. Two Have Blue planes were built to test both the flight dynamics and radar returns of the stealth concept. These prototypes flew at Groom Lake, Nevada, between 1977 and While they appear similar to the later F-117, the Have Blue prototypes were smaller aircraft, about 60% scale, with greater wing sweep and inward-canted vertical tails. The nose of Have Blue prototypes was also sharper and offered a slightly higher degree of stealth compared to production F-117 planes, which had to have a flat windshield to incorporate a head-up display. During testing of the design, the aircraft was flown near (~100 miles away) to an army radar system, followed at some significant distance by a spotter plane; over a preplanned flight path. The cover story for the technology was that a black box in the nose of the aircraft was able to deflect the radar; whereas obviously the shape of the aircraft did all the real work. Radar only managed to detect the spotter plane; a soldier placed on the ground directly under the flight path had to witness the oddly shaped plane to verify that the flight had occurred. The design was inherently unstable about all three axes, control being fly-by-wire adapted from the F- 16's single-axis fly-by-wire system. Both aircraft were ultimately lost in the course of testing, the first from a hard landing incident which resulted in the gear being jammed in a semi-retracted position and the pilot ultimately being ordered to eject after attempts to enable the gear to lower and lock proved unsuccessful. The second was the result of an engine fire which severed hydraulic lines, forcing the pilot to eject. The debris from both aircraft were secretly buried somewhere within the Nellis complex. "Even though the test site was in a remote location, our airplane was kept under wraps inside its hangar most of the time. Soviet spy satellites made regular passes, and every time our airplane was rolled out everyone on the base who wasn't cleared for Have Blue had to go into the windowless mess hall and have a cup of coffee until we took off." Ben Rich, director of Lockheed's Skunk Works from 1975 to The Northrop Tacit Blue was a technology demonstrator aircraft created to demonstrate that a stealth low observable surveillance aircraft with a low probability of intercept radar and other sensors could operate close to the forward line of battle with a high degree of survivability (fig. 104). Unveiled by the U.S. Air Force on 30 April 1996, the Tacit Blue Technology Demonstration Program was designed to prove that such an aircraft could continuously monitor the ground situation deep behind the battlefield and provide targeting information in real-time to a ground command center. Tacit Blue represented the 'black' component in the larger Assault Breaker program, which intended to validate the concept of massed standoff attacks on advancing armoured formations using smart munitions. The Pave Mover radar demonstrators provided the non-stealthy portion of the program's targeting system, whereas Tacit Blue was intended to demonstrate a similar but stealthy capability, while validating a number of innovative stealth technology advances. Fig The Northrop Tacit Blue was a Stealth demonstrator. 119

120 Tacit Blue, nicknamed "the whale," featured a straight tapered wing with a V-tail mounted on an oversized fuselage with a curved shape. A single flush inlet on the top of the fuselage provided air to two highbypass turbofan engines. Tacit Blue employed a quadruply redundant, digital, fly-by-wire flight control system to help stabilize the aircraft about its longitudinal and directional axes. The sensor technology developed for Tacit Blue is now being used by the E-8 Joint STARS aircraft. The aircraft made its first flight in February 1982, and subsequently logged 135 flights over a three year period. The aircraft often flew three to four flights weekly and several times flew more than once a day. After reaching about 250 flight hours, the aircraft was placed in storage in In 1996, Tacit Blue was placed on display at the National Museum of the United States Air Force at Wright Patterson Air Force Base, near Dayton, Ohio. Tacit Blue is on display in the Research and Development Hangar (within the Wright-Patterson Air Force Base perimeter and away from the main National Museum site). The Avro Vulcan, sometimes referred to as the Hawker Siddeley Vulcan, is a delta wing subsonic jet strategic bomber that was operated by the Royal Air Force (RAF) from 1953 until It was developed by Avro in response to a specification released by the Air Ministry. At the time, both jet engines and delta wings were considered cutting-edge and relatively unexplored; thus, the small-scale Avro 707 was produced to test the principles of the design. In flight, the Vulcan was an agile aircraft for its size. The Vulcan B.1 was first delivered to the RAF in In service, the Vulcan was armed with nuclear weapons and was a part of the RAF's V bomber force, the United Kingdom's airborne deterrent against aggression from other powers such as the Soviet Union during the Cold War. Features such as an extensive electronic countermeasures suite and a low radar cross section for its size would have made the aircraft difficult to detect while carrying out the nuclear strike mission. A second batch of aircraft, the B.2, was produced with new features, including a larger wing and greater fuel capacity, along with more advanced electronics and radar systems. The B.2s were adapted into several other variants, the B.2A carrying the Blue Steel missile, the B.2 (MRR) for Marine Radar Reconnaissance use, and the K.2 tanker for aerial refuelling. The Vulcan was also used in the secondary role of conventional bombing near the end of its service life in the 1982 Falklands War against Argentina during Operation Black Buck. One example, XH558, was recently restored for use in display flights and commemoration of the employment of the aircraft in the Falklands conflict. Design work began at A. V. Roe in 1947 under Roy Chadwick, however, the delta wing design built upon the wartime work of Professor Alexander Lippisch, and the first design studies featured a radical tailless delta wing design. The Air Ministry specification B.35/46 required a bomber with a top speed of 575 mph (925 km/h), an operating ceiling of 50,000 ft (15,000 m), a range of 3,452 miles (5,556 km) and a bomb load of 10,000 lb (4,500 kg); intended to carry out delivery of Britain's nuclear-armed gravity bombs to strategic targets within Soviet territory. Design work also began at Vickers and Handley Page. All three designs were approved aircraft that would become the Valiant, the Victor, and the Avro Vulcan. The Type 698 as first envisaged by Chadwick, and upon his death in the crash of the Avro Tudor 2 prototype on 23 August 1947, later refined by his successor, Stuart Davies in March 1949, was a more conventional delta wing design initially with tail surfaces at the ends of the wing and finally with a "full" tail unit. Avro felt this would be able to give the required combination of large wing area and sweepback to offset the transonic effects and a thick wing root to embed the engines. The thick wing gave considerable space for the engines and made allowances for future larger models to be installed. Wingtip rudders provided the control instead of the traditional rear fuselage and tail, which were unnecessary on this design. This design was reworked multiple times to reduce weight, a restriction which was later loosened, and became more conventional, adopting a centre fuselage with four paired engines and a tail. As the delta wing was an unknown quantity, Avro began scale prototype testing in 1948 with a series of single-seater Avro 707 "proof-of-concept" aircraft. Despite the crash of the first 707 prototype on 30 September 1949, work continued and eventually four additional 707s were built to test low-speed as well as high-speed characteristics of the delta wing design. The first full-scale prototype Type 698 made its maiden flight piloted by Avro Chief Test Pilot retired Wing Commander Roly Falk on 30 August The Vulcan name was not chosen until 1952, after the Valiant had already been named. The 698's fourth flight was its appearance at the 1952 Farnborough airshow when Roly Falk demonstrated an "almost vertical bank". Falk made another public demonstration of the Vulcan's high performance and agility at the 1955 Farnborough Airshow; while flying the second production Vulcan, XA890, he performed an upward barrel roll shortly following takeoff. After the second occasion he rolled it at the show, the SBAC requested he stop as it was "inappropriate". Two prototypes were built and subsequently modified for development purposes. Both flew with a straight leading edge, which was then modified to have a kink further out towards the wingtip; this was to remove the occurrence of high frequency buffeting during flight. The production Vulcan bomber in service was fitted with a delta wing, but these were not pure delta wings for reason of better flying characteristics, and successive variants saw the wing altered and expanded again. 120

121 Cap. 6. PLANES WHICH HAVE MADE HISTORY Lockheed P-38 Lightning The Lockheed P-38 (fig. 105) Lightning was a World War II American fighter aircraft built by Lockheed. Developed to a United States Army Air Corps requirement, the P-38 had distinctive twin booms and a single, central nacelle containing the cockpit and armament. Named "fork-tailed devil" by the Luftwaffe and "two planes, one pilot" by the Japanese, the P-38 was used in a number of roles, including dive bombing, level bombing, ground-attack, photo reconnaissance missions, and extensively as a long-range escort fighter when equipped with drop tanks under its wings. Fig P-38H-5-LO, AAF Ser. No , of the AAF Tactical Center, Orlando Army Air Base, Florida, carrying two 1,000 lb bombs during capability tests, March The P-38 was used most successfully in the Pacific Theater of Operations and the China-Burma-India Theater of Operations as the mount of America's top aces, Richard Bong (40 victories) and Thomas McGuire (38 victories). In the South West Pacific theater, the P-38 was the primary long-range fighter of United States Army Air Forces until the appearance of large numbers of P-51D Mustangs toward the end of the war. The P- 38 was unusually quiet for a fighter, the exhaust muffled by the turbo-superchargers. It was extremely forgiving, and could be mishandled in many ways, but the rate of roll was too slow for it to excel as a dogfighter. The P-38 was the only American fighter aircraft in production throughout American involvement in the war, from Pearl Harbor to Victory over Japan Day. Lockheed designed the P-38 in response to a February 1937 specification from the United States Army Air Corps. Circular Proposal X-608 was a set of aircraft performance goals authored by First Lieutenant Benjamin S. Kelsey (later Brigadier General) and First Lieutenant Gordon P. Saville (later General) for a twinengine, high-altitude "interceptor" having "the tactical mission of interception and attack of hostile aircraft at high altitude." Kelsey recalled in 1977 that he and Saville drew up the specification using the word interceptor as a way to bypass the inflexible Army Air Corps requirement for pursuit aircraft to carry no more than 500 lb (227 kg) of armament including ammunition, as well as the restriction of single-seat aircraft to one engine. Kelsey was looking for a minimum of 1,000 lb (454 kg) of armament. Kelsey and Saville aimed to get a more capable fighter; better at dog-fighting and at high-altitude combat. Specifications called for a maximum airspeed of at least 360 mph (580 km/h) at altitude, and a climb to 20,000 ft (6,100 m) within six minutes; the toughest set of specifications USAAC had presented to that date. The unbuilt Vultee XP1015 was designed to the same requirement, but was not advanced enough to merit further investigation. A similar single-engine proposal was issued at the same time: Circular Proposal X-609, in response to which the Bell P-39 Airacobra was designed. Both proposals required liquid-cooled Allison V-1710 engines with turbo-superchargers and both gave extra points for tricycle landing gear. The Lockheed design team, under the direction of Hall Hibbard and Clarence "Kelly" Johnson, considered a range of twin-engine configurations including both engines in a central fuselage with push-pull propellers. The eventual configuration was rare in terms of contemporary fighter aircraft design, with only the preceding Fokker G.1 and later Northrop P-61 Black Widow having a similar planform. The Lockheed team chose twin booms to accommodate the tail assembly, engines, and turbo-superchargers, with a central nacelle for the pilot and armament. The XP-38 gondola mock-up was designed to mount two.50 in (12.7 mm) M2 Browning machine guns, with 200 rpg, two.30 in (7.62 mm) Brownings, with 500 rpg, and a T1 Army Ordnance 121

122 .90 in (23 mm) autocannon with a rotary magazine as a substitute for the non-existent 25 mm Hotchkiss aircraft autocannon specified by Kelsey and Saville. In the YP-38s, a larger John Browning-designed, Colt-made M9 37 mm (1.46 in) autocannon with 15 rounds replaced the T1. The 15 rounds were in three 5-round clips, an unsatisfactory arrangement according to Kelsey, and the M9 did not perform reliably in flight. Further armament experiments from March to June 1941 resulted in the P-38E combat configuration of four M2 Browning machine guns, and one Hispano 20 mm (.79 in) autocannon with 150 rounds. Clustering all the armament in the nose was unlike most other U.S. aircraft which used wing-mounted guns with trajectories set up to crisscross at one or more points in a "convergence zone." Guns mounted in the nose did not suffer from having their useful ranges limited by pattern convergence, meaning good pilots could shoot much farther. A Lightning could reliably hit targets at any range up to 1,000 yd (910 m), whereas other fighters had to pick a single convergence range between 100 and 250 yd (230 m). The clustered weapons had a "buzz saw" effect on any target at the receiving end, making the aircraft effective for strafing as well. The rate of fire on the guns was about 650 rounds per minute for the mm cannon round (130 gram shell) at a muzzle velocity of about 2,887 ft/s (880 m/s), and for the.50 inch machine guns (43 48 gram rounds), about 850 rpm at 2,756 ft/s (840 m/s) velocity. Combined rate of fire was over 4,000 rpm with roughly every sixth projectile a 20 mm. Time of firing for the 20 mm cannon and.50 caliber machine guns were approximately 14 seconds and 35 seconds respectively. The Lockheed design incorporated tricycle undercarriage and a bubble canopy, and featured two 1,000 hp (746 kw) turbo-supercharged 12-cylinder Allison V-1710 engines fitted with counter-rotating propellers to eliminate the effect of engine torque, with the superchargers positioned behind the engines in the booms. Counter-rotation was achieved with the use of "handed" engines, which meant that the crankshaft of each engine turned in the opposite direction of its counterpart. The V-12 engines only required that the spark plug firing order be changed in order for the direction of the crank shaft to be reversed, according to the General Motors Allison V1710 Service School Handbook. It was the first American fighter to make extensive use of stainless steel and smooth, flush-riveted buttjointed aluminum skin panels. It was also the first fighter to fly faster than 400 mph (640 km/h). Lockheed won the competition on 23 June 1937 with its Model 22 and was contracted to build a prototype XP-38 for US$163,000, though Lockheed's own costs on the prototype would add up to US$761,000. Construction began in July 1938 and the XP-38 first flew on 27 January 1939 at the hands of Ben Kelsey. Kelsey then proposed a speed dash to Wright Field on 11 February 1939 to relocate the aircraft for further testing. General Henry "Hap" Arnold, commander of the USAAC, approved of the record attempt, and recommended a cross-country flight to New York. The flight set a speed record by flying from California to New York in seven hours and two minutes, not counting two refueling stops, but the aircraft was downed by carburetor icing short of the Mitchel Field runway in Hempstead, New York, and was wrecked. However, on the basis of the record flight, the Air Corps ordered 13 YP-38s on 27 April 1939 for US$134,284 apiece. (The initial "Y" in "YP" was the USAAC's designation for a prototype while the "X" in "XP" was for experimental.) Lockheed's Chief test pilot Tony LeVier angrily characterized the accident as an unnecessary publicity stunt, but according to Kelsey the loss of the prototype, instead of hampering the program, speeded the process by cutting short the initial test series. The success of the aircraft design contributed to Kelsey's promotion to captain in May, Fig One of 13 YP-38s constructed. 122

123 Manufacture of the YP-38s (fig. 106) fell behind schedule, at least partly due to the need for massproduction suitability making them substantially different in construction than the prototype. Another factor was the sudden required facility expansion of Lockheed in Burbank, taking it from a specialized civilian firm dealing with small orders to a large government defense contractor making Venturas, Harpoons, Lodestars, Hudsons, and designing the Constellation airliner for TWA. The first YP-38 was not completed until September 1940, with its maiden flight on 17 September. The 13th and final YP-38 was delivered to the Air Corps in June 1941; 12 aircraft were retained for flight testing and one for destructive stress testing. The YPs were substantially redesigned and differed greatly in detail from the hand-built XP-38. They were lighter, included changes in engine fit, and the propeller rotation was reversed, with the blades rotating outwards (away) from the cockpit at the top of their arc rather than inwards as before. This improved the aircraft's stability as a gunnery platform. Test flights revealed problems initially believed to be tail flutter. During high-speed flight approaching Mach 0.68, especially during dives, the aircraft's tail would begin to shake violently and the nose would tuck under, steepening the dive. Once caught in this dive, the fighter would enter a high-speed compressibility stall and the controls would lock up, leaving the pilot no option but to bail out (if possible) or remain with the aircraft until it got down to denser air, where he might have a chance to pull out. During a test flight in May 1941, USAAC Major Signa Gilkey managed to stay with a YP-38 in a compressibility lockup, riding it out until he recovered gradually using elevator trim. Lockheed engineers were very concerned at this limitation, but first they had to concentrate on filling the current order of aircraft. In June 1941, the Army Air Corps was renamed the U.S. Army Air Forces (USAAF) and a total of 65 Lightnings were finished for the service by September 1941 with more on the way for the USAAF, the Royal Air Force (RAF) and the Free French Air Force operating from England. By November 1941, many of the initial assembly line challenges had been met and there was some breathing room for the engineering team to tackle the problem of frozen controls in a dive. Lockheed had a few ideas for tests that would help them find an answer. The first solution tried was the fitting of spring-loaded servo tabs on the elevator trailing edge; tabs that were designed to aid the pilot when control yoke forces rose over 30 lb (14 kg), as would be expected in a high-speed dive. At that point, the tabs would begin to multiply the effort of the pilot's actions. The expert test pilot, 43-year-old Ralph Virden, was given a specific high-altitude test sequence to follow, and was told to restrict his speed and fast maneuvering in denser air at low altitudes since the new mechanism could exert tremendous leverage under those conditions. A note was taped to the instrument panel of the test craft, underscoring this instruction. On 4 November 1941, Virden climbed into YP- 38 #1 and completed the test sequence successfully, but 15 minutes later was seen in a steep dive followed by a high-g pullout. The tail unit of the aircraft failed at about 3,000 ft (910 m) during the high-speed dive recovery; Virden was killed in the subsequent crash. The Lockheed design office was justifiably upset, but their design engineers could only conclude that servo tabs were not the solution for loss of control in a dive. Lockheed still had to find the problem; the Army Air Forces personnel were sure it was flutter, and ordered Lockheed to look more closely at the tail. Although the P-38's empennage was completely skinned in aluminum (not fabric) and was quite rigid, in 1941, flutter was a familiar engineering problem related to a too-flexible tail. At no time did the P-38 suffer from true flutter. To prove a point, one elevator and its vertical stabilizers were skinned with metal 63% thicker than standard, but the increase in rigidity made no difference in vibration. Army Lieutenant Colonel Kenneth B. Wolfe (head of Army Production Engineering) asked Lockheed to try external mass balances above and below the elevator, though the P-38 already had large mass balances elegantly placed within each vertical stabilizer. Various configurations of external mass balances were equipped and dangerously steep test flights flown to document their performance. Explaining to Wolfe in Report No. 2414, Kelly Johnson wrote "... the violence of the vibration was unchanged and the diving tendency was naturally the same for all conditions." The external mass balances did not help at all. Nonetheless, at Wolfe's insistence, the additional external balances were a feature of every P-38 built from then on. After months of pushing NACA to provide Mach 0.75 wind tunnel speeds (and finally succeeding), the compressibility problem was revealed to be the center of lift moving back toward the tail when in high-speed airflow. The compressibility problem was solved by changing the geometry of the wing's underside when diving so as to keep lift within bounds of the top of the wing. In February 1943, quick-acting dive flaps were tried and proven by Lockheed test pilots. The dive flaps were installed outboard of the engine nacelles and in action they extended downward 35 in 1½ seconds. The flaps did not act as a speed brake, they affected the center of pressure distribution so that the wing would not lose its lift. Late in 1943, a few hundred dive flap field modification kits were assembled to give North African, European and Pacific P-38s a chance to withstand compressibility and expand their combat tactics. Unfortunately, these crucial flaps did not always reach their destination. In March 1944, 200 dive flap kits 123

124 intended for European Theater of Operations (ETO) P-38Js were destroyed in a mistaken identification incident in which a RAF fighter shot down the Douglas C-54 Skymaster taking the shipment to England. Back in Burbank, P-38Js coming off the assembly line in spring 1944 were towed out to the tarmac and modified in the open air. The flaps were finally incorporated into the production line in June 1944 on the last 210 P-38Js. Despite testing having proved the dive flaps were effective in improving tactical maneuvers, a 14-month delay in production limited their implementation with only the final 50% of all Lightnings built having the dive flaps installed as an assembly line sequence. Buffeting was another early aerodynamic problem, difficult to sort out from compressibility as both were reported by test pilots as "tail shake". Buffeting came about from airflow disturbances ahead of the tail; the airplane would shake at high speed. Leading edge wing slots were tried as were combinations of filleting between the wing, cockpit and engine nacelles. Air tunnel test number 15 solved the buffeting completely and its fillet solution was fitted to every subsequent P-38 airframe. Fillet kits were sent out to every squadron flying Lightnings. The problem was traced to a 40% increase in air speed at the wing-fuselage junction where the chord/thickness ratio was highest. An airspeed of 500 mph (800 km/h) at 25,000 ft (7,600 m) could push airflow at the wing-fuselage junction close to the speed of sound. Filleting forever solved the buffeting problem for the P-38E and later models. Another issue with the P-38 arose from its unique design feature of outwardly rotating counter-rotating propellers. Losing one of two engines in any twin engine non-centerline thrust aircraft on takeoff creates sudden drag, yawing the nose toward the dead engine and rolling the wingtip down on the side of the dead engine. Normal training in flying twin-engine aircraft when losing an engine on takeoff would be to push the remaining engine to full throttle; if a pilot did that in the P-38, regardless of which engine had failed, the resulting engine torque and p-factor force produced a sudden uncontrollable yawing roll and the aircraft would flip over and slam into the ground. Eventually, procedures were taught to allow a pilot to deal with the situation by reducing power on the running engine, feathering the prop on the dead engine, and then increasing power gradually until the aircraft was in stable flight. Single-engine takeoffs were possible, though not with a full fuel and ammunition load. The engines were unusually quiet because the exhausts were muffled by the General Electric turbosuperchargers on the twin Allison V12s. There were early problems with cockpit temperature regulation; pilots were often too hot in the tropical sun as the canopy could not be fully opened without severe buffeting, and were often too cold in northern Europe and at high altitude, as the distance of the engines from the cockpit prevented easy heat transfer. Later variants received modifications (such as electrically-heated flight suits) to solve these problems. On 20 September 1939, before the YP-38s had been built and flight tested, the USAAF ordered 66 initial production P-38 Lightnings, 30 of which were delivered to the USAAF in mid-1941, but not all these aircraft were armed. The unarmed aircraft were subsequently fitted with four.50 in (12.7 mm) machine guns (instead of the two.50 in/12.7 mm and two.30 in/7.62 mm of their predecessors) and a 37 mm (1.46 in) cannon. They also had armor glass, cockpit armor and fluorescent cockpit controls. One was completed with a pressurized cabin on an experimental basis and designated XP-38A. Due to reports the USAAF was receiving from Europe, the remaining 36 in the batch were upgraded with small improvements such as self-sealing fuel tanks and enhanced armor protection to make them combat-capable. The USAAF specified that these 36 aircraft were to be designated P-38D. As a result, there never were any P-38Bs or P-38Cs. The P-38D's main role was to work out bugs and give the USAAF experience with handling the type. In March 1940, the French and the British ordered a total of 667 P-38s for US$100M, designated Model 322F for the French and Model 322B for the British. The aircraft would be a variant of the P-38E. The overseas Allies wished for complete commonality of Allison engines with the large numbers of Curtiss P-40 Tomahawks both nations had on order, and thus ordered for the Model 322 twin right-handed engines instead of counterrotating ones, and without turbo-superchargers. After the fall of France in June 1940, the British took over the entire order and christened the aircraft "Lightning". By June 1941, the War Ministry had cause to reconsider their earlier aircraft specifications, based on experience gathered in the Battle of Britain and The Blitz. British displeasure with the Lockheed order came to the fore in July, and on 5 August 1941 they modified the contract such that 143 aircraft would be delivered as previously ordered, to be known as "Lightning (Mark) I", and 524 would be upgraded to US-standard P-38E specifications, to be called "Lightning II" for British service. Later that summer, an RAF test pilot reported back from Burbank with a poor assessment of the 'tail flutter' situation, bringing the British to cancel all but three of the 143 Lightning Is. Because a loss of approximately US$15M was involved, Lockheed reviewed their contracts and decided to hold the British to the original order. Negotiations grew bitter and stalled. Everything changed after December 7, 1941 when the United States government seized some 40 of the Model 322s for West Coast defense, subsequently all British Lightnings were delivered to the 124

125 USAAF starting in January The USAAF lent the RAF three of the aircraft which were delivered by sea in March 1942 and were test flown no earlier than May at Swaythling, Boscombe Down and Farnborough. These three were subsequently returned to the USAAF; one in December 1942 and the others in July Of the remaining 140 Lightning Is, 19 were not modified and were designated the USAAF as RP-322-I ('R' for 'Restricted', because non-counter-rotating props were considered more dangerous at takeoff), while 121 were converted to non-turbo-supercharged counter-rotating V-1710F-2 engines and were designated P-322-II. All 121 were used as advanced trainers; a few were still serving that role in A few RP-322s were later used as test modification platforms such as for smoke-laying canisters. The RP-322 was a fairly fast aircraft under 16,000 ft (4,900 m) and well-behaved as a trainer. One positive result of the failed British/French order was to give the aircraft its name. Lockheed had originally dubbed the aircraft Atalanta in the company tradition of naming planes after mythological and celestial figures, but the RAF name won out. The first unit to receive P-38s was the 1st Fighter Group. After the attack on Pearl Harbor, the unit joined the 14th Pursuit Group in San Diego to provide West Coast defense. The first Lightning to see active service was the F-4 version, a P-38E in which the guns were replaced by four K17 cameras. They joined the 8th Photographic Squadron out of Australia on 4 April Three F-4s were operated by the Royal Australian Air Force in this theater for a short period beginning in September On 29 May 1942, 25 P-38s began operating in the Aleutian Islands in Alaska. The fighter's long range made it well-suited to the campaign over the almost 1,200 mi (2,000 km) long island chain, and it would be flown there for the rest of the war. The Aleutians were one of the most rugged environments available for testing the new aircraft under combat conditions. More Lightnings were lost due to severe weather and other conditions than enemy action, and there were cases where Lightning pilots, mesmerized by flying for hours over gray seas under gray skies, simply flew into the water. On 9 August 1942, two P-38Es of the 343rd Fighter Group, 11th Air Force, at the end of a 1,000 mi (1,609 km) long-range patrol, happened upon a pair of Japanese Kawanishi H6K "Mavis" flying boats and destroyed them, making them the first Japanese aircraft to be shot down by Lightnings. After the Battle of Midway, the USAAF began redeploying fighter groups to Britain as part of Operation Bolero, and Lightnings of the 1st Fighter Group were flown across the Atlantic via Iceland. On 14 August, Second Lieutenant Elza Shahan of the 27th Fighter Squadron, and Second Lieutenant Joseph Shaffer of the 33rd Squadron operating out of Iceland shot down a Focke-Wulf Fw 200 Condor over the Atlantic. Shahan in his P-38F downed the Condor; Shaffer, flying either a P-40C or a P-39, had already set an engine on fire. This was the first Luftwaffe aircraft destroyed by the USAAF. P-38 Lightnings had a number of lucky escapes, exemplified by the arrival of the 78th fighter Group at RAF Goxhill (Lincolnshire, England) in July The official handover ceremony was scheduled for mid- August, but on the day before the ceremony, Goxhill experienced its only air raid of the war. A single German bomber flew overhead and dropped a very well aimed bomb right on the intersection between the two newly concreted runways, but it didn t explode and the aircraft were able to continue their mission. (As it turned out, the bomb could not be removed and, for the duration of the war, aircraft had to pass over it every time they took off.) After 347 sorties with no enemy contact, the 1st, 14th and 82nd Fighter Groups were transferred to the 12th Air Force in North Africa as part of the force being built up for Operation Torch. On 19 November 1942, Lightnings escorted a group of B-17 Flying Fortress bombers on a raid over Tunis. On 5 April 1943, 26 P-38Fs of the 82nd destroyed 31 enemy aircraft, helping to establish air superiority in the area, and earning it the German nickname "der Gabelschwanzteufel" the Fork-Tailed Devil. The P-38 remained active in the Mediterranean for the rest of the war. It was in this theatre that the P-38 suffered its heaviest losses in the air. On 25 August 1943, 13 P-38s were shot down in a single sortie by Jagdgeschwader 53 Bf 109s without achieving a single kill. On 2 September, 10 P-38s were shot down, in return for a single kill, the 67-victory ace Franz Schiess (who was also the leading "Lightning" killer in the Luftwaffe with 17 destroyed). Kurt Bühligen, third highest scoring German pilot on Western front with 112 victories, recalled later: The P-38 fighter (and the B- 24) were easy to burn. Once in Africa we were six and met eight P-38s and shot down seven. One sees a great distance in Africa and our observers and flak people called in sightings and we could get altitude first and they were low and slow. General der Jagdflieger Adolf Galland was unimpressed with the P-38, declaring, "it had similar shortcomings in combat to our ME-110, our fighters were clearly superior to it." Experiences over Germany had shown a need for long-range escort fighters to protect the Eighth Air Force's heavy bomber operations. The P-38Hs of the 55th Fighter Group were transferred to the Eighth in England in September 125

126 1943, and were joined by the 20th, 364th and 479th Fighter Groups soon after. P-38s soon joined Spitfires in escorting the early Fortress raids over Europe. Because its distinctive shape was less prone to cases of mistaken identity and friendly fire, Lieutenant General Jimmy Doolittle, Commander 8th Air Force, chose to pilot a P-38 during the Invasion of Normandy so that he could personally assess the progress of the air offensive over France. At one point in the mission, Doolittle flick-rolled through a hole in the cloud cover but his wingman, Earle E. "Pat" Partridge (later General), was looking elsewhere and failed to notice Doolittle's quick maneuver, leaving Doolittle to continue alone on his survey of the crucial battle. Of the P-38, Doolittle said that it was "the sweetest-flying plane in the sky". A little-known role of the P-38 in the European theater was that of fighter-bomber during the invasion of Normandy and the Allied advance across France into Germany. Assigned to the IX Tactical Air Command, the 370th Fighter Group and its P-38s initially flew missions from England, dive-bombing radar installations, enemy armor, troop concentrations, and flak towers. The 370th's group commander Howard F. Nichols and a squadron of his P-38 Lightnings attacked Field Marshal Günther von Kluge's headquarters in July 1944; Nichols himself skipped a 500 lb (227 kg) bomb through the front door. The 370th later operated from Cardonville France, flying ground attack missions against gun emplacements, troops, supply dumps and tanks near Saint-Lô in July and in the Falaise-Argentan area in August The 370th participated in ground attack missions across Europe until February 1945 when the unit changed over to the P-51 Mustang. Italian pilots in the Mediterranean theatre started to face P-38s from late 1942 and considered it a formidable foe compared to other fighters, including the Supermarine Spitfire. A small number of P-38s fell into the hands of German and Italian units and were subsequently tested and used in combat. On 12 June 1943, a P-38G, while flying a special mission between Gibraltar and Malta, landed on the airfield of Capoterra (Cagliari), in Sardinia, for navigation error due to a compass failure. Regia Aeronautica chief test pilot colonnello Lieutenant Colonel Angelo Tondi flew the aircraft to Guidonia airfield where the P- 38G was evaluated. On 11 August 1943, Tondi took off to intercept a formation of about 50 B-24s, returning from the bombing of Terni (Umbria). Tondi attacked a bomber that fell off the shore of Torvaianica, near Rome, while six airmen were parachuting. That was the first and last war mission for the plane, as the Italian petrol was too corrosive for the Lockheed tanks. The Lightning was eventually acquired by Italy for postwar service. If faced by more agile fighters at low altitudes in a constricted valley, Lightnings could suffer heavy losses. On the morning of 10 June 1944, 96 P-38Js of the 1st and 82nd Fighter Groups took off from Italy for Ploesti, the third-most heavily defended target in Europe, after Berlin and Vienna. Instead of bombing from high altitude as had been tried by the Fifteenth Air Force, USAAF planning had determined that a dive-bombing surprise attack, beginning at about 7,000 feet (2,100 m) with bomb release at or below 3,000 feet (900 m), performed by 46 82nd Fighter Group P-38s, each carrying one 1,000-pound (500 kg) bomb, would yield more accurate results. All of 1st Fighter Group and a few aircraft in 82nd Fighter Group were to fly cover, and all fighters were to strafe targets of opportunity on the return trip; a distance of some 1,255 miles (2,020 km), including a circuitous outward route made in an attempt to achieve surprise. Some fighters arrived in Romania to find enemy airfields alerted, with a wide assortment of aircraft scrambling for safety. P-38s shot down several enemy including heavy fighters, transports and observation aircraft. At Ploiești, defense forces were fully alert, the target was concealed by smoke screen, and anti-aircraft fire was very heavy seven Lightnings were lost to it at the target, and two more during strafing attacks on the return flight. German Bf 109 fighters from I./JG 53 and 2./JG 77 fought the Americans. One flight of 16, the 71st Fighter Squadron, was challenged by a large formation of Romanian single-seater IAR.81C fighters. The fight took place at and below 300 feet (100 m) in a narrow valley. Herbert Hatch saw two IAR 81Cs that he misidentified as Focke-Wulf Fw 190s hit the ground after taking fire from his guns, and his fellow pilots confirmed three more of his kills. However, the outnumbered 71st Fighter Squadron took more damage than it dished out, losing nine aircraft. In all, the USAAF lost 22 aircraft on the mission. The Americans claimed 23 aerial victories, though Romanian and German fighter units admitted losing only one aircraft each. Eleven enemy locomotives were strafed and left burning, and flak emplacements were destroyed, along with fuel trucks and other targets. Results of the bombing were not observed by the USAAF pilots because of the smoke. The dive-bombing mission profile was not repeated, though the 82nd Fighter Group was awarded the Presidential Unit Citation for their part. After some disastrous raids in 1944 with B-17s escorted by P-38s and Republic P-47 Thunderbolts, Jimmy Doolittle, then head of the U.S. Eighth Air Force, went to Farnborough asking for an evaluation of the various American fighters. RAF Captain Eric Brown recalled: 126

127 "We had found out that the Bf 109 and the Fw 190 could fight up to a Mach of 0.75, three-quarters the speed of sound. We checked the Lightning and it couldn't fly in combat faster than So it was useless. We told Doolittle that all it was good for was photo-reconnaissance and had to be withdrawn from escort duties. And the funny thing is that the Americans had great difficulty understanding this because the Lightning had the two top aces in the Far East." After evaluation tests at Farnborough, the P-38 was kept in fighting service in Europe for a while longer. However, even if many of the aircraft's problems were fixed with the introduction of the P-38J, by September 1944, all but one of the Lightning groups in the Eighth Air Force had converted to the P-51 Mustang. The Eighth Air Force continued to conduct reconnaissance missions using the F-5 variant. The P-38 was used most extensively and successfully in the Pacific theater, where it proved ideally suited, combining excellent performance with very long range. The P-38 was used in a variety of roles, especially escorting bombers at altitudes between 18-25,000 ft (5,500-7,600 m). The P-38 was credited with destroying more Japanese aircraft than any other USAAF fighter. Freezing cockpits were not a problem at low altitude in the tropics. In fact, since there was no way to open a window while in flight as it caused buffeting by setting up turbulence through the tailplane, it was often too hot; pilots taking low altitude assignments would often fly stripped down to shorts, tennis shoes, and parachute. While the P-38 could not out-maneuver the A6M Zero and most other Japanese fighters, its speed and rate of climb gave American pilots the option of choosing to fight or run, and its focused firepower was even more deadly to lightly armored Japanese warplanes than to the Germans'. The concentrated, parallel stream of bullets allowed aerial victory at much longer distances than fighters carrying wing guns. It is therefore ironic that Dick Bong, the United States' highest-scoring World War II air ace (40 victories solely in P-38s), would fly directly at his targets to make sure he hit them (as he himself acknowledged his poor shooting ability), in some cases flying through the debris of his target (and on one occasion colliding with an enemy aircraft which was claimed as a "probable" victory). The twin Allison engines performed admirably in the Pacific. On 2 4 March 1943, P-38s flew top cover for 5th Air Force and Australian bombers and attack-planes during the Battle of the Bismarck Sea, a crushing defeat for the Japanese. Two P-38 aces from the 39th Fighter Squadron were killed on the second day of the battle: Bob Faurot and Hoyt "Curley" Eason (a veteran with five victories who had trained hundreds of pilots, including Dick Bong). General George C. Kenney, commander of the USAAF Fifth Air Force operating in New Guinea, could not get enough P-38s, though since they were replacing serviceable but inadequate P-39s and P-40s, this might seem like guarded praise. Lightning pilots began to compete in racking up scores against Japanese aircraft. The Lightning figured in one of the most significant operations in the Pacific theater: the interception, on 18 April 1943, of Admiral Isoroku Yamamoto, the architect of Japan's naval strategy in the Pacific including the attack on Pearl Harbor. When American codebreakers found out that he was flying to Bougainville Island to conduct a front-line inspection, 16 P-38G Lightnings were sent on a long-range fighter-intercept mission, flying 435 miles (700 km) from Guadalcanal at heights from ft (3 15 m) above the ocean to avoid detection. The Lightnings met Yamamoto's two Mitsubishi G4M "Betty" fast bomber transports and six escorting Zeros just as they arrived. The first Betty crashed in the jungle and the second ditched near the coast. Two Zeros were also claimed by the American fighters with the loss of one P-38. Japanese searchers found Yamamoto's body at the jungle crash site the next day. The P-38's service record shows mixed results, but usually because of misinformation. P-38s have been described as being harder to fly than single-engined planes, but this was because of inadequate training in the first few months of the war. The P-38's engine troubles at high altitudes only occurred with the Eighth Air Force. One reason for this was the inadequate cooling systems of the G and H models; the improved P-38 J and L had tremendous success flying out of Italy into Germany at all altitudes. Up until the -J-25 variant, P-38s were easily avoided by German fighters because of the lack of dive flaps to counter compressibility in dives. German fighter pilots not wishing to fight would perform the first half of a Split S and continue into steep dives because they knew the Lightnings would be reluctant to follow. On the positive side, having two engines was a built-in insurance policy. Many pilots made it safely back to base after having an engine fail en route or in combat. On 3 March 1944, the first Allied fighters reached Berlin on a frustrated escort mission. Lieutenant Colonel Jack Jenkins of 55FG led the group of P-38H pilots, arriving with only half his force after flak damage and engine trouble took their toll. On the way in to Berlin, Jenkins reported one rough-running engine and one good one, causing him to wonder if he'd ever make it back. The B-17s he was supposed to escort never showed up, having turned back at Hamburg. Jenkins and his wingman were able to drop tanks and outrun enemy fighters to return home with three good engines between them. 127

128 In the ETO, P-38s made 130,000 sorties with a loss of 1.3% overall, comparing favorably with ETO P- 51s which posted a 1.1% loss, considering that the P-38s were vastly outnumbered and suffered from poorly thought-out tactics. The majority of the P-38 sorties were made in the period prior to Allied air superiority in Europe when pilots fought against a very determined and skilled enemy. Lieutenant Colonel Mark Hubbard, a vocal critic of the aircraft, rated it third best Allied fighter in Europe. The Lightning's greatest virtues were long range, heavy payload, high speed, fast climb, and concentrated firepower. The P-38 was a formidable fighter, interceptor and attack aircraft. In the Pacific theater, the P-38 downed over 1,800 Japanese aircraft, with more than 100 pilots becoming aces by downing five or more enemy aircraft. American fuel supplies contributed to a better engine performance and maintenance record, and range was increased with leaner mixtures. In the second half of 1944, the P-38L pilots out of Dutch New Guinea were flying 950 mi (1,530 km), fighting for 15 minutes and returning to base. Such long legs were invaluable until the P-47N and P-51D entered service. The end of the war left the USAAF with thousands of P-38s rendered obsolete by the jet age. The last P-38s in service with the United States Air Force were retired in A total of 100 late-model P-38L and F-5 Lightnings were acquired by Italy through an agreement dated April Delivered, after refurbishing, at the rate of one per month, they finally were all sent to the AMI by The Lightnings served in 4 Stormo and other units including 3 Stormo, flying reconnaissance over the Balkans, ground attack, naval cooperation and air superiority missions. Due to unfamiliarity in operating heavy fighters, old engines, and pilot errors, a large number of P-38s were lost in at least 30 accidents, many of them fatal. Despite this, many Italian pilots liked the P-38 because of its excellent visibility on the ground and stability at takeoff. The Italian P-38s were phased out in 1956; none survived the inevitable scrapyard. Surplus P-38s were also used by other foreign air forces with 12 sold to Honduras and fifteen retained by China. Six F-5s and two unarmed black two-seater P-38s were operated by the Dominican Air Force based in San Isidro Airbase, Dominican Republic in The majority of wartime Lightnings present in the continental U.S. at the end of the war were put up for sale for US$1,200 apiece; the rest were scrapped. P-38s in distant theaters of war were bulldozed into piles and abandoned or scrapped; very few avoided that fate. A single P-38M was used by the CIA during the 1954 Guatemalan coup d'etat. During the conflict this aircraft bombed and sank the British cargo ship SS Springfjord, carrying Czech armaments. The Guatemalan conflict was the last known combat seen by the P-38. P-38s were popular contenders in the air races from 1946 through 1949, with brightly colored Lightnings making screaming turns around the pylons at Reno and Cleveland. Lockheed test pilot Tony LeVier was among those who bought a Lightning, choosing a P-38J model and painting it red to make it stand out as an air racer and stunt flyer. Lefty Gardner, former B-24 and B-17 pilot and associate of the Confederate Air Force, bought a mid-1944 P-38L-1-LO that had been modified into an F-5G. Gardner painted it white with red and blue trim and named it White Lightnin'; he reworked its turbo systems and intercoolers for optimum lowaltitude performance and gave it P-38F style air intakes for better streamlining. White Lightnin' was severely damaged in a crash landing during an air show demonstration, and has since been bought, restored, and repainted with a brilliant chrome finish by the company that owns Red Bull. The plane is now located in Austria. F-5s were bought by aerial survey companies and employed for mapping. From the 1950s on, the use of the Lightning steadily declined, and only a little more than two dozen still exist, with few still flying. One example is a P-38L owned by the Lone Star Flight Museum in Galveston, Texas, painted in the colors of Charles H. MacDonald's Putt Putt Maru. Two other examples are F-5Gs which were owned and operated by Kargl Aerial Surveys in 1946, and are now located in Chino, California at Yanks Air Museum, and in McMinnville, Oregon at Evergreen Aviation Museum. Over 10,000 Lightnings were manufactured in all; becoming the only U.S. combat aircraft that remained in continuous production throughout the duration of American participation in World War II. The Lightning had a major effect on other aircraft; its wing, in a scaled-up form, was used on the L-049 Constellation. Delivered and accepted Lightning production variants began with the P38-D model. The few "hand made" YP-38s initially contracted were used as trainers and test aircraft. There were no Bs or Cs delivered to the government as the USAAF allocated the 'D' suffix to all aircraft with self-sealing fuel tanks and armor. Many secondary but still initial teething tests were conducted utilizing the earliest D variants. The first combat-capable Lightning was the P-38E (and its photo-recon variant the F-4) which featured improved instruments, electrical, and hydraulic systems. Part-way through production, the older Hamilton Standard Hydromatic hollow steel propellers were replaced by new Curtiss Electric duraluminum propellers. 128

129 The definitive (and now famous) armament configuration was settled upon, featuring four.50 in (12.7 mm) machine guns with 500 rpg, and a 20 mm (.79 in) Hispano autocannon with 150 rounds. While the machine guns had been arranged symmetrically in the nose on the P-38D, they were "staggered" in the P-38E and later versions, with the muzzles protruding from the nose in the relative lengths of roughly 1:4:6:2. This was done to ensure a straight ammunition-belt feed into the weapons, as the earlier arrangement led to jamming. The first P-38E rolled out of the factory in October 1941 as the Battle of Moscow in the Eastern Front Campaign of World War II filled the news wires of the world. Because of the versatility, redundant engines, and especially high speed and high altitude characteristics of the aircraft, as with later variants over a hundred P-38Es were completed in the factory or converted in the field to a photo-reconnaissance variant, the F-4, in which the guns were replaced by four cameras. Most of these early reconnaissance Lightnings were retained stateside for training, but the F-4 was the first Lightning to be used in action in April After 210 P-38Es were built, they were followed, starting in April 1942, by the P-38F, which incorporated racks inboard of the engines for fuel tanks or a total of 2,000 lb (907 kg) of bombs. Early variants did not enjoy a high reputation for maneuverability, though they could be agile at low altitudes if flown by a capable pilot, using the P-38's forgiving stall characteristics to their best advantage. From the P-38F-15 model onwards, a "combat maneuver" setting was added to the P-38's Fowler flaps. When deployed at the 8 maneuver setting, the flaps allowed the P-38 to out-turn many contemporary single-engined fighters at the cost of some added drag. However, early variants were hampered by high aileron control forces and a low initial rate of roll, and all such features required a pilot to gain experience with the aircraft, which in part was an additional reason Lockheed sent its representative to England, and later to the Pacific Theater. The aircraft was still experiencing extensive teething troubles as well as being victimized by "urban legends", mostly involving inapplicable twin engine factors which had been designed out of the aircraft by Lockheed. In addition to these, the early versions had a reputation as a "widow maker" as it could enter an unrecoverable dive due to a sonic surface effect at high sub-sonic speeds. The 527 P-38Fs were heavier, with more powerful engines that used more fuel, and were unpopular in the air war in Northern Europe. Since the heavier engines were having reliability problems and with them, without external fuel tanks, the range of the P-38F was reduced, and since drop tanks themselves were in short supply as the fortunes in the Battle of the Atlantic had not yet swung the Allies' way, the aircraft became relatively unpopular in minds of the bomber command planning staffs despite being the longest ranged fighter first available to the 8th Air Force in sufficient numbers for long range escort duties. Nonetheless, General Spaatz, then commander of the 8th Air Force in the UK, said of the P-38F: "I'd rather have an airplane that goes like hell and has a few things wrong with it, than one that won't go like hell and has a few things wrong with it." The P-38F was followed in early 1943 by the P-38G, utilizing more powerful Allisons of 1,400 hp (1,040 kw) each and equipped with a better radio. A dozen of the planned P-38G production was set aside to serve as prototypes for what would become the P-38J with further uprated Allison V-1710F-17 engines (1,425 hp/1,060 kw each) in redesigned booms which featured chin-mounted intercoolers in place of the original system in the leading edge of the wings and more efficient radiators. Lockheed subcontractors, however, were initially unable to supply both of Burbank's twin production lines with a sufficient quantity of new core intercoolers and radiators. War Production Board planners were unwilling to sacrifice production, and one of the two remaining prototypes received the new engines but retained the old leading edge intercoolers and radiators. As the P-38H, 600 of these stop-gap Lightnings with an improved 20 mm cannon and a bomb capacity of 3,200 lb (1,450 kg).were produced on one line while the near-definitive P-38J began production on the second line. The Eighth Air Force was experiencing high altitude and cold weather issues which while not unique to the plane, were perhaps more severe as the turbo-superchargers upgrading the Allisons were having their own reliability issues making the planes more unpopular with senior officers out of the line. This was a situation unduplicated on all other fronts where the commands were clamoring for as many P-38s as they could get. Both the P-38G and P-38H models' performance was restricted by an intercooler system integral to the wing's leading edge which had been designed for the YP-38's less powerful engines. At the higher boost levels, the new engine's charge air temperature would increase above the limits recommended by Allison and would be subject to detonation if operate at high power for extended periods of time. Reliability was not the only issue, either. For example, the reduced power settings required by the P-38H did not allow the maneuvering flap to be used to good advantage at high altitude. All these problems really came to a head in the unplanned P-38H and sped the Lightning's eventual replacement in the Eighth Air Force; fortunately the Fifteenth Air Force were glad to get them. 129

130 Some P-38G and H production was diverted on the assembly line to F-5A and F-5B reconnaissance aircraft. An F-5A was modified to an experimental two-seat reconnaissance configuration as the XF-5D, with a plexiglas nose, two machine guns and additional cameras in the tail booms. The P-38J was introduced in August The turbo-supercharger intercooler system on previous variants had been housed in the leading edges of the wings and had proven vulnerable to combat damage and could burst if the wrong series of controls were mistakenly activated. In the P-38J model, the streamlined engine nacelles of previous Lightnings were changed to fit the intercooler radiator between the oil coolers, forming a "chin" that visually distinguished the J model from its predecessors. While the P-38J used the same V /91 engines as the H model, the new core-type intercooler more efficiently lowered intake manifold temperatures and permitted a substantial increase in rated power. The leading edge of the outer wing was fitted with 55 gal (208 l) fuel tanks, filling the space formerly occupied by intercooler tunnels, but these were omitted on early P-38J blocks due to limited availability. The final 210 J models, designated P-38J-25-LO, alleviated the compressibility problem through the addition of a set of electrically-actuated dive recovery flaps just outboard of the engines on the bottom centerline of the wings. With these improvements, a USAAF pilot reported a dive speed of almost 600 mph (970 km/h), although the indicated air speed was later corrected for compressibility error, and the actual dive speed was lower. Lockheed manufactured over 200 retrofit modification kits to be installed on P-38J-10-LO and J-20- LO already in Europe, but the USAAF C-54 carrying them was shot down by an RAF pilot who mistook the Douglas transport for a German Focke-Wulf Condor. Unfortunately the loss of the kits came during Lockheed test pilot Tony LeVier's four-month morale-boosting tour of P-38 bases. Flying a new Lightning named "Snafuperman" modified to full P-38J-25-LO specs at Lockheed's modification center near Belfast, LeVier captured the pilots' full attention by routinely performing maneuvers during March 1944 that common Eighth Air Force wisdom held to be suicidal. It proved too little too late because the decision had already been made to re-equip with Mustangs. The P-38J-25-LO production block also introduced hydraulically-boosted ailerons, one of the first times such a system was fitted to a fighter. This significantly improved the Lightning's rate of roll and reduced control forces for the pilot. This production block and the following P-38L model are considered the definitive Lightnings, and Lockheed ramped up production, working with subcontractors across the country to produce hundreds of Lightnings each month. There were two P-38Ks developed in , one official and one an internal Lockheed experiment. The first was actually a battered RP-38E "piggyback" test mule previously used by Lockheed to test the P-38J chin intercooler installation, now fitted with paddle-bladed "high activity" Hamilton Standard Hydromatic propellers similar to those used on the P-47. The new propellers required spinners of greater diameter, and the mule's crude, hand-formed sheet steel cowlings were further stretched to blend the spinners into the nacelles. It retained its "piggyback" configuration that allowed an observer to ride behind the pilot. With Lockheed's AAF representative as a passenger and the maneuvering flap deployed to offset Army Hot Day conditions, the old "K-Mule" still climbed to 45,000 feet (14,000 m). With a fresh coat of paint covering its crude handformed steel cowlings, this RP-38E acts as stand-in for the "P-38K-1-LO" in the model's only picture. The twelfth G model originally set aside as a P-38J prototype was re-designated P-38K-1-LO and fitted with the aforementioned paddle-blade propellers and new Allison V /77 (F15R/L) powerplants rated at 1,875 bhp (1,398 kw) at War Emergency Power. These engines were geared 2.36 to 1, unlike the standard P-38 ratio of 2 to 1. The AAF took delivery in September 1943, at Eglin Field. In tests, the P-38K-1 achieved 432 mph (695 km/h) at military power and was predicted to exceed 450 mph (720 km/h) at War Emergency Power with a similar increase in load and range. The initial climb rate was 4,800 ft (1,500 m)/min and the ceiling was 46,000 ft (14,000 m). It reached 20,000 ft (6,100 m) in five minutes flat; this with a coat of camouflage paint which added weight and drag. Although it was judged superior in climb and speed to the latest and best fighters from all AAF manufacturers, the War Production Board refused to authorize P-38K production due to the twoto-three-week interruption in production necessary to implement cowling modifications for the revised spinners and higher thrust line. Some have also doubted Allison's ability to deliver the F15 engine in quantity. As promising as it had looked, the P-38K project came to a halt. The P-38L was the most numerous variant of the Lightning, with 3,923 built, 113 by Consolidated- Vultee in their Nashville plant. It entered service with the USAAF in June 1944, in time to support the Allied invasion of France on D-Day. Lockheed production of the Lightning was distinguished by a suffix consisting of a production block number followed by "LO," for example "P-38L-1-LO", while Consolidated-Vultee production was distinguished by a block number followed by "VN," for example "P-38L-5-VN." 130

131 The P-38L was the first Lightning fitted with zero-length rocket launchers. Seven high velocity aircraft rockets (HVARs) on pylons beneath each wing, and later, ten rockets on each wing on "Christmas tree" launch racks. The P-38L also had strengthened stores pylons to allow carriage of 2,000 lb (900 kg) bombs or 300 USgal (1,100 l) drop tanks. Lockheed modified 200 P-38J airframes in production to become unarmed F-5B photo-reconnaissance aircraft, while hundreds of other P-38Js and P-38Ls were field-modified to become F-5Es, F-5Fs, and F-5Gs. A few P-38Ls were field-modified to become two-seat TP-38L familiarization trainers. Late model Lightnings were delivered unpainted, as per USAAF policy established in At first, field units tried to paint them, since pilots worried about being too visible to the enemy, but it turned out the reduction in weight and drag was a minor advantage in combat. The P-38L-5, the most common sub-variant of the P-38L, had a modified cockpit heating system which consisted of a plug-socket in the cockpit into which the pilot could plug his heat-suit wire for improved comfort. These Lightnings also received the uprated V /113 (F30R/L) engines, and this dramatically lowered the amount of engine failure problems experienced at high altitude so commonly associated with European operations. The Lightning was modified for other roles. In addition to the F-4 and F-5 reconnaissance variants, a number of P-38Js and P-38Ls were field-modified as formation bombing "pathfinders" or "droopsnoots", fitted with a glazed nose with a Norden bombsight, or a H2X radar "bombing through overcast" nose. A pathfinder would lead a formation of other P-38s, each overloaded with two 2,000 lb (907 kg) bombs; the entire formation releasing when the pathfinder did. A number of Lightnings were modified as night fighters. There were several field or experimental modifications with different equipment fits that finally led to the "formal" P-38M night fighter, or Night Lightning. 75 P-38Ls were modified to the Night Lightning configuration, painted flat-black with conical flash hiders on the guns, an AN/APS-6 radar pod below the nose, and a second cockpit with a raised canopy behind the pilot's canopy for the radar operator. The headroom in the rear cockpit was limited, requiring radar operators who were preferably short in stature. The additional external clutter imposed surprisingly little penalty on the P-38M's performance[citation needed], and it remained faster than the purpose-built P-61 Black Widow night fighter. The Night Lightnings saw some combat duty in the Pacific towards the end of the war, but none engaged in combat. One of the initial production P-38s had its turbo-superchargers removed, with a secondary cockpit placed in one of the booms to examine how flightcrew would respond to such an "asymmetric" cockpit layout. One P-38E was fitted with an extended central nacelle to accommodate a tandem-seat cockpit with dual controls, and was later fitted with a laminar flow wing. Very early in the Pacific War, a scheme was proposed to fit Lightnings with floats to allow them to make long-range ferry flights. The floats would be removed before the aircraft went into combat. There were concerns that saltwater spray would corrode the tailplane, and so in March 1942, P-38E c/n 5204 was modified with a tailplane raised some in (41 46 cm), booms lengthened by two feet and a rearward-facing second seat added for an observer to monitor the effectiveness of the new arrangement. A second version was crafted on the same airframe with the twin booms given greater sideplane area to augment the vertical rudders. This arrangement was removed and a final third version was fabricated that had the booms returned to normal length but the tail raised 33 in (84 cm). All three tail modifications were designed by George H. "Bert" Estabrook. The final version was used for a quick series of dive tests on 7 December 1942 in which Milo Burcham performed the test maneuvers and Kelly Johnson observed from the rear seat. Johnson concluded that the raised floatplane tail gave no advantage in solving the problem of compressibility. At no time was this P-38E testbed airframe actually fitted with floats, and the idea was quickly abandoned as the U.S. Navy proved to have enough sealift capacity to keep up with P-38 deliveries to the South Pacific. Still another P-38E was used in 1942 to tow a Waco troop glider as a demonstration. However, there proved to be plenty of other aircraft, such as C-47s, available to tow gliders, and the Lightning was spared this duty. Standard Lightnings were used as crew and cargo transports in the South Pacific. They were fitted with pods attached to the underwing pylons, replacing drop tanks or bombs, that could carry a single passenger in a lying-down position, or cargo. This was a very uncomfortable way to fly. Some of the pods were not even fitted with a window to let the passenger see out or bring in light, and one fellow who hitched a lift on a P-38 in one of these pods later said that "whoever designed the damn thing should have been forced to ride in it." 131

132 Lockheed proposed a carrier-based Model 822 version of the Lightning for the United States Navy. The Model 822 would have featured folding wings, an arresting hook, and stronger undercarriage for carrier operations. The Navy was not interested, as they regarded the Lightning as too big for carrier operations and did not like liquid-cooled engines anyway, and the Model 822 never went beyond the paper stage. However, the Navy did operate four land-based F-5Bs in North Africa, inherited from the USAAF and redesignated FO-1. A P-38J was used in experiments with an unusual scheme for mid-air refueling, in which the fighter snagged a drop tank trailed on a cable from a bomber. The USAAF managed to make this work, but decided it was not practical. A P-38J was also fitted with experimental retractable snow ski landing gear, but this idea never reached operational service either. After the war, a P-38L was experimentally fitted with armament of three.60 in (15.2 mm) machine guns. The.60 in (15.2 mm) caliber cartridge had been developed early in the war for an infantry anti-tank rifle, a type of weapon developed by a number of nations in the 1930s when tanks were lighter but, by 1942, the idea of taking on a tank with a large-caliber rifle was considered to be somewhere between "outdated" and "suicidal". The cartridge was not abandoned, with the Americans designing a derivative of the German 15 mm (.59 in) MG 151 cannon around it and designating the weapon the "T17", but though 300 of these guns were built and over six million.60 in (15.2 mm) rounds were manufactured, they never worked out all the bugs, and the T17 never saw operational service. The cartridge was "necked up" to fit 20 mm projectiles and became a standard U.S. ammunition after the war. The T17-armed P-38L did not go beyond unsuccessful trials. Another P-38L was modified after the war as a "super strafer," with eight.50 in (12.7 mm) machine guns in the nose and a pod under each wing with two.50 in (12.7 mm) guns, for a total of 12 machine guns. Nothing came of this conversion, either. A P-38L was modified by Hindustan Aeronautics in India as a fast VIP transport, with a comfortable seat in the nose, leather-lined walls, accommodations for refreshments and a glazed nose to give the passenger a spectacular view. The 5,000th Lightning built, a P-38J-20-LO, , was painted bright vermilion red, and had the name YIPPEE painted on the underside of the wings in big white letters as well as the signatures of hundreds of factory workers. This aircraft was used by Lockheed test pilots Milo Burcham and Tony LeVier in remarkable flight demonstrations, performing such stunts as slow rolls at treetop level with one prop feathered to show that the P-38 was not the unmanageable beast of legend. Their exploits did much to reassure pilots that the Lightning might be a handful, but it was by no means a "widow maker." series. 132 In-flight footage of the YIPPEE P-38 can be seen in the pilot episode of the Green Acres television The American ace of aces and his closest competitor both flew Lightnings as they tallied 40 and 38 victories respectively. Majors Richard I. "Dick" Bong and Thomas J. "Tommy" McGuire of the USAAF competed for the top position. Both men were awarded the Medal of Honor. McGuire was killed in air combat in January 1945 over the Philippines, after racking up 38 confirmed kills, making him the second-ranking American ace. Bong was rotated back to the United States as America's ace of aces, after making 40 kills, becoming a test pilot. He was killed on 6 August 1945, the day the atomic bomb was dropped on Japan, when his P-80 Shooting Star jet fighter flamed out on takeoff. The famed aviator Charles Lindbergh toured the South Pacific as a civilian contractor for United Aircraft Corporation, comparing and evaluating performance of single- and twin-engined fighters for Vought. He worked to improve range and load limits of the F4U Corsair, flying both routine and combat strafing missions in Corsairs alongside Marine pilots. In Hollandia, he attached himself to the 475th FG flying P-38s so that he could investigate the twin-engine fighter. Though new to the machine, he was instrumental in extending the range of the P-38 through improved throttle settings, or engine-leaning techniques, notably by reducing engine speed to 1,600 rpm, setting the carburetors for auto-lean and flying at 185 mph (298 km/h) indicated airspeed which reduced fuel consumption to 70 gal/h, about 2.6 mpg. This combination of settings had been considered dangerous; it was thought it would upset the fuel mixture and cause an explosion. Everywhere Lindbergh went in the South Pacific, he was accorded the normal preferential treatment of a visiting colonel, though he had resigned his Air Corps Reserve colonel's commission three years before. While with the 475th, he held training classes and took part in a number of Army Air Corps combat missions. On 28 July 1944, Lindbergh shot down a Mitsubishi Ki-51 "Sonia" flown expertly by the veteran commander of 73rd Independent Flying Chutai, Imperial Japanese Army Captain Saburo Shimada. In an extended, twisting dogfight in which many of the participants ran out of ammunition, Shimada turned his aircraft directly toward Lindbergh who was just approaching the combat area. Lindbergh fired in a defensive reaction brought on by Shimada's

133 apparent head-on ramming attack. Hit by cannon and machine gun fire, the "Sonia's" propeller visibly slowed, but Shimada held his course. Lindbergh pulled up at the last moment to avoid collision as the damaged "Sonia" went into a steep dive, hit the ocean and sank. Lindbergh's wingman, ace Joseph E. "Fishkiller" Miller, Jr., had also scored hits on the "Sonia" after it had begun its fatal dive, but Miller was certain the kill credit was Lindbergh's. The unofficial kill was not entered in the 475th's war record. On 12 August 1944 Lindbergh left Hollandia to return to the United States. Robin Olds was the last P-38 ace in the Eighth Air Force and the last in the ETO. Flying a P-38J, he downed five German fighters on two separate missions over France and Germany. He subsequently transitioned to P-51s to make seven more kills. After World War II, he flew F-4 Phantom IIs in Vietnam, ending his career as brigadier general with 16 kills. A P-38 piloted by Clay Tice was the first American aircraft to land in Japan after VJ-Day, when he and his wingman set down on Nitagahara because his wingman was low on fuel. Noted aviation pioneer and writer Antoine de Saint-Exupéry vanished in a F-5B-1-LO, , c/n 2734, of Groupe de Chasse II/33, out of Borgo-Porreta, Bastia, Corsica, a reconnaissance variant of the P-38, while on a flight over the Mediterranean, from Corsica to mainland France, on 31 July His health, both physical and mental (he was said to be intermittently subject to depression), had been deteriorating and there had been talk of taking him off flight status. There have been suggestions (although no proof to date) that this was a suicide rather than an aircraft failure or combat loss. In 2000, a French scuba diver found the wreckage of a Lightning in the Mediterranean off the coast of Marseille, and it was confirmed in April 2004 as Saint- Exupéry's F-5B. No evidence of air combat was found. In March 2008, a former Luftwaffe pilot, Horst Rippert from Jagdgruppe 200, claimed to have shot down Saint-Exupéry. The RAF's legendary photo-recon "ace", Wing Commander Adrian Warburton DSO DFC, was the pilot of a Lockheed P-38 borrowed from the USAAF that took off on 12 April 1944 to photograph targets in Germany. W/C Warburton failed to arrive at the rendezvous point and was never seen again. In 2003, his remains were recovered in Germany from his wrecked USAAF P-38 Lightning. General Dynamics F-16 Fighting Falcon The General Dynamics F-16 Fighting Falcon is a multirole jet fighter aircraft originally developed by General Dynamics for the United States Air Force (USAF). Designed as a lightweight day fighter, it evolved into a successful all-weather multirole aircraft. Over 4,400 aircraft have been built since production was approved in Though no longer being purchased by the U.S. Air Force, improved versions are still being built for export customers. In 1993, General Dynamics sold its aircraft manufacturing business to the Lockheed Corporation, which in turn became part of Lockheed Martin after a 1995 merger with Martin Marietta. The Fighting Falcon (fig. 107) is a dogfighter with numerous innovations including a frameless bubble canopy for better visibility, side-mounted control stick to ease control while maneuvering, a seat reclined 30 degrees to reduce the effect of g-forces on the pilot, and the first use of a relaxed static stability/fly-by-wire flight control system that makes it a highly nimble aircraft. The F-16 has an internal M61 Vulcan cannon and has 11 hardpoints for mounting weapons, and other mission equipment. Although the F-16's official name is "Fighting Falcon", it is known to its pilots as the "Viper", due to it resembling a viper snake and after the Battlestar Galactica Colonial Viper starfighter. Fig F-16 Fighting Falcon. 133

134 In addition to USAF active, reserve, and air national guard units, the aircraft is used by the USAF aerial demonstration team, the U.S. Air Force Thunderbirds, and as an adversary/aggressor aircraft by the United States Navy. The F-16 has also been procured to serve in the air forces of 25 other nations. Experience in the Vietnam War revealed the need for air superiority fighters and better air-to-air training for fighter pilots. Based on his experiences in the Korean War and as a fighter tactics instructor in the early 1960s Colonel John Boyd with mathematician Thomas Christie developed the Energy-Maneuverability theory to model a fighter aircraft's performance in combat. Boyd's work called for a small, lightweight aircraft with an increased thrust-to-weight ratio. In the late 1960s, Boyd gathered a group of like-minded innovators that became known as the Fighter Mafia and in 1969 they secured DoD funding for General Dynamics and Northrop to study design concepts based on the theory. Air Force F-X proponents remained hostile to the concept because they perceived it as a threat to the F-15 program. However, the Advanced Day Fighter concept, renamed F-XX gained civilian political support under the reform-minded Deputy Secretary of Defense David Packard, who favored the idea of competitive prototyping. As a result in May 1971, the Air Force Prototype Study Group was established, with Boyd a key member, and two of its six proposals would be funded, one being the Lightweight Fighter (LWF). The Request for Proposals issued on 6 January 1972 called for a 20,000-pound (9,100 kg) class air-to-air day fighter with a good turn rate, acceleration and range, and optimized for combat at speeds of Mach and altitudes of 30,000 40,000 feet (9,100 12,000 m). This was the region where USAF studies predicted most future air combat would occur. The anticipated average flyaway cost of a production version was $3 million. This production plan, though, was only notional as the USAF had no firm plans to procure the winner. Five companies responded and in 1972, the Air Staff selected General Dynamics' Model 401 and Northrop's P-600 for the follow-on prototype development and testing phase. GD and Northrop were awarded contracts worth $37.9 million and $39.8 million to produce the YF-16 and YF-17, respectively, with first flights of both prototypes planned for early To overcome resistance in the Air Force hierarchy, the Fighter Mafia and other LWF proponents successfully advocated the idea of complementary fighters in a high-cost/low-cost force mix. The "high/low mix" would allow the USAF to be able to afford sufficient fighters for its overall fighter force structure requirements. The mix gained broad acceptance by the time of the flyoff between the prototypes, and would define the relationship of the LWF and the F-15. The first YF-16 was rolled out on 13 December 1973, and its 90-minute maiden flight was made at the Air Force Flight Test Center (AFFTC) at Edwards AFB, California, on 2 February Its actual first flight occurred accidentally during a high-speed taxi test on 20 January While gathering speed, a roll-control oscillation caused a fin of the port-side wingtip-mounted missile and then the starboard stabilator to scrape the ground, and the aircraft then began to veer off the runway. The GD test pilot, Phil Oestricher, decided to lift off to avoid crashing the machine, and safely landed it six minutes later. The slight damage was quickly repaired and the official first flight occurred on time. The YF-16's first supersonic flight was accomplished on 5 February 1974, and the second YF-16 prototype first flew on 9 May This was followed by the first flights of the Northrop's YF-17 prototypes on 9 June and 21 August 1974, respectively. During the flyoff, the YF-16s completed 330 sorties for a total of 417 flight hours; the YF-17s flew 288 sorties, covering 345 hours. Increased interest would turn the LWF into a serious acquisition program. North Atlantic Treaty Organization (NATO) allies Belgium, Denmark, the Netherlands, and Norway were seeking to replace their F- 104G fighter-bombers. In early 1974, they reached an agreement with the U.S. that if the USAF ordered the LWF winner, they would consider ordering it as well. The USAF also needed to replace its F-105 and F-4 fighter-bombers. The U.S. Congress sought greater commonality in fighter procurements by the Air Force and Navy, and in August 1974 redirected Navy funds to a new Navy Air Combat Fighter (NACF) program that would be a navalized fighter-bomber variant of the LWF. The four NATO allies had formed the Multinational Fighter Program Group (MFPG) and pressed for a U.S. decision by December The U.S. Air Force then advanced its plans to announce the LWF winner from May 1975 to the beginning of the year, and accelerated testing. To reflect this more serious intent to procure a new fighter-bomber design, the LWF program was rolled into a new Air Combat Fighter (ACF) competition in an announcement by U.S. Secretary of Defense James R. Schlesinger in April Schlesinger also made it clear that any ACF order would be for aircraft in addition to the F-15, which extinguished opposition to the LWF. ACF also raised the stakes for GD and Northrop because it brought in further competitors intent on securing the lucrative order that was touted at the time as the arms deal of the century. These were Dassault-Breguet's Mirage F1M-53, the SEPECAT Jaguar, and a proposed derivative of the Saab 37 Viggen named the Saab 37E Eurofighter. Northrop offered the P- 530 Cobra, which was very similar to its YF-17. The Jaguar and Cobra were dropped by the MFPG early on, 134

135 leaving two European and the two U.S. candidates. On 11 September 1974, the U.S. Air Force confirmed firm plans to place an order for the winning ACF design sufficient to equip five tactical fighter wings. On 13 January 1975, Secretary of the Air Force John L. McLucas announced that the YF-16 had been selected as the winner of the ACF competition. The chief reasons given by the Secretary for the decision were the YF-16's lower operating costs, greater range and maneuver performance that was significantly better than that of the YF-17, especially at nearsupersonic and supersonic speeds. Another advantage was the fact that the YF-16 unlike the YF-17 employed the Pratt & Whitney F100 turbofan engine, which was the same powerplant used by the F-15; such commonality would lower the unit costs of engines for both programs. Shortly after selection of the YF-16, Secretary McLucas revealed that the USAF planned to order at least 650 and up to 1,400 of the production F-16 version. In the Navy Air Combat Fighter (NACF) competition, the Navy announced on 2 May 1975 that it selected the YF-17 as the basis for what would become the McDonnell Douglas F/A-18 Hornet. The U.S. Air Force initially ordered 15 "Full-Scale Development" (FSD) aircraft (11 single-seat and four two-seat models) for its flight test program, but this was reduced to eight (six F-16A single-seaters and two F- 16B two-seaters). The YF-16 design was altered for the production F-16. The fuselage was lengthened by 10.6 in (0.269 m), a larger nose radome was fitted to house the AN/APG-66 radar, wing area was increased from 280 sq ft (26 m2) to 300 sq ft (28 m2), the tailfin height was decreased slightly, the ventral fins were enlarged, two more stores stations were added, and a single side-hinged nosewheel door replaced the original double doors. These modifications increased the F-16's weight approximately 25% over that of the YF-16 prototypes. Manufacture of the FSD F-16s got underway at General Dynamics' Fort Worth, Texas plant in late 1975, with the first example, an F-16A, being rolled out on 20 October 1976, followed by its first flight on 8 December. The initial two-seat model achieved its first flight on 8 August The initial production-standard F-16A flew for the first time on 7 August 1978 and its delivery was accepted by the USAF on 6 January The F-16 was given its formal nickname of Fighting Falcon on 21 July 1980, entering USAF operational service with the 388th Tactical Fighter Wing at Hill AFB on 1 October On 7 June 1975, the four European partners, now known as the European Participation Group, signed up for 348 aircraft at the Paris Air Show. This was split among the European Participation Air Forces (EPAF) as 116 for Belgium, 58 for Denmark, 102 for the Netherlands, and 72 for Norway. These would be produced on two European production lines, one in the Netherlands at Fokker's Schiphol-Oost facility and the other at SABCA's Gossellies plant in Belgium; production would be divided among them as 184 and 164 units, respectively. Norway's Kongsberg Vaapenfabrikk and Denmark's Terma A/S also manufactured parts and subassemblies for the EPAF aircraft. European co-production was officially launched on 1 July 1977 at the Fokker factory. Beginning in mid-november 1977, Fokker-produced components were shipped to Fort Worth for assembly of fuselages, which were in turn shipped back to Europe (initially to Gossellies starting in January 1978); final assembly of EPAF-bound aircraft began at the Belgian plant on 15 February 1978, with deliveries to the Belgian Air Force beginning in January The Dutch line started up in April 1978 and delivered its first aircraft to the Royal Netherlands Air Force in June In 1980 the first aircraft were delivered to the Royal Norwegian Air Force by SABCA and to the Royal Danish Air Force by Fokker. Since then, a further production line has been established at Ankara, Turkey, where Turkish Aerospace Industries (TAI) has produced 232 Block 30/40/50 F-16s under license for the Turkish Air Force during the late 1980s and 1990s, and has 30 Block 50 Advanced underway for delivery from 2010; TAI also built 46 Block 40s for Egypt in the mid-1990s. Korean Aerospace Industries opened another production line for the KF-16 program, producing 140 Block 52s from the mid-1990s to mid-2000s. If India selects the F-16IN for its Medium Multi-Role Combat Aircraft procurement, a sixth F-16 production line will be established in that nation to produce at least 108 fighters. One change made during production was the need for more pitch control to avoid deep stall conditions at high angles of attack, this issue was known about in development but had originally been discounted. Model tests of the YF-16 conducted by the Langley Research Center revealed a potential problem, but no other laboratory was able to duplicate it. YF-16 flight tests were not sufficient to expose the issue, it required later flight testing on the FSD aircraft to demonstrate there was a real concern. In response, the areas of the horizontal stabilizer were increased 25%; this so-called "big tail" was introduced on the Block 15 aircraft in 1981 and retrofitted later on earlier production aircraft. Besides significantly reducing (though not eliminating) the risk of deep stalls, the larger horizontal tails also improved stability and permitted faster takeoff rotation. In the 1980s, the Multinational Staged Improvement Program (MSIP) was conducted to evolve new capabilities for the F-16, mitigate risks during technology development, and ensure the aircraft's worth. The 135

136 program upgraded the F-16 in three stages. The MSIP process permitted the introduction of new capabilities quicker, at lower costs and with reduced risks, compared to traditional independent programs to upgrade and modernize aircraft. The F-16 has been involved in other upgrade programs including service life extension programs in the 2000s. The F-16 is a single-engined, supersonic, multi-role tactical aircraft. The F-16 was designed to be a costeffective combat "workhorse" that can perform various kinds of missions and maintain around-the-clock readiness. It is much smaller and lighter than its predecessors, but uses advanced aerodynamics and avionics, including the first use of a relaxed static stability/fly-by-wire (RSS/FBW) flight control system, to achieve enhanced maneuver performance. Highly nimble, the F-16 can pull 9-g maneuvers and can reach a maximum speed of over Mach 2. The Fighting Falcon includes innovations such as a frameless bubble canopy for better visibility, side-mounted control stick to ease control during combat maneuvers, and reclined seat to reduce the effect of g-forces on the pilot. The F-16 has an internal M61 Vulcan cannon in the left wing root and has 11 hardpoints for mounting various missiles, bombs and pods. It was also the first fighter aircraft purpose built to sustain 9-g turns. It has a thrust-to-weight ratio greater than one, providing power to climb and accelerate vertically. Early models could also be armed with up to six AIM-9 Sidewinder heat-seeking short-range air-to-air missiles (AAM), including a single missile mounted on a dedicated rail launcher on each wingtip. Some variants can also employ the AIM-7 Sparrow medium-range radar-guided AAM, and more recent versions can be equipped with the AIM-120 AMRAAM. It can also carry other AAM; a wide variety of air-to-ground missiles, rockets or bombs; electronic countermeasures (ECM), navigation, targeting or weapons pods; and fuel tanks on eleven hardpoints six under the wings, two on wingtips and three under the fuselage. The F-16 design employs a cropped-delta planform incorporating wing-fuselage blending and forebody vortex-control strakes; a fixed-geometry, underslung air intake inlet supplying airflow to the single turbofan jet engine; a conventional tri-plane empennage arrangement with all-moving horizontal stabilator tailplanes; a pair of ventral fins beneath the fuselage aft of the wing s trailing edge; a single-piece, bird-proof bubble canopy; and a tricycle landing gear configuration with the aft-retracting, steerable nose gear deploying a short distance behind the inlet lip. There is a boom-style aerial refueling receptacle located a short distance behind the rear of the canopy. Split-flap speedbrakes are located at the aft end of the wing-body fairing, and an arrestor hook is mounted underneath the aft fuselage. Another fairing is situated at the base of the vertical tail, beneath the bottom of the rudder, and is used to house various items of equipment such as ECM gear or drag chutes. Several later F-16 models, such as the F-16I variant of the Block 50 aircraft, also have a long dorsal fairing bulge that runs along the spine of the fuselage from the rear of the cockpit to the tail fairing; these fairings can be used to house additional equipment or fuel. The air intake was designed to be "far enough forward to allow a gradual bend in the air duct up to the engine face to minimize flow losses and far enough aft so it wouldn t weigh too much or be too draggy or destabilizing." The F-16 was designed to be relatively inexpensive to build and much simpler to maintain than earlier-generation fighters. The airframe is built with about 80% aviation-grade aluminum alloys, 8% steel, 3% composites, and 1.5% titanium. Control surfaces such as the leading-edge flaps, tailerons, and ventral fins make extensive use of bonded aluminum honeycomb structural elements and graphite epoxy laminate skins. The F- 16A had 228 access panels over the entire aircraft, about 80% of which can be reached without work stands. The number of lubrication points, fuel line connections, and replaceable modules was significantly reduced compared to its predecessors. Although the USAF s LWF program had called for an aircraft structural life of only 4,000 flight hours, and capable of achieving 7.33 g with 80% internal fuel, GD s engineers decided from the start to design the F- 16 s airframe life to last to 8,000 hours and for 9-g maneuvers on full internal fuel. This proved advantageous when the aircraft s mission was changed from solely air-to-air combat to multi-role operations. Changes over time in actual versus planned operational usage and continued weight growth due to the addition of further systems have required several structural strengthening programs. Aerodynamic studies in the early 1960s demonstrated that the phenomenon known as vortex lift could be beneficially harnessed by the adoption of highly swept wing configurations to reach higher angles of attack through use of the strong leading edge vortex flow off a slender lifting surface. Since the F-16 was being optimized for high agility in air combat, GD s designers chose a slender cropped-delta wing with a leading edge sweep of 40 and a straight trailing edge. To improve its ability to perform in a wide range of maneuvers, a variable-camber wing with a NACA 64A-204 airfoil was selected. The camber is adjusted through the use of leading-edge and trailing edge flaperons linked to a digital flight control system (FCS) that automatically adjusts 136

137 them throughout the flight envelope. The F-16 has a moderate wing loading, which is lower when fuselage lift is considered. This vortex lift effect can be increased by the addition of an extension of the leading edge of the wing at its root, the juncture with the fuselage, known as a strake. The strakes act as a sort of additional slender, elongated, short-span, triangular wing running from the actual wing root to a point further forward on the fuselage. Blended fillet-like into the fuselage, including along with the wing root, the strake generates a highspeed vortex that remains attached to the top of the wing as the angle of attack increases, thereby generating additional lift. This allows the aircraft to achieve angles of attack beyond the point at which it would normally stall. The use of strakes also allows a smaller, lower-aspect-ratio wing, which in turn increases roll rates and directional stability, while decreasing aircraft weight. The resulting deeper wingroots also increase structural strength and rigidity, reduce structural weight, and increase internal fuel volume. The F-16 was the first production fighter aircraft intentionally designed to be slightly aerodynamically unstable. This technique, called "relaxed static stability" (RSS), was incorporated to further enhance the aircraft s maneuver performance. Most aircraft are designed with positive static stability, which induces an aircraft to return to its original attitude following a disturbance. This hampers maneuverability, as the tendency to remain in its current attitude opposes the pilot s effort to maneuver; on the other hand, an aircraft with negative static stability will, in the absence of control input, readily deviate from level and controlled flight. Therefore, an aircraft with negative static stability will be more maneuverable than one that is positively stable. When supersonic, a negatively stable aircraft actually exhibits a more positive-trending (and in the F-16 s case, a net positive) static stability due to aerodynamic forces shifting aft between subsonic and supersonic flight. At subsonic speeds the fighter is constantly on the verge of going out of control. To counter this tendency to depart from controlled flight and avoid the need for constant minute trimming inputs by the pilot, the F-16 has a quadruplex (four-channel) fly-by-wire (FBW) flight control system (FLCS). The flight control computer (FLCC), which is the key component of the FLCS, accepts the pilot s input from the stick and rudder controls, and manipulates the control surfaces in such a way as to produce the desired result without inducing a loss of control. The FLCC also takes thousands of measurements per second of the aircraft s attitude, and automatically makes corrections to counter deviations from the flight path that were not input by the pilot; coordinated turn is also obtained in such a way that it updates itself by thousands of instructions and produces the required control deflection that comes from dynamics of F-16, thereby allowing for stable flight. This has led to a common aphorism among F-16 pilots: You don t fly an F-16; it flies you. The FLCC further incorporates a series of limiters that govern movement in the three main axes based on the jet s current attitude, airspeed and angle of attack, and prevent movement of the control surfaces that would induce an instability such as a slip or skid, or a high angle of attack inducing a stall. The limiters also act to prevent maneuvering that would place more than a 9 g load on the pilot or airframe. Though the FLCC's limiters work well to limit each axis of movement, it was discovered in early production flight testing that "assaulting" multiple limiters at high angles of attack and low speed can result in angles of attack far exceeding the 25-degree threshold of limiting. This is colloquially referred to as simply "departing". Depending on the attitude of the aircraft, it may settle into a deep stall; a near-freefall at 50 to 60 AOA, either upright or inverted. In this "pocket" of very high AOA, the aircraft's attitude is stable, but being far above stall AOA, the control surfaces do not operate effectively. Further, the pitch limiter of the jet, sensing the high AOA, "freezes" the stabilators in an extreme pitch-up or pitch-down in an attempt to recover. To recover, an override is provided that disables the pitch-limiting, which then allows the pilot to "rock" the aircraft's nose up and down using pitch control, eventually overcoming the 50 threshold and achieving a nose-down attitude which will reduce AOA and allow a return to controlled flight. Unlike the YF-17 which featured a FBW system with traditional hydromechanical controls serving as a backup, the F-16 s designers took the innovative step of eliminating mechanical linkages between the stick and rudder pedals and the aerodynamic control surfaces. The F-16 s sole reliance on electronics and wires to relay flight commands, instead of the usual cables and mechanical linkage controls, gained the F-16 the early moniker of "the electric jet". The quadruplex design permits graceful degradation in flight control response in that the loss of one channel renders the FLCS a triplex system. The FLCC began as an analog system on the A/B variants, but has been supplanted by a digital computer system beginning with the F-16C/D Block 40. The F-16 program has suffered from controls that were sensitive to static electricity or electrostatic discharge (ESD), including 70 80% of the electronics on the C/D models sensitive to ESD in the early 1980s. The F-16A/B was originally equipped with the Westinghouse AN/APG-66 fire-control radar. Its slotted planar-array antenna was designed to be sufficiently compact to fit into the F-16 s relatively small nose. In uplook mode, the APG-66 uses a low pulse-repetition frequency (PRF) for medium- and high-altitude target 137

138 detection in a low-clutter environment, and in downlook employs a medium PRF for heavy clutter environments. It has four operating frequencies within the X band, and provides four air-to-air and seven air-toground operating modes for combat, even at night or in bad weather. The Block 15 s APG-66(V)2 model added a new, more powerful signal processor, higher output power, improved reliability, and increased range in a clutter or jamming environments. The Mid-Life Update (MLU) program further upgrades this to the APG- 66(V)2A model, which features higher speed and memory. The AN/APG-68, an evolution of the APG-66, was introduced with the F-16C/D Block 25. The APG- 68 has greater range and resolution, as well as 25 operating modes, including ground-mapping, Doppler beamsharpening, ground moving target, sea target, and track-while-scan (TWS) for up to 10 targets. The Block 40/42 s APG-68(V)1 model added full compatibility with Lockheed Martin Low-Altitude Navigation and Targeting Infra-Red for Night (LANTIRN) pods, and a high-prf pulse-doppler track mode to provide continuous-wave (CW) target illumination for semi-active radar-homing (SARH) missiles like the AIM-7 Sparrow. The Block 50/52 F-16s initially received the more reliable APG-68(V)5 which has a programmable signal processor employing Very-High-Speed Integrated Circuit (VHSIC) technology. The Advanced Block 50/52 (or 50+/52+) are equipped with the APG-68(V)9 radar which has a 30% greater air-to-air detection range, and a synthetic aperture radar (SAR) mode for high-resolution mapping and target detection and recognition. In August 2004, Northrop Grumman received a contract to begin upgrading the APG-68 radars of the Block 40/42/50/52 aircraft to the (V)10 standard, which will provide the F-16 with all-weather autonomous detection and targeting for the use of Global Positioning System (GPS)-aided precision weapons. It also adds SAR mapping and terrain-following (TF) modes, as well as interleaving of all modes. The F-16E/F is outfitted with Northrop Grumman s AN/APG-80 Active Electronically Scanned Array (AESA) radar, making it only the third fighter to be so equipped. Northrop Grumman is continuing development upon this latest radar, to form the Scalable Agile Beam Radar (SABR). In July 2007, Raytheon announced that it was developing a new Raytheon Next Generation Radar (RANGR) based on its earlier AN/APG-79 AESA radar as an alternative candidate to Northrop Grumman s AN/APG-68 and AN/APG-80 for the F-16. The powerplant first selected for the single-engined F-16 was the Pratt & Whitney F100-PW-200 afterburning turbofan, a slightly modified version of the F100-PW-100 used by the F-15. Rated at 23,830 lbf (106.0 kn) thrust, it remained the standard F-16 engine through the Block 25, except for new-build Block 15s with the Operational Capability Upgrade (OCU). The OCU introduced the 23,770 lbf (105.7 kn) F100-PW-220, which was also installed on Block 32 and 42 aircraft; the main difference being a Digital Electronic Engine Control (DEEC) unit, which improved engine reliability and reduced the risk of engine stalls. Added to the F-16 production line in 1988, the "-220" also supplanted the F-15 s "-100," increasing commonality. Many of the "- 220" jet engines on Block 25 and later aircraft were upgraded from mid-1997 to the "-220E" standard, which enhanced reliability and engine maintainability; the changes allowed for a 35% reduction of unscheduled engine removals. Development of the F100-PW-220/220E was the result of the USAF s Alternate Fighter Engine (AFE) program (colloquially known as the Great Engine War ), which also saw the entry of General Electric as an F- 16 engine provider. Its F110-GE-100 turbofan required modification of the F-16 s inlet; the original inlet limited the GE jet s maximum thrust to 25,735 lbf (114.5 kn), while the new Modular Common Inlet Duct allowed the F110 to achieve its maximum thrust of 28,984 lbf (128.9 kn) in afterburner. (To distinguish between aircraft equipped with these two engines and inlets, from the Block 30 series on, blocks ending in "0" (e.g., Block 30) are powered by GE, and blocks ending in "2" (e.g., Block 32) are fitted with Pratt & Whitney engines.) Further development by these competitors under the Increased Performance Engine (IPE) effort led to the 29,588 lbf (131.6 kn) F110-GE-129 on the Block 50 and 29,160 lbf (129.4 kn) F100-PW-229 on the Block 52. F-16s began flying with these IPE engines on 22 October 1991 and 22 October 1992, respectively. Altogether, of the 1,446 F-16C/Ds ordered by the USAF, 556 were fitted with F100-series engines and 890 with F110s. The United Arab Emirates Block 60 is powered by the General Electric F110-GE-132 turbofan, which is rated at a maximum thrust of 32,500 lbf (144.6 kn), the highest ever developed for the F-16 aircraft. Due to their ubiquity, F-16s have participated in numerous conflicts, most of them in the Middle East. The F-16 is being used by the USAF active, reserve, and Air National Guard units, the USAF aerial demonstration team, the U.S. Air Force Thunderbirds, and as an adversary/aggressor aircraft by the United States Navy. The U.S. Air Force has flown the F-16 in combat during Operation Desert Storm in 1991, and in the Balkans later in the 1990s. F-16s have patrolled the no fly zones in Iraq during Northern Watch and Southern Watch. They have served during the wars in Afghanistan and Iraq in the 2000s. 138

139 Cap. 7. SEAPLANE A sea plane (fig ) is a fixed-wing aircraft capable of taking off and landing (alighting) on water. Seaplanes that can also take off and land on airfields are a subclass called amphibian aircraft. Seaplanes and amphibians are usually divided into two categories based on their technological characteristics: floatplanes and flying boats; the latter are generally far larger and can carry far more. These aircraft were sometimes called hydroplanes. Fig Grumman G-111 Albatross amphibious flying boat of Chalks International Airlines landing in Miami Harbor in March boat. The word "seaplane" is used to describe two types of air/water vehicles: the floatplane and the flying A floatplane has slender pontoons, or floats, mounted under the fuselage. Two floats are common, but other configurations are possible. Only the floats of a floatplane normally come into contact with water. The fuselage remains above water. Some small land aircraft can be modified to become float planes, and in general floatplanes are small aircraft. Floatplanes are limited by their inability to handle wave heights typically greater than 12 inches (0.31 m). These floats add to the empty weight of the airplane, and to the drag coefficient, resulting in reduced payload capacity, slower rate-of-climb, and slower cruise speed. In a flying boat, the main source of buoyancy is the fuselage, which acts like a ship's hull in the water. Most flying boats have small floats mounted on their wings to keep them stable. Not all small seaplanes have been floatplanes, but most large seaplanes have been flying boats, their great weight supported by their hulls. The term "seaplane" is used by some instead of "floatplane". This is the standard British usage, which treats both flying boats and floatplanes as types of seaplane, in the US fashion. An amphibious aircraft can take off and land both on conventional runways and water. A true seaplane can only take off and land on water. There are amphibious flying boats and amphibious floatplanes, as well as some hybrid designs, e.g., floatplanes with retractable floats. Modern production seaplanes are typically light aircraft, amphibious, and of a floatplane design. Fig De Havilland Otter floatplane. The first manned and controlled (though unpowered) seaplane flight was established by French aircraft designer, builder and pilot Gabriel Voisin in June 1905, on the river Seine (Paris); it was a towed flight, at 15 to 20 m altitude (50 to 66 ft), and 600 meters (2000 ft) long. The aircraft was a biplane configuration with an aft tail and a front elevator, supported at rest by 2 planing floats (catamaran). 139

140 The first autonomous flight by a seaplane was made by the French engineer Henri Fabre in March Its name was Le Canard ('the duck'), and took off from the water and flew 1,650 feet on its first flight on March 28, These experiments were closely followed by the aircraft pioneers Gabriel and Charles Voisin, who purchased several of the Fabre floats and fitted them to their Canard Voisin airplane. In October 1910, the Canard Voisin became the first seaplane to fly over the river Seine, and in March 1912, the first seaplane to be used in military exercises from a seaplane carrier, La Foudre ('the lightning'). In the United States, early development was carried out at Hammondsport, New York by Glenn Curtiss who had beaten Alexander Graham Bell and others in the Aerial Experiment Association. The first American seaplane flight occurred on January 26, 1911 by Curtiss in his "hydroaeroplane" from the waters of San Diego Bay. In June 1911, in co-operation with Edouard Perrot (Edouard Perrot & Cie), Emile Taddéoli started to design the seaplane "La Mouette" in Switzerland, and before, began tests with a Dufaux 4 biplane equipped with swimmers. On March 26, 1912, a first takeoff was not successful, and "La Mouette" was destroyed. In summer 1912, René Grandjean replaced the skis of his aircraft by floats designed and engineered by himself, resulting in the first takeoff of a Swiss hydroplane (seaplane) on August 4, The first British seaplane flight, by Sydney Sippe, also took place in The first in history combat missions of a seaplane was probably those of a Greek "Astra Hydravion" between December 1912 and January 1913, during the Balkan Wars. In one of them, on January 24, 1913, the seaplane with two Greek pilots flew at 1200 meters over the Dardanelles from the European to the Asian coast, did a reconnaissance of the Turkish fleet, dropped 4 bombs and after 2 hours flight landed at sea near the island of Imbros. The plane was targeted by canons and rifles unsuccessfully. Englishman John Cyril Porte joined with Curtiss to design a transatlantic flying boat, and developed a more practical hull for Curtiss' airframe and engines with the distinctive 'step' which enabled the hull and floats to cleanly break free of the water's surface at take-off. In the UK the Curtiss flying boat was developed into the Felixstowe series of flying boats, which were used in the First World War to patrol for German submarines. Curtiss N-9 seaplanes were used during World War I as primary trainers, and over 2,500 Navy pilots learned to fly in them. A handful of N-9s were used in the Hewitt-Sperry Automatic Airplane project to develop an "aerial torpedo" or flying bomb, an early RPV. On March 27, 1919, the first transatlantic flight was completed by a U.S. Navy NC flying boat piloted by Albert Read, from Canada to Portugal via the Azores Islands. The first flight over the south Atlantic was made by Portuguese naval pilots Gago Coutinho and Sacadura Cabral in 1922, from Lisbon, Portugal to Rio de Janeiro, Brazil. They used a Fairey III-D MkII. On May 12, 1930, Jean Mermoz made a flight across the South Atlantic Ocean from Dakar in French West Africa to Natal, Brazil, in a Latecoere 28 floatplane. Because of the lack of runways and the perceived safety factor over water, many commercial airlines including Imperial Airways (fore-runner of BOAC), and Pan-American World Airways used large seaplanes to provide service for long distance service across the Atlantic, Pacific and Indian Oceans. Aircraft specially built for these routes included some of the largest aircraft built between the wars. The Naval Aircraft Factory further redesigned the Felixstowe F.5 for American production with numerous modifications made, including fitting 400 hp Liberty 12A engines. The American-built version was also known as the Curtiss F5L and (in civilian operation) as the Aeromarine 75. The F5L was built by the US Naval Aircraft Factory (137), Curtiss (60) and Canadian Aeroplanes Limited (30). Some were converted for civilian use by the Aeromarine Plane and Motor Company in 1919 (fig. 110). Fig Aeromarine 75 on regular flights in the Caribbean. 140

141 The F5L entered USN service at the end of the war and was the US Navy s standard patrol aircraft until 1928, when it was replaced by the PN-12. In civil service, named the Aeromarine 75, the Felixstowe F5L could accommodate 10 passengers and was operated by Aeromarine Airways on flights from Key West to Havana, carrying the first US Post Office international air mail on flights from New York City to Atlantic City, and from Cleveland to Detroit. The Boeing 314 Clipper (fig. 111) was a long-range flying boat produced by the Boeing Airplane Company between 1938 and 1941 and is comparable to the British Short S.26. One of the largest aircraft of the time, it used the massive wing of Boeing s earlier XB-15 bomber prototype to achieve the range necessary for flights across the Atlantic and Pacific Oceans. Twelve Clippers were built for Pan Am, three of which were sold to BOAC in 1941 before delivery. Fig A Boeing 314 Clipper flying low (1939). The 314 was a response to Pan American's request for a flying boat with unprecedented range capability that could augment the airline's trans-pacific Martin M-130. Boeing's bid was successful and on July 21, 1936, Pan American signed a contract for six. Boeing engineers adapted the cancelled XB-15's 149 feet (45 m) wing, and replaced the original 850 horsepower (630 kw) Pratt & Whitney Twin Wasp radial engines with the more powerful 1,600 horsepower (1,200 kw) Wright Twin Cyclone. The first flight was carried out with a single, conventional tail before experiments with twin tail and triple tail configurations led to the choice of a triple tail to provide more rudder area for controllability. Pan Am ordered an additional six aircraft with increased engine power and a larger carrying capacity of 77 daytime passengers as the Boeing 314A. The first prototype of the series flew on March 20, Internally, the 314 used a series of heavy ribs and spars to create a robust fuselage and cantilevered wing. This sturdy structure obviated the need for external drag-inducing struts to brace the wings, something other flying boats of the day could not boast. Boeing addressed the flying boats' other drag-inducing issue, stabilizing pontoons, by incorporating Dornier-style sponsons into the hull structure. The sponsons, which were broad lateral extensions placed at the water line, on both the port and starboard sides of the hull, served several purposes: they provided a wide platform to stabilize the craft while floating on water, they acted as an entryway for passengers boarding the flying boat and they were shaped to contribute additional lift in flight. With weight an extremely sensitive concern, passengers and their baggage were weighed, with each passenger allowed up to 77 pounds (35 kg) free baggage allowance (in the later 314 series) but then charged $3.25 per lb ($7.15/kg) for exceeding the limit. To fly the long ranges needed for trans-pacific service, the 314 carried 4,246 US gallons (16,070 l; 3,536 imp gal) of gasoline. The later 314A model carried a further 1,200 US gallons (4,500 l; 1,000 imp gal). To quench the radial engines thirst for oil, a capacity of 300 US gallons (1,100 l; 250 imp gal) was required. Pan Am's "Clippers" were built for "one-class" luxury air travel, a necessity given the long duration of transoceanic flights. The seats could be converted into 36 bunks for overnight accommodation; with a cruise speed of only 188 miles per hour (303 km/h) (typically flights at maximum gross weight were carried out at 155 miles per hour (249 km/h)), many flights lasted over 12 hours. The 314s had a lounge and dining area, and the galleys were crewed by chefs from four-star hotels. Men and women were provided with separate dressing rooms, and white-coated stewards served five and six-course meals with gleaming silver service. Although the transatlantic flights were only operated for three months in 1939, their standard of luxury has not been matched by heavier-than-air transport since then; they were a form of travel for the super-rich, at $675 return from New York to Southampton, comparable to a round trip aboard Concorde in Most of the flights were 141

142 transpacific with a one-way ticket from San Francisco to Hong Kong, via the "stepping-stone" islands posted at $760 (or $1,368 round-trip). Equally critical to the 314's success was the proficiency of its Pan Am flight crews, who were extremely skilled at long-distance, over-water flight operations and navigation. For training, many of the transpacific flights carried a second crew. Only the very best and most experienced flight crews were assigned Boeing 314 flying boat duty. Before coming aboard, all Pan Am captains as well as first and second officers had thousands of hours of flight time in other seaplanes and flying boats. Rigorous training in dead reckoning, timed turns, judging drift from sea current, astral navigation, and radio navigation were conducted. In conditions of poor or no visibility, pilots sometimes made successful landings at fogged-in harbors by landing out to sea, then taxiing the Clipper into port. The first 314, Honolulu Clipper, entered regular service on the San Francisco-Hong Kong route in January A one-way trip on this route took over six days to complete. Commercial passenger service lasted less than three years, ending when the United States entered World War II in December At the outbreak of the war in the Pacific, the Pacific Clipper was enroute to New Zealand. Rather than risk flying back to Honolulu and being shot down by Japanese fighters, it was decided to fly west to New York. Starting on December 8, 1941 at Auckland, New Zealand, the Pacific Clipper covered over 8,500 miles (13,700 km) via such exotic locales as Surabaya, Karachi, Bahrain, Khartoum and Leopoldville. The Pacific Clipper landed at Pan American's LaGuardia Field seaplane base at 7:12 on the morning of January 6, The Yankee Clipper flew across the Atlantic on a route from Southampton to New York with intermediate stops at Foynes, Ireland, Botwood, Newfoundland, and Shediac, New Brunswick. The inaugural trip occurred on June 24, The Clipper fleet was pressed into military service during World War II, and the flying boats were used for ferrying personnel and equipment to the European and Pacific fronts. In actual fact, only the markings on the aircraft changed: the Clippers continued to be flown by their experienced Pan Am civilian crews. American military cargo was carried via Natal, Brazil to Liberia, to supply the British forces at Cairo and even the Russians, via Teheran. The Model 314 was then the only aircraft in the world that could make the 2,150-statute mile (3,460 km) crossing over water and were given the military designation C-98. Since the Pan Am pilots and crews had extensive expertise in using flying boats for extreme long-distance, over-water flights, the company's pilots and navigators continued to serve as flight crew. In 1943, President Franklin D. Roosevelt traveled to the Casablanca Conference in a Pan-Am crewed Boeing 314. Winston Churchill also flew on them several times adding to the Clippers fame during the war. After the war, several Clippers were returned to Pan American hands. However, even before hostilities had ended, the Clipper had become obsolete. The introduction of long-range airliners such as the Lockheed Constellation and Douglas DC-4, together with a prodigious wartime runway construction program, made the flying boat all but obsolete. The new landplanes were relatively easy to fly, and did not require the extensive pilot training programs required for seaplane operations. One of the 314's most experienced pilots said, "We were indeed glad to change to DC-4s and I argued daily for eliminating all flying boats. The landplanes were much safer. No one in the operations department... had any idea of the hazards of flying boat operations. The main problem now was lack of the very high level of experience and competence required of seaplane pilots". The Consolidated Commodore was a flying boat built by Consolidated Aircraft and used for passenger travel in the 1930s, mostly in the Caribbean operated by companies like Pan American Airlines. A pioneer of long haul passenger aircraft industry, the Commodore "Clipper" grew out of a Navy design competition in the 1920s to create an aircraft capable of nonstop flights between the mainland of the United States and Panama, Alaska, and the Hawaiian Islands. In response to these requirements, Consolidated produced the prototype XPY-1 Admiral designed by Isaac M. Laddon in January 1929 but lost the contract to the Martin aircraft company. The aircraft represented a marked change from earlier patrol boat designs such as the Curtiss NC. In response to losing the Navy contract, Consolidated offered a passenger-carrying version of the XPY- 1, which became known as the Commodore. The monoplane all-metal hull could accommodate 32 passengers and a crew of 3. The full complement of passengers, located in three cabins, could only be carried on relatively short-route segments. For a 1000-mile flight, the boat probably could accommodate no more than 14 people including the crew. Wing and tail construction consisted of metal-frame structure covered with fabric except for metal-covered leading edges. With a first flight in 1931, a total of 14 Commodore boats were built. They were used in airline service from the United States to South America where routes extended as far south as Buenos Aires, a distance of 9000 miles from Miami. They were out of service by 1935, having been superseded by more efficient aircraft such as 142

143 the Sikorsky S-42, Boeing 314, and Martin 156, (the China Clipper). The Commodore may be considered as a first step in the United States along a road that was to lead to the highly efficient monoplane-type patrol and transport flying boats later in the 1930s. The XPY-1 and its civil counterpart. the Commodore, may be considered as progenitors in a series of flying-boat developments that led to the famous Consolidated PBY Catalina of World War II fame. The Dornier Do J (later designated Do 16 by the Reich Air Ministry) was better known as the Wal ("whale"). The Do J was a fairly modern (compared to World War I types) flying boat with a high-mounted strutbraced monoplane wing. Two piston engines were mounted in tandem in a nacelle above the wing and in line with the hull; one engine drove a tractor propeller and the other drove a pusher propeller. The Do J made its maiden flight on 6 November The flight, as well as most of the production until 1932, took place in Italy because a lot of aviation activity in Germany was prohibited after World War I under the terms of the Treaty of Versailles. Dornier started producing Whales in Germany in 1931, with the production lasting to In the military version (Militärwal in German), a crew of two to four rode in an open cockpit near the nose of the hull. There were one MG-position in the bow in front of the cockpit and one to two amidships. Beginning with Spain, military versions were delivered to Argentina, Chile, the Netherlands for use in their colonies, Yugoslavia, the Soviet Union and to the end of the production Italy and Germany. The main military users, Spain and the Netherlands, manufactured their own versions under licence. Several countries, notably Italy, Norway, Portugal, Urugay, Great Britain and Germany, used the Wal for military raids. The civil version (Kabinenwal or Verkehrswal) had a cabin in the nose, offering space for up to 12 passengers, while the open cockpit was moved further aft. Main users of this version were Germany, Italy, Brazil, Colombia. The Do J was first powered by two 265 kw (355 hp) Rolls-Royce Eagle IX engines. Later versions used nearly every available engine on the market from makers like Hispano-Suiza, Napier Lion, Lorraine-Dietrich, BMW, and even the Liberty Engine. The 10 to-whales used by Lufthansa for their mail service across the South Atlantic fom 1934 to 1938 had a range of 3,600 km (2,240 mi), and a ceiling of 3,500 m (11,480 ft). Over 250 Wals were built by CMASA and Piaggio in Italy, CASA in Spain (fig. 112), Kawasaki in Japan, Aviolanda in the Netherlands, and Dornier in Germany. Fig Spanish Dornier Do J "Plus Ultra", build by CASA. Numerous airlines operated Dornier Wals on scheduled passenger and mail services with great success. The source Gandt,1991 (pages 47-48) lists the following carriers: SANA and Aero Espresso of Italy; Aero Lloyd and Deutsche Luft Hansa of Germany; SCADTA of Columbia; Syndicato Condor of Brazil; Nihon Koku Yuso Kaisha of Japan. According to Nicolaou,1996 the Dornier Wal was "easily the greatest commercial success in the history of marine aviation". The Colombian Air Force used Dornier Wals in the Colombia-Peru War in

144 The Norwegian polar explorer Roald Amundsen The Norwegian polar explorer Roald Amundsen accompanied by Lincoln Ellsworth, pilot Hjalmar Riiser-Larsen, and three other team members used two Dornier seaplanes in his unsuccessful attempt to reach the North Pole in His two aircraft, N-24 and N-25, landed at 87 44' north. It was the northernmost latitude reached by any aircraft up to that time. The planes landed a few miles apart without radio contact, yet the crews managed to reunite. One of the aircraft, the N-24 was damaged. Amundsen and his crew worked for over three weeks to prepare an airstrip to take off from ice. They shoveled 600 tons of ice while consuming only one pound (454 g) of daily food rations. In the end, six crew members were packed into the N-25. Riiser-Larsen took off, and they barely became airborne over the cracking ice. They returned triumphant when everyone thought they had been lost forever. On 18 August 1930, Wolfgang von Gronau started on a transatlantic flight in the same Dornier Wal (D- 1422) Amundsen had flown, establishing the northern air route over the Atlantic flying Sylt(Germany)-Iceland- Greenland-Labrador-New York (4670 miles) in 47 flight hours. In 1932 Wolfgang von Gronau flew a Dornier Wal (D-2053) called the "Grönland Wal" (Greenland Whale) on a round-the-world flight. In 1926 Ramón Franco became a national Spanish hero when he piloted the Dornier Plus Ultra on a trans-atlantic flight. His co-pilot was Julio Ruiz de Alda Miqueleiz; the other crew members were Teniente de Navio (Navy Lieutenant) Juan Manuel Duran and the mechanic Pablo Rada. The Plus Ultra departed from Palos de la Frontera, in Huelva, Spain on 22 January and arrived in Buenos Aires, Argentina on 26 January. It stopped over at Gran Canaria, Cape Verde, Pernambuco, Rio de Janeiro and Montevideo. The 10,270 km journey was completed in 59 hours and 39 minutes. The event appeared in most of the major newspapers world wide, though some of them underlining the fact that the airplane itself plus the technical expertise were foreign. Throughout the Spanish-speaking world the Spanish aviators were glamorously acclaimed, particularly in Argentina and Spain where thousands gathered at Plaza de Colón in Madrid. (Wikimedia Commons has media related to Plus Ultra - see below.) In 1929 Franco attempted another trans-atlantic flight, this time crashing the airplane to the sea near the Azores. The crew was rescued days later by the aircraft carrier Eagle of the British Royal Navy. The Portuguese military aviator Sarmento de Beires and his crew made the first night aerial crossing of the South Atlantic in a Dornier J named Argos. The crossing was made on the night of 17 March 1927 from Portuguese Guinea to Brazil. Two Dornier Wals (D-ALOX Passat and D-AKER Boreas) also played an important role in the Third German Antarctic Expedition of The biggest and last versions of the Wal, the 8-tonne Wal and 10-tonne Wal (both versions also known as Katapultwal), were operated by Deutsche Lufthansa on their South Atlantic Airmail service from Stuttgart, Germany to Natal, Brazil. On route proving flights in 1933, and scheduled service beginning in February 1934, Wals flew the trans-ocean sector of the route, between Bathurst, The Gambia in West Africa and Fernando de Noronha an island group off South America. Launched by catapult from converted merchant ships. The Wals had to be catapulted due to the sea states in the mid-atlantic and because they could not take off from the water under their own power with enough fuel to fly the distance. The first merchant converted as a mid-atlantic refueling stop was the Westfalen a passenger liner which became out dated shortly after World War I to carry mail and passengers due to its small size and cruising speed. Wals made over 300 crossings of the South Atlantic in regular mail service.(gandt, 1991, pages 47 48) The 8-tonne Wal was not a success, only two being built. The six 10-tonne Wals remained in use on the South Atlantic until 1938, although aircraft of more recent design began replacing them from From 1925 the French airline Compagnie Générale Aéropostale operated an airmail service on much the same route, from France to Brazil. Originally the mail was flown only as far as Dakar in West Africa, and then shipped across the South Atlantic by steamer. In 1930 the Aéropostale began making ocean crossings by air, but was not able to fly regularly because their planes were too unreliable. Air France, which Aéropostale had become a part of, only began operating a regular all air service from Europe to South America in December 1935, nearly two years after Lufthansa (if we can trust the information on the Transatlantic flight page). That Lufthansa succeeded, where Aéropostale failed, in establishing the worlds first regular intercontinental airline service, was due in no small part to the Wals reliability, ruggedness and seaworthyness. The Grumman HU-16 Albatross (fig. 113) is a large twin-radial engine amphibious flying boat. Originally designated SA-16, it was renamed HU-16 in

145 An improvement of the design of the Grumman Mallard, the Albatross was developed to land in open ocean situations to rescue downed pilots. Its deep-v cross-section and substantial length enable it to land in the open sea. The Albatross was designed for optimal 4 ft seas, and could land in more severe conditions, but required JATO for takeoff in 8-10 ft seas or greater. Since the aircraft weighs over 12,500 pounds, pilots of US-registered Albatross aircraft must have a type rating. There is a yearly Albatross fly-in at Boulder City, Nevada where Albatross pilots can become type rated. Fig The Grumman HU-16 Albatross. The majority of Albatrosses were used by the U.S. Air Force, primarily by the Air Rescue Service, and initially designated as SA-16. The USAF utilized the SA-16 extensively in Korea for combat rescue, where it gained a reputation as a rugged and seaworthy craft. Later, the redesignated HU-16B (long-wing variant) Albatross was used by the U.S. Air Force's Aerospace Rescue and Recovery Service and saw extensive combat service during the Vietnam War. In addition a small number of Air National Guard Air Commando Groups were equipped with HU-16s for covert infiltration and extraction of special forces from 1956 to The U.S. Navy also employed the HU-16C/D Albatross as a Search and rescue (SAR) aircraft from coastal naval air stations, both stateside and overseas. It was also employed as an operational support aircraft worldwide and for "skunk runs" from the former NAS Agana, Guam during the Vietnam War. Goodwill flights were also common to the surrounding Trust Territory of the Pacific Islands in the early 1970s. Open water landings and water takeoff training using JATO was also conducted frequently by U.S. Navy HU-16s from locations such as NAS Agana, Guam; Naval Station Guantanamo Bay, Cuba; NAS Barbers Point, Hawaii; and NAS Pensacola, Florida, among other locations. The HU-16 was also operated by the U.S. Coast Guard as both a coastal and long-range open ocean SAR aircraft for many years until it was supplanted by the HU-25 Guardian and HC-130 Hercules. The final USAF HU-16 flight was the delivery of Serial to the National Museum of the USAF at Wright Patterson AFB, OH in July, 1973 after setting an altitude record of 32,883 ft earlier in the month. The final Navy HU-16 flight was made 13 August 1976 when an Albatross was delivered to the Naval Aviation Museum at NAS Pensacola. The final USCG flight of the Albatross was at USCG Cape Cod in March, 1983, when the aircraft type was retired by the USCG. The Albatross continued to be used in the military service of other countries, the last being retired by the Hellenic Navy (Greece) in In the mid-1960s the U.S. Department of the Interior bailed 3 military Grumman HU-16's from the U.S. Navy and established the Trust Territory Airlines in the Pacific to serve the islands of Micronesia. Pan American World Airways and finally Continental Airlines' Air Micronesia operated the Albatrosses serving Yap, 145

146 Palau, Chuuk (Truk) and Pohnpei from Guam until 1970, when adequate island runways were built, allowing land operations. In 1970, Conroy Aircraft marketed a remanufactured HU-16A with Rolls-Royce Dart turboprop engines as the Conroy Turbo Albatross, but only one prototype (registration N16CA) was ever built. Many surplus Albatrosses were sold to civilian operators, mostly to private owners. These aircraft are operated under either Experimental - Exhibition or Restricted category and cannot be used for commercial operations, except under very limited conditions. In the early 1980s Chalk's International Airlines owned by Merv Griffin's Resorts International had 13 Albatrosses converted to Standard category as G-111s. This made them eligible to be used in scheduled airline operations. These aircraft had extensive modification from the standard military configuration, including rebuilt wings with titanium wing spar caps, additional doors and modifications to existing doors and hatches, stainless steel engine oil tanks, dual engine fire extinguishing systems on each engine and propeller auto feather systems installed. The G-111s were only operated for a few years and then put in storage in Arizona. Most are still parked there, but some have been returned to regular flight operations with private operators. The Latécoère 631 was a civil transatlantic flying boat built by Latécoère, the largest ever built up to its time. The last Latécoère 631 was withdrawn from service in 1955 after the losses of aircraft no.7 (owned by Latécoère, lost at sea), 6 (Air France, lost in the Atlantic), 3 (SEMAF, off Cap Ferret) and 8 (France-Hydro, in Cameroon). The Martin M-130 was a commercial flying boat designed and built in 1935 by the Glenn L. Martin Company in Baltimore, Maryland, for Pan American Airways. Only three M-130s were built: the China Clipper, the Philippine Clipper and the Hawaii Clipper. A fourth flying boat (designated as M-156) called the Russian Clipper was built for the Soviet Union which was essentially identical to the three Pan Am models except that it had a larger wing (giving it a longer range) and twin vertical stabilizers. Martin designated them as the Martin Ocean Transports, but to the public they were all referred to as the China Clipper, a name which evolved into a generic term for Pan Am's entire fleet of large flying boats - the Martin M-130, Sikorsky S-42, and Boeing 314. Designed to meet Pan American Airways President Juan Trippe's desire for a trans-pacific aircraft, the M-130 was an all-metal flying boat which employed streamlined aerodynamics and powerful engines, selling at US$417,000 a copy, to achieve Pan Am's specifications for range and payload. The M-130's first flight was on December 30, On November 22, 1935, the China Clipper, piloted by Captain Edwin C. Musick and First Officer R.O.D. Sullivan flew the first trans-pacific airmail route. As illustrated on this page, a postage stamp, Scott Catalog C-20, was printed for use on the transpacific service. With extended service two more denominations were later issued. All three have the same design showing the M-130 in flight. The Philippine Clipper inaugurated passenger service between the United States and Hong Kong on October 14, while later the same month, the Hawaii Clipper inaugurated scheduled trans-pacific passenger service between California and the Philippines. The flight departed the United States on October 21, 1936, and the round trip to and from Manila required two weeks to complete. In July 1938, the Hawaii Clipper disappeared over the Pacific on a flight between Guam and Manila with the loss of nine crew and six passengers. No cause for the loss was determined. Their range and capacity made them prime candidates to fulfill the over ocean hauling needs of the military during World War II. Beginning in 1942, the two remaining planes were pressed into transport roles for the United States Navy. The Philippine Clipper which survived the Japanese attack on Wake Island following Pearl Harbor crashed in January 1943 when it hit the side of a mountain as it descended to land in San Francisco. It was in this accident COMSUBPAC Admiral Robert H. English was killed, along with 18 others. The final M-130, the China Clipper, was wrecked at Port of Spain, Trinidad and Tobago during landing on January 8, The Sikorsky VS-44 (fig. 114) was a large four-engined flying boat built in the USA in the early 1940s. The VS-44 was designed primarily for the trans-atlantic passenger market, with a capacity of 40+ passengers. Only three aircraft were produced: Excalibur, Excambian, and Exeter. In the early 1930s, the primary mode of long distance air travel over oceans was the flying boat design, due to the ease of constructing docking facilities on shore without having to construct runways and the very real possibility of equipment malfunctions forcing a sea landing. Among the top flying boat designers was Russian immigrant Igor Sikorsky who had founded Sikorsky Aero Engineering Company when he came to the US in In 1930, his company became a subsidiary of United Aircraft. 146

147 In March 1935, the United States Navy was making plans for a new patrol bomber that would have increased performance and weapon load capability from their newly procured Consolidated YP3Y-1. Prototypes were ordered from Sikorsky in June 1935 and Consolidated Aircraft in July Sikorsky's entry, the XPBS-1 (BuNo. 9995), made its first flight on 9 September 1937, the Consolidated XPB2Y-1 on 17 December of the same year. The XPBS-1 was evaluated by the National Advisory Committee for Aeronautics (NACA) in 1938, but the Navy contract ultimately went to Consolidated. The XPBS-1 remained in naval service, temporarily operated by Patrol Wing Five at Norfolk, Virginia in 1939, then by Patrol Wing Two at Pearl Harbor, Hawaii, until it was finally assigned to transport squadron VR-2 at Naval Air Station Alameda, in On 30 June 1942, the XPBS- 1 hit a submerged log upon landing at NAS Alameda. Among its passengers was CINCPAC Admiral Chester W. Nimitz who suffered minor injuries, while one member of the flight crew, Lt. Thomas M. Roscoe, died. The XPBS-1 sank and was lost. By 1940 Sikorsky had merged with Chance Vought under the umbrella of United Aircraft and hoped to regain the Pan Am Clipper routes once serviced by their S-42 with the new Vought-Sikorsky VS-44, based on the XPBS-1. A single deck seaplane with four twin-row Pratt & Whitney Twin Wasps rated at 1,200 horsepower (895 kw) each, the new aircraft was 80 feet (24 m) in length and weighed in at 57,500 pounds (26,100 kg) for takeoff. The Boeing 314 Clipper was larger and boasted more powerful Wright Twin Cyclones of 1,600 horsepower (1,193 kw), but the VS-44 was 30 miles per hour (48 km/h) faster and could fly an average payload more than 4,000 miles (6,400 km), out distancing the big Boeing by 500 miles (800 km) and earning bragging rights with the longest full-payload range of any aircraft in the world. The VS-44 brought home several new world records after it went into operation, but, missing out on a Pan Am contract, who instead purchased the Martin M-130 and later the Boeing 314 Clipper. The VS-44 s limited production would never even recoup the development costs. American Export Airlines (AEA) ordered three VS-44s, dubbed Flying Aces and named Excalibur (NX41880; later as NC41880), Excambian (no NX; later as NC41881), and Exeter (no NX; later as NC41882) after the parent company's Four Aces passenger liners. AEA had grown out of the American Export Lines steamship line, so naturally these planes gave nothing away to cruise ships. Sikorsky s standard of luxury boasted full-length beds, dressing rooms, full galley, snack bar, lounge and fully controlled ventilation. The outbreak of World War II put civilian transatlantic air services on hold. Now under a Navy contract, with the Navy designation JR2S-1, AEA s three VS-44 s continued flying between New York, New York and Foynes, Ireland, carrying passengers, freight and materiel. The first VS-44, Excalibur, crashed on takeoff in 1942 at Botwood, Newfoundland, killing 11 of the 37 aboard. After the war, the two remaining VS-44s continued to fly for AEA, now renamed American Overseas Airlines (AOA) and operated by American Airlines. Fig Sikorsky VS-44 NC41881 displayed at the New England Air Museum wearing American Export Airlines colours in June In 1946, Exeter was sold to TACI of Montevideo, Uruguay, as CX-AIR. It crashed on August 15, 1947 while landing in River Plate off Montevideo when (allegedly) returning from a smuggling flight to Paraguayan rebels. 4 out of the 5 crew were killed, but both passengers survived. In 1949, AOA sold Excambian to Tampico Airlines. A short-lived effort to restore the only remaining VS-44 to run freight in the Amazon was unsuccessful, leaving the flying boat boat stranded in Ancon Harbor, Peru. 147

148 By the late 1950s, two Southern California businessmen had heard of the Excambian's plight and had her ferried to Long Beach, where restoration work began. Dick Probert and Walter von Kleinsmid of Avalon Air Transport, (AAT) thought the big VS-44 would be perfect for the Catalina tourist trade. AAT named her Mother Goose, to complement the line s Grumman Goose amphibians, and plans were made to utilize her to meet summer travel demands. In the winter, N41881 would undergo maintenance. Excambian carried thousands of passengers for AAT until 1967 when it was sold to Charles Blair of Antilles Air Boats. Blair, husband of actress Maureen O'Hara, acquired Excambian to ferry passengers among the Virgin Islands. On January 3, 1969 she was extensively damaged by rocks while taxiing at Charlotte Amalie, US Virgin Islands. Assessed as being damaged beyond economic repair, it was beached in March 1972 and converted into a hot dog stand. The Short S.17 Kent was a British 4-engined 15-seat biplane luxury flying-boat airliner, designed and built by Shorts to meet a requirement from Imperial Airways Limited for an aircraft with greater range than the Calcutta. The new aircraft was to have sufficient range to fly the stage from Mirabella, Crete, to Alexandria in Egypt without the need for refuelling stops in Italian colonial territory, there having been a political row which had led the Italian Government to ban British aircraft from its ports. Three aircraft were built, each receiving its own name: "Scipio", "Sylvanus" and "Satyrus"; they were referred to collectively within Imperial Airlines as the "Scipio Class" boats. Each had an aircrew of three (two pilots and a radio operator/navigator) and a steward to prepare meals and light refreshments for the passengers. The Short Kent Flying boat was essentially an enlarged, four-engined version of the Calcutta, with the same passenger carrying capacity but with an increased payload for mail. It was powered by four Bristol Jupiter XFBM radial engines mounted on vertical struts between the upper and lower planes. The wings were constructed using corrugated duralumin box spars, tubular rib assemblies, with a fabric covering and Frise ailerons on all four wings. Duralumin walkways were provided to allow ready access to the engines for maintenance purposes. The tail unit comprised a braced monoplane tailpane with a single fin; the rudder was fitted with a Flettner trimming aerofoil on the Short Scylla which had the same aerostructure as the Kent. The anodised duralumin fuselage was mounted below the lower wing, with the planing bottom of the hull made of stainless steel (as on the Singapore II) with a transverse main step. The use of stainless steel reduced the frequency of land inspections of the hull. The bimetallic corrosion problems experienced on the Singapore II hull had been solved, so Short Brothers became the first company to master the technique of building seaplane floats and flying-boat hulls in this combination of metals. A quick-release hook (controlled by the pilots) was provided, which enabled the captain to start, warm up and (when required) run all four engines up to full power for take-off while the aircraft was still attached to the mooring buoy. Maximum comfort was required for passengers and crew: the Kent's passenger cabin was 8 ft 6 in (2.59 m) wide and 14 ft (4.27 m) long. The seating was arranged in four rows of facing pairs, with a centre aisle, Pullman style. The steward's pantry, situated on the port side aft of the passenger cabin, was equipped with twinburner oil stoves on which IAL Stewards (and the valets of valued passengers) could cook meals in flight. The toilet and washroom were opposite the pantry; the mail and freight compartment was further aft. Special attention was paid to sound levels in the passenger cabin and crew's stations; accordingly the engines were fitted with exhaust collector rings and long tail pipes, to reduce exhaust noise inside the hull. The cockpit, for two pilots, was fully enclosed with a separate Radio Officer's station directly aft of the cockpit. In October 1930, Short Bros. started building the first of the three S.17 Kent flying-boats (G-ABFA, named Scipio). It was launched and flown on 24 February 1931 by Shorts' Chief Test Pilot J. Lankester Parker and was in service in the Mediterranean in May of that year. The second (G-ABFB, named Sylvanus) was launched on 31 March 1931; the third Kent (G-ABFC, Satyrus) was launched on 30 April 1931 and flown for the first time on 2 May Imperial Airways used the Kent aircraft on the Mediterranean stages of its routes to India and beyond, also using them to survey planned routes to South Africa and Australia. On 22 August 1936 "Scipio", on its way back from India, flipped over and sank in "Mirabella Harbour" (between the mainland and the island of Spinalonga) after landing heavily, killing the two crew members. "Sylvanus" was destroyed by fire at Brindisi on 9 November 1935, killing all on board. Only "Satyrus" survived to be taken out of service and scrapped in June

149 In 1933 Imperial Airways placed an order for two landplanes based on the Kent; known initially as the S.17/L and later as the L.17, these became the Short Scylla, of which two were built and given the names "Scylla" and "Syrinx". The Short Empire (fig. 115) was a passenger and mail carrying flying boat, of the 1930s and 1940s, that flew between Britain and British colonies in Africa, Asia and Australia. It was manufactured by Short Brothers and was the precursor to the more famous Short Sunderland of World War II. The origins of the Empire boats lay in an Air Ministry requirement for passenger and mail carriers that could service the colonies particularly to make the connection to Australia. The Empire was officially known as the C-class and each aircraft was christened with a name beginning with C. The first aircraft, G-ADHL Canopus, was completed in June 1936 and launched on 3 July. A total of 42 Empires were built, all at Short's Rochester factory. Imperial Airways (and its successor BOAC), Qantas and TEAL operated the Short Empire. The first series of the Short Empires, the S.23, could carry 5 crew, 17 passengers, and 4,480 lb (2,035 kg) of cargo at a maximum speed of 174 knots (320 km/h). The Short Empire was designed to operate along the Imperial Airways routes to South Africa and Australia, where no leg was much over 500 miles. After the design was finalized and production was started it was realized, with some pressure from the US, that it would be desirable to offer a similar service across the Atlantic. The range of the S.23 was less than that of the equivalent US Sikorsky "Clipper" flying boats and as such they could not provide a true trans-atlantic service. Two boats (Caledonia and Cambria) were lightened and given long range tanks and experimented with in-flight refuelling so they could make the trip but that meant they could carry fewer passengers and cargo. In an attempt to manage the Altantic crossing a piggy-back approach was tried. Using a similar, the S.21, design as the main carrier and a smaller four-engined floatplane design, the Short S.20, mounted on its back. Only a single example was built of a carrier aircraft, the S.21 (known as Maia) and one S.20 (Mercury) together known as the Short Mayo Composite. A successful mid-air launch of Mercury was made in 1938, and it was to set a number of long distance records however a launch aircraft was required for both sides of the Atlantic and it was limited to carrying mail, and no further development of this concept occurred in the UK. The S.30 series were fitted with the slightly more efficient, but lower powered 815 hp Bristol Perseus sleeve valve engines and had a strengthened airframe allowing the take off weight to be increased to 46,000 pounds and giving a range of 1,500 miles. Cabot, Caribou, Clyde and Connemara were fitted with in-flight refuelling equipment and extra fuel tanks so they could be used for a regular trans-atlantic airmail service. The idea behind this was for the aircraft to take off and once airborne take on extra fuel to an all up weight of 53,000 pounds giving a range of over 2,500 miles. The extra fuel did reduce the payload to 4,270 pounds against the 6,250 pounds of the standard craft. The refuelling was by three converted Handley Page Harrow bombers, one operating out of Ireland and two out of Newfoundland. The S.33 was a further follow-on to the S.30 with a later version of the Pegasus to what had been fitted to the S.23 While originally deemed unable to takeoff with sufficient fuel, wartime experiences at operating in overload resulted in the realization that the Empires could be flown at considerably higher weights than the very conservative estimates provided by Shorts and by late in the war were flying across the Atlantic without resorting to in-flight refuelling, and while still carrying a reasonable cargo. In addition to the C class flying boats there were also three S.26 type built; these were known as the "G class" and had names starting with "G": Golden Hind, Golden Fleece and Golden Horn. They were considerably larger than the C class and benefited from improvements to hull design made after the finalization of the S.23 design but aside from a general resemblance were an entirely new design which had been intended for provide a regular trans-atlantic service. They had a wing span of 134 ft (40.9 m) and a length of 101 ft. (30.9 m). In 1937 Caledonia was flown experimentally from Foynes on the River Shannon west to Newfoundland while an American Sikorsky S-42 flew the opposite direction. Caledonia took just over 15 hours (including a period looking for landing spot) flying at an altitude of 1,500 to 5,000 ft (460 to 1,500 m) to cover 1,993 miles (3,207 km) - an average speed of about 130 mph (0.058 km). The Sikorsky took about half an hour less on flying at 10,000 ft (3,000 m). During the Second World War the UK-Australia route was stopped and a new route was established which ran from Sydney to Durban via Cairo. This was stopped after the loss of Singapore but restarted when the Japanese were ousted from Burma and Malaya. 149

150 Fig Qantas Short C Class Empire flying boat VH-ABB 'Coolangatta', ca The Grumman G-21 Goose amphibious aircraft (fig. 116) was designed as an eight-seat "commuter" plane for businessmen in the Long Island area. The Goose was Grumman s first monoplane to fly, its first twinengined aircraft, and its first aircraft to enter commercial airline service. During World War II, the Goose became an effective transport for the US military (including the Coast Guard), as well as serving with many other air forces. During hostilities, the Goose took on an increasing number of combat and training roles. The adaptable transport continued in postwar use. In 1936, a group of wealthy residents of Long Island, including E. Roland Harriman, approached Grumman and commissioned an aircraft that they could use to fly to New York City. In response the Grumman Model G-21 was designed as a light amphibian transport. The typical Grumman rugged construction was matched to an all-metal, high-winged monoplane powered by two 450 horsepower (340 kw) Pratt & Whitney R- 985 Wasp Jr. nine-cylinder, air-cooled radial engines mounted on the leading edge of high-set wings. The deep fuselage served also as a hull and was equipped with hand-cranked retractable landing gear. First flight of the prototype took place on May 29, The fuselage also proved versatile as it provided generous interior space that allowed fitting for either a transport or luxury airliner role. Having an amphibious configuration also allowed the G-21 to go just about anywhere, and plans were made to market it as an amphibian airliner. Some had a hatch in the nose, which could remain open in flight. Fig The Grumman G-21 Goose amphibious aircraft. The Supermarine Sea Eagle was a British, passenger carrying, amphibious flying boat. It was designed and built by the Supermarine Aviation Works for its subsidiary, the British Marine Air Navigation Co Ltd, to be used on their cross-channel route between Southampton, the Channel Islands and France. Three aircraft were constructed, G-EBFK, G-EBGR and G-EBGS and the regular service between Southampton and Guernsey began on 25 September 1923 (the planned service to France was never implemented). This was the world's first scheduled passenger air service by flying boat. However, G-EBFK crashed on 21 May 1924; in January 1927, G-EBGS was lost when it was rammed by a ship in the harbor of St Peter Port, Guernsey. The third aircraft continued on the route until 1928 when it was replaced by a Short S.8 Calcutta. The wooden hull of the surviving Sea Eagle, G-EBGR, was retained by Vickers until 1949, when they presented it to the British Overseas Airways Corporation; BOAC burnt it in 1954 because of a lack of storage space. The Vickers Viking was a British single-engine amphibious aircraft designed for military use shortly after the World War I. Later versions of the aircraft were known as the Vickers Vulture and Vickers Vanellus. 150

151 Research on Vickers' first amphibious aircraft type began in December 1918 with tests of alternative fuselage/hull designs occurring in an experimental tank at St Albans in Hertfordshire, England. A prototype, registered G-EAOV, was a five-seat cabin biplane with a pusher propeller driven by a Rolls-Royce Falcon watercooled V 12 engine. Sir John Alcock died taking this aircraft to the Paris exhibition on 18 December 1919, whilst trying to land at Côte d'evrard, near Rouen, Normandy in foggy weather. The next example, G-EASC, known as the Viking II, had a greater wing span and a 360 hp Rolls-Royce Eagle VIII motor. The Viking III machine, piloted by Captain Cockerell, won first prize in the amphibian class in Air Ministry competitions held in September and October, The Type 54 Viking IV incorporated further refinements and had a wider cabin above a hull one foot wider, an example being G-EBBZ in which Ross Smith and J.M. Bennett (partners in the 1919 England to Australia flight) died on 13 April 1922 just outside the Brooklands racetrack near Weybridge in Surrey. Most of these Mark IV Vikings had a Napier Lion engine. The next version was the Viking V, two were built for the RAF for service in Iraq. The last Viking amphibians were built during 1923, but the name was re-used for the twin-engine VC.1 Viking airliner some 22 years later, which saw service as the Valetta with the RAF and other air arms. Some Viking amphibians were built by Canadian Vickers Limited, a subsidiary company in Montreal with no previous plane making experience. A further development with a redesigned wing structure using the 450 hp (340 kw) Napier Lion would have been the Viking VI (Vickers designation Type 78) but known as the Vulture I. A second with a Rolls-Royce Eagle IX (360 hp, 270 kw) was the Type 95 Vulture II. Both Vultures were used for an unsuccessful around the world attempt in 1924 after the Eagle engine of the Vulture II was replaced with a Lion. With registration G- EBHO, the first set off from Calshot Seaplane Base on 25 March 1924, the other was shipped as a spare machine to Tokyo. After mechanical difficulties in earlier staged G-EBHO crashed at Akyab where it was replaced by G-EBGO on 25 June. Encountering heavy fog on the Siberian side of the Bering Sea G-ENGO crashed. Vickers salvaged a large proportion. The Viking Mark VII ("Type 83" in Vickers numbering) was a development of the Vulture, a three-seat open-cockpit fleet spotter to Air Ministry specification 46/22 given the service name Vanellus when taken on for evaluation by the RAF against the Supermarine Seagull design. The Canadian Vickers Vedette was the first aircraft in Canada designed and built to meet a specification for Canadian conditions. It was a single-engine biplane flying boat purchased to meet a Royal Canadian Air Force (RCAF) demand for a smaller aircraft than the Vickers Viking with a much greater rate of climb, to be suitable for forestry survey and fire protection work. The type went on to have a long and distinguished career in civil operations in Canada. Most of the topographical maps in use in Canada today are based on photos taken from one of these aircraft. Based on a preliminary design in early 1924 for a "flying boat" by R.K.Pierson of the home company, Vickers (UK), the Canadian Vickers Vedette was a two/three-seat single-engine pusher aircraft. The design was passed over to the Canadian Vickers Limited of Longueuil, Quebec (formed in 1911) where Wilfrid Thomas Reid served as Chief Engineer. The prototype Vedette I was first flown on 4 November 1924, powered by a 200 hp Rolls-Royce Falcon III. It was subsequently fitted with 210 hp Wolseley Viper, 200 hp Wright J-4 and 215 hp Armstrong Siddeley Lynx engines for testing. Several versions of the Vedette were produced, including two amphibious versions and one with an enclosed cabin on an all-metal hull. With the exception of these major changes, most of the remaining differences between versions were relatively minor and not externally visible. Each version was produced with a range of optional engine types. The first production example was provided to Fairchild Aerial Surveys (c/n 31 G-CAFF) before they started designing their own survey aircraft. The majority of the production run was purchased by the RCAF where the aircraft proved popular and versatile, if somewhat temperamental due to leaky hulls that required constant maintenance (a problem afflicting all wooden hulled flying boats). The Vedette undertook photographic and forestry patrols satisfactorily and provided a backbone for RCAF flying operations through the lean peacetime years. Vedettes started a coast-to-coast photographic survey that was needed to map out the large areas of the country still unmapped. These missions lasted until the outbreak of the Second World War, and would be completed after the war with newer types. Vedettes stationed on both coasts were also used for fishing and smuggling patrols, both with the RCAF and with Western Canada Airways. 151

152 The Vedette featured prominently in a number of mercy missions, while some airmen discovered it was nearly ideal for aerial goose hunting, at least until a pilot was hit by a goose. The first Canadian to join the Caterpillar Club by using a parachute to escape from an aircraft did so from RCAF Vedette "ZF" on 17 May The pilot, C.S. (Jack) Caldwell, while testing the aircraft at the Canadian Vickers factory, entered an uncontrollable spin after the engine failed and bailed out successfully over the St. Lawrence River. The RCAF acquired one Wright J-4 engined Vedette I in 1925 and 18 Armstrong-Siddeley Lynx IV (210 hp) engined Vedette IIs from 1926 onwards; all of these were out of service before the Second World War began. Starting in 1929, the RCAF acquired 13 Vedette Vs with higher gross weight, and 11 Vedette VAs featuring Handley Page wing slots. The single Vedette VI, with Wright J-6 engine, featured a metal hull and an enclosed cockpit. A mark V was refurbished by the factory and as the sole Vam was given a new metal hull, as well as a new serial number (the last), but it retained its RCAF call sign as "ZD." Seven Vedette VAs and the Mk VI survived into wartime service, flying with No 4(BR) Squadron and the Seaplane and Bomber Reconnaissance Training School (later No 13 OT Sqn) in Vancouver, BC until May In addition to the RCAF, The Ontario, Manitoba and Saskatchewan governments used Vedettes extensively for scouting out forest fires in the heavily wooded areas of those provinces. The company exported six Wright J-5 powered Vedette Vs to Chile, where they were based at Puerto Montt (which is on an inlet off the Pacific coast) with the Escuadrilla de Anfibios N 1 (now known as the Grupo de Aviación N 5). They were used to forge an air link between there and the capital Santiago, 569 miles (916 km) up the coast. At least one of the Vedettes, and possibly all six were lost due to hurricane force winds, which also caused the loss of two lives when one of the aircraft overturned while on the water. The Beriev MBR-2 (fig. 117) was a reconnaissance flying boat which entered service with the Soviet Navy in Fig Aeroflot MP-1 at Yalta, circa The MBR-2 was designed by Georgy Mikhailovich Beriev and first flew in 1931, powered by an imported 373 kw (500 hp) BMW VI.Z engine. Production models, which arrived in 1934, used a licence-built version of this engine, the Mikulin M-17 of 508 kw (680 hp), and could be fitted with a fixed wheel or ski undercarriage. Beriev also designed a commercial airliner derivation, the MP-1, which entered airline service in 1934, and a freighter version, which followed in In 1935, an improved version was developed, the MBR-2bis, powered by the Mikulin AM-34N engine, and fitted with an enclosed cockpit, dorsal gun-turret and enlarged vertical tail. In this configuration, the machine remained in production until As with the MBR-2, the bis spawned a commercial derivative and the MP-1bis entered service in The Aichi E13A (fig. 118), (Allied reporting name: "Jake") was a long-range reconnaissance seaplane used by the Imperial Japanese Navy (IJN) from 1941 to Numerically the most important floatplane of the IJN, it could carry a crew of three and a bombload of 250 kg (550 lb). The Navy designation was "Navy Type Zero Reconnaissance Seaplane". Fig The Aichi E13A. 152

153 In China, it operated from seaplane tenders and cruisers. Later, it was used as a scout for the Attack on Pearl Harbor, and was encountered in combat by the United States Navy during the Battles of Coral Sea and Midway. It was in service throughout the conflict, for coastal patrols, strikes against navigation, liaison, officer transports, castaway rescues, and other missions, along with some kamikaze missions in the last days of war. Eight examples were operated by the French Navy Air Force during the First Indochina War from , while others were believed to be operated by the Naval Air Arm of the Royal Thai Navy before the war. One example captured by New Zealand forces was flown by RNZAF personnel in theatre, but sank and was not repaired after a float leaked. The Ar 196 (fig. 119) was a shipboard reconnaissance aircraft built by the German firm Arado starting in The next year it was selected as the winner of a design contest, and became the standard aircraft of the Kriegsmarine (German Navy) throughout World War II. Fig The Ar 196 (a shipboard reconnaissance aircraft built by the German firm Arado starting in 1936). In 1933, the Kriegsmarine looked for a standardized shipboard reconnaissance aircraft. After a brief selection period, the Reichsluftfahrtministerium (German Air Ministry, RLM) decided on the Heinkel He 60 biplane. This was one of a line of developments of a basic biplane airframe that appeared as a number of floatplanes, trainers, and fighters. Deliveries started in a matter of months. By 1935, it was clear that the He 60's performance was lacking, and the RLM asked Heinkel to design its replacement. The result was the He 114. The first prototype was powered by the Daimler-Benz DB 600 inline engine, but it was clear that supplies of this engine would be limited, and the production versions turned to the BMW 132 radial engine instead. The plane proved to have only slightly better performance than the He 60, and its sea-handling was poor. Rushed modifications resulted in a series of nine prototypes in an attempt to solve some of the problems, but they didn't help much. The Navy gave up, and the planes were eventually sold off to Romania, Spain and Sweden. In October 1936, the RLM asked for a He 114 replacement. The only stipulations were that it would use the BMW 132, and they wanted prototypes in both twin-float and single-float configurations. Designs were received from Dornier, Gotha, Arado and Focke-Wulf. Heinkel declined to tender, contending that the He 114 could still be made to work. With the exception of the Arado design, they were all conventional biplanes. That gave the Arado better performance than any of the others, and the RLM ordered four prototypes. The RLM was also rather conservative by nature, so they also ordered two of the Focke-Wulf Fw 62 design as a backup. It quickly became clear that the Arado would work effectively, and only four prototypes of the Fw 62 were built. The Ar 196 prototypes were all delivered in summer 1937, V1 (which flew in May) and V2 with twin floats as A models, and V3 and V4 on a single float as B models. Both versions demonstrated excellent water handling, and there seemed to be little to decide one over the other. Since there was a possibility of the smaller outrigger floats on the B models "digging in", the twin-float A model was ordered into production. A single additional prototype, V5, was produced in November 1938 to test final changes. 10 A-0s were delivered in November and December 1938, with a single 7.92 mm (.312 in) MG 15 machine gun in the rear seat for defense. Five similarly equipped B-0s were also delivered to land-based 153

154 squadrons. This was followed by 20 A-1 production models starting in June 1939, enough to equip the surface fleet. Starting in November production switched to the heavier land-based A-2 model. It added shackles for two 50 kg (110 lb) bombs, two 20 mm MG FF cannons in the wings, and a 7.92 mm (.312 in) MG 17 machine gun in the cowling. The A-4 replaced it in December 1940, strengthening the airframe, adding another radio, and switching props to a VDM model. The apparently mis-numbered A-3 replaced the A-4, with additional strengthening of the airframe. The final production version was the A-5 from 1943, which changed radios and cockpit instruments, and switched the rear gun to the much-improved MG 81Z. In all versions, 541 Ar 196s (526 production models) were built before production ended in August 1944, about 100 of these from SNCA and Fokker plants The Ar 196C was a proposed aerodynamically-refined version. The Ar 196C project was cancelled in The plane was loved by its pilots, who found it handled well both in the air and on the water. With the loss of the German surface fleet the A-1s were added to coastal squadrons, and continued to fly reconnaissance missions and submarine hunts into late Two notable operations were the capture of HMS Seal, and the repeated interception of RAF Armstrong-Whitworth Whitley bombers. Although it was no match for a fighter, it was considerably better than its Allied counterparts, and generally considered the best of its class. Owing to its good handling on water, the Finnish Air Force utilized Ar 196 solely on transporting and supplying special forces patrols behind enemy lines, landing on small lakes in remote areas. Several fully equipped soldiers were carried in the fuselage. The Blohm & Voss BV 222 Wiking (German: "Viking") (fig. 120), was a large, six-engined German flying boat of World War II. Originally designed as a commercial transport, and produced in only limited quantities, it was both the largest flying boat and largest aircraft to achieve operational status during the war. Fig The BV 222 Wiking in flight. Prior to World War II, the German airline Lufthansa had carried out many transatlantic mail flights. However, their main interest was passenger transport, and they initiated a program in 1936 that culminated in an order for three BV 222 flying boats designed by Dr. Richard Vogt. Construction of the first prototype, V1, began in January 1938, with construction of the V2 and V3 following within weeks. V1 made its test flight on 7 September 1940, carrying the civil registration D-ANTE. During trials it demonstrated that it could carry up to 92 passengers, or 72 patients on stretchers over short distances at a maximum speed of 239 mph (385 km/h). The flight characteristics were found to be satisfactory, but with some improvements required. Further trials lasted until December 1940, when the V1 passed into Luftwaffe service, receiving a military paint scheme and the Stammkennzeichen registration code of CC+EQ, later changed to the Geschwaderkennung designation of X4+AH, when in service with Lufttransportgruppe (See) 222. The type was noted for a long flat floor inside the cabin and a large square cargo door aft of the wing on the starboard side. The flat floor was a welcome novelty for that era. Only 13 aircraft are thought to have been completed. Originally powered by Bramo 323 Fafnir radial engines, later aircraft were powered by six 746 kw (1,000 hp) Jumo 207C inline two-stroke opposed-piston diesel engines. The use of diesels permitted refueling at sea by special re-supply U-boats. C-13 aircraft was a sole example fitted with Jumo 205C and later Jumo 205D engines. 154

155 Early aircraft were identified as V1 to V8. Production examples were designated C-09 to C-13. V1 made seven flights between Hamburg and Kirkenes up to 19 August 1941, transporting a total of 65,000 kg (140,000 lb) of supplies and 221 wounded men, covering a distance of 30,000 km (19,000 mi) in total. After being overhauled at Hamburg, V1 was sent to Athens, from where it carried supplies for the Afrika Corps, making 17 flights between 16 October and 6 November The V1 was at this time unarmed, and was given an escort of two Messerschmitt Bf 110 heavy fighters. Following these flights, the V1 returned to Hamburg to have defensive armament fitted, comprising a 7.92 mm (.312 in) MG 81 machine gun in the hull, two turret-mounted 13 mm (.51 in) MG 131 machine guns, and four 7.92 mm (.312 in) MG 81s in waist mounts. The registration was changed to X4+AH at the same time and the V1 formed the basis for the new air transport squadron Lufttransportstaffel 222 (LTS 222). Between 1942 and 1943, the aircraft flew in the Mediterranean theatre, until in mid-february 1943 it sank following a collision with a submerged wreck while landing at Piraeus harbour. The V2 (CC+ER) made its first flight on 7 August 1941, and after extensive testing was assigned to LTS 222 on 10 August 1942 as X4+AB. Since the aircraft was intended for long-distance overwater flights, in addition to the armament fitted to the V1 she received two rear-facing wing-mounted turrets with dual 13 mm (.51 in) MG 131s, accessed via the tubular wing spar which was 1 m (3 ft 3 in) in diameter. In 1944, the V2 participated in Operation Schatzgräber ("Treasure Seeker"), the code name of a German weather station at Alexandra Land in the Arctic, whose sick crew needed to be evacuated. The BV 222 dropped a spare wheel for a Fw 200 which had sustained damage during landing near the station. The V3 (initially DM+SD) first flew on 28 November 1941, and was transferred to LTS 222 on 9 December 1941 After V1's sinking, V3 returned to Hamburg where she was armed. She was destroyed along with V5 on 20 June 1943 at Biscarrosse by RAF de Havilland Mosquitos of No. 264 Squadron RAF. V4, which had an altered height tail, was also assigned to LTS 222 for Africa flights. V6 was shot down on 21 August 1942 on the Taranto to Tripoli route by a Bristol Beaufighter; V8 was shot down on the same route on 10 December The V7 (TB+QL), which made its first flight on 1 April 1943, was fitted with six 746 kw (1,000 hp) Jumo 207C inline two-stroke diesel engines. With a takeoff weight of 50,000 kg (110,000 lb) and a range of 6,100 km (3,800 mi), it was intended as the prototype BV 222C. Following the Invasion of Normandy in June 1944, the remaining BV 222 aircraft were transferred to KG 200. Of these, C-09 was probably the BV 222 reported to have been strafed and destroyed by Hawker Typhoon aircraft of No. 439 Squadron RCAF on 24 April 1945 at Seedorf, while V7 and V4 were scuttled by their crews at Travemünde and Kiel-Holtenau airport respectively, at the end of the war. C-10 was probably the BV 222 reported shot down southwest of Biscarosse on the night of 8 February 1944 by a Mosquito of No. 157 Squadron RAF. One BV 222, V4, is said to have shot down a US Navy PB4Y Liberator of VB-105 (BU#63917) commanded by Lieutenant Evert, on October 22, Since the war this has often been mistakenly quoted as a BV 222 shooting down an Avro Lancaster. Following the invasion of the Soviet Union in June 1941, plans were made to connect Germany and Japan by air using Luftwaffe aircraft modified for very long range flights since commercial flights to the Far East by Lufthansa were no longer possible, and it had become very dangerous for ships or U-boats to make the trip by sea. Field Marshal Erhard Milch authorized a study in to the feasibility of such direct flights and various routes were considered, including departing from German-occupied Russia and Bulgaria, and a sea route using a BV 222 flying from Kirkenes in north Norway to Tokyo via Sakhalin Island, a distance of 6,400 km (4,000 mi). The BV 222 was one of three aircraft considered seriously for the program, along with the Focke-Wulf Fw 200 and the Heinkel He 177. The He 177 was ruled out due to it being considered unreliable and in 1943 the Junkers Ju 290 was selected for the flights. Three BV 222s were captured and subsequently operated by Allied forces: C-011, C-012, and C-013. C-012, captured at Sørreisa in Norway after the war along with V2, was flown by Captain Eric "Winkle" Brown from Norway to the RAF station at Calshot in 1946, with RAF serial number "VP501". After testing at Marine Aircraft Experimental Establishment at Felixstowe it was assigned to No. 201 Squadron RAF, who operated it up to 1947, when it was scrapped. 155

156 C-011 and C-013, captured by US forces at the end of World War II. On August 15 and again on August 20, 1945 LT Cmdr Richard Schreder of the US Navy performed test flights along with the German crew of one of the BV 222 aircraft that had been acquired by the US. In two flights resulting in a total flight time of 38 minutes they experienced 4 engine fires. While many spare engines were available they were of substandard quality due to the lack of quality alloys near the end of the war, and caught fire easily. Since the aircraft was unairworthy with these engines, the aircraft was supposedly taken out to open water and sunk by a Navy Destroyer. Other reports indicate the US captured aircraft were flown or shipped to the US. Convair acquired one for evaluation at the Naval Air Station Patuxent River, the intensive studies leading to the hull design of their Model 117 which in turn led to the R3Y Tradewind. Their subsequent fate is unknown. The V2 aircraft briefly wore US markings in Strangely the V2 aircraft had identification markings given to her from the original V5 aircraft for Operation Schatzgräber. V2 was later scuttled by the British who filled her with BV 222 spare parts from the base at Ilsvika to weigh her down. V2 was towed to a position between Fagervika and Monk's island where it is thought she now rests perfectly preserved on the seabed, owing to low oxygen levels in the water. There are plans to raise and restore this aircraft. The CANT Z.501 Gabbiano (Italian: Gull, fig. 121) was a single engine flying boat that served with the Italian Regia Aeronautica during World War II. It had a crew of four or five and was used mainly for reconnaissance. Initially a successful aircraft, it was obsolete by 1940, but was still used throughout World War II, suffering many losses. The last aircraft was retired in It was also the holder of two world records for long-distance flight. Fig CANT Z.501 with beaching gear. Note the closed position in the nose and the pilot's cockpit just under the propeller. The engine nacelle was also used as a machine gun position. Filippo Zappata was one of the foremost Italian aircraft designers. He worked for Cantieri Navali Trieste (CANT), for some years, but went to France in 1927 to work for Blériot. He returned to Italy at the prompting of Italo Balbo and resumed work at CANT on a series of new aircraft. The first of these was the Z.501, designed to replace the Savoia-Marchetti S.78. The prototype Z.501, was first flown in 1934 by test pilot Mario Stoppani. The aircraft had a very slim fuselage, a high parasol wing and a single wing-mounted engine nacelle. In the prototype a 560 kw (750 hp) inline Isotta-Fraschini Asso-750.RC engine was fitted, with an annular radiator that resembled a radial engine (it had no liquid cooling). The engine nacelle was extended to carry a rear-facing machine gun, while other guns were mounted in the centre fuselage and nose. All were 7.7 mm (.303 in) Breda- SAFAT. Bombs up to 640 kg/1,410 lb (4 160 kg/350 lb) were carried under the wings. The aerodynamic low-drag design was typical of Zapata-designed aircraft, as was the wooden construction. Overall, the aircraft was similar to the PBY Catalina, although this aircraft had two engines and was larger. The production aircraft had an endurance of 12 hours. However, the record-breaking version, as was quite common at the time (mainly due to the low fuel consumption of the piston engine), greatly exceeded this. The USA had established a new endurance record of 3,860 km (2,400 mi); a Z.501 with the civilian registration I-AGIL was used to re-take the record in accordance with dictator Benito Mussolini's wishes. It was manned by Stoppani and two others, fitted with a special metal three-blade propeller, and other modifications. 156

157 On May 1934, the modified Z.501 established a new seaplane distance record of 4,130 km (2,570 mi), by flying from Monfalcone to Massawa, in Eritrea, in 26 hours and 35 minutes. This distance record was lost to a French aircraft that flew 4,335 km (2,694 mi) on 23 June the same year, so another record flight was made on 16 July. The plan was to fly to Djibouti, a distance of 4,700 km (2,900 mi), but instead the aircraft flew 4,930 km (3,060 mi) to Berbera, Somaliland, in 25 hours. Production of the Z.501 began in 1935 with 24 aircraft ordered from CANT, and 30 from Aereonautica Sicula, a company in Palermo. Registration numbers started with MM The Z.501 was put into service with some modifications, including; turrets for the machine guns, and some reinforcement of the airframe that increased the overall weight by 500 kg (1,100 lb). The more powerful 656 kw (880 hp) Isotta-Fraschini Asso XI.RC engine was fitted, but even with an additional 97 kw (130 hp), the maximum speed dropped to 245 km/h (152 mph), cruise speed to 200 km/h (120 mph), and range to 2,400 km (1,500 mi). The first units equipped were No.141 Sqn., Eritrea, No.83 Group, Augusta, No.85, Elmas, and No.62, Spain (for operations). By the time Italy entered World War II on 10 June 1940, 202 aircraft were in service in 15 squadrons. They were used by 20 Sqn. and patrolled the Mediterranean, as well as performing air-sea rescue operations. During the short campaign against France, seven Z.501's were destroyed by a French attack on their base in Sardinia. Another crashed the next day. In July, encounters with Royal Navy Fleet Air Arm fighters and accidents claimed many Z.501s, with a total of 11 destroyed in action, while the number that were operational dropped to 77. The Z.501 operated in all theatres and 62 aircraft were lost in 1940, leaving 126, of which only 87 were operational. New orders were placed with the manufacturer Aereonautica Sicula. Z.501's were used for search-and-rescue missions and anti-submarine patrols. They were responsible, in collaboration with Italian ships, for the destruction of HMS Union and damaged three other submarines. But their effectiveness was limited by their bombload of only four 50 kg (110 lb) or two 160 kg (352 lb) bombs. At the end of 1941, there were Z.501's in 15 of the 27 squadrons dedicated to naval reconnaissance. Strangely, the number of operational aircraft increased to an average of 100, rising six months later to 108 in 11 squadrons, probably due to the arrival of new aircraft. By the end of 1942, there were 199 aircraft in service, 88 of which were operational. Maritime reconnaissance had at that time 290 aircraft in total. By September 1943, there were still 240 aircraft assigned to maritime reconnaissance: only 84 were Z.501's, in three squadrons, and another 11 (mixed), out of 20 in total. Only around forty aircraft were operational. Total production, 218 by CANT and 236 by Aereonautica Sicula, was in fact less, as 12 aircraft were captured incomplete after the invasion of Sicily. Later, Aereonautica Sicula repaired many of the ICAF aircraft. Some modifications were adopted during production, such as the removal of the nose machine gun; it was replaced by an enclosed fairing. Some Z.501s were supplied to Romania and to the Nationalists during the Spanish Civil War. Following Italy's surrender in 1943, a few of these flying boats continued to operate with both the Axis Aeronautica Nazionale Repubblicana and the Allied Italian Co-Belligerent Air Force. After the armistice, several flew to southern Italy, including the 9 aircraft of 149 Sqn with 80 persons aboard. In October, there were 16 aircraft operational in southern Italy, which dropped to 10 by May The squadrons involved were No's 141, 147, and 183. After the war 183 Sqn. was based at Elmas with four Z.501s, and these were scrapped in Generally, the Z.501 had a mixed reputation. It was pleasant to fly, having low wing loading and good performance. It was quite reliable despite having only one liquid-cooled engine. However, there were problems with the durability of the wooden fuselage, particularly the aircraft built during the war. Its seafaring qualities were poor and the aircraft was susceptible to bad weather conditions. The fuselage would often break up in rough seas. Another problem was the engine nacelle: if the aircraft landed heavily the propeller could crash down into the cockpit. The aircraft was used in the reconnaissance role thanks to its long endurance, but it was very vulnerable to enemy fighters or even bombers. Perhaps its only air victory was in the Aegean, when a fighter stalled while chasing a Z.501. The aircraft was more often relegated to second-line duties. Sometimes, with well-trained crews, 157

158 it was able to attack submarines, damaging several of them (perhaps six in total) and contributing to the destruction of two others. The aircraft had no advanced detection systems, only depth charges. Generally the aircraft's main task was search and rescue missions, and perhaps because of this it was called Mammaiut (another theory is that because it was helpless against enemy aircraft). Even its sea capabilities were not good and often the Z.501 needed to be helped by ships. As for its flying qualities, it was too slow, unmanoeuvrable, and under-armed to put up a defence against enemy fighters. As a result many were shot down. The Dornier Do 18 was a development of the Do 16 flying boat. It was developed for the Luftwaffe, but Lufthansa got 5 aircraft and used these for tests between the Azores and the North American continent in 1936 and on their mail route over the South Atlantic from 1937 to March 1938 a "Do 18 W" established a seaplane record flying non-stop a straight distance of 8,391 km (5,214 mi) from Start Point, Devon to Caravelas in Brazil. In 1934, the Dornier Flugzeugwerke started development of a new twin engined flying boat to replace the Dornier Do J "Wal" (Whale) in both military and civil roles. The resultant design, Do 18 retained the layout of the Wal, with a metal hull fitted with distinctive stabilising sponsons, and powered by two engines above the wing in a push-pull layout, but was aerodynamically and hydrodynamically more efficient. It was planned to be powered by two of the new Junkers Jumo 205 diesel engines. Although heavy, these promised to give much lower fuel consumption than conventional petrol engines of similar power. The first prototype, the Do 18a, registration D-AHIS (and named Monsun by Lufthansa) flew on 15 March 1935, powered by two of the earlier 410 kw (550 hp) Junkers Jumo 5c diesels as the planned Jumo 205s were not yet available. It was lost on 2 November 1935 over the Baltic during high-speed tests. Three further prototypes followed, two (the Do 18d and Do 18b) being prototype military aircraft, and the Do 18c (later redesignated Do 18 V3), a civil prototype. The Do 18c was delivered to Lufthansa as a Do 18E civil transport (D-ABYM Aeolus), quickly followed by a further two aircraft, (D-AANE Zyklon and D-ARUN Zephir) with a final Do 18E (D-AROZ Pampero) being built in A further civil Do 18 was the Do 18F, a modified aircraft with longer wingspan and higher weights built for extended-range flights. The sole Do 18F, D-ANHR, first flew on 11 June It was later modified with 656 kw (880 hp) BMW 132N radial engines to test a possible upgrage for the Luftwaffe's aircraft, flying in this from on on 21 November 1939 as the Do 18L. It suffered cooling problems, however, and further development of the radial powered Do 18 was abandoned. In 1936, Lufthansa started a series of endurance trials, culminating on September when Zephir, flown by Flugkapitän Blankenburg with Lufthansa Director Freiherr von Gablenz as passenger, was launched by catapult from the seaplane tender Schwabenland at Horta, Azores, flying the 4,460 km (2,270 mi) to New York in 22 hours 12 minutes. Also on 11 September, Aeolus flew from Horta to Hamilton, Bermuda in 18 hours 15 minutes, continuing to New York the next day. For the main leg of the North Atlantic the aircraft needed the help of the catapult on Schwabenland. On 22 September Aeolus returned to Horta in 17:50 h (3850 km). Zephir was catapulted on 28 September at Hamilton. The second Flights to New York followed on 5-6 and 6 7 October and the returnflights this time 17 and 18 October from Sydney, Nova Scotia. The flying boats did not wait for their tender and went on to Lisbon and Travemünde. In April 1937 D-ARUN Zephir and D-ABYM Aeolus started their service on the South Atlantic mail route from Bathurst, now Banjul, Gambia to Natal, Brazil (3040 km). Catapult ships were based in Bathurst and Fernando de Noronha to allow the aircraft to cross the Atlantic carrying a full load of mail. In June they were joined by V6 D-AROZ Pampero. Aeolus was lost on 30 July 1937, when it had to make an ocean landing due to engine problems and was heavily damaged when Ostmark tried to retrieve the plane. Pampero (20 August) and Zephir (29 January 1938) also had to make ocean landings. Pampero was lost at sea nearly without trace on 1 October 1938 with a crew of five. Lufthansa's fifth aircraft was the only Do 18F V7 D-ANNE Zyklon, that first took to the skies on 11 June This was the only Do 18 with a wider span which enable it to stay in the air with one engine out. This was a special demand of Lufthansa Zyklon was used over the South Atlantic between September 1937 and March The Do 18s crossed the South Atlantic 73 times. Zyklon is not the aircraft, that established the England to Brazil distance record from March 1938 as often stated. 158

159 The record-aircraft D-ANHR was taken from the military production line and was specially prepared. It was flown as a builder's machine with a Lufthansa crew augmented by the works pilot Gundermann. On the way back to the South American station the seaplane tender Westfalen took the plane in the English Channel where it was catapulted to Brazil. On the record flight the conditions were not optimal and the plane did not reached Rio de Janeiro as planned. In Luftwaffe service, it was obsolete by the outbreak of World War II, but - as the only military flying boat - 62 (58 serviceable) in 6 squadrons were in use mainly on North Sea reconnaissance missions. In 1940 some squadrons changed their base to Norway. The vulnerable and underpowered flying boat was soon relegated to training and the air/sea rescue role. In the middle of 1941 only one Squadron was still operational on Do 18. The Blohm & Voss BV 138 had superseded the Dornier. A Do 18 was the first German aircraft to be shot down by British aircraft during the war, when one of a formation of three was caught over the North Sea by nine Fleet Air Arm Blackburn Skua fighter-bombers of 803 Naval Air Squadron flying from HMS Ark Royal on 26 September The flying boat was able to make an emergency landing but was sunk by the destroyer HMS Somali. The Dornier Do 24 is a 1930s German three-engine flying boat designed by the Dornier Flugzeugwerke for maritime patrol and search and rescue. According to Dornier records, some 12,000 people were rescued by Do 24s during its flying career. A total of 279 were built among several factories from The Dornier Do 24 was designed to meet a Dutch navy requirement for a replacement of the Dornier Wals being used in the Dutch East Indies. It was an all-metal monoplane with a broad-beamed hull and stabilising sponsons. The aircraft was powered by three wing-mounted radial engines. The first two aircraft built were fitted with 447 kw (600 hp) Junkers Jumo 205C diesel engines. The next two had 652 kw (875 hp) Wright R-1820-F52 Cyclones, this was to meet a Dutch requirement to use the same engines as the Martin 139. The third aircraft (with Cyclone engines) was the first to fly on 3 July Six Dutch aircraft (designated Do 24K-1) were built in Germany, followed by a further aircraft built under licence by Aviolanda in the Netherlands (designated Do 24K-2). Only 25 aircraft had been built on the Aviolanda assembly line before the German occupation. The Luftwaffe were interested in the completed and partially completed aircraft. The Dutch production line continued to produce aircraft under German control. 11 airframes were completed with Dutch-bought Wright Cyclone engines, but later models used the BMW Bramo 323R-2. A further 159 Do 24s were built in the Netherlands during the occupation, most under the designation Do 24T-1. Another production line for the Do 24 was established in Sartrouville, France, during the German occupation. This line was operated by SNCA and was able to produce another 48 Do 24s. After the liberation, this facility produced a further 40 Do 24s, which served in the French Navy until Dutch- and German-built Do 24s had been sent to the East Indies by the time of the German occupation of the Netherlands in June Until the outbreak of war, these aircraft would have flown the tricolor roundel. Later, to avoid confusion with British or French roundels, Dutch aircraft flew a black-bordered orange triangle insignia. After the Japanese invasion, six surviving Do 24s were transferred to the Royal Australian Air Force in February They served in RAAF through most of 1944 as transports in New Guinea, making the Do 24 one of the few aircraft serving operationally on both sides during World War II. During the war, a German Do 24 made a forced landing in neutral Sweden, was impounded and paid for, and remained in Swedish service until In 1944, 12 Dutch-built Do 24s were delivered to Spain with the understanding that they would assist downed airmen of both sides. After the war, a few French-built Do 24s also found their way to Spain. Spanish Do 24s were operational at least until 1967, and possibly later. In 1971, one of the last flying Spanish Do 24s was returned to the Dornier facility on Lake Constance for permanent display. The Kawanishi H8K, (Nishiki Daitei, Nishiki Taitei, fig. 122) was an Imperial Japanese Navy flying boat used during World War II for maritime patrol duties. The Allied reporting name for the type was "Emily". At the same time the type's predecessor, the Kawanishi H6K, was going into service in 1938 the Navy ordered the development of a larger, longer-ranged patrol aircraft under the designation Navy Experimental 13- Shi Large-size Flying Boat. The result was a large, shoulder-winged design that is widely regarded as the best flying boat of the war. Despite this, initial development was troublesome, with the prototype displaying terrible handling on the water. Deepening of the hull, redesigning of the planing bottom and the addition of spray strips under the nose rectified this Two further prototypes -actually pre-production aircraft- joined the development program in December

160 The IJNAF accepted the first production version as the H8K1, Navy Type 2 Flying Boat, Model 11, of which 14 would be built. The improved H8K2 variant soon appeared, and its extremely heavy defensive armament earned it deep respect among Allied aircrews. The H8K2 was an upgrade over the H8K1, having more powerful engines, slightly revised armament, and an increase in fuel capacity. This was to be the definitive variant, with 112 produced. 36 examples of a dedicated transport version, the H8K2-L, were also built, capable of carrying 62 troops. This aircraft was also known as Seiku ("Clear Sky"). The side defensive blisters, ventral defensive hatch, and dorsal turret were discarded. To increase the available space within the aircraft, its hull tanks were removed, thus reducing its range. Fig Kawanishi H8K2 at Kanoya museum, Japan. The H8K entered production in 1941 and first saw operational use on the night of 4 March 1942 in a second raid on Pearl Harbor. Since the target lay out of range for the flying boats, this audacious plan involved a refuelling by submarine at French Frigate Shoals, some 550 miles north-west of Hawaii, en route. Two planes from the Yokohama Kokutai (Naval Air Corps) attempted to bomb Pearl Harbor, but, due to poor visibility, did not accomplish any significant damage. H8K2s were used on a wide range of patrol, reconnaissance, bombing, and transport missions throughout the Pacific war. The H8K2 was given the Allied code name "Emily". Four aircraft survived until the end of the war. One of these, an H8K2, was captured by U.S. forces at the end of the war and was evaluated before being eventually returned to Japan in It was on display at Tokyo's Museum of Maritime Science until 2004, when it was moved to Kanoya Air Base in Kagoshima. The submerged remains of an H8K can be found off the west coast of Saipan, where it is a popular scuba diving attraction known erroneously as the "B-29", or the "Emily". Another wrecked H8K lies in Chuuk Lagoon, Chuuk, in Micronesia. This aircraft is located off the south-western end of Dublon Island. The Mitsubishi F1M (fig. 123), (Allied reporting name "Pete") was a Japanese reconnaissance floatplane of World War II. It was the last biplane type of the Imperial Japanese Navy, with 1,118 built between 1936 and The Navy designation was "Type Zero Observation Seaplane", not to be confused with the Type Zero Carrier Fighter or the Type Zero Reconnaissance Seaplane. The F1M1 was powered by the Nakajima Hikari MK1 radial engine, delivering 611 kw (820 hp), a maximum speed of 368 km/h (230 mph) and operating range of up to 1,072 km (670 mi) (when overloaded). It provided the Imperial Japanese Navy with a very versatile operations platform. Optionally armed with a maximum of three 7.7 mm (.303 in) machine guns (two fixed forward-firing and one flexible rear-firing) and two 60 kg (132 lb) bombs. Fig Mitsubishi F1M2 on patrol, (c. 1943). 160

161 The F1M was originally built as a catapult-launched reconnaissance float plane, specializing in gunnery spotting. However the "Pete" took on a number of local roles including area-defense fighter, convoy escort, bomber, anti-submarine, maritime patrol, rescue and transport. The type fought dogfights in the Aleutians, the Solomons and several other theaters. See also PT 34 sunk 9 April 1942 by "Petes". The Consolidated PBY Catalina (fig. 124) was an American flying boat of the 1930s and 1940s produced by Consolidated Aircraft. It was one of the most widely used multi-role aircraft of World War II. PBYs served with every branch of the United States Armed Forces and in the air forces and navies of many other nations. In the United States Army Air Forces and later in the United States Air Force their designation was the OA-10, while Canadian-built PBYs were known as the Canso. During World War II, PBYs were used in anti-submarine warfare, patrol bombing, convoy escorts, search and rescue missions (especially air-sea rescue), and cargo transport. The PBY was the most successful aircraft of its kind; no other flying boat was produced in greater numbers. The last active military PBYs were not retired from service until the 1980s. Even today, over 70 years after its first flight, the aircraft continues to fly as an airtanker in aerial firefighting operations all over the world. The initialism of "P.B.Y." was determined in accordance with the U.S. Navy aircraft designation system of 1922; PB representing "Patrol Bomber" and Y being the code used for the aircraft's manufacturer, Consolidated Aircraft. Fig PBY-5 landing at Naval Air Station Jacksonville. The PBY was originally designed to be a patrol bomber, an aircraft with a long operational range intended to locate and attack enemy transport ships at sea in order to compromise enemy supply lines. With a mind to a potential conflict in the Pacific Ocean, where troops would require resupply over great distances, the U.S. Navy in the 1930s invested millions of dollars in developing long-range flying boats for this purpose. Flying boats had the advantage of not requiring runways, in effect having the entire ocean available. Several different flying boats were adopted by the Navy, but the PBY was the most widely used and produced. Although slow and ungainly, PBYs distinguished themselves in World War II as exceptionally reliable. Allied armed forces used them successfully in a wide variety of roles that the aircraft was never intended for. They are remembered by many veterans of the war for their role in rescuing downed airmen, in which they saved the lives of thousands of aircrew downed over water. PBY airmen called their aircraft the "cat" on combat missions and "Dumbo" in air-sea rescue service. As American dominance in the Pacific Ocean began to face competition from Japan in the 1930s, the U.S. Navy contracted Consolidated Aircraft and Douglas Aircraft Corporation in October 1933 to build competing prototypes for a patrol flying boat. Naval doctrine of the 1930s and 1940s used flying boats in a wide variety of roles that today are handled by multiple special-purpose aircraft. The U.S. Navy had adopted the Consolidated P2Y and Martin P3M models for this role in 1931, but both aircraft proved to be underpowered and hampered by short ranges and low maximum payloads. Consolidated and Douglas both delivered single prototypes of their designs, the XP3Y-1 and XP3D-1, respectively. Consolidated's XP3Y-1 was an evolution of the XPY-1 design that had originally competed unsuccessfully for the P3M contract two years earlier and of the XP2Y design that the Navy had authorized for a limited production run. Although the Douglas aircraft was a good design, the Navy opted for Consolidated's because the projected cost was only $90,000 per aircraft. Consolidated's XP3Y-1 design (company Model 28) was revolutionary in a number of ways. The aircraft had a parasol wing with internal bracing that allowed the wing to be a virtual cantilever, except for two small streamlined struts on each side. Stabilizing floats, retractable in flight to form streamlined wingtips, were another aerodynamic innovation, a feature licensed from the Saunders-Roe company. The two-step hull design was similar to that of the P2Y, but the Model 28 had a cantilever cruciform tail unit instead of a strut-braced twin tail. Cleaner aerodynamics gave the Model 28 better performance than earlier designs. 161

162 The prototype was powered by two 825 hp (615 kw) Pratt & Whitney R Twin Wasp engines mounted on the wing s leading edges. Armament comprised four 0.30 in (7.62 mm) Browning machine guns and up to 2,000 lb (907 kg) of bombs. The XP3Y-1 had its maiden flight on 28 March 1935, after which it was transferred to the US Navy for service trials. The XP3Y-1 soon proved to have significant performance improvements over current patrol flying boats. The Navy requested further development in order to bring the aircraft into the category of patrol bomber, and in October 1935, the prototype was returned to Consolidated for further work, including installation of 900 hp (671 kw) R engines. For the redesignated XPBY-1, Consolidated introduced redesigned vertical tail surfaces. The XPBY-1 had its maiden flight on 19 May 1936, during which a record non-stop distance flight of 3,443 miles (5,541 km) was achieved. The XPBY-1 was delivered to VP-11F in October The second squadron to be equipped was VP- 12, which received the first of its aircraft in early The second production order was placed on 25 July Over the next three years, the PBY design was gradually developed further and successive models introduced. The Naval Aircraft Factory made significant modifications to the PBY design, many of which would have significantly interrupted deliveries had they been incorporated on the Consolidated production lines. The new aircraft, officially known as the PBN-1 Nomad, had several differences from the basic PBY. The most obvious upgrades were to the bow, which was sharpened and extended by two feet, and to the tail, which was enlarged and featured a new shape. Other improvements included larger fuel tanks, increasing range by 50%, and stronger wings permitting a 2,000 pound (908 kg) higher gross takeoff weight. An auxiliary power unit was installed, along with a modernized electrical system, and the weapons were upgraded with continuous-feed mechanisms. A total of 138 of the 156 PBN-1s that were produced served with the Soviet Navy. The remaining 18 of them were assigned to training units at NAS Whidbey Island and the Naval Air Facility in Newport, Rhode Island. Later, improvements found in the PBN-1 notably, the larger tail were incorporated into the amphibious PBY-6A. The final PBY construction figure is estimated at around 4,000 aircraft, and these were deployed in practically all of the operational theatres of World War II. The PBY served with distinction and played a prominent and invaluable role in the war against the Japanese. This was especially true during the first year of the war in the Pacific, because the PBY and the Boeing B-17 Flying Fortress were the only two available aircraft with the range necessary. As a result, they were used in almost every possible military role until a new generation of aircraft became available. A Catalina of No. 205 Squadron RAF was also involved in a dogfight with a Mitsubishi G3M Nell bomber of Mihoro Air Group near the Anambas Islands on 25 December 1941, in which the Catalina was shot down. PBYs were the most extensively used ASW aircraft in both the Atlantic and Pacific Theaters of the Second World War, and were also used in the Indian Ocean, flying from the Seychelles and from Ceylon. Their duties included escorting convoys to Murmansk. By 1943, U-boats were well-armed with anti-aircraft guns and two Victoria Crosses were won by Catalina pilots pressing home their attacks on U-boats in the face of heavy fire: John Cruickshank of the RAF, in 1944, against the U-347 and in the same year Flight Lt. David Hornell of the RCAF (posthumously) against the U Catalinas destroyed 40 U-boats in all, but they suffered losses of their own. One of the Brazilian-operated Catalinas attacked and sank the U-199 in Brazilian territorial waters on 31 July Later, the aircraft was baptized as Arará, in honor of a merchant ship that carried that name and was previously attacked and sunk by another U-boat, the U-507. In their role as patrol aircraft, Catalinas participated in some of the most notable engagements of World War II. The aircraft's parasol wing and large waist blisters allowed for a great deal of visibility and combined with its long range and endurance, made it well suited for the task. A Coastal Command Catalina located the German battleship Bismarck on 26 May 1941 while she tried to evade Royal Navy forces. A flight of Catalinas spotted the Japanese fleet approaching Midway Island, beginning the Battle of Midway. A RCAF Canso flown by Squadron Leader L.J. Birchall foiled Japanese plans to destroy the Royal Navy's Indian Ocean fleet on 4 April 1942 when it detected the Japanese carrier fleet approaching Ceylon (Sri Lanka). 162

163 Several squadrons of PBY-5As and -6As in the Pacific theater were specially modified to operate as night convoy raiders. Outfitted with state-of-the-art magnetic anomaly detection gear and painted flat black, these "Black Cats" attacked Japanese supply convoys at night. Catalinas were surprisingly successful in this highly unorthodox role. Between August 1943 and January 1944, Black Cat squadrons had sunk 112,700 tons of merchant shipping, damaged 47,000 tons, and damaged 10 Japanese warships. The Royal Australian Air Force (RAAF) also operated Catalinas as night raiders, with four squadrons Nos. 11, 20, 42, and 43 mounting mine-laying operations from 23 April 1943 until July 1945 in the southwest Pacific deep into Japanese-held waters, that bottled up ports and shipping routes and kept ships in the deeper waters to become targets for US submarines; they tied up the major strategic ports such as Balikpapan that shipped 80% of Japanese oil supplies. In late 1944, their precision mining sometimes exceeded 20 hours in duration from as low as 200 feet in the hours of darkness. One included the bottling up the Japanese fleet in Manila Bay planned to assist General MacArthur's landing at Mindoro in the Philippines. They also operated out of Jinamoc in Leyte Gulf, and mined ports on the Chinese coast from Hong Kong as far north as Wenchow. They were the only non-american heavy bombers squadrons operating north of Morotai in The RAAF Catalinas regularly mounted nuisance night bombing raids on Japanese bases, they earned the motto of "The First and the Furthest" as a testimony to their design and endurance. These raids included the major base at Rabaul. RAAF aircrews, like their US Navy counterparts, developed 'terror bombs', ranging from mere machine gunned scrap metal and rocks to empty beer bottles with razor blades inserted into the necks, to produce high pitched screams as they fell, keeping Japanese soldiers awake and scrambling for cover. PBYs were employed by every branch of the US military as rescue aircraft. A PBY piloted by Lt. Cmdr. Adrian Marks (USN) rescued 56 sailors from the USS Indianapolis after the ship was sunk during World War II. PBYs continued to function in this capacity for decades after the end of the war. PBYs were also used for commercial air travel. The longest commercial flights (in terms of time aloft) ever made in aviation history were the Qantas flights flown weekly from 29 June 1943 through July 1945 over the Indian Ocean. Qantas offered non-stop service between Perth and Colombo, a distance of 3,592 nm (5,652 km). As the PBY typically cruised at 110 knots, this took from hours and was called the "flight of the double sunrise", since the passengers saw two sunrises during their non-stop journey. The flight was made with radio silence (because of the possibility of Japanese attack) and had a maximum payload of 1000 lbs or three passengers plus 65 kg of armed forces and diplomatic mail. An Australian PBY made the first trans-pacific flight across the South Pacific between Australia and Chile in 1946, making numerous stops at islands along the way for refueling, meals, and overnight sleep of its crew. With the end of the war, all of the flying boat versions of the Catalina were quickly retired from the U.S. Navy, but the amphibious ones remained in service for some years. The last Catalina in U.S. service was a PBY- 6A operating with a Naval Reserve squadron, which was retired from use on 3 January The PBY subsequently equipped the world's smaller armed services, in fairly substantial numbers, into the late 1960s. The U.S. Air Force's Strategic Air Command had PBYs (designated OA-10s) in service as scouting aircraft from 1946 through The Brazilian Air Force flew Catalinas in naval air patrol missions against German submarines starting in The flying boats also carried out air mail deliveries. In 1948, a transport squadron was formed and equipped with PBY-5As converted to the role of amphibious transports. The 1st Air Transport Squadron (ETA- 1) was based in the port city of Belem and flew Catalinas and C-47s in well-maintained condition until Catalinas were convenient for supplying military detachments scattered among the Amazon waterways. They reached places where only long-range transport helicopters would dare to go. ETA-1 insignia was a winged turtle with the motto "Though slowly, I always get there". Today, the last Brazilian Catalina (a former RCAF one) is displayed at the Airspace Museum (MUSAL), in Rio de Janeiro. Jacques-Yves Cousteau Jacques-Yves Cousteau used a PBY-6A (N101CS) as part of his diving expeditions. His second son, Philippe, was killed while attempting a water landing in the Tagus river near Lisbon, Portugal, 28 June His PBY had just been repaired when he took it out for a flight. As he landed, one of the aircraft's propellers separated, cut through the cockpit and killed the younger Cousteau. 163

164 Paul Mantz converted an unknown number of surplus PBYs to flying yachts at his Orange County California hangar in the late 40's/early50's. Chilean navy captain Roberto Parragué in his PBY Catalina "Manu-Tara" undertook the first flight between Easter Island and the continent (from Chile) and the first flight to Tahiti; making him a national hero of France as well of Chile. The flight wasn't authorized by authorities. Of the few dozen remaining airworthy Catalinas, the majority of them are in use today as aerial firefighting planes. China Airlines, the official airline of the Republic of China (Taiwan) was founded with two PBY amphibious flying boats. The Catalina Affair is the name given to a Cold War incident in which a Swedish Air Force PBY Catalina was shot down by Soviet fighters over the Baltic Sea in June 1952 while investigating the disappearance of a Swedish Douglas DC-3 (later found out to be shot down by a Soviet fighter while on a SIGINT mission; found 2003 and raised ). The PB2Y Coronado (fig. 125) was a large flying boat patrol bomber designed by Consolidated Aircraft. As of 2005, one Coronado remains at the Pensacola, Florida National Museum of Naval Aviation. After deliveries of the PBY Catalina, also a Consolidated aircraft, began in 1935, the United States Navy began planning for the next generation of patrol bombers. Orders for two prototypes, the XPB2Y-1 and the Sikorsky XPBS-1, were placed in 1936; the prototype Coronado first flew in December After trials with the XPB2Y-1 prototype revealed some stability issues, the design was finalized as the PB2Y-2, with a large cantilever wing, twin tail, and four Pratt & Whitney R-1830 radial engines. The two inner engines were fitted with four-bladed reversible pitch propellers; the outer engines had standard three-bladed feathering props. (However, note the three-bladed prop on the inner engine in the picture at the left.) Like the PBY Catalina before it, the PB2Y's wingtip floats retracted to reduce drag and increase range, with the floats' buoyant hulls acting as the wingtips when retracted. Development continued throughout the war. The PB2Y-3, featuring self-sealing fuel tanks and additional armor, entered service just after the attack on Pearl Harbor and formed most of the early-war Coronado fleet. The prototype XPB2Y-4 was powered by four Wright R-2600 radials and offered improved performance, but the increases were not enough to justify a full fleet update. However, most PB2Y-3 models were converted to the PB2Y-5 standard, with the R-1830 engines replaced with single-stage R models. As most existing PB2Y-3s were used as transports, flying low to avoid combat, removing the excess weight of unneeded superchargers allowed an increased payload without harming low-altitude performance. Fig An early PB2Y-2 in flight. Coronados served in combat in the Pacific, in both bombing and anti-submarine roles, but transport and hospital aircraft were the most common. The British Royal Air Force Coastal Command had hoped to use the Coronado as a maritime patrol bomber, as it already used the PBY Catalina. However, the range of the Coronado (1,070 miles) compared poorly with the Catalina (2,520 mi), and the Short Sunderland (1,780 mi). Consequently, the Coronados supplied to the RAF under Lend-Lease were outfitted purely as transports, serving with RAF Transport Command. The 10 aircraft were used for trans-atlantic flights, staging through the RAF base at Darrell's Island, Bermuda, and Puerto Rico, though the aircraft were used to deliver vital cargo and equipment in a transportation network that stretched down both sides of the Atlantic, from Newfoundland, to Brazil, and to Nigeria, and other parts of Africa. After the war ended 5 of the RAF aircraft were scrapped, one was already lost in collision with a Martin Mariner and the last four were scuttled off the coast of Bermuda in Coronados served as a major component in the Naval Air Transport Service (NATS) during World War II in the Pacific theater. Most had originally been acquired as combat patrol aircraft, but the limitations noted 164

165 above quickly relegated them to transport service in the American naval air fleet also. By the end of World War II the Coronado was outmoded as both a bomber and a transport, and virtually all of them were quickly scrapped, being melted down to aluminum ingots and sold as metal scrap. The Martin PBM Mariner (fig. 126) was a patrol bomber flying boat of World War II and the early Cold War period. It was designed to complement the PBY Catalina in service. 1,366 were built, with the first example flying on February 18, 1939 and the type entering service in September In 1937, the Glenn L. Martin Company designed a new twin engined flying boat to succeed its earlier Martin P3M and supplement the Consolidated PBY, the Model 162. It received an order for a single prototype XPBM-1 on 30 June This was followed by an initial production order for 21 PBM-1 aircraft on 28 December To test the PBM's layout, Martin built a ⅜ scale flying model, the Martin 162A Tadpole Clipper with a crew of one and powered by a single 120 hp (90 kw) Chevrolet engine, this flying in December The first genuine PBM, the XPBM-1, flew on 18 February The aircraft was fitted with five gun turrets and bomb bays that were in the engine nacelles. The gull wing was of cantilever design, and featured clean aerodynamics with an unbraced twin tail. The PBM-1 was equipped with retractable wing landing floats that were hinged inboard, like the Catalina. The PBM-3 had fixed floats, and the fuselage was three feet longer than that of the PBM-1. Fig An Australian Mariner in The first PBM-1s entered service with Patrol Squadron FIFTY-FIVE (VP-55) of the United States Navy on 1 September Prior to the outbreak of World War II, PBMs were used (together with PBYs) to carry out Neutrality Patrols in the Atlantic, including operations from Iceland. Following the Japanese Attack on Pearl Harbor, PBMs were used on anti-submarine patrols, sinking their first German U-Boat, U-158 on 30 June In total, PBMs were responsible, wholly or in part, for sinking 10 U-Boats during World War II. PBMs were also heavily used in the Pacific, operating from bases at Saipan, Okinawa, Iwo Jima and the South-West Pacific. The United States Coast Guard acquired 27 Martin PBM-3 aircraft during the first half of In late 1944, the service acquired 41 PBM-5 models and more were delivered in the latter half of Ten were still in service in 1955, although all were gone from the active Coast Guard inventory by 1958 when the last example was released from CGAS San Diego and returned to the US Navy. These flying boats became the backbone of the long-range aerial search and rescue efforts of the Coast Guard in the early post-war years until supplanted by the P5M and the HU-16 Albatross in the mid-1950s. PBMs continued in service with the US Navy following the end of World War II, flying long patrol missions during the Korean War. It continued in front-line use until replaced by its direct development, the P5M Marlin, with the last USN squadron equipped with the PBM, Patrol Squadron FIFTY (VP-50), retiring them in July The British Royal Air Force acquired 32 Mariners, but they were not used operationally, with some returned to the United States Navy. A further twelve PBM-3Rs were transferred to the Royal Australian Air Force for transporting troops and cargo. The Royal Netherlands Navy acquired 17 PBM-5A Mariners at the end of 1955 for service in Netherlands New Guinea. The PBM-5A was an amphibian plane with retractable landing gear. The engines were 2,100 hp (1,566 kw) Pratt & Whitney R After a series of crashes, the Dutch withdrew their remaining aircraft from use in December

166 The Short S.25 Sunderland (fig. 127) was a British flying boat patrol bomber developed for the Royal Air Force by Short Brothers. Based in part upon the S.23 Empire flying boat, the flagship of Imperial Airways, the S.25 was extensively re-engineered for military service. It was one of the most powerful and widely used flying boats throughout the Second World War, and was involved in countering the threat posed by German U- boats in the Battle of the Atlantic. It took its name from the town (latterly, city) of Sunderland in northeast England. The early 1930s saw intense competition in developing long-range flying boats for intercontinental passenger service, but the United Kingdom had no match for the new American Sikorsky S-42 flying boats, which were making headlines all over the world. Then, in 1934, the British Postmaster General declared that all first-class Royal Mail sent overseas was to travel by air, effectively establishing a subsidy for the development of intercontinental air transport in a fashion similar to the U.S. domestic program a decade earlier. In response, Imperial Airways announced a competition between aircraft manufacturers to design and produce 28 flying boats, each weighing 18 tons (18.2 tonnes) and having a range of 700 miles (1,100 km) with capacity for 24 passengers. The contract went almost directly to Short Brothers of Rochester. Although Short had long built flying boats for the military and for Imperial Airways, none of them was in the class of size and sophistication requested, but the business opportunity was too great to pass up. Oswald Short, head of the company, began a fast-track program to come up with a design for a flying boat far beyond anything they had ever built. While the first S.23 was under development, which would later be a success in its own right, the British Air Ministry was taking actions that would result in a purely military version of the Short flying boats. The 1933 Air Ministry Specification R.2/33 called for a next-generation flying boat for ocean reconnaissance. The new aircraft had to have four engines but could be either a monoplane or biplane design. The R.2/33 specification was released roughly in parallel with the Imperial Airways requirement, and while Shorts continued to develop the S.23, they also worked on a response to the Air Ministry's need at a lower priority. Chief Designer Arthur Gouge originally intended that a 37 mm COW gun be mounted in the bow with a single Lewis gun in the tail. As with the S.23, he tried to make the drag as low as possible, while the nose was much longer than that of the S.23. The military flying boat variant was designated S.25 and the design was submitted to the Air Ministry in Saunders-Roe also designed a flying boat, the Saro A.33, in response to the R.2/33 competition, and prototypes of both the S.25 and A.33 were ordered by the Ministry for evaluation. The initial S.25 prototype first took flight in October Fig A Sunderland Mk V. The bulges under the outer wings are the ASV6 radar antenna. The S.25 shared much in common with the S.23 but was most notably different in that it had a deeper hull profile. As construction proceeded the armament was changed to a single Vickers K machine gun in the nose turret and four Browning machine guns in the tail. Then there was a change in the tail turret to a powered version and Gouge had to devise a solution for the resulting movement aft of the aircraft's centre of gravity. The prototype first flew, without armament, on 16 October After the preliminary flight trials the prototype (K4774) had its wings swept back by 4 15' by adding a spacer into the front spar attachments. This moved the centre of lift enough to compensate for the changed centre of gravity. This arrangement flew on 7 March 1938 with Bristol Pegasus XXII engines of 1,010 hp (750 kw). As with the S.23, the Sunderland's fuselage contained two decks with six bunks on the lower one, a galley with a twin kerosene pressure stove, a yacht-style porcelain flush toilet, an anchoring winch, and a small machine shop for inflight repairs. The crew was originally intended to be seven but increased in later versions to 11 crew members or more. It was of all-metal, mainly flush-riveted construction except for the control surfaces, which were of fabric-covered metal frame construction. The flaps were Gouge-patented devices that moved rearwards and down, increasing the wing area and adding 30% more lift for landing. 166

167 The thick wings carried the four nacelle-mounted Pegasus engines and accommodated six drum fuel tanks with a total capacity of 9,200 litres (2,025 Imperial gallons, 2,430 U.S. gallons). Four smaller fuel tanks were added later behind the rear wing spar to give a total fuel capacity of 11,602 litres (2,550 Imperial gallons, 3,037 U.S. gallons), enough for eight- to 14-hour patrols. The specification called for an offensive armament of a 37 mm gun and up to 2,000 pounds (910 kg) of bombs, mines or (eventually) depth charges. The ordnance was stored inside the fuselage and was winched up to racks, under the wing centre section, that could be traversed out through doors on each side of the (bomb room) fuselage above the waterline to their release position. Defensive armament included a Nash & Thomson FN-13 powered turret with four.303 British Browning machine guns in the extreme tail and a manually operated.303 on either side of the fuselage, firing from ports just below and behind the wings. These were later upgraded to 0.5-inch calibre Brownings. There were two different nose turret weapons, the most common, later, being two Browning machine guns. The nose weapons were later augmented by four fixed guns, two each side, in the forward fuselage that were fired by the pilot. Much later a twin-gun turret was to be dorsal-mounted on the upper fuselage, about level with the wing trailing edge, bringing the total defensive armament from three to 16 machine guns. Portable beaching gear could be attached by ground crew so that the aircraft could be pulled up on land. The gear consisted of two 2-wheeled struts that could be attached to either side of the fuselage, below the wing, with a two- or four-wheel trolley and towbar attached under the rear of the hull. As with all water-based aircraft, there was a need to be able to navigate on water and to control the craft up to and at a mooring. In addition to the standard navigation lights, there was also a demountable mooring mast that was positioned on the upper fuselage just aft of the astrodome hatch with a 360-degree white light to show that the aircraft was moored. The crew were trained in common marine signals for watercraft to ensure safety in busy waters. References in this section. The craft could be moored to a buoy by a pendant that attached to the keel under the forward fuselage. When the craft was off the buoy, the forward end of the pendant was attached to the front of the hull just below the bomb aimer's window. For anchoring, there was a demountable bollard that fixed to the forward fuselage from where the front turret was retracted to allow an airman to man the position and pick up the buoy cage or to toss out the anchor. A standard stocked anchor was stowed in the forward compartment alongside the anchor winch. Depending on the operating area, a number of different kinds of anchor could be carried to cope with different anchorages. For taxiing after landing, the galley hatches were used to extend sea drogues that could be used to turn the aircraft or maintain its crosswind progress (by deploying the drogue on one side only), or to slow forward motion as much as possible (both deployed). When not in use, the drogues were hand hauled back inboard, folded, and stowed in wall-mounted containers just below the hatches. Operation of the drogues could be a very dangerous exercise if the aircraft was travelling on the water at speed or in strong currents, because the approximately three-foot (1 m) -diameter drogue would haul up on its five-tonne attachment cable end inside the galley very sharply and powerfully. Once deployed, it was normally impossible to recover a drogue unless the aircraft was stationary relative to the local tidal flow. Another means of direction control on the water was by application of the rudder and aileron flight controls. The ailerons would cause asymmetric lift from the airflow and, ultimately, drop a float into the water to cause drag on that wing. The pilots could vary engine power to control the direction and speed of the aircraft on the water. In adverse combinations of tide, wind, and destination, this could be very difficult. The Sunderland was usually entered through the bow compartment door on the left forward side of the aircraft. The internal compartments bow, gun room, ward room, galley, bomb room, and the after compartments were fitted with swash doors to keep them watertight to about two feet (610 mm) above normal water level. These doors were normally kept closed. There was another external door in the tail compartment on the right side. This door was intended for boarding from a Braby (U-shaped) pontoon that was used where there was a full passenger service mooring alongside a wharf or similar. This door could also be used to accept passengers or stretcher-bound patients when the aircraft was in the open water. This was because the engines had to be kept running to maintain the aircraft's position for the approaching vessel and the front door was too close to the left inboard propeller. Normal access to the external upper parts of the aircraft was through the astrodome hatch at the front of the front spar of the wing centre section, just at the rear of the navigator's station. 167

168 Bombs were loaded in through the "bomb doors" that formed the upper half walls of the bomb room on both sides. The bomb racks were able to run in and out from the bomb room on tracks in the underside of the wing. To load them, weapons were hoisted up to the extended racks that were run inboard and either lowered to stowages on the floor or prepared for use on the retracted racks above the stowed items. The doors were spring-loaded to pop inwards from their frames and would fall under gravity so that the racks could run out through the space left in the top of the compartment. The doors could be released locally or remotely from the pilot's position during a bomb run. Normally the weapons were either bombs or depth charges and the racks were limited to a maximum of 1,000 lb (450 kg) each. After the first salvo was dropped, the crew had to get the next eight weapons loaded before the pilot had the aircraft positioned on the next bombing run. The fixed nose guns (introduced by the Australians) were demounted when the aircraft was on the water and stowed in the gun room just aft of the bow compartment. The toilet was in the right half of this same compartment and stairs from the cockpit to the bow area divided the two. Maintenance was performed on the engines by opening panels in the leading edge of the wing either side of the powerplant. A plank could be fitted across the front of the engine on the extensions of the open panels. A small manually-started auxiliary petrol engine, which was fitted into the leading edge of the right wing, powered a bilge and a fuel pump for clearing water and other fluids from the fuselage bilges and for refuelling. Generally, the aircraft were reasonably water tight, and two people on a wobble pump could transfer fuel faster than the auxiliary pump. In sheltered moorings or at sea, fuelling was accomplished by a powered or unpowered barge and with engine driven or hand powered pumps. At regular moorings, there would be specially designed refuelling barges to do the job, normally manned by trained marine crew. These vessels could refuel many aircraft during the course of the day. Handling of the fuel nozzles and opening/closing the aircraft fuel tanks would normally be an aircraftman's task. Where there were unreliable fuel supplies, usually at outlying moorings away from any fixed base, it might take a crew of four 3 4 hours to transfer 2,000 gallons (9,092 litres) of fuel into the aircraft. If the barge had a capacity of only about 800 gallons (as was usual), it could take three times that long. Oil supplies and minor spares were carried in the aircraft at such outlying bases if the crew were operating autonomously. In serious cases, where refuelling from drums or when the supplies were otherwise in doubt, aircraft were refuelled through Chamois leather filters to separate the dirt, rust, and water from the fuel. Airframe repairs were either effected from the inside or delayed until the aircraft was in a sheltered mooring or beached. One of the serious problems was that the heat-treated rivets in the hull plates were susceptible to corrosion after a period in salt water (depending on the quality of the heat treatment process). The heads would pop off from stress corrosion, and leaks would start into the bilges. The only resort was to haul the aircraft out onto the hard and replace them, usually at the cost of many additional heads coming off because of the riveting vibrations. Most maintenance and servicing personnel had tools modified to attach them to their person because dropping a tool normally meant it was gone forever. Glooped was the explanation for the loss, being the sound of the tool entering the water. The beaching gear was large and unwieldy. The main legs had to be ballasted to sink, wheels down, so that the leg could be raised upright into its housing under the wing centre section, and then the lower part was pressed against the fuselage wall where it was pinned. This usually meant that two people would get completely wet. The tail trolley was also ballasted to sink under the aft fuselage where the seagoing section of the hull ended. The upper arms of the trolley were raised to locate in mating holes in the exterior skin of the hull where the main weight of the aircraft would ultimately keep it in place; but until then it was precariously unstable. Meanwhile a rope from the shore to the header buoy at the nose of the aircraft was threaded through the pulley on the buoy and attached to the aircraft's bollard. The shore end of this rope was managed by a person positioned at an electric capstan that would control the release of the aircraft from the buoy. A short rope connected the tail towing eye in the fuselage to another hauling device, most often a tractor, that was able to manoeuvre the aircraft on the slipway and on the hardstanding beyond. When all was ready, the bowman cast off from the buoy pendant. The tail was pulled carefully to the slipway and the header buoy rope was paid out from the capstan off to the side. The idea was that the tail trolley should be brought into contact with the submerged section of the slipway as gently as possible, ensuring that the aircraft remained securely in place on the trolley as it started rolling up the slip. A sharp impact on the trolley wheels, located approximately five ft (1.6 m) below the keel, was enough to rotate the trolley around its fuselage attachment arms and dislodge it, allowing the keel to strike the slip and thereby sustain damage. 168

169 When tidal flow or wind adversely affected the positioning of the aircraft, a situation could arise where the tail and attachments were running true, but the nose of the aircraft had now swung to one extreme of the slipway, preventing the main wheels on one side from correctly contacting the slip. Consequently, it is not surprising that Sunderlands were not beached for minor reasons. Once the tail trolley was well up the slipway, a steering arm could be inserted into the lower part of the trolley and used to turn the wheels so that the assemblage could be guided to follow the tractor. Movement in the opposite direction was effected by a bridle attached to the front of the lower part of the main legs. On the slipway, the tail towing eye was used to restrain the aircraft from running away down the slope. A large float mounted under each wing stopped the aircraft from toppling over on the water. With no wind, the float on the heavier side was always in the water; with some wind, the aircraft could be held using the ailerons with both floats out of the water. If a float was lost as the craft lost airspeed after landing, crew members would go out onto the opposite wing to keep the remaining float in the water until the aircraft could reach its mooring. Aircraft with lower hull damage were patched or had the holes filled with any materials to hand before landing. The aircraft would then be immediately put onto a slipway with its wheeled beaching gear or beached on a sandy shore before it could sink. More than two fuselage compartments had to be full of water to sink the aircraft. During the Second World War, a number of severely damaged aircraft were deliberately landed on grass airfields ashore. In at least one case, an aircraft that made a grass landing was repaired to fly again. Marine growths on the hull were a problem; the resulting drag could be enough to prevent a fullyloaded aircraft from gaining enough speed to become airborne. The aircraft could be taken to a freshwater mooring for sufficient time to kill off the fauna and flora growing on the bottom, which would then be washed away during takeoff runs. The alternative was to scrub it off, either in the water or on the hard. The takeoff run of a flying boat was often dependent only on the length of water that was available. The first problem was to gain sufficient speed for the craft to plane, otherwise there would never be enough speed to become airborne. Once planing, the next problem was to break free from the suction (from Bernoulli's principle) of the water on the hull. This was partly helped by the "step" in the hull just behind the craft's centre of buoyancy at planing speed. The pilot could rock the ship about this point to try to break the downward pull of the water on the surface of the hull. Somewhat rough water was a help in freeing the hull from the water, but on calm days it was often necessary to have a high speed launch cross in front of the aircraft to cause a break in the water flow under the aircraft. It was a matter of judgement of the coxswain to get the crossing close enough but not too close. Because it was expected that some takeoffs would be protracted affairs, often the crews were not very careful to keep within maximum all-up weight limitations, and getting airborne just took a little longer. In such cases, the flight engineer would ignore the rising cylinder head temperatures and maintain the use of takeoff power for more than five minutes at a time. On Mk V aircraft, fuel could be dumped from retractable pipes that extended from the hull and were attached the bomb room side of the galley aft bulkhead. It was expected that dumping would be done while airborne, but it could also be done on the water, with care to ensure that the floating fuel went downwind away from the aircraft. During the Second World War, although British anti-submarine efforts were disorganized and ineffectual at first, Sunderlands quickly proved useful in the rescue of the crews from torpedoed ships. On 21 September 1939, two Sunderlands rescued the entire 34-man crew of the torpedoed merchantman Kensington Court from the North Sea. As British anti-submarine measures improved, the Sunderland began to show its claws as well. A Royal Australian Air Force (RAAF) Sunderland (of No. 10 Squadron) made the type's first unassisted kill of a U-boat on 17 July As aircrew honed their combat skills, the Sunderland Mark I received various improvements. The nose turret was upgraded with a second.303 (7.7 mm) gun. New propellers together with pneumatic rubber wing deicing boots were also fitted. Although the.303 guns lacked range and hitting power, the Sunderland had a fair number of them and it was a well-built machine that was hard to destroy. On 3 April 1940, a Sunderland operating off Norway was attacked by six German Junkers Ju 88 medium bombers. It shot one down, damaged another enough to send it off to a forced landing and drove off the rest. The Germans are reported to have nicknamed the Sunderland the Fliegendes Stachelschwein ("Flying Porcupine") due to its defensive firepower. Sunderlands also proved themselves in the Mediterranean theatre. They performed valiantly in evacuations during the German seizure of Crete, carrying a surprising number of passengers. One flew the 169

170 reconnaissance mission to observe the Italian fleet at anchor in Taranto before the famous Royal Navy Fleet Air Arm's torpedo attack on 11 November New weapons made the flying boats more deadly in combat. In 1939, one 100 lb anti-submarine bomb hit HMS Snapper merely breaking its light bulbs whilst other bombs had reportedly bounced up and hit their launch aircraft. In early 1943, these ineffective weapons were replaced by Torpex-filled depth charges that would sink to a determined depth and then explode. This eliminated the problem of bounce back and the shock wave propagating through the water augmented the explosive effect. While the bright Leigh searchlight was rarely fitted to Sunderlands, ASV Mark II radar enabled the flying boats to attack U-boats on the surface. In response, the German submarines began to carry a radar warning system known as "Metox", also known as the "Cross of Biscay" due to the appearance of its receiving antenna, that was tuned to the ASV frequency and gave the submarines early warning that an aircraft was in the area. Kills fell off drastically until ASV Mark III radar was introduced in early 1943, which operated in the centimetric band and used antennae mounted in blisters under the wings outboard of the floats, instead of the cluttered stickleback aerials. Sunderland Mark IIIs fitted with ASV Mark III were called Sunderland Mark IIIAs. Centimetric radar was invisible to Metox and baffled the Germans at first. Admiral Karl Dönitz, commander of the German U-boat force, suspected that the British were being informed of submarine movements by spies. In August 1943, a captured RAF airman misled the Germans by telling them that the aircraft were homing in on the signals radiated by the Metox, and consequently U-boat commanders were instructed to turn them off. In any case, the Germans responded by fitting U-boats with one or two 37 mm and twin quad 20 mm flak guns to shoot it out with the attackers. While Sunderlands could suppress flak to an extent by hosing the U- boat with their nose turret guns, the U-boats had the edge by far in range and hitting power. To help improve the odds, the Australians first fitted their aircraft in the field with an additional four.303s in fixed mounts in the nose, allowing the pilot to add fire while diving on the submarine before bomb release. Most aircraft were similarly modified. The addition of single.50 inch (12.7 mm) flexibly mounted M2 Browning machine guns in the (previously emptied) beam hatches behind and above the wing trailing edge also became common. The rifle calibre.303 guns lacked hitting power but the Sunderland retained its reputation for being able to take care of itself. This reputation was enhanced by an air battle between eight Junkers Ju 88C long range heavy fighters and a single RAAF Sunderland Mark III of No. 461 Squadron RAAF on 2 June This was one of several stories of the type's operations related by author Ivan Southall, who flew in Sunderlands during the war. There were 11 crewmen on board the Sunderland; nine Australians and two British. The aircraft was on an anti-submarine patrol and also searching for remains of BOAC Flight 777, an airliner that had left Lisbon the day before and had subsequently been shot down over the Bay of Biscay, killing actor Leslie Howard. In the late afternoon, one of the crew spotted the eight Ju 88s. Bombs and depth charges were dumped and the engines "redlined". Two Ju 88s made passes at the flying boat, one from each side, scoring hits and disabling one engine while the Sunderland went through wild "corkscrew" evasive manoeuvres. On the third pass, the dorsal turret gunner shot one down. Another Ju 88 disabled the tail turret, but the next one that made a pass was hit by both the dorsal and nose turrets and shot down. Another destroyed the Sunderland's radio gear, wounding most of the crew to varying degrees and mortally wounding one of the side gunners. A Ju 88 tried to attack from the rear, but the tail turret gunner had regained some control over the turret and shot it down. The surviving Ju 88s continued to attack, but the nose gunner damaged one of these, setting its engines on fire. Two more of the attackers were also hit and the final pair disengaged and departed, the only two to make it back to base. The Sunderland had been heavily damaged. The crew threw everything they could overboard and nursed the aircraft back to the Cornish coast, where pilot Colin Walker managed to land and beach it at Praa Sands. The crew waded ashore, carrying their dead comrade, while the surf broke the Sunderland up. Walker received the Distinguished Service Order and several of the other crew members also received medals. With the exception of Walker, the crew returned to Sunderlands - they disappeared without trace over the Bay of Biscay two months later after reporting that they were under attack by six Ju 88s. At the end of the Second World War, a number of new Sunderlands built at Belfast were simply taken out to sea and scuttled as there was nothing else to do with them. In Europe it was removed from service relatively quickly but in the Far East, where well developed runways were less common and large land based maritime patrol aircraft like the new Avro Shackleton could not be used so easily, there was still a need for it, and it remained in service with the RAF Far East Air Force at Singapore until 1959, and with the Royal New Zealand Air Force's No. 5 Squadron RNZAF and No. 6 Squadron RNZAF until During the Berlin Airlift (June August 1949) 10 Sunderlands and two Hythes were used to transport goods from Finkenwerder on the Elbe near Hamburg to the isolated city, landing on the Havelsee lake 170

171 beside RAF Gatow until it iced over. This is the only known operational use of flying boats within central Europe. The Sunderlands were particularly used for transporting salt, as their airframes were already protected against corrosion from seawater. Transporting salt in standard aircraft risked rapid and severe structural corrosion in the event of a spillage. When the Havelsee did freeze over the Sunderland's role was taken by freight-converted Handley Page Halifaxes with salt being carried in panniers fitted under the fuselage to avoid the corrosion problem. From mid-1950, RAF Sunderlands also saw service during the Korean War initially with No. 88 Squadron but shortly followed by Nos. 205 and 209 Squadrons. The three squadrons shared the operational task equally with rotational detachments of three or four aircraft and crews based at Iwakuni, Japan. Missions lasting 10 to 13 hours were flown daily throughout the war, and also during the Armistice period that followed, until September The Sunderland also saw service with the Royal New Zealand Air Force until The French Navy Escadrille 7FE, which received Sunderlands when it was formed in 1943 as No. 343 Squadron RAF, continued to operate them until December 1960, the last unit to operate Sunderlands in the Northern Hemisphere. The first S.25, now named the Sunderland Mark I, flew from the River Medway on 16 October 1937 with Shorts' Chief Test Pilot, John Lankester Parker at the controls. The deeper hull and installation of nose and tail turrets gave the Sunderland a considerably different appearance from the Empire flying boats. The prototype was fitted with Bristol Pegasus X engines, each providing 950 hp (709 kw ), as the planned Pegasus XXII engines of 1,010 hp (753 kw) were not available at the time. The 37 mm gun, originally intended as a primary anti-submarine weapon, was dropped from the plans during the prototype phase and replaced with a Nash & Thomson FN-11 nose turret mounting a single.303 inch (7.7 mm) Vickers GO machine gun. The turret could be winched back into the nose, revealing a small "deck" and demountable marine bollard used during mooring manoeuvres on the water. The change of armament in the nose to the much lighter gun moved the centre of gravity rearwards. After the first series of flights the aircraft was returned to the workshop and the wing was swept 4.25 to the rear, thereby moving the centre of pressure into a more reasonable position in relation to the new centre of gravity. This left the engines and wing floats canted out from the aircraft's centreline. Although the wing loading was much higher than that of any previous Royal Air Force flying boat, a new flap system kept the takeoff run to a reasonable length and the aircraft first flew with the new wing sweep and the uprated Pegasus XXII engines on 7 March Official enthusiasm for the type had been so great that in March 1936, well before the first flight of the prototype, the Air Ministry ordered 21 production examples. Meanwhile, delivery of the other contender Saro A.33 was delayed and it did not fly until October The aircraft was written off after it suffered structural failure during high speed taxi trials and no other prototypes were built. The RAF received its first Sunderland Mark I in June 1938 when the second production aircraft (L2159) was flown to 230 Squadron at RAF Seletar, Singapore. By the outbreak of war in Europe, in September 1939, RAF Coastal Command was operating 40 Sunderlands. The main offensive load was up to 2,000 lb (910 kg) of bombs (usually 250 or 500 lb), mines (1,000 lb) or other stores that were hung on traversing racks under the wing centre section (to and from the bomb room in the fuselage). Later, depth charges (usually 250 lb) were added. By late 1940 two Vickers K machine guns had been added to new hatches that were inserted into the upper sides of the fuselage just aft of the wing, with appropriate slipstream deflectors. A second gun was added to the nose turret. New constant speed propellers and deicing boots were installed as well during As the defensive weaponry improved the aircraft became a formidable foe, even though it was far from base, travelled fairly slowly (120 knots and down to about 90 kt for long range cruise) and was usually at low altitude. But a Sunderland off Norway on 3 April 1940 was attacked by six Junkers Ju 88 with the result that one was shot down, one forced to immediately land and the others went home, much wiser. Later, over the Bay of Biscay eight Ju 88 attacked one Sunderland escorting a convoy and three were shot down by the patrol aircraft. 171

172 A Sunderland made the vital reconnaissance of Taranto before the Royal Navy Fleet Air Arm's attack on the Italian navy there on 11 November The aircraft was not a great success at landing and taking off from rough water, but, other than in the open sea, it could be handled onto and off a short chop, by a skilled pilot. Many rescues were made, early in the war, of crews that were in the Channel having abandoned or ditched their aircraft, or abandoned their ship. In May 1941, during the Battle of Crete Sunderlands transported as many as 82 armed men from place to place in one load. Steep ocean swells were never attempted, however a calm ocean could be suitable for landing and takeoff. Beginning in October 1941, Sunderlands were fitted with ASV Mark II "Air to Surface Vessel" radar. This was a primitive low frequency radar system operating at a wavelength of 1.5 m. It used a row of four prominent "stickleback" yagi antennas on top of the rear fuselage, two rows of four smaller aerials on either side of the fuselage beneath the stickleback antennas, and a single receiving aerial mounted under each wing outboard of the float and angled outward. A total of 75 Sunderland Mark I were built: 60 at Shorts' factories at Rochester and Belfast, Northern Ireland, and 15 by Blackburn Aircraft at Dumbarton. The RAF allocated the AP1566 series of air publications to the Sunderland. In August 1941, production moved on to the Sunderland Mark II which used Pegasus XVIII engines with two-speed superchargers, producing 1,065 hp (794 kw) each. The tail turret was changed to an FN.4A turret that retained the four.303 guns of its predecessor but provided twice the ammunition capacity with 1,000 rounds per gun. Late production Mark IIs also had an FN.7 dorsal turret, mounted offset to the right just behind the wings and fitted with twin.303 machine guns. The hand held guns behind the wing were removed in these versions. Only 43 Mark IIs were built, five of these by Blackburn. Production quickly went on in December 1941 to the Sunderland Mark III which featured a revised hull configuration which had been tested on a Mark I the previous June. This modification improved seaworthiness, which had suffered as the weight of the Sunderland increased with new marks and field changes. In earlier Sunderlands, the hull "step" that allows a flying boat to "unstick" from the surface of the sea was an abrupt one, but in the Mk III it was a curve upwards from the forward hull line. The Mark III turned out to be the definitive Sunderland variant, with 461 built. Most were built by Shorts at Rochester and Belfast, a further 35 at a new (but temporary) Shorts plant at White Cross Bay, Lake Windermere; while 170 were built by Blackburn Aircraft. The Sunderland Mark III proved to be one of the RAF Coastal Command's major weapons against the U-boats, along with the Consolidated Catalina. As the U-boats began to use Metox passive receivers the ASV Mk II radar gave away the presence of aircraft and the number of sightings diminished drastically. The RAF response was to upgrade to the ASV Mk III, which operated in the 50 cm band, with antennas that could be faired into fewer more streamlined blisters. During the Mk III's life there were a large number of almost continuous improvements made, including the ASV Mk IIIA and four more machine guns in a fixed position in the wall of the forward fuselage just behind the turret (developed on RAAF aircraft first) with a simple bead and ring sight for the pilot. Despite the 14-hour-long patrols expected of their crews, early Sunderland gunners were provided with only 500 rounds of ammunition each. Later 1,000 round ammunition boxes were installed in the turrets. The beam hatch guns were removed from Mk II aircraft but Mk IIIs and then Mk Is gained much more capable.5 guns, one each side. Offensive weapons loads increased too. The introduction of the hydrostatically fused 250 lb (110 kg) depth charge meant that additional weapons could be carried on the floor of the bomb room in wooden restraints, along with ammunition boxes of 10 and 25 lb anti-personnel bombs that could be hand launched from various hatches to harass U-boat crews otherwise manning the twin 37 and dual quadruple 20 mm cannons that U-boats were fitted with. As radar detection became more effective there were more night patrols to catch U-boats on the surface charging their batteries. Attacking in the dark was a problem that was solved by carrying one inch (25.4 mm), electrically initiated flares and dropping then out of the rear chute of the aircraft as it got close to the surface vessel. Sunderlands never carried Leigh lights, probably because the flares were sufficient. 172

173 By this time the crew workload had increased so much that it needed at least 10 to crew the aircraft. During attacks they were sorely pressed to get all of the necessary work done and crews took many shortcuts that possibly proved fatal in some cases. In early 1944 the ordnance load in the aircraft and the long length of patrols, meaning maximum fuel loads, required that much more powerful engines were needed. It was decided to fit 1,200 hp (890 kw) P&W R B, Twin Wasp, powerplants. These were commonly available and maintenance crews on Catalina, Liberator and Dakota aircraft were familiar with them. This led to the production of the Mk V aircraft. The Sunderland Mark IV was an outgrowth of the 1942 Air Ministry Specification R.8/42, for a generally improved Sunderland with more powerful Bristol Hercules engines, better defensive armament and other enhancements. The new Sunderland was intended for service in the Pacific. Although initially developed and two prototypes built as the "Sunderland Mark IV" it was different enough from the Sunderland line to be given a different name, the S.45 "Seaford". Relative to the Mark III, the Mark IV had a stronger wing, larger tailplanes and a longer fuselage with some changes in hull form for better performance in the water. The armament was heavier with.50 inch (12.7 mm) machine guns and 20 mm Hispano cannon. The changes were so substantial that the new aircraft was redesignated the Short Seaford. Thirty production examples were ordered; the first delivered too late to see combat and only eight production Seafords were completed and never got beyond operational trials with the RAF. The next production version was the Sunderland Mark V, which evolved out of crew concerns over the lack of power of the Pegasus engines. The weight creep (partly due to the addition of radar) that afflicted the Sunderland had resulted in running the Pegasus engines at combat power as a normal procedure and the overburdened engines had to be replaced regularly. Australian Sunderland crews suggested that the Pegasus engines be replaced by Pratt & Whitney R B Twin Wasp engines. The 14-cylinder engines provided 1,200 hp (895 kw) each and were already in use on RAF Consolidated Catalinas and Douglas Dakotas, and so logistics and maintenance were straightforward. Two Mark IIIs were taken off the production lines in early 1944 and fitted with the American engines. Trials were conducted in early 1944 and the conversion proved all that was expected. The new engines with new propellors provided greater performance with no real penalty in range. In particular, a Twin Wasp Sunderland could stay airborne if two engines were knocked out on the same wing while, in similar circumstances, a standard Mark III would steadily lose altitude. Production was switched to the Twin Wasp version and the first Mark V reached operational units in February Defensive armament fits were similar to those of the Mark III, but the Mark V was equipped with new centimetric ASV Mark VI C radar that had been used on some of the last production Mark IIIs as well. A total of 155 Sunderland Mark Vs were built with another 33 Mark IIIs converted to Mark V specification. With the end of the war, large contracts for the Sunderland were cancelled and the last of these flying boats was delivered in June 1946, with a total production of 749 aircraft completed. In late 1942, the British Overseas Airways Corporation (BOAC) obtained six Sunderland Mark IIIs and modified them for service as mail carriers to Nigeria and India, with primitive accommodation for seven passengers. Armament was removed, the gun positions being faired over, and simple seating fitted in place of the bunks. As such they were operated by BOAC and the RAF jointly from Poole to Lagos and Calcutta. Minor modifications to the engine angles and flight angle resulted in a significant increase in the cruise speed, which was a relatively unimportant issue for the combat Sunderlands. In late 1944, the Royal New Zealand Air Force acquired four new Sunderland Mk IIIs already configured for transport duties. In the immediate postwar period, these were used by New Zealand's National Airways Corporation to link South Pacific Islands in the "Coral Route" before TEAL Short Sandringhams took over after BOAC obtained more Mark IIIs and gradually came up with better accommodation for 24 passengers, including sleeping berths for 16. These conversions were given the name Hythe and BOAC operated 29 of them by the end of the war. In February 1946 the first of these, G-AGJM, made a 35,313 mile route survey from Poole to Australia, New 173

174 Zealand, Hong Kong, Shanghai and Tokyo in 206 flying hours. It was the first British civil flying boat to visit China and Japan. A more refined civilian conversion of the Sunderland was completed by the manufacturer as the postwar Short Sandringham. The Sandringham Mk. I used Pegasus engines while the Mk. II used Twin Wasp engines. The Supermarine Sea Otter (fig. 128) was a British amphibian aircraft designed and built by Supermarine. It was a longer-range development of the Walrus and was the last biplane flying boat to be designed by Supermarine. It was also the last biplane to enter service with the Royal Navy and the RAF. Fig Sea Otter I of the Marine Aircraft Experimental Establishment in The main difference between the Walrus and the Sea Otter was in the mounting of the power plant. The Walrus had a rear-facing engine with a pusher propeller. The Sea Otter's engine faced forward with a tractor propeller. There was considerable development of the power plant/propeller combination during the design of the Sea Otter, which at its concept was called the "Stingray". The original test aircraft had a Bristol Perseus XI radial engine with a two-bladed propeller. This gave insufficient thrust so a two-position three blade was tried. This was changed again to a four-bladed type with the pairs of blades set at an angle of 35, instead of the usual 90. The first flight took place on 23 September 1938, but it was not until January 1942 that the Air Ministry placed a production order. Due to cooling troubles found with the Perseus, the power plant was changed for production aircraft to the Bristol Mercury XXX engine driving a three-bladed airscrew. The Sea Otter was used by both the RAF and the Royal Navy for air-sea rescue (ASR) and patrol roles. Post-war, Sea Otters were converted for civilian use. The cabin was soundproofed and fitted with heating. Seating for four passengers, a chemical toilet and a stowage for baggage were provided. As they were intended for use as Bush airplanes in remote areas, versatility was important. To allow cargo to be carried, the cabin floor was strengthened and fitted with lashing points, and the passenger seats made easily removable. Of the 592 aircraft ordered, only 292 were built due to the end of the Second World War. Eight aircraft were bought for the Royal Danish Air Force, and another eight were supplied to the Dutch Naval Air Arm. The colonial service of France purchased six Sea Otters for use in Indo-China. The Supermarine Stranraer (fig. 129) was a 1930s British flying boat designed and built by Supermarine Aviation Works which marked the end of biplane flying-boat development for the Royal Air Force. They entered operations in 1937 and many were still in service at the outbreak of the Second World War undertaking anti-submarine and convoy escort patrols. They were withdrawn from operational service in March 1941 but continued to serve in a training capacity until October Fig The Supermarine Stranraer. Designed by R. J. Mitchell as a tender to Air Ministry R.24/31 Specification for a coastal reconnaissance flying boat for the RAF, it was initially turned down but Supermarine proceeded with the type as a private 174

175 venture first known as the Southampton V. A contract was placed in 1933 for a prototype powered by two 820 hp (611 kw) Bristol Pegasus IIIM and the type became known as the Stranraer. The structure was mainly duralumin, with the hull covered with sheet metal and the wings with fabric. Following the initial flight-test programme, the Stranraer prototype (K3973) on 24 October 1934 was delivered to the RAF. On 29 August 1935, an initial order was placed for 17 aircraft (serial numbers K7287 to K7303) to the Air Ministry Specification 17/35. The production version was fitted with the 920 hp (686 kw) Pegasus X and first flew in December 1936, entering service operations on 16 April 1937; the last Stranraer was delivered 3 April An additional order for six aircraft (K9676 to K9681) was placed in May 1936, but subsequently cancelled. A total of 40 Stranraers were built in Canada by Canadian Vickers Limited; Supermarine and Canadian Vickers being subsidiaries of Vickers-Armstrongs. In service, only 17 Stranraers were operated by the RAF primarily by No. 228, No, 209, No. 240 Squadrons along with limited numbers at the No. 4 OTU. Generally, the aircraft was not well-received as its performance was considered marginal. Due to its less than favourable reception by flight and ground crews, the Stranraer gained a large number of derisive nicknames. It was sometimes referred to as a "whistling shithouse" because the toilet opened out directly to the air and when the seat was lifted, the airflow caused the toilet to whistle. The Stranraer also acquired "Flying Meccano Set," "The Marpole Bridge," "Seymour Seine Net," "Strainer," "Flying Centre Section of the Lion's Gate Bridge" as well as a more genteel variant of its usual nickname, "Whistling Birdcage." Royal Canadian Air Force Stranraers were exact equivalents of their RAF counterparts and while they were employed in coastal patrol against submarine threats in a similar role to the British Stranraers, no enemy action was recorded. The Canadian Vickers-built Stranraers served with the RCAF until examples were sold through Crown Assets (Canadian government) and passed into civilian use after the war, several serving with Queen Charlotte Airlines (QCA) in British Columbia and operated until A re-engine project by the airline substituted 1,000 hp (746 kw) Wright GR-1820-G202GA engines in place of the original Pegasus units. In QCA use, the Stranraer gained a more suitable reputation and was "well liked" by its crews. A total of eight surplus Stranraers were also sold to Aero Transport Ltd. of Tampa, Florida. A single intact Stranraer, 920/CF-BXO, survives in the collection of the Royal Air Force Museum London. This aircraft was built in 1940, one of 40 built by Canadian Vickers. In service with the Royal Canadian Air Force, it flew with several squadrons, on anti-submarine patrols, as a training aircraft and carrying passengers. In 1944, it was disposed of. In civil service, it was flown by Canadian Pacific Airlines until 1947, then Queen Charlotte Airlines, who replaced its original British engines with American Wright R-1820s. Queen Charlotte Airlines flew it on passenger flights until 1952, flying from Vancouver along the Pacific coast of British Columbia. It flew with several other private owners until damaged by a ship in In 1970, it was bought by the RAF Museum and transported to the UK. The parts of a second Stranraer, 915/CF-BYJ are owned by the Shearwater Aviation Museum, Halifax, Canada. This aircraft also operated with Queen Charlotte Airlines until it crashed on Christmas Eve 1949 at Belize Inlet, British Columbia. Most of the aircraft was recovered in the 1980s, with the exception of the forward fuselage and cockpit. The Supermarine Walrus (fig. 130) was a British single-engine amphibious biplane reconnaissance aircraft designed by R. J. Mitchell and operated by the Fleet Air Arm (FAA). It also served with the Royal Air Force (RAF), Royal Australian Air Force (RAAF), Royal Canadian Air Force (RCAF), Royal New Zealand Navy (RNZN) and Royal New Zealand Air Force (RNZAF). Perhaps surprisingly it was the first British squadron-service aircraft to incorporate a fully-retractable main undercarriage, completely enclosed crew accommodation, and having an all-metal fuselage. 175

176 Fig Supermarine Walrus (1935). The Walrus was initially developed for service from cruisers in response to a request from the Royal Australian Air Force (RAAF), and was originally called the Seagull V; although there was little resemblance to the earlier Supermarine Seagull III. It was designed to be launched from ship-borne catapults, and was the first amphibious aircraft in the world to be launched by catapult with a full military load. The lower wings of this biplane were set in the shoulder position with a stabilising float mounted under each one, with its horizontal tail-surfaces being positioned high on the tail-fin. The wings could be folded on ship, giving a stowage width of 17 feet 11 inches (5.46 m). The single Bristol Pegasus VI radial engine was housed in a nacelle slung from the centre section of the upper wing and powered a four-blade propeller in pusher configuration. The propeller consisted of two, two-bladed wooden propellers that were bolted onto the same hub, but offset by 90 degrees. The vortex of air created by the propeller created unequal forces on the rudder, making the aircraft yaw. The engine was offset by three degrees to starboard to counter this. Although the aircraft typically flew with one pilot, there were positions for two. The left-hand position was the main one, with an instrument panel and a fixed seat; while the right-hand, co-pilot's seat could be folded away to allow access to the nose gun-position via a crawl-way. One of the more unusual characteristics of the aircraft was that the control column was not a fixed fitting in the usual way, but could be unplugged from either of two sockets at floor level. It became a habit for only one column to be in use; and when control was passed from the pilot to co-pilot or vice-versa, the control column would simply be unplugged and handed over. Behind the cockpit, there was a small cabin with work stations for a navigator and a radio operator. As the Walrus was stressed to a level suitable for catapult-launching, rather surprisingly for such an ungainly-looking machine, it could be looped and bunted. This was first done by the test pilot Joseph Summers, flying the prototype at the SBAC show at Hendon in June 1933; this feat surprised even R. J. Mitchell, who was amongst the spectators. However, in practice any water in the bilges would make its presence felt when the aircraft was inverted. This usually discouraged the pilot from any future aerobatics on this type. In 1934 an early pre-production Walrus became the first amphibian according to its manufacture to be launched from a land-based catapult. The strength of the aircraft was demonstrated in 1935, when the prototype was attached to the battleship HMS Nelson at Gibraltar. With the naval commander-in-chief on board (Admiral Roger Backhouse) the pilot attempted a water touch-down, but with the undercarriage accidentally lowered. The Walrus was immediately flipped over but the occupants only had minor injuries; the machine was later repaired and returned to flight. Soon afterwards, the Walrus became one of the first aircraft to be fitted with an undercarriage position indicator on the instrument panel. When flying from a warship, the Walrus would be recovered by touching-down alongside, then lifted from the sea by a ship's crane. The aircraft's lifting-gear was kept in a compartment in the section of wing directly above the engine one of the Walrus' crew would climb onto the top wing and attach this to the crane hook. This was a straightforward procedure in calm waters, but could be very difficult if the conditions were rough. One procedure was for the parent ship to slew several degrees just before the aircraft touched down, thus creating an evanescent 'smooth' astern of the ship on which the Walrus could alight, this being followed by a fast taxi up to the ship before the 'smooth' dissipated. Armament usually consisted of two.303 in (7.7 mm) Vickers K machine guns, one in each of the "open" positions in the nose and rear fuselage; with the capability of carrying 760 pounds (340 kg) of bombs or depth charges mounted beneath the lower wings. Like other flying boats, the Walrus carried marine equipment for use on the water, including an anchor, towing and mooring cables, drogues and a boat-hook. The RAAF ordered 24 examples of what was originally Seagull V directly off the drawing boards which were delivered for service from cruisers from 1935; this was followed by orders from the RAF with the first production Walrus, serial number K5772, flying on 16 March It was also hoped to capitalise on the aircraft's successful exports to Japan and Spain among others. 176

177 A total of 740 Walruses were built in three major variants: the Seagull V, Walrus I, and the Walrus II. The Mark IIs were all constructed by Saunders-Roe and the prototype first flew in May This aircraft had a wooden hull, which was heavier but had the advantage of using less of the precious wartime stockpiles of light metal alloys. Saunders-Roe would go on to build under license 270 metal Mark Is and 191 wooden-hulled Mark IIs. The successor to the Walrus was the Supermarine Sea Otter a similar but more powerful design. Sea Otters never completely replaced the Walruses, and served alongside them in the air-sea rescue role during the latter part of the war. A post-war replacement for both aircraft, the Supermarine Seagull, was cancelled in 1952, with only prototypes being constructed. By that time, helicopters were taking over from small flying-boats in the air-sea rescue role. The Walrus was affectionately known as the "Shagbat" or sometimes "Steam-pigeon"; the latter name coming from the steam produced by water striking the hot Pegasus engine. The first Seagull V, A2-1, was handed over to the Royal Australian Air Force in 1935, with the last, A2-24 delivered in The type served aboard HMA Ships Australia, Canberra, Sydney, Perth and Hobart. Walrus deliveries started in 1936 when the first example to be deployed was with the New Zealand division of the Royal Navy, on HMS Achilles one of the Leander class light cruisers that carried one Walrus each. The Royal Navy Town class cruisers carried two Walruses during the early part of the war and Walruses also equipped the York class and County class heavy cruisers. Some battleships, such as HMS Warspite and HMS Rodney carried Walruses, as did the monitor HMS Terror and the seaplane tender HMS Albatros. By the start of World War II the Walrus was in widespread use. Although its principal intended use was gunnery spotting in naval actions, this only occurred twice: Walruses from HMS Renown and HMS Manchester were launched in the Battle of Cape Spartivento and a Walrus from HMS Gloucester was used in the Battle of Cape Matapan. The main task of ship-based aircraft was patrolling for Axis submarines and surface-raiders, and by March 1941, Walruses were being deployed with Air to Surface Vessel (ASV) radars to assist in this. During the Norwegian Campaign and the East African Campaign, they also saw very limited use in bombing and strafing shore targets. By 1943, catapult-launched aircraft on cruisers and battleships were being phased out; their role at sea was taken over by much improved radar. Also, a hangar and catapult occupied a considerable amount of valuable space on a warship. However, Walruses continued to fly from Royal Navy carriers for air-sea rescue and general communications tasks. Their low landing speed meant they could make a carrier landing despite having no flaps or tailhook. The RAF used Walruses mainly in the Air-sea rescue role. The specialist air-sea rescue squadrons flew a variety of aircraft, using Spitfires and Boulton Paul Defiants to patrol for downed aircrew, Avro Ansons to drop supplies and dinghies, and Walruses to pick up aircrew from the water. RAF air-sea rescue squadrons were deployed to cover the waters around the United Kingdom, the Mediterranean Sea and the Bay of Bengal. Three Walruses, delivered in March 1939, were used by Irish Air Corps as maritime patrol aircraft during the Irish Emergency of World War II. After the war, some Walruses continued to see limited military use with the RAF and foreign navies. Eight were operated by Argentina, two flew from the cruiser ARA La Argentina as late as Other aircraft were used for training by the French Navy's Aviation navale. Walruses also found civil and commercial use. They were briefly used by a whaling company, United Whalers. Operating in the Antarctic, they were launched from the Factory ship FF Balaena, that had been equipped with an ex-navy aircraft catapult. A Dutch whaling company embarked Walruses, but never flew them. Other Walruses found use carrying passengers. An amphibious aircraft or amphibian An amphibious aircraft or amphibian (fig. 131) is an aircraft that can take off and land on either land or water. All Amphibian aircraft are thus classified both as seaplanes and make up the rarest subclass of seaplanes. Like all seaplanes, Amphibious aircraft are typically flying boats and floatplanes but while their major physical attributes are those placing them within those broad classes, amphibians are also engineered with retractable wheels making them amphibious at the expense of extra weight and complexity, plus diminished range and fuel economy factors comparative to planes specialized for land or water only. 177

178 Fig Canadair CL-415 operating on "Fire watch" out of Red Lake, Ontario, c While floatplanes sometimes have floats that are interchangeable with wheeled landing gear (thereby producing a conventional land-based aircraft), it is rare for a floatplane to successfully incorporate retractable wheels whilst retaining its floats; the Grumman J2F Duck would be a notable example of one exception which does. Some amphibian floatplanes, such as the amphibian version of the Cessna Caravan, incorporate retractable wheels within their floats. The majority of amphibian aircraft are of the flying boat type. These aircraft, and those designed as floatplanes with a single main float under the fuselage centerline (such as the J2F Duck), require small outrigger floats to be fitted underneath the wings: while these impose additional drag and weight on all seaplanes of this type, amphibious aircraft also face the possibility that these floats would hit the runway during wheeled landings. A solution would be to have the aircraft fitted with wing-mounted retractable floats such as those found on the Grumman Mallard, a flying boat type of seaplane designed and built in the mid 1940s with dozens still employed today in regular small volume commercial (ferry service) air taxi roles. The class which has retractable floats which also act as extra fuel tanks since fuel liquids weigh less than water of equal volume; these floats are removable for extended land/snow operations if and when use of extra fuel tanks is undesired but the plane type and class serves as an example of a true amphibious aircraft since they also retract up off the ground. Amphibious aircraft are heavier and slower, more complex and more expensive to purchase and operate than comparable landplanes but are also more versatile. They do compete favorably, however, with helicopters that compete for the same types of jobs, if not quite as versatile. Amphibious aircraft have longer range than comparable helicopters, and can indeed achieve nearly the range of land-only airplanes, as an airplane's wing is more efficient than a helicopter's lifting rotor. This makes an amphibious aircraft, such as the Grumman Albatross and the ShinMaywa US-1, ideal for long-range air-sea rescue tasks. In addition, amphibious aircraft are particularly useful as "bush" aircraft engaging in light transport in remote areas, where they are required to operate not only from airstrips, but also from lakes and rivers. Amphibious aircraft have been built in various nations since the early 1920s, but it was not until World War II that saw their widespread service. The Grumman Corporation, a United States-based pioneer of amphibious aircraft, introduced a family of light utility amphibious aircraft - the Goose, the Widgeon and the Mallard - during the 1930s and the 1940s, originally intended for civilian market. However, the military potential of these very capable aircraft could not be ignored, and large numbers of these versatile aircraft were ordered by the Military of the United States and their allies during World War II, for service in air-sea rescue, anti-submarine patrol, and a host of other tasks. The concept of military amphibious aircraft was so successful that the PBY Catalina, which began life as a pure flying boat, introduced an amphibian variant during the war. In the United Kingdom, Supermarine Aircraft produced the Walrus and the Sea Otter single-engined biplane amphibians which were widely used for observation and air-sea rescue duties before and during World War Two. After the war, the United States military ordered hundreds of the HU-16 Albatross and its variants for use in open ocean rescue, for the United States Air Force, Coast Guard and Navy. 178

179 The capabilities of these amphibious aircraft were found to be particularly useful in the unforgiving terrains of Alaska and northern Canada, where some remained in civilian service long after the war, providing remote communities in these regions with vital links to the outside world. Nonetheless, with the increased availability of airstrips and amenities in remote communities, fewer amphibious aircraft are manufactured today than in the past, although a handful of manufacturers around the world still produce amphibious aircraft (flying boats or floatplanes with retractable landing gear), such as the Bombardier 415, the Grumman Albatross and the amphibian version of the Cessna Caravan. The largest amphibious aircraft currently in service is the Beriev A-40 of the Russian Navy, with a wingspan of meter and a takeoff weight of 86 metric tons. The Beriev Be-200 is a smaller model for civil applications and had its first flight in It can carry 72 passengers and is also built in a version for fire fight. A floatplane (or pontoon plane) A floatplane (or pontoon plane) is a type of seaplane, with slender pontoons (known as "floats") mounted under the fuselage; only the floats of a floatplane normally come into contact with water, with the fuselage remaining above water. By contrast a flying boat uses its fuselage for buoyancy like a ship's hull. A floatplane is essentially a straightforward development of land-based aircraft, with floats mounted under the fuselage instead of wheeled landing gear. Floatplanes are traditionally more popular than flying boats for small aircraft designs, since it permits a single piston engine to be installed in the conventional manner, that is at the nose of the fuselage (this could be done on flying boats only by mounting the engine high above the fuselage). Moreover, the fuselages of floatplanes are typically more aerodynamic than flying boats; while the large floats underneath the fuselages inevitably impose extra drag and weight to floatplanes, rendering them less manoeuvrable during flight than their land-based counterparts. Historically it did little to affect their speed, as the contestants in the Schneider Trophy demonstrated. However, there is loss of speed, slower rate of climb and increased empty weight. There are two basic arrangements for floats on floatplanes. One is the single float design, in which a single large float is mounted directly underneath the fuselage, with smaller stabilizing floats underneath the wings. The other is the twin float design, with a pair of floats mounted beneath the wing roots, in place of wheeled landing gear. The main advantage of the single float design is its rough sea landing capability: the large central float is directly attached to the fuselage, this being the strongest part of the aircraft structure, while the small floats under the outer wings provide the aircraft with good lateral stability. Dual floats on aircraft limit wave handling to minimal levels, often to an average of one foot in height. However the twin float design facilitates mooring and boarding, and in the case of a military floatplane, leaves the belly free to carry a torpedo or a heavy bombload. II. Whatever the float layout, a floatplane tends to be much less stable on water than flying boats. Floatplanes first appeared during World War I, and remained in widespread naval use until World War Most larger warships of that era carried floatplanes - typically four for each battleship, and one to two for each cruiser - to be launched by catapults; their main task was to spot targets over the horizon for the big guns. Other floatplanes, sometimes carried on seaplane tenders, were used for bombings, reconnaissance, airsea rescue, and even as fighters. During the interwar period, civilian use of floatplanes were rather rare, given the larger fuselage (hence greater payload) of flying boats; however floatplane racing aircraft were very popular, as exemplified by those which participated in the Schneider Trophy. After World War II, the advent of radar and helicopters, and the advanced development of aircraft carriers and land-based aircraft, saw the demise of military seaplanes. This, coupled with the increased availability of civilian airstrips, have greatly reduced the number of flying boats being built. However, numerous modern civilian aircraft have floatplane variants, most of these are 179

180 offered as third-party modifications under a supplemental type certificate (STC), although there are several aircraft manufacturers that build floatplanes from scratch. These floatplanes have found their niche as one type of bush plane, for light duty transportation to lakes and other remote areas, as well as to small/hilly islands without proper airstrips. They may operate on a charter basis (including, but not limited to, pleasure flights), provide scheduled service, or be operated by residents of the area for private, personal use. Tigerfish Aviation Tigerfish Aviation is an aerospace research and development company based in Norwood, South Australia. Since the late 1990s, the company has been developing a retractable pontoon system for the float plane industry, which has been patented as Retractable Amphibious Pontoon Technology or RAPT. The retractable float concept aims to reduce aerodynamic drag by folding the floats into a streamlined pannier under the fuselage of the aircraft. The reduction in drag improves performance of the aircraft and reduces its operating cost, such as fuel consumption. Reduction in drag also increases the range, payload, speed, and productivity of the aircraft. The drag reduction occurs due to the reduction of surface area exposed to the airstream and concealing the hydrodynamic features of the floats. It is designed as a retrofit, and is potentially capable of application to any existing aircraft. The technology has been applied on a one-sixth scale Cessna Caravan for concept-proving. As of 2010, Dornier 228 NG is the first proposed aircraft to be retrofitted for the RAPT system, besides the small-scale Cessna. The retractable float system can be used in a wide range of aircraft including regional aircraft, utility aircraft, executive aircraft, military transports, VLJs, and UAVs. The University of Adelaide, with assistance of the South Australian Government, has performed CFD analysis and other studies on the DHC-6 Twin Otter showing that the RAPT system would result in a significant cost benefit. Unlike traditional floats, RAPT pontoons are made of lightweight composite materials, but suffer additional mass penalties due to the electric, hydraulic and structural systems required to retract the pontoons. Total mass penalty has been estimated at 1,420 pounds (640 kg) for a Dornier 228 NG variant (comparable to existing Wipline floats). Flying boat A flying boat is a fixed-winged seaplane with a hull, allowing it to land on water. It differs from a float plane as it uses a purpose-designed fuselage which can both float, granting the aircraft buoyancy, and give aerodynamic sheath. Flying boats may be stabilized by under-wing floats or by wing-like projections (called sponsons) from the fuselage. Flying boats were some of the largest aircraft of the first half of the 20th century, superseded in size only by bombers developed during World War II. Their advantage lay in using water instead of expensive landbased runways, making them the basis for international airlines in the interwar period. They were also commonly used for maritime patrol and air-sea rescue. The craft class or type came about after The Daily Mail offered a large monetary prize for an aircraft with transoceanic range in This prompted a collaboration between British and American air pioneers, resulting in the Curtiss Model H. Following World War II, their use gradually tailed off, partially because of the investments in airports during the war. In the 21st century, flying boats maintain a few niche uses, such as for dropping water on forest fires, air transport around archipelagos, and access to undeveloped or roadless areas. Many modern seaplane variants, whether float or flying boat types are convertible amphibians planes where either landing gear or flotation modes may be used to land and take off. 180

181 Henri Fabre, a French aviator, invented and successfully flight tested a seaplane which he named Le Canard; it is acknowledged as the first seaplane in history. It was a 'landmark' invention that inspired other aviators. Over the next few years, Fabre designed "Fabre floats" for several other flyers. American pioneer aviator Glenn Curtiss had built experimental floatplanes before 1910, without proceeding to flight testing. But after Fabre's successful seaplane flights, Curtiss focused mainly on land-based aircraft. He made only small experimental models of floatplanes, and slowly improved upon his earlier work. In 1911 Curtiss unveiled a development of his floatplane experiments married to a larger version of his successful Curtiss Model D land plane, but with a larger engine and a rudimentary hull and fuselage, designated as the Model E. The was the first air plane with a hull, and arguably the creation of the "flying boat" type that dominated long distance air travel for the next four to five decades. Consequently he soon became acquainted with others interested in both seaplane based and long range commercial aviation development two aspects which were hopelessly interrelated in those days when airports were yet to be built throughout most of the world. The design also brought him in contact with Lieutenant Commander John Cyril Porte RN, an influential British aviation pioneer. In February 1911, the United States Navy took delivery of its very first airplane, a Curtiss Model E, and soon tested landing and take-offs from ships using the Curtiss Model D. In 1913, London's Daily Mail newspaper put up a 10,000 prize for the first non-stop aerial crossing of the Atlantic which was soon "'enhanced by a further sum"' from the "Women's Aerial League of Great Britain". American businessman Rodman Wanamaker became determined that the prize should go to an American aircraft and commissioned the Curtiss Aeroplane and Motor Company to design and build two aircraft capable of making the flight. In Great Britain in 1913, similarly, the boat building firm J. Samuel White of Cowes on the Isle of Wight set up a new aircraft division and produced a flying boat in the United Kingdom. This was displayed at the London Air Show at Olympia in In that same year, a collaboration between the S. E. Saunders boatyard of East Cowes and the Sopwith Aviation Company produced the "Bat Boat", an aircraft with a consuta laminated hull that could operate from land or on water, which today we call amphibious aircraft. The "Bat Boat" completed several landings on sea and on land and was duly awarded the Mortimer Singer Prize. It was the first all-british aeroplane capable of making six return flights over five miles within five hours. In America, Wanamaker's commission built on Glen Curtiss' previous development and experience with the Model E for the U.S. Navy and soon resulted in the Model H. The H series began as a conventional biplane design with two-bay, unstaggered wings of unequal span with two tractor (pulling, not pushing) inline engines mounted side-by-side above the fuselage in the interplane gap. Wingtip pontoons were attached directly below the lower wings near their tips. The Model H resembled Curtiss' earlier flying boat designs, but was built considerably larger so it could carry enough fuel to cover 1,100 mi (1,800 km). The three crew members were accommodated in a fully-enclosed cabin. Trials of the Model H (christened America) began in June 1914, with Lt. Cmdr. Porte as test pilot. Testing soon revealed a serious shortcoming in the design; especially the tendency for the nose of the aircraft to try to submerge as engine power increased while taxiing on water. This phenomenon had not been encountered before, since Curtiss' earlier designs had not used such powerful engines nor large fuel/cargo loads and so were relatively much more buoyant. In order to counteract this effect, Curtiss fitted fins to the sides of the bow to add hydrodynamic lift, but soon replaced these with sponsons, a type of underwater pontoon mounted in pairs on either side of a hull, to add more buoyancy. These sponsons (or their engineering equivalents) would remain a prominent feature of flying boat hull design in the decades to follow. With the problem resolved, preparations for the crossing resumed. While the craft was found to handle 'heavily' on take-off, and required rather longer take-off distances than expected, 5 August 1914 was selected as the trans-atlantic flight date. Porte was to pilot the America. Curtiss and Porte's plans were interrupted by the outbreak of World War I. Porte was recalled to service with the Royal Naval Air Service. He became commander of the Seaplane Experimental Station at Felixstowe in

182 Impressed by the capabilities he had witnessed, Porte persuaded the Admiralty to commandeer (and later, purchase) the America and her sister from Curtiss. H-4's. This was followed by an order for 12 more similar aircraft, one Model H-2 and the remaining as Model Four examples of the latter were actually assembled in the UK by Saunders. All of these were essentially identical to the design of the America, and indeed, were all referred to as Americas in Royal Navy service. The initial batch was followed by an order for 50 more (totalling 64 Americas overall during the war). Porte also acquired permission to modify and experiment with the Curtiss aircraft. At Felixstowe, Porte advanced flying boat design and developed a practical hull design with the distinctive "Felixstowe notch". The notch could be added to Curtiss' airframe and engine design, creating the Atlantic or Type A flying boat (as it became known in Great Britain). After that initial mass upgrade Porte modified the H4 with a new hull with improved hydrodynamic qualities. This design was later designated the Felixstowe F.1, of which only four were built as they were deemed underpowered for arduous North Atlantic patrol conditions. Consequently, Curtiss was asked to develop a larger flying boat, which was designated the "Large American" or Curtiss Model H8 when it became available in But when some H8s were tested at Felixstowe, they too were found to be under powered. Porte soon upgraded the H8s with 250 HP Rolls-Royce Eagle engines and replaced the hulls with a larger Felixstowe hull variant. These became the Felixstowe F.2 and F.2a variants and saw both wide use and long service. The innovation of the "Felixstowe notch" enabled the craft to overcome suction from the water more quickly and break free for flight much more easily. This made operating the craft far safer and more reliable. The "notch" break through would soon after evolve into a 'step', with the rear section of the lower hull sharply recessed above the forward lower hull section, and that characteristic became a feature of both flying boat hulls and seaplane floats. The resulting aircraft would be large enough to carry sufficient fuel to fly long distances and could berth alongside ships for refueling. After several years of war development and upon getting negative reports on the H-8, Curtiss produced upscaled flying boats which by 1917 were designated as the Curtiss Model H12. Porte then designed a similar hull for the H12, designated the Felixstowe F.2a, which was greatly superior to the original Curtiss boat. This entered production and service with about 100 being completed by the end of the War. Another seventy were built later, and these were followed by two F.2c also built at Felixstowe. In February 1917, the first prototype of the Felixstowe F.3 was flown. It was larger and heavier than the F.2, giving it greater range and heavier bomb load, but poorer agility. Approximately 100 Felixstowe F.3s were produced before the end of the war. The Felixstowe F.5 was intended to combine the good qualities of the F.2 and F.3, with the prototype first flying in May The prototype showed superior qualities to its predecessors but, to ease production, the production version was modified to make extensive use of components from the F.3, which resulted in lower performance than the F.2A or F.5. F.2, F.3, and F.5 flying boats were extensively employed by the Royal Navy for coastal patrols, and to search for German U-boats. The Curtiss Aeroplane and Motor Company independently developed its designs into the small Model 'F', the larger Model 'K' (several of which were sold to the Russian Naval Air Service), and the Model 'C' for the US Navy. Curtiss among others also built the Felixstowe F.5 as the Curtiss F5L, based on the final Porte hull designs and powered by American Liberty engines. Macchi L and M series flying boats. The original Macchi L.1 was a copy of the Austrian Lohner L flying boat of A Curtiss NC-4 became the first aircraft to fly across the Atlantic Ocean in 1919, crossing via the Azores. Of the four that made the attempt, only one completed the flight. In the 1930s, flying boats made it possible to have regular air transport between the US and Europe, opening up new air travel routes to South America, Africa, and Asia. Foynes, Ireland and Botwood, Newfoundland and Labrador were the termini for many early transatlantic areas where there were no airfields for land-based aircraft, flying boats could stop at small island, river, lake or coastal stations to refuel and 182

183 resupply. The Pan Am Boeing 314 "Clipper" planes brought exotic destinations like the Far East within reach of air travelers and came to represent the romance of flight. In 1923, the first British commercial flying boat service was introduced with flights to and from the Channel Islands. The British aviation industry was experiencing rapid growth. The Government decided that nationalization was necessary and ordered five aviation companies to merge to form the state-owned Imperial Airways of London (IAL). IAL became the international flag-carrying British airline, providing flying boat passenger and mail transport links between Britain and South Africa using aircraft such as the Short S.8 Calcutta. In 1928, four Supermarine Southampton flying boats of the RAF Far East flight arrived in Melbourne, Australia. The flight was considered proof that flying boats had evolved to become reliable means of long distance transport. By 1931, mail from Australia reached Britain in just 16 days - less than half the time taken by sea. In that year, government tenders on both sides of the world invited applications to run new passenger and mail services between the ends of Empire, and Qantas and IAL were successful with a joint bid. A company under combined ownership was then formed, Qantas Empire Airways. The new ten day service between Rose Bay, New South Wales (near Sydney) and Southampton was such a success with letter-writers that before long the volume of mail was exceeding aircraft storage space. A solution to the problem was found by the British government, who in 1933 had requested aviation manufacturer Short Brothers to design a big new long-range monoplane for use by IAL. Partner Qantas agreed to the initiative and undertook to purchase six of the new Short S23 'C' class or 'Empire' flying boats. Delivering the mail as quickly as possible generated a lot of competition and some innovative solutions. One variant of the Short Empire flying boats was the strange-looking "Maia and Mercury'". It was a fourengined floatplane "Mercury" (the winged messenger) fixed on top of "Maia", a heavily modified Short Empire flying boat. The larger Maia took off, carrying the smaller Mercury loaded to a weight greater than it could take off with. This allowed the Mercury to carry sufficient fuel for a direct trans-atlantic flight with the mail. Unfortunately this was of limited usefulness, and the Mercury had to be returned from America by ship. The Mercury did set a number of distance records before in-flight refuelling was adopted. Sir Alan Cobham devised a method of in-flight refuelling in the 1930s. In the air, the Short Empire could be loaded with more fuel than it could take off with. Short Empire flying boats serving the trans-atlantic crossing were refueled over Foynes; with the extra fuel load, they could make a direct trans-atlantic flight. A Handley Page H.P.54 Harrow was used as the fuel tanker. The German Dornier Do-X flying boat was noticeably different from its UK and US-built counterparts. It had wing-like protrusions from the fuselage called sponsons, to stabilize on the water without the need for wing-mounted outboard floats. This feature was pioneered by Claudius Dornier during World War I on his Dornier Rs. I giant flying boat, and perfected on the Dornier Wal in The enormous Do X was powered by 12 engines and carried 170 persons. It flew to America in 1929 crossing the Atlantic via an indirect route. It was the largest flying boat of its time but was severely underpowered and was limited by a very low operational ceiling. Only three were built with a variety of different engines installed, in an attempt to overcome the lack of power. Two of these were sold to Italy. The military value of flying boats was well-recognized, and every country bordering on water operated them in a military capacity at the outbreak of the war. They were utilized in various tasks from anti-submarine patrol to air-sea rescue and gunfire spotting for battleships. Aircraft such as the PBY Catalina, Short Sunderland, and Grumman Goose recovered downed airmen and operated as scout aircraft over the vast distances of the Pacific Theater and Atlantic. They also sank numerous submarines and found enemy ships. In May 1941 the German battleship Bismarck was discovered spotted by a PBY Catalina flying out of Castle Archdale Flying boat base, Lower Lough Erne, Northern Ireland. The largest flying boat of the war was the Blohm & Voss BV 238, which was also the heaviest plane to fly during World War II and the largest aircraft built and flown by any of the Axis Powers. In November 1939, IAL was restructured into three separate companies: British European Airways, British Overseas Airways Corporation (BOAC), and British South American Airways (which merged with BOAC in 1949), with the change being made official in 1 April BOAC continued to operate flying boat services from the (slightly) safer confines of Poole Harbour during wartime, returning to Southampton in

184 The Martin Company produced the prototype XPB2M Mars based on their PBM Mariner patrol bomber, with flight tests between 1941 and The Mars was converted by the Navy into a transport aircraft designated the XPB2M-1R. Satisfied with the performance, 20 the modified JRM-1 Mars were ordered. The first, named Hawaii Mars, was delivered in June 1945, but the Navy scaled back their order at the end of World War II, buying only the five aircraft which were then on the production line. The 5 Mars were completed, and the last delivered in The Hughes H-4 Hercules, in development in the U.S. during the war, was even larger than the Bv238 but it did not fly until The "Spruce Goose", as the H-4 was nicknamed, was the largest flying boat ever to fly. That short 1947 hop of the 'Flying Lumberyard' was to be its last, however; it became a victim of post-war cutbacks and the disappearance of its intended mission as a transatlantic transport. During the Berlin Airlift (which lasted from June 1948 until August 1949) ten Sunderlands and two Hythes were used to transport goods from Finkenwerder on the Elbe near Hamburg to the isolated city, landing on Lake Havelsee beside RAF Gatow until it iced over. The Sunderlands were particularly used for transporting salt, as their airframes were already protected against corrosion from seawater. Transporting salt in standard aircraft risked rapid and severe structural corrosion in the event of a spillage. In addition, three Aquila flying boats were used during the airlift. This is the only known operational use of flying boats within central Europe. After World War II the use of flying boats rapidly declined, though the US Navy continued to operate them (notably the Martin P5M Marlin) until the early 1970s. The Navy even attempted to build a jet-powered seaplane bomber, the Martin Seamaster. Several factors contributed to the decline. The ability to land on water became less of an advantage owing to the considerable increase in the number and length of land based runways during World War II. Further, as the speed and range of land-based aircraft increased, the commercial competitiveness of flying boats diminished; their design compromised aerodynamic efficiency and speed to accomplish the feat of waterborne takeoff and landing. Competing with new civilian jet aircraft like the de Havilland Comet and Boeing 707 proved impossible. BOAC ceased flying boat services out of Southampton in November Bucking the trend, in 1948 Aquila Airways was founded to serve destinations that were still inaccessible to land-based aircraft. This company operated Short S.25 and Short S.45 flying boats out of Southampton on routes to Madeira, Las Palmas, Lisbon, Jersey, Majorca, Marseilles, Capri, Genoa, Montreux and Santa Margherita. From 1950 to 1957, Aquila also operated a service from Southampton to Edinburgh and Glasgow. The flying boats of Aquila Airways were also chartered for one-off trips, usually to deploy troops where scheduled services did not exist or where there were political considerations. The longest charter, in 1952, was from Southampton to the Falkland Islands. In 1953 the flying boats were chartered for troop deployment trips to Freetown and Lagos and there was a special trip from Hull to Helsinki to relocate a ship's crew. The airline ceased operations on 30 September The technically advanced Saunders-Roe Princess (fig. 132) first flew in 1952 and later received a certificate of airworthiness. Despite being the pinnacle of flying boat development none were sold, though Aquila Airways reportedly attempted to buy them. Of the three Princesses that were built, two never flew, and all were scrapped in In the late 1940s Saunders-Roe also produced the jet-powered SR.A/1 flying boat fighter, which did not progress beyond flying prototypes. Fig Saunders-Roe Princess G-ALUN at the Farnborough SBAC Show in September

185 Helicopters ultimately took over the air-sea rescue role. The land-based P-3 Orion and carrier-based S-3 Viking became the US Navy's fixed-wing antisubmarine patrol aircraft. Ansett Australia operated a flying boat service from Rose Bay to Lord Howe Island until 1974, using Short Sandringhams. The shape of the Short Empire was a harbinger of the shape of later aircraft yet to come, and the type also contributed much to the designs of later ekranoplans. However, true flying boats have largely been replaced by seaplanes with floats and amphibian aircraft with wheels. The Beriev Be-200 twin-jet amphibious aircraft has been one of the closest 'living' descendants of the earlier flying boats, along with the larger amphibious planes used for fighting forest fires. There are also several experimental/kit amphibians such as the Volmer Sportsman, Quikkit Glass Goose, Airmax Sea Max, Aeroprakt A-24, and Seawind 300C. The ShinMaywa US-2 (Japanese: US-2, fig. 133) is a large STOL amphibious aircraft designed for air-sea rescue work. The US-2 is operated by the Japan Maritime Self Defense Force. Fig Japanese Shin Maywa US-2. The Canadair CL-215 and successor Bombardier 415 are examples of modern flying boats and are used for forest fire suppression. Dornier announced plans in May 2010 to build CD2 SeaStar composite flying boats in Quebec, Canada. The Iranian military unveiled a squadron of flying boats, named Bavar 2, equipped with machine guns in September

186 Cap. 8. AIRCRAFT CARRIERS An aircraft carrier (fig. 134) is a warship designed with a primary mission of deploying and recovering aircraft, acting as a seagoing airbase. Aircraft carriers thus allow a naval force to project air power worldwide without having to depend on local bases for staging aircraft operations. They have evolved from wooden vessels, used to deploy balloons, into nuclear-powered warships that carry dozens of fixed- and rotary-wing aircraft. Aircraft carriers are typically treated as the capital ship of a fleet and are extremely expensive to build and important to protect: of the nine nations which possess an aircraft carrier, seven of these navies only possess one such ship. There are 20 active aircraft carriers in the world as of June Fig From bottom to top: Principe de Asturias, amphibious assault ship USS Wasp, USS Forrestal and light V/STOL carrier HMS Invincible, showing size differences of late 20th century carriers. The 1903 advent of heavier-than-air, fixed-wing aircraft was closely followed in 1910 by the first experimental take-off of such an airplane from the deck of a US Navy vessel (cruiser USS Birmingham), and the first experimental landings in Seaplane tender support ships came next; in September 1914, the Imperial Japanese Navy Wakamiya conducted the world's first successful naval-launched air raids. It lowered four Maurice Farman seaplanes into the water using its crane, which were taking off to bombard German forces and could be retrieved back from surface afterwards. The development of flat top vessels produced the first large fleet ships. In 1918, HMS Argus became "the world's first carrier capable of launching and landing naval aircraft". Carrier evolution was well underway in the mid-1920s, resulting in ships such as HMS Hermes and Hōshō. Most early aircraft carriers were conversions of ships that were laid down (or had served) as different ship types: cargo ships, cruisers, battlecruisers, or battleships. The Washington Naval Treaty of 1922 affected aircraft carrier plans. The US and UK were permitted up to 135,000 tons of carriers each while specific exemptions on the upper tonnage of individual ships permitted conversion of capital ship hulls to carriers such as the Lexington-class aircraft carriers. During the 1920s, several navies started ordering and building aircraft carriers that were specifically designed as such. This allowed the design to be specialized to their future role, and resulted in superior ships. During the Second World War, these ships would become the backbone of the carrier forces of the US, British, and Japanese navies, known as fleet carriers. World War II saw the first large-scale use and further refinement of the aircraft carrier, spawning several types. Escort aircraft carriers, such as USS Bogue, were built only during World War II. Although some were purpose-built, most were converted from merchant ships as a stop-gap measure to provide air support for convoys and amphibious invasions. 186

187 Light aircraft carriers, such as USS Independence, represented a larger, more "militarized" version of the escort carrier concept. Although the light carriers usually carried the same size air groups as escort carriers, they had the advantage of higher speed as they had been converted from cruisers under construction. Modern navies that operate such ships treat aircraft carriers as the capital ship of the fleet, a role previously played by the battleship. The change, part of the growth of air power as a significant factor in warfare, took place during World War II. This change was driven by the superior range, flexibility and effectiveness of carrier-launched aircraft. Following the war, carrier operations continued to increase in size and importance. Supercarriers, the latest aircraft carriers, typically displacing 75,000 tonnes or greater, have become the pinnacle of carrier development. Most are powered by nuclear reactors and form the core of a fleet designed to operate far from home. Amphibious assault ships, such as USS Tarawa and HMS Ocean, serve the purpose of carrying and landing Marines, and operate a large contingent of helicopters for that purpose. Also known as "commando carriers" or "helicopter carriers", many have a secondary capability to operate VSTOL aircraft. Lacking the firepower of other warships, carriers by themselves are considered vulnerable to attack by other ships, aircraft, submarines, or missiles. Therefore, aircraft carriers are generally accompanied by a number of other ships, to provide protection for the relatively unwieldy carrier, to carry supplies, and to provide additional offensive capabilities. This is often termed a battle group or carrier group, sometimes a carrier battle group. Before World War II international naval treaties of 1922, 1930 and 1936 limited the size of capital ships including carriers. Aircraft carrier designs since World War II have been effectively unlimited by any consideration save budgetary, and the ships have increased in size to handle the larger aircraft. The large, modern Nimitz class of United States Navy carriers has a displacement nearly four times that of the World War II era USS Enterprise, yet its complement of aircraft is roughly the same a consequence of the steadily increasing size and weight of military aircraft over the years. Wartime emergencies also saw the creation or conversion of unconventional aircraft carriers. CAM ships, like SS Michael E, were cargo-carrying merchant ships which could launch but not retrieve fighter aircraft from a catapult. These vessels were an emergency measure during World War II as were Merchant aircraft carriers (MACs), such as MV Empire MacAlpine, another emergency measure which saw cargo-carrying merchant ships equipped with flight decks. Battle carriers were created by the Imperial Japanese Navy to partially compensate for the loss of carrier strength at Midway. Two of them were made from Ise-class battleships during late The aft turrets were removed and replaced with a hangar, deck and catapult. The heavy cruiser Mogami concurrently received a similar conversion. This "half and half" design was an unsuccessful compromise, being neither one thing nor the other. Submarine aircraft carriers, such as the French Surcouf and the Japanese I-400 class submarine, which was capable of carrying three Aichi M6A Seiran aircraft, were first built in the 1920s, but were generally unsuccessful at war. Today's aircraft carriers are so expensive that many countries risk significant political and economic, as well as military, ramifications if they were ever to lose one during any kind of operation. Also, observers have opined that modern anti-ship weapons systems, such as torpedoes and missiles, have made aircraft carriers obsolete as too vulnerable for modern combat. Countries appear, however, willing to take the risks in building and fielding aircraft carriers because of the geo-political and military prestige they give by being able to project power at some distance from their national land boundaries. Furthermore, aircraft carriers facilitate quicker projections of military power into local and regional conflicts. A fleet carrier is intended to operate with the main fleet and usually provides an offensive capability. These are the largest carriers capable of fast speeds. By comparison escort carriers were developed to provide defence for convoys of ships. They were smaller and slower with lower numbers of aircraft carried. Most were built from mercantile hulls or, in the case of merchant aircraft carriers, were bulk cargo ships with a flight deck added on top. Light aircraft carriers were carriers that were fast enough to operate with the fleet but of smaller size with reduced aircraft capacity. Anti-submarine warfare carrier An ASW carrier (Anti-Submarine Warfare carrier, fig. 135) is a type of small aircraft carrier whose primary role is to hunt and destroy submarines. This type of ship came into existence during the Cold War as a development of the escort carriers used in the ASW role in the North Atlantic during World War II. 187

188 Fig USS Yorktown (CVS-10) at sea of Hawaii, circa the early 1960s. After World War II, the main naval threat to most western nations was confrontation with the Soviet Union. The Soviets ended the war with a small navy and took the route of asymmetric confrontation against western surface ship superiority by investing heavily in submarines both for attack and later fielding submarine launched missiles. Several nations who purchased British and US surplus light carriers were most easily able to accommodate slow moving, less expensive, and easy to land antisubmarine aircraft from the 1960s forward such as the S-2 Tracker which flew from the decks of US, Canadian, Australian, Dutch, Argentine, and Brazilian carriers or Alizé which flew from French and Indian ships and still remain useful especially in the framework of NATO even as newer fighter and strike aircraft were becoming too heavy for the equipment designed for WW- II aircraft. Improvement in long range shore based patrol and conventional ship based ASW helicopter capability combined with the increasing difficulty maintaining surplus WW-II carriers lead to most of these ships to be retired or docked by smaller nations from the 1970s to the mid-1980s. This trend in ASW force draw down only accelerated with the massive reduction in the operational Soviet/Russian submarine fleet which rarely went to sea in large numbers in the 1990s. Ships that could be called dedicated ASW carriers are now only found with the Japanese navy which operates helicopters and no fixed wing carrier based aircraft of any kind. Even the United States Navy, the last nation to regularly operate a dedicated fixed wing carrier based ASW aircraft, the S-3 Viking, on its mixed role super carriers had already removed most ASW equipment in the 1990s from this aircraft and has now removed this type from service as of January 2009 without replacement. Interestingly the Argentine Navy currently without much hope of a replacement CATOBAR carrier its own still trains several times a year landing S-2 Turbo Trackers aboard the Brazilian carrier São Paulo. Much easier to operate from small decks than fixed-wing aircraft were ASW helicopters which flew from the decks of nearly all allied conventional carriers to this day and most LPH or STOVL carriers operated by the Soviet, Spanish, Italian, Japanese, British, and Thai navies. Since the only navy currently building new ASW though-deck helicopter-only ships is Japan, who terms their vessels as helicopter destroyers instead of ASW carriers, it is disputable if a ASW helicopter only vessel is best defined as a ASW carrier or perhaps a new designation. 188

189 Helicopter carrier Helicopter carrier (fig. 136) is a term for an aircraft carrier whose primary purpose is to operate helicopters. The term is sometimes used for both ASW carriers and amphibious assault ships. Fig Australian Army S-70A-9 Black Hawk helicopters operating from a U.S. Navy Wasp class amphibious assault ship. Helicopter carriers can either have a full-length aircraft deck like HMS Ocean, or have a large helicopter deck, usually aft, as in the Soviet Navy's Moskva class or RFA Argus. The large aft deck design is becoming less common, as the configuration represents a compromise. A full-length deck maximises deck space for helicopter landing spots. Such a design also allows for a hangar deck. Pure helicopter carriers are difficult to define in the 21st century. The advent of STOVL aircraft such as the Harrier Jump Jet have complicated the classification; the United States Navy's Wasp class, for instance, carries six to eight Harriers as well as 30 helicopters. Only smaller carriers unable to operate the Harrier and older pre- Harrier-era carriers can be regarded as true helicopter carriers. In many cases, other carriers, able to operate STOVL aircraft, are classified as "light aircraft carriers". Other vessels, such as the Wasp class, are also capable of embarking troops such as Marines and landing them ashore; they are typically classified as amphibious assault ships. HMS Hermes and two of her sisters were 22,000 ton fleet carriers converted to operate helicopters only as "commando carriers". Hermes was later converted to a STOVL carrier. Light aircraft carrier A light aircraft carrier (fig. 137) is an aircraft carrier that is smaller than the standard carriers of a navy. The precise definition of the type varies by country; light carriers typically have a complement of aircraft only ½ to ⅔ the size of a full-sized or "fleet" carrier. 189

190 Fig AV-8S Harriers embarked on the Spanish Navy's Dédalo, the former USS Cabot (CVL-28), an Independence class light aircraft carrier. hulls. In World War II, the United States Navy produced a number of light carriers by converting cruiser The Independence-class aircraft carriers, converted from Cleveland-class light cruisers, were unsatisfactory ships for aviation with their narrow, short decks and slender, high-sheer hulls; in virtually all respects the escort carriers were superior aviation vessels. The Independence-class ships, however, had the virtue of being available at a time when available carrier decks had been reduced to Enterprise and Saratoga in the Pacific and Ranger in the Atlantic. In addition, unlike escort carriers, they had enough speed to take part in fleet actions with the larger carriers. carrier. Late in the war, a follow on design to the Independence-class, the Saipan-class, was designed. Two vessels in this class Saipan and Wright were completed after the war's end. After very brief lives as carriers, the Saipans were converted to command and communication ships. The British 1942 design light fleet carrier was a scaled-down version of their Illustrious-class fleet The design could be built in a yard with little or no experience of warship construction. Although built to merchant standards, the design incoporated better water-tight subdivision. Expected to have a lifetime of about three years, the last of the design was taken out of service in In the post-war period, the Royal Navy operated a force of ten Colossus class carriers including the two maintenance carriers. In all, fifteen ships were completed from the 1942 design, of which most of the Colossus class and all the eventually completed Majestics were variously sold to Argentina, Australia, Brazil, Canada, France, India and The Netherlands. Currently 7 light aircraft carriers are in service. The newest light carriers are the Italian Cavour and the Spanish Juan Carlos I, which were commissioned in 2009 respectively in Amphibious assault ship An amphibious assault ship (fig. 138), (also referred to as a commando carrier or an amphibious assault carrier) is a type of amphibious warfare ship employed to land and support ground forces on enemy territory by an amphibious assault. The design evolved from the helicopter carrier, but includes support for amphibious landing craft, with most designs including a well deck. 190

191 Fig Six of the U.S. Navy's assault ships in formation; lead ship and the ship seen to its right are Tarawa-class, all others are Wasp-class. The role of the amphibious assault ship is fundamentally different from a standard aircraft carrier: its aviation facilities have the primary role of hosting helicopters to support forces ashore rather than to support strike aircraft. However, they are capable of serving in the sea-control role, embarking aircraft like Harrier fighters and ASW helicopters. Most of these ships can also carry or support landing craft, such as air-cushioned landing craft (hovercraft) or LCUs. The largest fleet of these types is operated by the United States Navy, including the Tarawa class dating back to the 1970s and the larger Wasp class ships that debuted in Amphibious assault ships are also operated by the British Royal Navy, the French Navy, the Italian Navy, the Republic of Korea Navy, and the Spanish Navy. Although the term amphibious assault ship is often used interchangeably with the more-general term amphibious warfare ship, it specifically applies only to the large-deck amphibious ships within the US Navy, the LPH, LHA, and LHD types. This does not include the amphibious transport dock (LPD), and dock landing ship (LSD). In the Pacific theater of World War II, escort carriers would often escort the landing ships and troop carriers during the island-hopping campaign. In this role, they would provide air cover for the troopships as well as fly the first wave of attacks on the beach fortifications in amphibious landing operations. On occasion they would even escort the large carriers, serving as emergency airstrips and providing fighter cover for their larger sisters while these were busy readying or refueling their own planes. In addition to this, they would also transport aircraft and spare parts from the US to the remote island airstrips. Despite all the progress that was seen during World War II, there were still fundamental limitations in the types of coastline that were suitable for assault. Beaches had to be relatively free of obstacles, and have the right tidal conditions and the correct slope. However, the development of the helicopter fundamentally changed the equation. The first use of helicopters in an amphibious assault came during the invasion of Egypt during the Suez War in In this engagement two British light fleet carriers, Ocean and Theseus, were converted to perform a battalion-size airborne assault with helicopters. 191

192 The techniques were developed further by American forces during the Vietnam War and refined during training exercises. The modern amphibious assault can take place at virtually any point of the coast, making defending against them extremely difficult. Most early amphibious assault ships were converted from small aircraft carriers. As well as the two Colossus class light aircraft carriers converted for use in the Suez War, the British Royal Navy converted the Centaur class carriers Albion and Bulwark into "commando carriers" during the 1950s. Sister ship HMS Hermes was also converted to a commando carrier in the early 1970s, but was restored to aircraft carrier operations before the end of the 1970s. The United States Navy used three Essex class aircraft carriers; US Ships Boxer, Princeton, and Valley Forge, and the Casablanca class escort carrier USS Thetis Bay as the basis of their amphibious assault fleet, before constructing the five Iwo Jima class ships specifically for the Landing Platform Helicopter role. Later amphibious assault craft were constructed for the role. The United States Navy constructed the Tarawa class of five Landing Helicopter Assault ships, which began to enter service from the late 1970s, and the Wasp class of eight Landing Helicopter Dock ships, the first of which was commissioned in The United States Navy is also designing a new class of assault ships: the first America class ship is predicted to enter service in The first British ship to be constructed specifically for the amphibious assault role was HMS Ocean, which was commissioned into the Royal Navy in Other nations have built amphibious assault ships; the French Mistral class, South Korea's ROKS Dokdo, and Spain's Juan Carlos I (L61) are all currently active, while Australia is building two Canberra class ships based on the Spanish design. Due to their aircraft carrier heritage, all amphibious assault ships resemble aircraft carriers in design. The flight deck is used to operate helicopters for landing troops and supplies and Harrier Jump Jets to provide air support to landing operations. STOL aircraft such as the OV-10 were sometimes deployed on and were able to perform short takeoffs and landings on large deck amphibious assault ships without needing catapults or arresting wires, although for safety and clearance reasons the latter was most often not permitted. Landing craft are also carried, either on deck-mounted davits, or in an internal well deck. Seaplane tender A seaplane tender (or seaplane carrier) is a ship that provides facilities for operating seaplanes. These ships were the first aircraft carriers and appeared just before the First World War. The first seaplane tender appeared in 1911 with the French Navy La Foudre, following the invention of the seaplane in 1910 with the French Le Canard. La Foudre carried float-equipped planes under hangars on the main deck, from where they were lowered on the sea with a crane. La Foudre was further modified in November 1913 with a 10 meter-long flat deck to launch her seaplanes. Another early seaplane carrier was HMS Hermes, an old cruiser converted and commissioned with a flying-off deck in mid In the Battle of Tsingtao, from September 5, 1914 the Imperial Japanese Navy seaplane carrier Wakamiya conducted the world's first naval-launched air raids from Kiaochow Bay. The four Maurice Farman seaplanes bombarded German-held land targets (communication centers and command centers) and damaged a German minelayer in the Tsingtao peninsula from September to November 6, 1914 when the Germans surrendered. On Christmas Day 1914 the British carried out the Cuxhaven Raid - seaplanes carried within range of their targets attacked German naval targets in the Heligoland Bight. These carriers had hangars for storing and maintaining the aircraft, but no flight deck as in a true aircraft carrier. Instead they used cranes to lower the aircraft into the sea for takeoff and to recover them after landing. The ships were normally converted merchant vessels rather than specially constructed for the task. As aircraft improved the problems of using seaplanes became more of a handicap. The aircraft could only be operated in a smooth sea and the ship had to stop for launching or recovery, both of which took around 20 minutes. The tender was often stationed ten miles or so in front of the main battle fleet with the cruiser screen so that it would not fall hopelessly behind when it launched its aircraft. Seaplanes also had poorer performance than other aircraft because of the drag and weight of the floats. Seaplane tenders had largely been superseded by aircraft carriers in the battle fleet by the end of the First World War, although aircraft were still of minor importance compared to the firepower of naval artillery. The British Ark Royal was a seaplane tender with a flying-off deck. Seaplanes could be recovered while the ship was under way through the "Hein Mat" - a sheet towed behind the vessel, once the aircraft was on the mat it was effectively stationary with respect to the ship and could be hoisted aboard. 192

193 In the inter-war years, it was common for cruisers and battleships to be equipped with catapultlaunched reconnaissance seaplanes. A few navies, especially those without true aircraft carriers, also acquired catapult-equipped seaplane carriers for fleet reconnaissance. During the Second World War both the United States Navy and the Imperial Japanese Navy built a number of seaplane tenders to supplement their aircraft carrier fleets. However, these ships often had their catapults removed, and were used as support vessels that operated seaplanes from harbours rather than in a seaway. These aircraft were generally for long range reconnaissance patrols. The tenders allowed the aircraft to be rapidly deployed to new bases because their runways did not have to be constructed, and support facilities were mobile much like supply ships for submarines or destroyers. Seaplane tenders became obsolete at the end of the Second World War. A few remained in service after the war but by the late-1950s most had been scrapped or converted to other uses such as helicopter repair ships. Supercarrier Supercarrier (fig. 139) is an unofficial descriptive term for the largest type of aircraft carrier, usually displacing over 70,000 long tons. The U.S. Navy currently has 11 such ships. In comparison, a few countries operate medium carriers of around 40,000 tons (such as Charles de Gaulle), whereas light carriers closer to 20,000 tons (such as HMS Illustrious) are more typical. Supercarriers are the largest warships ever built. Fig USS Enterprise, a supercarrier, and the medium-sized carrier Charles de Gaulle. The first ship to be described by The New York Times as a supercarrier was HMS Ark Royal in 1938; with a length of 685 ft and a displacement of 22,000 tons, it was designed to carry 72 aircraft. In 1943, the superlative was transferred to the 45,000-ton carriers of the Midway class, as a step-up from the 27,000-ton Essex class. The post-war standard for supercarriers was set by the proposed USS United States and USS Forrestal. 193

194 Forrestal displaced 60,000 tons standard, and 78,000 tons in deep load, when launched, and is considered the first operational supercarrier in the present-day sense, as dubbed by the American press. The similarly-sized United States would have been in service earlier, had it been completed; its cancellation triggered the "Revolt of the Admirals". The Soviet Union's 85,000-ton nuclear carrier Ulyanovsk, closely comparable in size to earlier American supercarriers, was 40% complete when it and a follow-on vessel were canceled in 1991, due to post-cold War funding cuts. The United States is no longer alone in building supercarriers, with the United Kingdom building two 65,600-ton carriers Queen Elizabeth class, and France considering building one vessel, possibly based on the same design. These ships are routinely referred to as supercarriers by British legislators and the media. The two Queen Elizabeth class vessels will provide the Royal Navy with capabilities much closer to United States Navy carriers than its current Invincible class vessels. Giving evidence to the House of Commons Defence Committee, the then First Sea Lord Admiral Sir Alan West explained that interoperability with the United States Navy was as much a deciding factor of the size of the carriers as the firepower of the carrier's airwing: I have talked with the CNO (Chief of Naval Operations) in America. He is very keen for us to get these because he sees us slotting in with his carrier groups. He really wants us to have these, but he wants us to have the same sort of clout as one of their carriers. Future plans for supercarriers in the United States involve the construction of the US Navy's next generation of carriers, the Gerald R. Ford class, which will have a 100,000 ton displacement. The United States maintains eleven of these ships. Given their vulnerability to conventional and asymmetrical threats, more and smaller carriers have been suggested over the years, such as Zumwalt's Sea Control Ship. However, supercarriers are considered to be more cost effective than smaller carriers. The mobile offshore base (MOB) is a concept for a modular floating military base as large as 10 aircraft carriers. If realized, it could be moved anywhere throughout the world's oceans, obviating the need to seek permission from allied nations for use of land bases. The concept was studied in the 1990s by the U.S. government, but was abandoned in 2001 as cost prohibitive. A fleet carrier is an aircraft carrier that is designed to operate with the main fleet of a nation's navy. The term was coined during the Second World War, to distinguish it from the escort carrier and light carrier types. Unlike those types, that were usually conversions of other ship types (fitting cargo ships, cruisers, battlecruisers, battleships with a flight deck), the fleet carrier is designed from the very beginning as an aircraft carrier, allowing full specialization to its future role. Fleet carriers have grown to become the capital ships of a fleet, replacing battleships in that role. Escort aircraft carrier The escort aircraft carrier or escort carrier, also called a "jeep carrier" or "baby flattop" in the USN or "Woolworth Carrier" by the Royal Navy, was a small and slow type of aircraft carrier used by the British Royal Navy (RN), the Imperial Japanese Navy and Imperial Japanese Army Air Force, and the United States Navy (USN) in World War II. They were typically half the length and one-third the displacement of the larger fleet carriers. While they were slower, less armed and armored, and carried fewer planes, they were less expensive and could be built in less time. This was their principal advantage, as escort carriers could be completed in greater numbers as a stop-gap when fleet carriers were scarce. However, the lack of protection made escort carriers particularly vulnerable and several were sunk with great loss of life. The light carrier (hull classification symbol CVL) was a similar concept to escort carriers in most respects, however they were intended for higher speeds to be deployed alongside fleet carriers. Escort carriers were too slow to keep up with the main forces consisting of fleet carriers, battleships, and cruisers. Instead, they were used to defend convoys from enemy threats such as submarines and planes. In the invasions of mainland Europe and Pacific islands, escort carriers provided air support to ground forces 194

195 during amphibious operations. Escort carriers also served as backup aircraft transports for fleet carriers, and ferried aircraft of all military services to points of delivery. In the Atlantic, the escort carriers were used to protect convoys against U-boats. Initially escort carriers accompanied the merchant ships and fended off attacks from aircraft and submarines. Later in the war, escort carriers were part of hunter-killer groups which sought out submarines instead of being attached to a particular convoy. During the Leyte Campaign, at the Battle off Samar, the Japanese Center Force of cruisers and battleships, including Yamato, the largest battleship ever built, met the US task force of escort carriers and destroyers known as "Taffy 3". The escort carriers and destroyers were not expected to put up much of a fight against major big-gun warships. Nonetheless, the Japanese were turned back by furious defence put up by "Taffy 3", with the Wildcat and Avenger planes playing a key role against the Japanese who had no air cover, as well as the US destroyers who made torpedo runs. The US sunk three Japanese cruisers in that engagement, at the cost of one escort carrier and three destroyers. Of the 151 aircraft carriers built in the United States during WWII, 122 were escort carriers. Though no examples survive to this day, the Casablanca class holds the distinction of being the most numerous single class of aircraft carrier ever built, with 50 having been launched. The Bogue class escort carrier comes in a close second, with 45 launched. The Washington Naval Treaty imposed limits on the maximum size and total tonnage of aircraft carriers for the five main naval powers. Later treaties largely kept these provisions. As a result construction between the World Wars had been insufficient to meet operational needs for aircraft carriers as the Second World War expanded from Europe. Too few fleet carriers were available to simultaneously transport aircraft to distant bases, support amphibious invasions, offer carrier landing training for replacement pilots, conduct antisubmarine patrols, and provide defensive air cover for deployed battleships and cruisers. The foregoing mission requirements limited use of fleet carriers' unique offensive strike capability demonstrated at the Battle of Taranto and the Attack on Pearl Harbor. Conversion of existing ships (and hulls under construction for other purposes) provided additional aircraft carriers until new construction became available. Conversions of cruisers, passenger liners, and fleet oilers with speed similar to fleet carriers were identified by the United States as "light aircraft carriers" (hull classification symbol CVL) able to operate at battle fleet speeds. Slower conversions were classified as "escort carriers" and were considered naval auxiliaries suitable for pilot training and transport of aircraft to distant bases. The Royal Navy had recognized a need for carriers to defend its trade routes in the 1930s. No construction was undertaken until HMS Audacity (D10) was converted from the captured German merchant ship MV Hannover and commissioned in July For defence from German aircraft, convoys were supplied first with Fighter catapult ships and CAM Ships which could carry a single (disposable) fighter. In the interim, before escort carriers could be supplied, they also brought in Merchant aircraft carriers which could operate 4 aircraft. In 1940, Admiral William Halsey recommended construction of naval auxiliaries for pilot training. On 1 February 1941, the United States Chief of Naval Operations gave priority to construction of naval auxiliaries for aircraft transport. United States ships built to meet these needs were initially referred to as auxiliary aircraft escort vessels (AVG) in February 1942 and then auxiliary aircraft carrier (ACV) on 5 August The first United States example of the type was USS Long Island (AVG-1). Operation Torch and North Atlantic antisubmarine warfare proved these ships capable aircraft carriers for ship formations moving at the speed of trade or amphibious invasion convoys. United States classification revision to escort aircraft carrier (CVE) on 15 July 1943 reflected upgraded status from auxiliary to combatant. They were informally known as "Jeep carriers" or "baby flattops." It was quickly found that the escort carriers had better performance than light carriers, which tended to pitch badly in moderate to high seas. The Commencement Bay class was designed to incorporate the best features of American CVLs on a more stable hull with a less expensive propulsion system. Amongst their crews, CVE was sarcastically said to stand for "Combustible, Vulnerable, and Expendable". Magazine protection was minimal in comparison to fleet aircraft carriers. HMS Avenger was sunk within minutes by a single torpedo, and HMS Dasher (D37) exploded from undetermined causes with very heavy loss of life. Three escort carriers USS St. Lo (CVE-63), Ommaney Bay (CVE-79) and Bismarck Sea (CVE-95) were destroyed by kamikazes, the largest ships to meet such a fate. Allied escort carriers were typically around 500 ft (150 m) long, not much more than half the length of the almost 900 ft (300 m) fleet carriers of the same era, but were less than one-third of the weight. A typical escort carrier displaced about 8,000 tons, as compared to almost 30,000 tons for a full-size fleet carrier. The 195

196 aircraft hangar typically ran only a third of the way under the flight deck and housed a combination of 24 to 30 fighters and bombers organized into one single "composite squadron". By comparison a late Essex-class fleet carrier could carry a total of 103 aircraft organized into separate fighter, bomber and torpedo-bomber squadrons. The island on these ships was small and cramped, and located well forward of the funnels (unlike on a normal-sized carrier where the funnels were integrated into the island). Although the first escort carriers had only one aircraft elevator, two elevators, one fore and one aft, quickly became standard, so did the one aircraft catapult. The carriers employed the same system of arresting cables and tailhooks as on the big carriers, and procedures for launch and recovery were the same as well. The crew size was less than a third of that of a large carrier, but this was still a bigger complement than most naval vessels. It was large enough to justify the existence of facilities such as a permanent canteen or snack bar, called a gedunk bar, in addition to the mess. The bar was open for longer hours than the mess and sold several flavors of ice cream, along with cigarettes and other consumables. There were also several vending machines, which made a "gedunk" sound when operated. In all, 130 Allied escort carriers were launched or converted during the war. Of these, six were British conversions of merchant ships: HMS Audacity (D10), Nairana (D05), Campania (D48), Activity (D94), Pretoria Castle F61) and Vindex (D15). The remaining escort carriers were US-built. Like the British, the first US escort carriers were converted merchant vessels (or in the Sangamon class, converted military oilers). The Bogue class carriers were based on the hull of the Type C3 cargo ship. The last 69 escort carriers of the Casablanca and Commencement Bay classes were purpose-designed and purpose-built carriers drawing on the experience gained with the previous classes. Originally developed at the behest of the United Kingdom to operate as part of a North Atlantic convoy escort rather than as part of a naval strike force, many of the escort carriers produced were assigned to the Royal Navy for the duration of the war under the Lend-lease act. They supplemented and then replaced the converted merchant aircraft carriers which were put into service by the British and Dutch as an emergency measure until the escort carriers became available. As convoy escorts, they were used by the Royal Navy to provide air scouting, to ward off enemy long-range scouting aircraft and, increasingly, to spot and hunt submarines. Often additional escort carriers also joined convoys, not as fighting ships but as transporters, ferrying aircraft from the US to Britain. In this case the aircraft cargo could be doubled by storing aircraft on the flight deck as well as in the hangar. The ships sent to the Royal Navy were slightly modified, partly to suit the traditions of that service. Among other things the ice cream making machines were removed, since they were considered unnecessary luxuries on ships, which served grog and other alcoholic beverages. The heavy duty washing machines of the laundry room were also removed since "all a British sailor needs to keep clean is a bucket and a bar of soap" (quoted from Warrilow). Other modifications were due to the need for a completely enclosed hangar when operating in the North Atlantic and in support of the Arctic convoys. Meanwhile the U.S. discovered their own use for the escort carriers. In the North Atlantic, they supplemented the escorting destroyers by providing air support for anti-submarine warfare. One of these escort carriers, USS Guadalcanal (CVE-60), was instrumental in the capture of the German submarine) U-505 off North Africa in In the Pacific theatre, escort carriers lacked the speed to sail with fast carrier attack groups, so were often tasked to escort the landing ships and troop carriers during the island-hopping campaign. In this role they provided air cover for the troopships and flew the first wave of attacks on beach fortifications in amphibious landing operations. On occasion they even escorted the large carriers, serving as emergency airstrips and providing fighter cover for their larger sisters while these were busy readying or refueling their own planes. They also transported aircraft and spare parts from the US to remote island airstrips. Perhaps the finest moment for these escort carriers was the relatively little known Battle off Samar. Aircraft from sixteen escort carriers in three task groups (many unarmed or armed only for harassment), along with their hopelessly outmatched defending destroyers and destroyer escorts, faced a Japanese task force of four battleships, including Yamato, eight cruisers, and eleven detroyers. The American escort carriers not only fended off but turned back the attackers. The slow carriers could not hope to outrun 30 kn (35 mph; 56 km/h) cruisers. They launched their aircraft and maneuvered to avoid shellfire for over an hour. They endured dozens of hits, mostly from armor piercing rounds which passed right through their thin, unarmored hulls without exploding. USS Gambier Bay (CVE-73), lost in this action, was the only U.S. carrier lost to gunfire in the war. The carriers 196

197 carried only a single 5-inch anti-aircraft gun as a stinger, but to land accurate hits, pursuing Japanese cruisers had to close within range of the carriers' own guns. One of the guns caused critical damage to the burning Japanese cruiser Chokai and a subsequent bomb dropped from one of the task force's aircraft hit the forward machinery room on Chokai, leaving her dead in the water. Several kamikaze aircraft were shot down by carrier gunners, with only St Lo lost to air attack. In the costly victory, the small task force had suffered a number of ships and men lost comparable to the Battle of Coral Sea and Battle of Midway combined. There are three basic tactics for operating an escort carrier in defence of a convoy: Within the convoy, which gives it the protection of the convoy's escort but limits the space to turn into the wind to operate aircraft. Near the convoy, which gives the carrier freedom of manoeuvre, but puts it outside the screen provided by the convoy's escort, making it necessary for the carrier to have its own separate escort. The carrier is also likely to be spotted by enemy forces approaching the convoy, making it vulnerable to attack. Some distance away from the convoy. This increases the time required for aircraft to reach the convoy but reduces the risk of being spotted by forces attacking the convoy. The years following World War II brought many revolutionary new technologies to the navy, most notably the helicopter and the jet fighter, and with this a complete rethinking of its strategies and ships' tasks. Although several of the latest Commencement Bay-class CVE were deployed as floating airfields during the Korean War, the main reasons for the development of the escort carrier had disappeared or could be dealt with better by newer weapons. The emergence of the helicopter meant that helicopter-deck equipped frigates could now take over the CVE's role in a convoy while also performing their own traditional role as submarine hunters. Ship-mounted guided missile launchers took over much of the aircraft protection role, and in-flight refueling abolished the need for floating stopover points for transport or patrol aircraft. As a result, after the Commencement Bay class, no new escort carriers were designed, and with every downsizing of the navy, the CVEs were the first to be mothballed. Several escort carriers were pressed back into service during the first years of the Vietnam War because of their ability to carry large numbers of aircraft. Redesignated AKV (air transport auxiliary), they were manned by a civilian crew and used to ferry whole aircraft and spare parts from the United States to Army, Air Force and Marine bases in South Vietnam. However, CVEs were only useful in this role for a limited period. Once all major aircraft were equipped with refueling probes, instead of shipping a plane overseas to its pilot, it became much easier to fly the aircraft directly to its base. The last chapter in the saga of the escort carriers consisted out of two conversions: As an experiment, the USS Thetis Bay (CVE-90) was converted from an aircraft carrier into a pure helicopter carrier (CVHA-1) and used by the Marine Corps to carry assault helicopters for the first wave of amphibious warfare operations. Later, the Thetis Bay became a full amphibious assault ship (LHP-6). Although in service only from 1955 (the year of her conversion) to 1964, the experience gained in her training exercises greatly influenced the design of today's amphibious assault ships. In the second conversion, in 1961, the USS Gilbert Islands (CVE-107) had all her aircraft handling equipment removed and four tall radio antennas installed on her long, flat deck. In lieu of aircraft, the hangar deck now had no less than 24 military radio transmitter trucks bolted to its floor. Rechristened USS Annapolis (AGMR-1), the ship was used as a communication relay ship and served dutifully through the Vietnam War as a floating radio station, relaying transmissions between the forces on the ground and the command centers back home. Like the Thetis Bay, the experience gained before she was stricken in 1976 helped develop today's purpose-built amphibious command ships of the Blue Ridge class. Unlike almost all other major classes of ships and patrol boats from World War II, most of which can be found in a museum or port, no escort carrier or American light carrier has survived: all were destroyed during the war or broken up in the following decades. The last escort carrier, USS Gilbert Islands, was broken up for scrap starting in The last American light carrier (the escort carrier's faster sister type) was the USS Cabot (CVL-28), which was broken up in 2002 after a decade-long attempt to preserve the vessel. The United States designed the Sea Control Ship to serve a similar role, whilst none where actually built the Spanish aircraft carrier Principe de Asturias and HTMS Chakri Naruebet are all based on the concept. 197

198 Cap. 9. THE BATTLE OF MIDWAY The Battle of Midway is widely regarded as the most important naval battle of the Pacific Campaign of World War II. Between 4 and 7 June 1942, approximately one month after the Battle of the Coral Sea and six months after Japan's attack on Pearl Harbor, the United States Navy decisively defeated an Imperial Japanese Navy (IJN) attack against Midway Atoll, inflicting irreparable damage on the Japanese fleet. Military historian John Keegan has called it "the most stunning and decisive blow in the history of naval warfare." The Japanese operation, like the earlier attack on Pearl Harbor, sought to eliminate the United States as a strategic power in the Pacific, thereby giving Japan a free hand in establishing its Greater East Asia Co- Prosperity Sphere. The Japanese hoped that another demoralizing defeat would force the U.S. to capitulate in the Pacific War. The Japanese plan was to lure the United States' aircraft carriers into a trap. The Japanese also intended to occupy Midway Atoll as part of an overall plan to extend their defensive perimeter in response to the Doolittle Raid. This operation was also considered preparatory for further attacks against Fiji and Samoa. The plan was handicapped by faulty Japanese assumptions of the American reaction and poor initial dispositions. Most significantly, American codebreakers were able to determine the date and location of the attack, enabling the forewarned U.S. Navy to set up an ambush of its own. Four Japanese aircraft carriers and a heavy cruiser were sunk for a cost of one American aircraft carrier and a destroyer. After Midway, and the exhausting attrition of the Solomon Islands campaign, Japan's shipbuilding and pilot training programs were unable to keep pace in replacing their losses while the U.S. steadily increased its output in both areas. Japan had been highly successful in swiftly securing its initial war goals, including the conquest of the Philippines, Malaya, Singapore, and the Dutch East Indies (now Indonesia) with its vital resources. As such, preliminary planning for a second phase of operations commenced as early as January However, because of strategic differences between the Imperial Army and Imperial Navy, as well as infighting between the Navy's GHQ and Admiral Isoroku Yamamoto's Combined Fleet, the formulation of effective strategy was hampered, and the follow-up strategy was not finalized until April Admiral Yamamoto succeeded in winning a bureaucratic struggle, placing his operational concept further operations in the Central Pacific ahead of other contending plans. These included operations either directly or indirectly aimed at Australia and into the Indian Ocean. In the end, Yamamoto's thinly veiled threat to resign unless he got his way carried his agenda forward. Yamamoto's primary strategic concern was the elimination of America's carrier forces, which he perceived as the principal obstacle to the overall Pacific campaign. This concern was acutely heightened by the Doolittle Raid (18 April 1942) in which USAAF B-25 Mitchells launched from USS Hornet bombed targets in Tokyo and several other Japanese cities. The raid, while militarily insignificant, was a severe psychological shock to the Japanese and showed the existence of a gap in the defenses around the Japanese home islands. Sinking America's aircraft carriers and seizing Midway, the only strategic islands besides Hawaii in the eastern Pacific, was seen as the only means of nullifying this threat. Yamamoto reasoned an operation against the main carrier base at Pearl Harbor would induce the U.S. to fight. However, given the strength of American land-based air power on Hawaii, he judged the powerful American base could not be attacked directly. Instead, he selected Midway, at the extreme northwest end of the Hawaiian Island chain, some 1,300 mi (1,100 nmi; 2,100 km) from Oahu. Midway was not especially important in the larger scheme of Japan's intentions, but the Japanese felt the Americans would consider Midway a vital outpost of Pearl Harbor and would therefore strongly defend it. The U.S. did consider Midway vital; after the battle, establishment of a U.S. submarine base on Midway allowed submarines operating from Pearl Harbor to refuel and reprovision, extending their radius of operations by 1,200 mi (1,900 km). An airstrip on Midway served as a forward staging point for bomber attacks on Wake Island. Typical of Japanese naval planning during World War II, Yamamoto's battle plan was exceedingly complex. Additionally, his design was predicated on optimistic intelligence suggesting USS Enterprise and USS Hornet, forming Task Force 16, were the only carriers available to the U.S. Pacific Fleet at the time. At the Battle of the Coral Sea just a month earlier, USS Lexington had been sunk and USS Yorktown damaged severely enough that the Japanese believed it also to have been sunk. The Japanese were also aware that USS Saratoga was undergoing repairs on the West Coast after suffering torpedo damage from a submarine. However, more important was Yamamoto's belief the Americans had been demoralized by their frequent defeats during the preceding six months. Yamamoto felt deception would be required to lure the U.S. 198

199 fleet into a fatally compromised situation. To this end, he dispersed his forces so that their full extent (particularly his battleships) would be unlikely to be discovered by the Americans prior to battle. Critically, Yamamoto's supporting battleships and cruisers would trail Vice-Admiral Nagumo Chūichi's carrier striking force by several hundred miles. Japan's heavy surface forces were intended to destroy whatever part of the U.S. fleet might come to Midway's relief, once Nagumo's carriers had weakened them sufficiently for a daylight gun duel; this was typical of the battle doctrine of most major navies. Unbeknownst to Yamamoto, the United States had broken the main Japanese naval code (dubbed JN- 25 by the Americans). Yamamoto's emphasis on dispersal also meant that none of his formations could support each other. For instance, the only significant warships larger than destroyers that screened Nagumo's fleet were two battleships and three cruisers, despite his carriers being expected to carry out the strikes and bear the brunt of American counterattacks. By contrast, the flotillas of Yamamoto and Kondo had between them two light carriers, five battleships, and six cruisers, none of which would see any action at Midway. Their distance from Nagumo's carriers would also have grave implications during the battle, since the larger warships in Yamamoto and Kondo's forces carried scout planes, an invaluable reconnaissance capability denied to Nagumo. Likewise, the Japanese operations in the Aleutian Islands (Operation AL) removed yet more ships that could otherwise have augmented the force striking Midway. Whereas prior historical accounts have often characterized the Aleutians operation as a feint to draw American forces away, recent scholarship on the battle has suggested that AL was supposed to be launched simultaneously with the attack on Midway. However, a oneday delay in the sailing of Nagumo's task force meant that Operation AL began a day before the Midway attack. To do battle with an enemy force anticipated to muster four or five carriers, Admiral Chester W. Nimitz, Commander in Chief, Pacific Ocean Areas, needed every available U.S. flight deck. He already had Vice Admiral William Halsey's two-carrier (Enterprise and Hornet) task force at hand, though Halsey was stricken with shingles and had to be replaced by Rear Admiral Raymond A. Spruance, Halsey's escort commander. Nimitz also hurriedly recalled Rear Admiral Frank Jack Fletcher's task force, including the carrier Yorktown (which had suffered considerable damage at Coral Sea), from the South West Pacific Area. It reached Pearl Harbor just in time to provision and sail. Despite estimates that Yorktown would require several months of repairs at Puget Sound Naval Shipyard, her elevators were intact, and her flight deck largely so. The Pearl Harbor Naval Shipyard worked around the clock and in 72 hours, she was restored to a battle-ready state, judged good enough for two or three weeks of operations, as Nimitz required. Her flight deck was patched, whole sections of internal frames cut out and replaced, and several new squadrons were drawn from Saratoga; they did not, however, get time to train. Nimitz disregarded established procedure in getting his third and last available carrier ready for battle. Just three days after putting into dry dock at Pearl Harbor, Yorktown was again under way. Repairs continued even as she sortied, with work crews from the repair ship USS Vestal, herself damaged in the attack on Pearl Harbor six months earlier, still aboard. On Midway Island, the USAAF stationed four squadrons of B-17 Flying Fortresses, along with several B-26 Marauders. The Marine Corps had 19 SBD Dauntlesses, seven F4F-3 Wildcats, 17 Vought SBU-3 Vindicators, 21 Brewster F2A-3s, and six Grumman TBF-1 Avengers, the latter a detachment of VT-8 from Hornet. Meanwhile, as a result of her participation in the Battle of the Coral Sea, the Japanese carrier Zuikaku was in port in Kure, awaiting a replacement air group. That there were none immediately available was a failure of the IJN crew training program, which already showed signs of being unable to replace losses. Instructors from the Yokosuka Air Corps were employed in an effort to make up the shortfall. The heavily damaged Shōkaku had suffered three bomb hits at Coral Sea, and required months of repair in drydock. Despite the likely availability of sufficient aircraft between the two ships to re-equip Zuikaku with a composite air group, the Japanese made no serious attempt to get her into the forthcoming battle. Consequently, Admiral Nagumo would only have four fleet carriers: Kaga and Akagi forming Carrier Division 1; Hiryū and Sōryū as Carrier Division 2. At least part of this was a product of fatigue; Japanese carriers had been constantly on operations since 7 December 1941, including raids on Darwin and Colombo. The main Japanese strike aircraft to be used were the Aichi D3A1 "Val" dive bomber and the Nakajima B5N2 "Kate", which was capable of being used either as a torpedo bomber or as a level attack bomber. The main carrier fighter was the fast and highly maneuverable Mitsubishi A6M2 Zero. However, the carriers of the Kido Butai were suffering from a shortage of frontline aircraft. For various reasons, production of the "Val" had been drastically reduced, while that of the B5N had been stopped completely. As a consequence, there were none available to replace losses. This also meant that many of the aircraft being used during the June 1942 operations had been operational since late November 1941; although well maintained, they were almost worn 199

200 out and had become increasingly unreliable. These factors meant that all carriers had fewer than their normal aircraft complement and few spare aircraft. Japanese strategic scouting arrangements prior to the battle were also in disarray. A picket line of Japanese submarines was late getting into position (partly because of Yamamoto's haste), which let the American carriers reach their assembly point northeast of Midway (known as "Point Luck") without being detected. A second attempt at reconnaissance, using four-engine Kawanishi H8K "Emily" flying boats to scout Pearl Harbor prior to the battle (and thereby detect the absence or presence of the American carriers), part of Operation K, was also thwarted when Japanese submarines assigned to refuel the search aircraft discovered that the intended refueling point a hitherto deserted bay off French Frigate Shoals was occupied by American warships (because the Japanese had carried out an identical mission in March). Thus, Japan was deprived of any knowledge concerning the movements of the American carriers immediately before the battle. Japanese radio intercepts did notice an increase in both American submarine activity and message traffic. This information was in Yamamoto's hands prior to the battle. However, Japanese plans were not changed; Yamamoto, at sea on Yamato, did not dare inform Nagumo for fear of exposing his position and assumed that Nagumo had received the same signal from Tokyo. Nagumo's radio antennae, however, were unable to receive such long-wave transmissions, and he was left unaware of any American ship movements. Admiral Nimitz had one priceless asset: cryptanalysts had broken the JN-25 code. Commander Joseph J. Rochefort and his team at Station Hypo were able to confirm Midway as the target of the impending Japanese strike, to determine the date of the attack as either 4 or 5 June, and to provide Nimitz with a complete IJN order of battle. Japan's efforts to introduce a new codebook had been delayed, giving HYPO several crucial days; while it was blacked out shortly before the attack began, the important breaks had already been made. As a result, the Americans entered the battle with a very good picture of where, when, and in what strength the Japanese would appear. Nimitz was aware, for example, that the vast Japanese numerical superiority had been divided into no less than four task forces. This dispersal resulted in few fast ships being available to escort the Carrier Striking Force, limiting the anti-aircraft guns protecting the carriers. Nimitz thus calculated that his three carrier decks, plus Midway Island, to Yamamoto's four, gave the U.S. rough parity, especially since American carrier air groups were larger than Japanese ones. The Japanese, by contrast, remained almost totally unaware of their opponent's true strength and dispositions even after the battle began. The first air attack took off at 12:30 on 3 June, consisting of nine B-17s operating from Midway. Three hours later, they found the Japanese transport group 570 nmi (660 mi; 1,060 km) to the west. Under heavy antiaircraft fire, they dropped their bombs. Though hits were reported, none of the bombs actually landed on target and no significant damage was inflicted. Early the following morning, Japanese oil tanker Akebono Maru sustained the first hit when a torpedo from an attacking PBY flying boat struck her around 01:00. At 04:30 on 4 June, Nagumo launched his initial attack on Midway itself, consisting of 36 Vals and 36 Kates, escorted by 36 Zeros. At the same time, he launched combat air patrol (CAP), as well as his eight search aircraft (one from the heavy cruiser Tone launched 30 minutes late due to technical difficulties). Japanese reconnaissance arrangements were flimsy, with too few aircraft to adequately cover the assigned search areas, laboring under poor weather conditions to the northeast and east of the task force. Yamamoto's faulty dispositions had now become a serious liability. American radar picked up the enemy at a distance of several miles and interceptors were soon scrambled. Unescorted bombers headed off to attack the Japanese carrier fleet, their fighter escorts remaining behind to defend Midway. At 06:20, Japanese carrier aircraft bombed and heavily damaged the U.S. base. Midway-based Marine fighter pilots, flying F4F-3 Wildcats and obsolete Brewster F2A-3 Buffalos, intercepted the Japanese and suffered heavy losses, though they managed to destroy four "Val"s and at least three Zeros. Most of the U.S. planes were downed in the first few minutes; several were damaged, and only two remained flyable. In all, three F4Fs and 13 F2As were shot down. American anti-aircraft fire was accurate and intense, damaging many Japanese aircraft and claiming one-third of the Japanese planes destroyed. The initial Japanese attack did not succeed in neutralizing Midway. American bombers could still use the airbase to refuel and attack the Japanese invasion force; another aerial attack would be necessary if troops were to go ashore by 7 June. 200

201 Having taken off prior to the Japanese attack, American bombers based on Midway made several attacks on the Japanese carrier fleet. These included six TBFs from Hornet's VT-8, their crews on their first combat operation, and four USAAF B-26 Marauders armed with torpedoes. The Japanese shrugged off these attacks with almost no losses (as few as two fighters lost), while destroying all but one TBF and two B-26s. One B-26, hit by anti-aircraft fire from Akagi, made no attempt to pull out of its run and narrowly missed crashing directly into the carrier's bridge. This experience may well have contributed to Nagumo's determination to launch another attack on Midway, in direct violation of Yamamoto's order to keep the reserve strike force armed for anti-ship operations. Admiral Nagumo, in accordance with Japanese carrier doctrine at the time, had kept half of his aircraft in reserve. These comprised two squadrons each of dive bombers and torpedo bombers, the latter armed with torpedoes, should any American warships be located. The dive bombers were, as yet, unarmed. As a result of the attacks from Midway, as well as the morning flight leader's recommendation of a second strike, at 07:15, Nagumo ordered his reserve planes to be re-armed with contact-fused general purpose bombs for use against land targets. Some sources maintain that this had been underway for about 30 minutes when, at 07:40 the delayed scout plane from Tone signaled the discovery of a sizable American naval force to the east; however, new evidence suggests Nagumo did not receive the sighting report until 08:00, so the rearming operation actually proceeded for 45 minutes. Nagumo quickly reversed his order and demanded the scout plane ascertain the composition of the American force. Another 40 minutes elapsed before Tone's scout finally radioed the presence of a single carrier in the American force, TF 16 (the other carrier being missed). Nagumo was now in a quandary. Rear Admiral Tamon Yamaguchi, leading Carrier Division 2 (Hiryū and Sōryū), recommended Nagumo strike immediately with the forces at hand: 18 Aichi D3A2 dive bombers each on Sōryū and Hiryū, and half the ready cover patrol aircraft. Nagumo's seeming opportunity to hit the American ships, however, was now limited by the fact his Midway strike force would be returning shortly and needing to land promptly or ditch (as is commonly believed). Because of the constant flight deck activity associated with combat air patrol operations during the preceding hour, the Japanese never had an opportunity to "spot" (position) their reserve for launch. The few aircraft on the Japanese flight decks at the time of the attack were either defensive fighters, or (in the case of Sōryū) fighters being spotted to augment the task force defenses. Spotting his flight decks and launching aircraft would have required at least minutes. Furthermore, by spotting and launching immediately, Nagumo would be committing some of his reserve to battle without proper anti-ship armament; he had just witnessed how easily unescorted American bombers had been shot down. (In the event, poor discipline saw many of the Japanese bombers ditch their bombs and attempt to dogfight intercepting F4Fs.) Japanese carrier doctrine preferred fully constituted strikes, and without confirmation (until 08:20) of whether the American force included carriers, Nagumo's reaction was doctrinaire. In addition, the arrival of another American air strike at 07:53 gave weight to the need to attack the island again. In the end, Nagumo chose to wait for his first strike force to land, then launch the reserve, which would by then be properly armed and ready. In the final analysis, it made no difference; Fletcher's carriers had launched beginning at 07:00, so the aircraft which would deliver the crushing blow were already on their way. There was nothing Nagumo could do about it. This was the fatal flaw of Yamamoto's dispositions: they followed strictly traditional battleship doctrine. Meanwhile, the Americans had already launched their carrier aircraft against the Japanese. Admiral Fletcher, in overall command aboard Yorktown, and benefiting from PBY patrol bomber sighting reports from the early morning, ordered Spruance to launch against the Japanese as soon as was practical, while initially holding Yorktown in reserve should there be any other Japanese carriers discovered. Fletcher's directions to Spruance were relayed via Nimitz who, unlike Yamamoto, had remained ashore. Spruance gave the order "Launch the attack" at around 06:00 and left Halsey's Chief of Staff, Captain Miles Browning, to work out the details and oversee the launch. It took until a few minutes after 07:00 before the first plane was able to depart from Spruance's carriers, Enterprise and Hornet. Fletcher, upon completing his own scouting flights, followed suit at 08:00 from Yorktown. Fletcher, Yorktown's commanding officer Captain Elliott Buckmaster, and their staffs had acquired first-hand experience in organizing and launching a full strike against an enemy force at Coral Sea, but there was no time to pass these lessons to Enterprise and Hornet which were tasked with launching the first strike. Spruance gave his second crucial command, to run toward the target quickly, as neutralizing an enemy carrier was the key to their own carriers' survival. He judged that the need to throw something at the enemy as soon as possible was greater than the need for a coordinated attack among the different types of aircraft (fighters, bombers, torpedo planes). Accordingly, American squadrons were launched piecemeal and proceeded to the target in several different groups. The lack of coordination was expected to diminish the overall impact of the 201

202 American attacks as well as increasing their casualties. However, Spruance calculated that this risk was worth it, since keeping the Japanese under aerial attack hampered their ability to launch a counterstrike (Japanese doctrine preferred fully constituted attacks), and he gambled that he could find Nagumo with his decks at their most vulnerable. American carrier aircraft had difficulty locating the target, despite the positions they had been given. The strike from Hornet, led by Commander Stanhope C. Ring, followed an incorrect heading of 263 degrees rather than the 240 heading indicated by the contact report. As a result, Air Group Eight's dive bombers missed the Japanese carriers. Torpedo Squadron 8 (VT-8, from Hornet), led by Lieutenant Commander John C. Waldron broke formation from Ring and followed the correct heading. Waldron's squadron sighted the enemy carriers and began attacking at 09:20, followed by Torpedo Squadron 6 (VT-6, from Enterprise) at 09:40. Without fighter escort, all fifteen TBD Devastators of VT-8 were shot down without being able to inflict any damage, with Ensign George H. Gay, Jr. the only survivor. VT-6 met nearly the same fate, with no hits to show for its effort, thanks in part to the abysmal performance of their Mark 13 aircraft torpedoes; senior Navy and BuOrd officers never questioned why half a dozen torpedoes, released so close to the Japanese carriers, produced no results. The Japanese combat air patrol, flying the much faster Mitsubishi A6M2 "Zeros", made short work of the unescorted, slow, under-armed TBDs. A few TBDs managed to get within a few ship-lengths range of their targets before dropping their torpedoes, being close enough to be able to strafe the enemy ships and force the Japanese carriers to make sharp evasive maneuvers. Despite their losses, the American torpedo attacks indirectly achieved three important results. First, they kept the Japanese carriers off balance, with no ability to prepare and launch their own counterstrike. Second, their attacks pulled the Japanese combat air patrol out of position. Third, many of the Zeros ran low on ammunition and fuel. The appearance of a third torpedo plane attack from the southeast by Torpedo Squadron 3 (VT-3) at 10:00 very quickly drew the majority of the Japanese CAP to the southeast quadrant of the fleet. Better discipline, and employment of all the Zeroes aboard, might have enabled Nagumo to succeed. By chance, at the same time VT-3 was sighted by the Japanese, two squadrons of American SBDs from Enterprise and Yorktown, VB-6 and VB-3 respectively, were approaching the Japanese fleet from the northeast and southwest. They were running low on fuel because of the time spent looking for the enemy. However, squadron commander C. Wade McClusky, Jr. decided to continue the search and by good fortune saw the wake of the Japanese destroyer Arashi. The destroyer was steaming at full speed to rejoin Nagumo's carrier force after having unsuccessfully depth-charged the U.S. submarine Nautilus, which had earlier unsuccessfully attacked the battleship Kirishima. Some bombers were lost from fuel exhaustion before the attack commenced. McClusky's decision to continue the search was credited by Admiral Chester Nimitz, and his judgment "decided the fate of our carrier task force and our forces at Midway..." The American dive-bombers arrived at the perfect time to attack. Armed Japanese strike aircraft filled the hangar decks, fuel hoses snaked across the decks as refueling operations were hastily completed, and the repeated change of ordnance meant bombs and torpedoes were stacked around the hangars, rather than stowed safely in the magazines, making the Japanese carriers extraordinarily vulnerable. Enterprise's VB-6 air group split up and attacked two targets. Beginning at 10:22, McClusky and his wingmen scored hits on Kaga, while to the north Akagi was attacked four minutes later by three bombers, led by Lieutenant Commander Richard Halsey Best.Yorktown's VB-3 commanded by Max Leslie went for Sōryū scoring hits. Simultaneously, VT-3 targeted Hiryū, which was sandwiched between Sōryū, Kaga, and Akagi, but scored no hits. The dive-bombers, within six minutes, left Sōryū and Kaga ablaze. Akagi was hit by just one bomb (dropped by LCDR Best), which penetrated to the upper hangar deck and exploded among the armed and fueled aircraft there. One bomb exploded underwater very close astern, the resulting geyser bending the flight deck upward and also causing crucial rudder damage. Sōryū took three bombs in her hangar deck; Kaga, at least four, possibly five. All three carriers were out of action and were eventually abandoned and scuttled. Hiryū, the sole surviving Japanese aircraft carrier, wasted little time in counterattacking. The first wave of Japanese dive bombers badly damaged Yorktown with three bomb hits that snuffed out her boilers, immobilizing her, yet her damage control teams patched her up so effectively (in about an hour) that the second wave's torpedo bombers mistook her for an undamaged carrier. Despite Japanese hopes to even the odds by eliminating two carriers with two strikes, Yorktown absorbed both Japanese attacks, the second wave mistakenly believing Yorktown had already been sunk and that they were attacking Enterprise. After two torpedo hits, Yorktown lost power and developed a 26 list to port, which put her out of action and forced Admiral Fletcher to move his command staff to the heavy cruiser Astoria. Both carriers of Spruance's Task Force 16 were undamaged. 202

203 News of the two strikes, with the reports that each had sunk an American carrier, greatly improved morale in the Kido Butai. Its few surviving aircraft were all recovered aboard Hiryū, where they were prepared for a strike against what was believed to be the only remaining American carrier. Late in the afternoon, a Yorktown scout aircraft located Hiryū, prompting Enterprise to launch a final strike of dive bombers (including 10 bombers from Yorktown). This delivered a killing blow, leaving Hiryū ablaze, despite being defended by a strong cover of more than a dozen Zero fighters. Rear Admiral Yamaguchi chose to go down with his ship when she sank on 5 June, costing Japan perhaps her best carrier sailor. Hornet's strike, launching late because of a communications error, concentrated on the remaining escort ships, but failed to score any hits (fig. 140). As darkness fell, both sides took stock and made tentative plans for continuing the action. Admiral Fletcher, obliged to abandon derelict Yorktown and feeling he could not adequately command from a cruiser, ceded operational command to Spruance. Spruance knew the United States had won a great victory, but was still unsure of what Japanese forces remained and was determined to safeguard both Midway and his carriers. To aid his aviators, who had launched at extreme range, he had continued to close with Nagumo during the day, and persisted as night fell. Fearing a possible night encounter with Japanese surface forces, Spruance changed course and withdrew to the east, turning back west towards the enemy at midnight. For his part, Yamamoto initially decided to continue the engagement and sent his remaining surface forces searching eastward for the American carriers. Simultaneously, a cruiser raiding force was detached to bombard the island. The Japanese surface forces failed to make contact with the Americans due to Spruance's decision to briefly withdraw eastward, and Yamamoto ordered a general retirement to the west. American search planes failed to detect the retiring Japanese task forces on 5 June. An afternoon strike narrowly missed detecting Yamamoto's main body and failed to score hits on a straggling Japanese destroyer. The strike planes returned to the carriers after nightfall, prompting Spruance to order Enterprise and Hornet to turn on searchlights in order to aid their landings. At 02:15 on 5/6 June, Commander John Murphy's Tambor, lying some 90 nmi (100 mi; 170 km) west of Midway, made the second of the Submarine Force's two major contributions to the battle's outcome. Sighting several ships, he (along with his exec, Ray Spruance, Jr.) could not identify them (and feared they might be friendly, so he held fire), but reported their presence, omitting their course. This went to Admiral Robert English, Commander, Submarine Force, Pacific Fleet (COMSUBPAC), and from him through Nimitz to the senior Spruance. Unaware of the exact location of Yamamoto's "Main Body" (a persistent problem since PBYs had first sighted the Japanese), Spruance presumed this was the invasion force. Thus, he moved to block it, taking station some 100 nmi (120 mi; 190 km) northeast of Midway; this frustrated Yamamoto's efforts, and the night passed without any contact between the opposing forces. Actually, this was Yamamoto's bombardment group of four cruisers and two destroyers, which at 02:55 was ordered to retire west with the rest of his force. Tambor was sighted around the same time; turning to avoid her, Mogami and Mikuma collided, inflicting serious damage to Mogami's bow, the most any of the 18 submarines deployed for the battle achieved. Only at 04:12 did the sky brighten enough for Murphy to be certain the ships were Japanese, by which time staying surfaced was a hazard, and he dived to approach for an attack. This was unsuccessful, and at around 06:00, he finally reported two Mogami-class cruisers, westbound, placing Spruance at least 100 nmi (120 mi; 190 km) out of position. It may have been fortunate Spruance did not pursue, for had he come in contact with Yamamoto's heavy ships, including Yamato, in the dark, his cruisers would have been overwhelmed, and his carriers helpless. (At that time, only Britain's Fleet Air Arm was capable of night carrier operations.) Over the following two days, first Midway and then Spruance's carriers launched several successive strikes against the stragglers. Mikuma was eventually sunk by Dauntlesses, while Mogami survived severe damage to return home for repairs. Captain Richard E. Fleming, a U.S. Marine Corps aviator, was posthumously awarded the Medal of Honor for his attack on Mikuma (fig. 141). Another Marine aviator, Major Lofton Henderson, killed while leading his squadron into action against the Japanese carriers and becoming the first Marine aviator to perish during the battle, was also honored, by having the airfield at Guadalcanal named after him in August Meanwhile, salvage efforts on Yorktown were encouraging and she was taken in tow by USS Vireo, until late afternoon on 6 June when Yorktown was struck by two torpedoes from I-168. There were few casualties aboard Yorktown, since most of the crew had already been evacuated, but a third torpedo from this 203

204 salvo also struck and sank the destroyer USS Hammann, which had been providing auxiliary power to Yorktown. Hammann broke in two with the loss of 80 lives, most due to her own depth charges exploding. Yorktown lingered until just after 05:00 on 7 June. Fig Hiryū, shortly before sinking. By the time the battle ended, 3,057 Japanese had died. The four carriers sunk and their casualties were: Akagi: 267; Kaga: 811; Hiryu: 392; Soryu: 711; a combined total of 2,181. The heavy cruisers Mikuma (sunk): 700; and Mogami (badly damaged): 92; between them took a total of 792 casualties. In addition, the destroyers Arashio (bombed): 35; and Asashio (strafed by aircraft): 21; were both attacked while escorting the damaged heavy cruisers. Floatplanes were lost from the cruisers Chikuma: 3; and Tone: 2. Dead aboard the destroyers Tanikaze: 11; Arashi: 1; Kazagumo: 1; and the fleet oiler Akebono Maru: 10; make up the remaining 23 casualties. After winning a clear victory, and as pursuit became too hazardous near Wake, American forces retired. Historian Samuel E. Morison wrote in 1949 that Spruance was subjected to much criticism for not pursuing the retreating Japanese, and allowing the retreating Japanese surface fleet to escape. Clay Blair argued in 1975 that had Spruance pressed on, he would have been unable to launch his aircraft after nightfall, and his cruiser escorts would have been overwhelmed by Yamamoto's larger and more powerful surface units, including Yamato. And with his torpedo bombers lost it is doubtful that his aircraft would have been effective against battleships. On 10 June, the Imperial Japanese Navy conveyed to the military liaison conference an incomplete picture of the results of the battle. Chūichi Nagumo's detailed battle report was submitted to the high command 15 June. It was intended only for the highest echelons in the Japanese Navy and government, and was guarded closely throughout the war. In it, one of the more striking revelations is the comment on the Mobile Force Commander's (Nagumo's) estimates: "The enemy is not aware of our plans (we were not discovered till early in the morning of the 5th at the earliest)." The Japanese public were kept in the dark as to the extent of the defeat, as was much of the military command structure. Japanese news announced a great victory. Only Emperor Hirohito and the highest Navy command personnel were accurately informed of the carrier and pilot losses. Subsequently, Army planners continued to believe, for at least a short time, that the fleet was in good condition. On the return of the Japanese fleet to Hashirajima on 14 June the wounded were immediately transferred to naval hospitals; most were classified as "secret patients", placed in isolation wards and quarantined from other patients and their own families to prevent the secret of this major defeat from getting out to the general populace. 204

205 The remaining officers and men were quickly dispersed to other units of the fleet and, with no chance to see family or friends, were shipped to units in the South Pacific where the majority died. By contrast none of the flag officers or staff of the Combined Fleet were penalized, with Nagumo later being placed in command of the rebuilt carrier force. The Japanese Navy did learn some lessons from Midway: new procedures were adopted whereby more aircraft were refueled and re-armed on the flight deck, rather than in the hangars, and the practice of draining all unused fuel lines was adopted. The new carriers being built were redesigned to incorporate only two flight deck elevators and new firefighting equipment. More carrier crew members were trained in damage-control and firefighting techniques, although the losses later in the war of Shōkaku, Hiyō and Taihō showed that there were still problems in this area. Replacement pilots went through an abbreviated training regimen, meeting the short-term needs of the fleet; however, this led to a decline in the quality of training. These inexperienced pilots were fed into front-line units, while the veterans who remained after Midway and the Solomons campaign were forced to share an increased workload in increasingly desperate conditions, with few being given a chance to rest in rear areas or in the home islands. As a result, Japanese naval air groups progressively declined in overall quality during the war. Three U.S. airmen, Ensign Wesley Osmus (pilot, Yorktown), Ensign Frank O'Flaherty (pilot, Enterprise) and Aviation Machinist's Mate B. F. (or B. P.) Gaido (radioman-gunner of O'Flaherty's SBD) were captured by the Japanese during the battle. Osmus was held on the destroyer Arashi, with O'Flaherty and Gaido on the cruiser Nagara (or destroyer Makigumo, sources vary), and it is alleged they were later killed. sea". The report filed by Admiral Nagumo states of Ensign Osmus, "He died on 6 June and was buried at Nagumo recorded obtaining seven items of information, including the enemy's strength, but did not mention the death of O'Flaherty or Gaido. O'Flaherty and Gaido were tied to five-gallon kerosene cans filled with water and dumped overboard at unknown date several days or more after the battle. The battle has often been called "the turning point of the Pacific". However, the Japanese continued to try to advance in the South Pacific, and it was many more months before the U.S. moved from a state of naval parity to one of increasingly clear supremacy. Thus, although Midway was the Allies' first major victory against the Japanese, it did not change the course of the war in the same sense as Salamis; instead, it was the cumulative attrition of Midway, combined with that of the inconclusive Coral Sea battle, which reduced Japan's ability to undertake major offensives. Midway also paved the way for the landings on Guadalcanal and the prolonged attrition of the Solomon Islands campaign, which allowed the Allies to take the strategic initiative and swing to the offensive for the rest of the Pacific War. The battle showed the worth of pre-war naval cryptologic training and efforts. These efforts continued and were expanded throughout the war in both the Pacific and Atlantic theaters. Successes were numerous and significant. For instance, the shooting down of Admiral Yamamoto's airplane was only possible because of navy cryptanalysis. Some authors have stated heavy losses in carriers and veteran aircrews at Midway permanently weakened the Imperial Japanese Navy. Parshall and Tully, however, have pointed out that the losses in veteran aircrew, while heavy (110, just under 25% of the aircrew embarked on the four carriers), was not crippling to the Japanese naval air-corps as a whole: the Japanese navy had some 2,000 carrier qualified aircrew at the start of the Pacific war. A few months after Midway, the JNAF sustained similar casualty rates at both the Battle of the Eastern Solomons and Battle of Santa Cruz, and it was these battles, combined with the constant attrition of veterans during the Solomons campaign, which were the catalyst for the sharp downward spiral in operational capability. However, the loss of four large fleet carriers, and over 40% of the carriers' highly trained aircraft mechanics and technicians, plus the essential flight-deck crews and armorers, and the loss of organizational knowledge embodied by such highly trained crew, were heavy blows to the Japanese carrier fleet. 205

206 The loss of the carriers meant that only Shōkaku and Zuikaku were left for offensive actions. Of Japan's other carriers, Taihō was the only Fleet carrier worth teaming with Shōkaku and Zuikaku, while Ryūjō, Junyo, and Hiyō, were second-rate ships of comparatively limited effectiveness. By the time of the Battle of the Philippine Sea, while the Japanese had somewhat rebuilt their carrier forces, the planes were largely flown by inexperienced pilots so the carrier fleet was not as potent a striking force as it was before Midway. In the time it took Japan to build three carriers, the U.S. Navy commissioned more than two dozen fleet and light fleet carriers, and numerous escort carriers. By 1942, the United States was already three years into a shipbuilding program, mandated by the Second Vinson Act, intended to make the navy larger than Japan's. The greater part of USN aviators survived the Battle of Midway and subsequent battles of 1942, and combined with growing pilot training programs, the US was able to develop a large number of skilled pilots to complement its material advantages in ships and planes. Because of the extreme depth of the ocean in the area of the battle (more than 17,000 ft (5,200 m)), researching the battlefield has presented extraordinary difficulties. However, on 19 May 1998, Robert Ballard and a team of scientists and Midway veterans from both sides located and photographed (artist's rendering) Yorktown. The ship was remarkably intact for a vessel that sank in 1942; much of the original equipment and even the original paint scheme were still visible. Ballard's subsequent search for the Japanese carriers was ultimately unsuccessful. In September 1999, a joint expedition between Nauticos Corp. and the U.S. Naval Oceanographic Office searched for the Japanese aircraft carriers. Using advanced renavigation techniques in conjunction with the ship's log of the submarine USS Nautilus, the expedition located a large piece of wreckage, subsequently identified as having come from the upper hangar deck of Kaga. The main wreck, however, has yet to be located. Fig Mikuma shortly before sinking. Chicago Municipal Airport, important to the war efforts in World War II, was renamed Chicago Midway International Airport (or simply Midway Airport) in 1949 in honor of the battle. Waldron Field, an outlying training landing strip, at Corpus Christi NAS as well Waldron Road leading to the strip, was named in honor of the commander of USS Hornet's Torpedo Squadron 8. Yorktown Blvd leading away from the strip was named for the U.S. carrier sunk in the battle. An escort carrier, USS Midway (CVE-63) was commissioned on 17 August

207 She was renamed St. Lo on 10 October 1944 to clear the name Midway for a large fleet aircraft carrier, USS Midway (CV-41), commissioned on 10 September 1945 (eight days after the Japanese surrender). The latter ship is now docked in San Diego, California and is in use as the USS Midway Museum. The First Bombardment of Midway, or the First Bombardment of Sand Island, or Attack on Midway, was a small land and sea engagement of World War II. It occurred on the very first day of the Pacific War, 7 December 1941, not long after the major Battle of Pearl Harbor. Two Imperial Japanese destroyers bombarded Sand Island of Midway Atoll (fig. 142). The Japanese successfully damaged the U.S. Marine base before being engaged by American shore batteries and forced to flee. When the Japanese withdrew after taking fire, the Americans won their first victory of World War II. Fig Midway Atoll, on November 24, 1941 (up), and on December 07, 1941 (down). Before the beginning of the Pacific War, American marines were stationed on Midway and had established a small base with the ability to service land, sea and air forces. The marines also constructed all of the bases' fortifications, civilian contractors constructed the buildings. They used 5 in (130 mm) guns, built in 1916, and 3 in (76 mm) guns of 1921 to defend the islands. Fortifications dating back to 1905 were also manned. At this time, the U.S. had been focused on the war against Nazi Germany, and once the war began, generally all of the new military equipment produced was sent to the African and European theaters of operations. The newest military equipment sent to Europe and Africa ranged from warships to small arms, leaving only the relics for the U.S. Marines in the Pacific. Not only were Pearl Harbor, Wake Island and the Philippines attacked in the opening phase of the conflict, but Midway was shelled as well by two Japanese destroyers, Ushio and Sazanami. The two destroyers were part of the Japanese fleet that had just attacked Pearl Harbor. Overall, the unit was under the command of Captain Ohishi Kaname, though Lieutenant Commander Yoshitake Uesugi skippered Ushio and Lieutenant Commander Hiroshi Uwa skippered the other destroyer. The engagement began at 09:31 and lasted 54 minutes. The American command, communications and power plant building was damaged by a 5 in (130 mm) shell, which deflected off an adjacent laundromat. Battery "H" commander First Lieutenant George H. Cannon was hit by shrapnel in the pelvis while inside the command building. By this time the communications were down from enemy fire so Lieutenant Cannon refused medical attention until he was assured that the communications were restored to the post and until the wounded marines around him were evacuated. By the time Cannon received aid from a medic, it was too late and he perished due to blood loss. For Cannon's "distinguished conduct in the line of his profession, extraordinary courage, and disregard of his own condition", he received the first Medal of Honor issued to a U.S. Marine for actions in the Second World War. A street on Sand Island was named after Cannon and continues to be known by that name, a 1943 destroyer escort USS Cannon (DE-99) was also named after him. 207

208 Six Japanese rounds struck and entered the main PBY Catalina hangar and destroyed a PBY inside, the civilians inside survived without injury. The hospital was hit also and burned. All of the damaged buildings were quickly rebuilt by the civilian contractors. Shell craters littered the ground all around the buildings of Sand Island. The Marines did not use aircraft against the attacking Japanese. They did use their artillery batteries and managed to damage one of the destroyers when they came within range. The other destroyer quickly laid a smokescreen and the two vessels retired. Four men died on Midway that morning, other marines had slight injuries. Several United States Navy sailors were on the island during the attack, two of them were killed, Ensigns Donald J. Kraker and Ralph E. Tuttle. Two marines were killed, Lieutenant Cannon and Private First Class Elmer R. Morrell. Japanese casualties are unknown, Ushio fired 109 rounds and Sazanami fired 193. In February 1942 a Japanese submarine bombarded the atoll and a few months later, the great naval Battle of Midway was won, which is regarded as the most important naval battle of the war and the turning point in the Pacific theatre of operations. The marines by that time had received reinforcements, both personnel and some newer and bigger guns. All of which were used by the marine garrison when they engaged attacking Japanese A6M2 Zeros in June The marines also fought a deadly dog fight ending with heavy casualties for American forces and a loss of seven Japanese aircraft. Summary of enemy losses in the Battle of Midway Four carriers sunk: Akagi, Kaga, Soryu, Hiryu, with the loss of all their planes and many of their personnel. Estimated 275 planes, 2400 men. Two and probably three battleships damaged, one severely. Two Mogami class heavy cruisers sunk,61 three or more heavy cruisers damaged, some severely. One light cruiser damaged. Three destroyers sunk, a fourth possibly sunk. Four transport and cargo vessels hit, one or more possibly sunk. Estimated total number of personnel lost: 4,800. Summary of USA losses in the Battle of Midway Ships: Yorktown and Hammann sunk. Planes: About 150 lost in action or damaged beyond repair. Personnel: 92 officers and 215 men. The Battle of Midway was an important victory, which has exchanged the war's liders. Japan and Germany became losers. From this historical moment (June 07, 1942), the USA total victory there was just a matter of time. 208

209 Cap. 10 NEW AIRCRAFT Abstract: Speaking about a new ionic engine means to speak about a new aircraft. The chapter presents shortly the actual ionic engines (called ion thrusters) and the new ionic (pulse) engines proposed by the author. Ionic engine (ion thruster, which accelerates the positive ions through a potential difference) is about 10 times more effective than classic system based on combustion. We can still improve the efficiency of times if one uses pulses of positive ions accelerated in a cyclotron mounted on the ship; the efficiency can easily grow for 1000 times if the positive ions will be accelerated in a high energy synchrotron, synchrocyclotron or isochronous cyclotron (1-100 GeV). In this, the big classic synchrotron is reduced to a ring surface (magnetic core). Future (ionic) engine will have mandatory a circular particle accelerator (high or very high energy). We can thus increase the speed and autonomy of the ship using a less quantity of fuel and power. One can use synchrotron radiation (synchrotron light, high intensity beams), like high intensity (X-ray or Gamma ray) radiation, as well. In this case will be a beam engine (not an ionic engine), it ll use only the power (energy, which can be solar energy, nuclear energy, or both) and so we will remove the fuel. It proposes using a powerful LINAC at the exit of synchrotron (especially when one accelerates electrons) to not lose energy by photons premature emission. With a new ionic engine one builds a new aircraft, which can travel through water and. This new aircraft will can accelerate directly, without an additional combustion engine and without gravity assists from other planets. Keywords: high energy synchrotron, synchrocyclotron or isochronous cyclotron, circular particle accelerator, new aircraft, new ionic engine 1. ION THRUSTER 1.1. About the ion thruster An ion thruster is a form of electric propulsion used for spacecraft propulsion that creates thrust by accelerating ions. Ion thrusters are characterized by how they accelerate the ions, using either electrostatic or electromagnetic force. Electrostatic ion thrusters use the Coulomb Force and accelerate the ions in the direction of the electric field. Electromagnetic ion thrusters use the Lorentz Force to accelerate the ions. Note that the term "ion thruster" frequently denotes the electrostatic or gridded ion thrusters, only. The thrust created in ion thrusters is very small compared to conventional chemical rockets, but a very high specific impulse, or propellant efficiency, is obtained. Due to their relatively high power needs, given the specific power of power supplies, and the requirement of an environment void of other ionized particles, ion thrust propulsion currently is only practicable in outer space. The first experiments with ion thrusters were carried out by Robert Goddard at Clark College from The technique was recommended for near-vacuum conditions at high altitude, but thrust was demonstrated with ionized air streams at atmospheric pressure. The idea appeared again in Hermann Oberth's "Wege zur Raumschiffahrt (Ways to Spaceflight), published in A working ion thruster was built by Harold R. Kaufman in 1959 at the NASA Glenn facilities. It was similar to the general design of a gridded electrostatic ion thruster with mercury as its fuel. Suborbital tests of the engine followed during the 1960s and in 1964 the engine was sent into a suborbital flight aboard the Space Electric Rocket Test 1 (SERT 1). It successfully operated for the planned 31 minutes before falling back to Earth Hall effect thruster The Hall effect thruster was studied independently in the U.S. and the USSR in the 1950s and 60s. However, the concept of a Hall thruster was only developed into an efficient propulsion device in the former Soviet Union, whereas in the U.S., scientists focused instead on developing gridded ion thrusters. Hall effect thrusters were operated on Soviet satellites since Until the 1990s they were mainly used for satellite stabilization in North-South and in East-West directions. Some engines completed their mission on Soviet and Russian satellites until the late 1990s. Soviet thruster design was introduced to the West in 1992 after a team of electric propulsion specialists, under the support of the Ballistic Missile Defense Organization, visited Soviet laboratories. Ion thrusters utilize beams of ions (electrically charged atoms or molecules) to create thrust in accordance with Newton's third law. The method of accelerating the ions varies, but all designs take advantage of the charge/mass ratio of the ions. This ratio means that relatively small potential differences can create very high exhaust velocities. This reduces the amount of reaction mass or fuel required, but increases the amount of specific power required compared to chemical rockets. Ion thrusters are therefore able to achieve extremely high specific impulses. The drawback of the low thrust is low spacecraft acceleration because the mass of current electric power units is directly correlated with the amount of power given. This low thrust makes ion thrusters unsuited for launching spacecraft into orbit, but they are ideal for in-space propulsion applications. 209

210 Hall effect thrusters accelerate ions with the use of an electric potential maintained between a cylindrical anode and a negatively charged plasma which forms the cathode. The bulk of the propellant (typically xenon or bismuth gas) is introduced near the anode, where it becomes ionised, and the ions are attracted towards the cathode, they accelerate towards and through it, picking up electrons as they leave to neutralize the beam and leave the thruster at high velocity. The anode is at one end of a cylindrical tube, and in the center is a spike which is wound to produce a radial magnetic field between it and the surrounding tube. The ions are largely unaffected by the magnetic field, since they are too massive. However, the electrons produced near the end of the spike to create the cathode are far more affected and are trapped by the magnetic field, and held in place by their attraction to the anode. Some of the electrons spiral down towards the anode, circulating around the spike in a Hall current. When they reach the anode they impact the uncharged propellant and cause it to be ionised, before finally reaching the anode and closing the circuit Gridded electrostatic ion thrusters Gridded electrostatic ion thrusters commonly utilize xenon gas. This gas has no charge and is ionized by bombarding it with energetic electrons. These electrons can be provided from a hot cathode filament and accelerated in the electrical field of the cathode fall to the anode (Kaufman type ion thruster). Alternatively, the electrons can be accelerated by the oscillating electric field induced by an alternating magnetic field of a coil, which results in a self-sustaining discharge and omits any cathode (radiofrequency ion thruster). The positively charged ions are extracted by an extraction system consisting of 2 or 3 multi-aperture grids. After entering the grid system via the plasma sheath the ions are accelerated due to the potential difference between the first and second grid (named screen and accelerator grid) to the final ion energy of typically 1-2 kev, thereby generating the thrust. Ion thrusters emit a beam of positive charged xenon ions only. In order to avoid the charging-up of the spacecraft another cathode, placed near the engine, emits additional electrons (basically the electron current is the same as the ion current) into the ion beam. This also prevents the beam of ions from returning to the spacecraft and thereby cancelling the thrust. Gridded electrostatic ion thruster research (past/present): NASA Solar electric propulsion Technology Application Readiness (NSTAR) NASA s Evolutionary Xenon Thruster (NEXT) Nuclear Electric Xenon Ion System (NEXIS) High Power Electric Propulsion (HiPEP) EADS Radio-Frequency Ion Thruster (RIT) Dual-Stage 4-Grid (DS4G) 1.4. Field Emission Electric Propulsion Field Emission Electric Propulsion (FEEP) thrusters use a very simple system of accelerating liquid metal ions to create thrust. Most designs use either caesium or indium as the propellant. The design consists of a small propellant reservoir that stores the liquid metal, a very small slit that the liquid flows through, and then the accelerator ring. Caesium and indium are used due to their high atomic weights, low ionization potentials, and low melting points. Once the liquid metal reaches the inside of the slit in the emitter, an electric field applied between the emitter and the accelerator ring causes the liquid metal to become unstable and ionize. This creates a positive ion, which can then be accelerated in the electric field created by the emitter and the accelerator ring. These positively charged ions are then neutralized by an external source of electrons in order to prevent charging of the spacecraft hull Pulsed Inductive Thrusters Pulsed Inductive Thrusters (PIT) use pulses of thrust instead of one continuous thrust, and have the ability to run on power levels in the order of Megawatts (MW). PITs consist of a large coil encircling a cone shaped tube that emits the propellant gas. Ammonia is the gas commonly used in PIT engines. For each pulse of thrust the PIT gives, a large charge 210

211 first builds up in a group of capacitors behind the coil and is then released. This creates a current that moves circularly. The current then creates a magnetic field in the outward radial direction (Br), which then creates a current in the ammonia gas that has just been released in the opposite direction of the original current. This opposite current ionizes the ammonia and these positively charged ions are accelerated away from the PIT engine due to the electric field crossing with the magnetic field Br, which is due to the Lorentz Force Magnetoplasmadynamic Magnetoplasmadynamic (MPD) thrusters and Lithium Lorentz Force Accelerator (LiLFA) thrusters use roughly the same idea with the LiLFA thruster building off of the MPD thruster. Hydrogen, argon, ammonia, and nitrogen gas can be used as propellant. The gas first enters the main chamber where it is ionized into plasma by the electric field between the anode and the cathode. This plasma then conducts electricity between the anode and the cathode. This new current creates a magnetic field around the cathode which crosses with the electric field, thereby accelerating the plasma due to the Lorentz Force. The LiLFA thruster uses the same general idea as the MPD thruster, except for two main differences. The first difference is that the LiLFA uses lithium vapor, which has the advantage of being able to be stored as a solid. The other difference is that the cathode is replaced by multiple smaller cathode rods packed into a hollow cathode tube. The cathode in the MPD thruster is easily corroded due to constant contact with the plasma. In the LiLFA thruster the lithium vapor is injected into the hollow cathode and is not ionized to its plasma form/corrode the cathode rods until it exits the tube. The plasma is then accelerated using the same Lorentz Force Electrodeless Plasma Thrusters Electrodeless Plasma Thrusters have two unique features, the removal of the anode and cathode electrodes and the ability to throttle the engine. The removal of the electrodes takes away the factor of erosion which limits lifetime on other ion engines. Neutral gas is first ionized by electromagnetic waves and then transferred to another chamber where it is accelerated by an oscillating electric and magnetic field, also known as the ponderomotive force. This separation of the ionization and acceleration stage give at the engine the ability to throttle the speed of propellant flow, which then changes the thrust magnitude and specific impulse values Plasma Micro Thruster In the picture number 143 one presents A Plasma Micro Thruster Schematic and Prototype (see the figure 143, and [36]). Fig. 143: Plasma Micro Thruster, Schematic and Prototype 2. THE HiPEP ENGINE 2.1. Powerful ion engine relies on microwaves A powerful new ion propulsion system has been successfully ground-tested by NASA. The High Power Electric Propulsion ion engine trial marks the "first measurable milestone" for the ambitious $3 billion Project Prometheus, says director Alan Newhouse. 211

212 The HiPEP engine is the first tested propulsion technology with the potential power and longevity to thrust spacecraft as far as Jupiter without gravity assists from other planets. These assists involve slingshot manoeuvres around planets and can boost the speed of craft significantly. But they require specific planetary alignments, meaning suitable launch dates are rare. In contrast, a probe powered by a HiPEP engine could launch any time. One goal of Project Prometheus, formerly called the Nuclear Systems Initiative, is to launch a spacecraft towards Jupiter by The flight would take at least eight years. The key elements of the HiPEP engine are a high exhaust velocity, a microwave-based method for producing ions that performs for longer than existing technologies and a rectangular design that can more easily be scaled up than circular ones. Spacecraft are increasingly being built with ion engines rather than engines that burn rocket fuel. This is because ion engines produce more power for a given amount of propellant, and provide a smooth output rather than intermittent spurts. "Jupiter is such a far away target. Using a chemical system, you just couldn't do it," says John Foster, one of the principal creators of the engine at NASA's Glenn Research Center in Cleveland, Ohio. The HiPEP engine differs from earlier ion engines, such as that powering NASA's Deep Space One mission, because the xenon ions are produced using a combination of microwaves and spinning magnets. Previously the electrons required were provided by a cathode. Using microwaves significantly reduces the wear and tear on the engine by avoiding any contact between the speeding ions and the electron source Nuclear fission A Japanese asteroid-chasing spacecraft is already using microwave-based technology to produce ions, but Hayabusa uses a small device that could not produce enough power to fly to Jupiter. The HiPEP engine is currently capable of 12 kilowatts of power but its output will be boosted to at least 50 kw for the Jupiter mission. The rectangular cross section of the HiPEP engine will make this easier, as it can be expanded along one of its sides. A circular engine would have to be rebuilt, says NASA. Nonetheless, other researchers at NASA's Jet Propulsion Laboratory in Pasadena, California, are working on a cylindrical high-power ion engine, also for the Prometheus project. But Newhouse notes that building a powerful, longlasting propulsion system is just "one of the pieces we need to get to Jupiter". The electricity for the ion engine is slated to come from on-board nuclear fission reactor. This part of the Prometheus Project is just beginning, with safety considerations, the miniaturisation of the reactor and the identity of the fuel all needing to be decided. 3. NEW IONIC OR BEAM PULSES ENGINES By this chapter the author propose a new pulse engine which works with beam or ionic (ionic beam) pulses. With a new ionic engine one builds a new aircraft (a new ship). The principal characteristic of this kind of engine is the high power (energy) which accelerates the beam at very high energy, in circular accelerators, in modern linear accelerators (LINAC), or in both. One can use accelerators similar with the static physics accelerators (synchrotron, synchrocyclotron or isochronous cyclotron) [36]. Ionic engine (ion thruster, which accelerates the positive ions through a potential difference) is about 10 times more effective than classic system based on combustion. We can still improve the efficiency of times if one uses positive ions accelerated in a cyclotron mounted on the ship; the efficiency can easily grow for 1000 times if the positive ions will be accelerated in a high energy synchrotron, synchrocyclotron or isochronous cyclotron (1-100 GeV). Future (ionic) engine will have mandatory a circular particle accelerator (high or very high energy; see the figure 3). Sure that the difficulties will arise from design, but they need to be resolved step by step. We can thus increase the speed and autonomy of the ship using a less quantity of fuel. One can use synchrotron radiation (synchrotron light, high intensity beams), like high intensity (X-ray or Gamma ray) radiation, as well. In this case will be a beam engine (not an ionic engine). A linear particle accelerator (also called a LINAC) is an electrical device for the acceleration of subatomic particles. This sort of particle accelerator has many applications. It used recently as to an injector into a higher energy synchrotron at a dedicated experimental particle physics laboratory. In this, the big classic synchrotron is reduced to a ring surface (magnetic core). The design of a LINAC depends on the type of particle that is being accelerated: electron, proton or ion. 212

213 It proposes using a powerful LINAC at the exit of synchrotron (especially when one accelerates electrons) to not lose energy by photons premature emission (figure 145). One can use a LINAC in the entry in the Synchrotron and one at out (figure 144). To use a small entrance LINAC, between him and synchrotron, one put an additional speed circuit in a stadium form (fig. 144). The end LINAC can be reduced if one put more end LINACs. See diagram below (fig. 144.) 2008 Florian Ion TIBERIU-PETRESCU Fig. 144: A high energy synchrotron schema Fig. 145: Some flying synchrotron prototypes 4. CONCLUSION Speaking about a new ionic engine means to speak about a new aircraft. The book presents shortly the actual ionic engines (called ion thrusters) and the new ionic (pulse) engines proposed by the author. Ionic engine (ion thruster, which accelerates the positive ions through a potential difference) is about 10 times more effective than classic system based on combustion. We can still improve the efficiency of times if one uses pulses of positive ions accelerated in a cyclotron mounted on the ship; the efficiency can easily grow for 1000 times if the positive ions will be accelerated in a high energy synchrotron, synchrocyclotron or isochronous cyclotron (1-100 GeV). Future (ionic) engine will have mandatory a circular particle accelerator (high or very high energy). We can thus increase the speed and autonomy of the ship using a less quantity of fuel and power. One can use synchrotron radiation (synchrotron light, high intensity beams), like high intensity (X-ray or Gamma ray) radiation, as well. In this case will be a 213

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