INNOVATIONS TROUGH HISTORY OF UNMANNED AIRCRAFT SYSTEM

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1 Doktorski studij na FSB: Uvod u znanstveno istraživački rad 2015/2016 Marijan Andrić INNOVATIONS TROUGH HISTORY OF UNMANNED AIRCRAFT SYSTEM Summary UDC Essay This essay presents a historical perspective of Unmanned Aircraft System (UAS) with an emphasis on key innovations leading to its today s amazing capabilities. A comprehensive insight of the evolution of such vehicles, starting from Ancient Greece to the most recent models shows that the idea of a flying machine is a very old one, and provides proof of the tremendous progress in the field. Key words: unmanned aircraft system; innovation; technology; drone 1. Introduction The history of innovations and technology that enabled present unmanned aircraft systems (UAS), is in fact the history of all aircraft. From centuries past, when Chinese kites graced the skies, to the first hot air balloon, unmanned flying craft came first before the risk of someone climbing on board occurred. There have been numerous bursts of innovation and eras of widespread employment. On the other hand, there have also been long periods where the technologies were all but forgotten. Even the name assigned to unoccupied aircraft has changed over the years and have taken many forms over their long history. Names used to describe a flying machine absent of humans include: unmanned aircraft system (UAS), unmanned aerial vehicle (UAV), remotely piloted vehicle (RPV), uninhabited combat aerial vehicle (UCAV), organic aerial vehicle (OAV), uninhabited combat aircraft system (UCAS), remotely piloted aircraft (RPA), remotely piloted helicopter (RPH), aerial robotics, micro aerial vehicle (MAV) and finally - drone. In modern times, UAS appeared during the World War I (1917), but the idea for a flying machine originated and it was first conceived about 2500 years ago [1]. 2. Early Days It has been documented that the first major breakthrough contribution to autonomous mechanisms occurred during the era of Pythagoras. The first breakthrough on autonomous mechanisms is attributed to Archytas from the city of Tarantas in South Italy, also referred to as Leonardo da Vinci of the Ancient World. Archytas was not only the inventor of the number one, but he was also the first engineer. By applying a series of geometric notions and observations to the study of structures, links and joints, he created Mechanics. In 425 BC he created the first UAV of all times by building a mechanical bird, a pigeon that could fly by moving its wings getting energy from a mechanism in its stomach, see Figure 1. It is alleged that it flew about 200 meters propelled by streams of water and vapor.

2 Marijan Andrić Innovations Trough History of UAS Fig. 1 An artist s depiction of the flying pigeon, the first documented UAS in history Another early user of unmanned aircraft was by the Chinese General Zhuge Liang ( BC) who used paper balloons fitted with oil-burning lamps to heat the air. Then he flew these over the enemy at night to make them think there was a divine force at work. In 1483 Leonardo da Vinci designed an aircraft capable of hovering, called air screw or air gyroscope, shown in Figure 2. This machine is considered by some experts as the ancestor of today s helicopter. Further, da Vinci devised a mechanical bird in 1508 that could flap its wings by means of a double crank mechanism as it descended along a cable [2]. First time someone had thought of the idea of using unmanned platforms to deliver some form of military effect were the Austrians [3]. In 1849 they launched over 200 pilotless balloons carrying bombs controlled by timing fuses over the city of Venice. When the balloon exploded, the bomb would drop on the city and one actually detonated over St. Mark's Square. The obvious flaw in this scheme, however, was all too apparent when the wind changed direction. Balloons in their original unpowered configuration were simply not the right platform. In the early years of aviation, the idea of flying highly experimental contraptions with no one inside had the obvious advantage of removing the risk to the pilots life. During 1890s German aviation pioneer Otto Lilienthal employed unmanned gliders as experimental test beds for main lifting wing designs and the development of lightweight aero structures. As a result, several mishaps are recorded where advances were made without injury to an onboard pilot. Although such approaches to remove people from the equation, the lack of a satisfactory method to affect control limited the use of these early unmanned aircraft. Early aviation developmental efforts quickly turned to the use of the first test pilots to fly these groundbreaking craft. Fig. 2 Leonardo da Vinci s air screw 2

3 Innovations Trough History of UAS Marijan Andrić 3. Search for Control Sir George Cayley showed his first interest in at the end of the eighteenth century. At the age of 26 he produced the first detailed analysis of the founding principles of aviation: weight, lift, drag and thrust. He sketched out an idea for a fixed wing airplane and saw the problem of flight as one of overcoming drag through generating lift using a source of propulsion and then having controls that could stabilize the aircraft in flight and ensure it could turn. The culmination of this saw him publish a series of three papers called On Aerial Navigation that were published in His experiments led him to discover the benefits of a cambered airfoil and also the importance of the dihedral angle and its impact upon stability in flight of an aircraft around the roll axis. The Wright Brothers success in flying the first airplane in 1903 is more of a technical success story in solving the ability to control a piloted, heavier-than-air craft. Doctor Samuel Pierpont Langley, the early airplane designer competing with those two bicycle mechanics from Ohio, also wrestled with the problem of how to control an airplane in flight. In 1896 he launched an unmanned, steam powered aircraft over the Potomac River [4]. The unmanned aircraft, dubbed the Aerodrome, flew for almost a mile. The Aerodrome had no guidance system, but it was a UAS in all other regards. This historic flight predates the Wright Brothers first flight by seven years. The missing element of Langley s flight was a guidance, navigation, and control system. After the Wright Brothers taught the fledgling aviation world the secrets of controlled flight, namely, their wing-warping approach to roll control, development experienced a burst of technical advancement, furthered by the tragedy of World War I. The demands of the war on early aviation drove an incredible cycle of innovations in all aspects of aircraft design ranging from power plants, fuselage structures, lifting wing configurations, to control surface arrangements. 4. Radio and the Autopilot Even before the first Wright Brothers flight, the famous inventor Nikola Tesla promoted the idea of a remotely piloted aircraft in the late 1890s, see Figure 3. He preceded the invention of the radio in 1893 by demonstrating one of the first practical applications of a device known as a full spectrum spark-gap transmitter. Tesla went on to help develop frequency separation and is attributed by many as the real inventor of the modern radio. Fig. 3 Nikola Tesla with his wirelessly controlled airship 3

4 Marijan Andrić Innovations Trough History of UAS At that time, another inventor, Elmer Sperry, was developing the first practical gyrocontrol system. Sperry s work, like Tesla s, focused initially on underwater torpedoes for the Navy. He developed a three-axis mechanical gyroscope system that took inputs from the gyros and converted them to simple magnetic signals, which in turn were used to affect actuators. After perfecting his design of the world s first practical mechanical autopilot used for maritime applications, Sperry turned his attention to the growing new aircraft industry as a possible market for his invention, not for the purpose of operating an unmanned aircraft, but as a safety device to help tame early unstable manned aircraft, and to assist the pilot in maintaining their bearings in bad weather. 5. Early Modern Unmanned Aircraft In late 1916, with war raging in Europe, the U.S. Navy, funded Sperry to begin developing an unmanned aerial torpedo [5]. Elmer Sperry put together a team to tackle the most daunting aerospace endeavor of the time. The task was to build a small, lightweight airplane that could be self-launched without a pilot, fly unmanned out to 1000 meters guided to a target and detonate its warhead at a point close enough to be effective against a warship. The fact that the airplane had just been invented 13 years earlier, the ability to even build and integrate an airframe capable of carrying a large warhead, a sizable radio with batteries, heavy electrical actuators, and a large mechanical three-axis gyro-stabilization unit was spectacular. Two years later he succeeded and the first true unmanned aircraft system was born. Surprisingly, most of the world s aviation efforts in unmanned aircraft after World War I did not pursue weapon platforms like the wartime aerial torpedo and bomb, but instead, work focused primarily on employing unmanned aircraft technology as target drones. One such aircraft was British converted de Havilland Gypsy Moth called the Queen Bee. This name led to the designation of an unmanned aircraft being described by the letter Q to denote unmanned operation. Although unverified by research, the term drone is believed by some to have originated with the Queen name as meaning a bee or drone, see Figure 4. The most significant unmanned aircraft of the World War II was Nazi Germany s V-1 (Vengeance Weapon-1). The aircraft was based on the earlier 1930s work by inventor Paul Schmidt in developing a practical pulse jet, and an advanced, lightweight, and reliable threeaxis gyro-stabilized autopilot, a radio signal baseline system for accurate launch point data, and a robust steel fuselage that was resistant to battle damage. The V-1 represented the first mass-produced, cruise-missile type unmanned aircraft, and its configuration influenced many postwar unmanned aircraft designs. Fig. 4 The DH.82B Queen Bee drone 4

5 Innovations Trough History of UAS Marijan Andrić 6. Modern Unmanned Aircraft System The Lockheed D-21 was the most impressive system of the Cold War era. This Mach 3+ ramjet-powered UAS was air launched first from a modified SR-71 Blackbird and later from a B-52 aircraft. This long range platform was designed to fly preprogrammed missions autonomously. Only the camera payload and avionics were recovered. The module housing these systems was jettisoned from the aircraft, descended under a parachute, and was snagged by a fixed-wing aircraft using the Mid-Air Recovery System (MARS). Decades after the system was retired, we still have no equivalent to this remarkable UAS. The years after the Vietnam War were more like the Dark Ages for UAS. The impressive technology gains and operational systems were shelved as defense budgets shrank after the war, and new UASs were either not developed to completion or were visible programmatic failures. The early 1990s saw the maturation of enabling technical innovations such as digital electronics, global positioning systems (GPS), digital data links, and satellite communications. The turn of the century brought us many new technologies including miniature digital avionics, GPS-based autopilots, low Reynolds number unmanned aircraft design, miniature payloads, in-flight reconfiguration technologies, electric propulsion, and micro unmanned aircraft. In addition to the fixed-wing and helicopter systems, the quad-rotor configuration, shown in Figure 5, became popular lately, especially in academic environments. 7. Conclusion The UAS history, from a very early dream to today s reality, illustrates the unmanned vehicle evolution and innovations over a period of almost 2500 years. This accurate glimpse of history shows the tremendous level of growth in the unmanned systems field. The future will be brightest for civil and scientific applications including climate science, telecommunications, air freight, forest fire protection, law enforcement, news coverage, agricultural missions, and disaster relief. Limitations considering UAS airspace access provide the opportunity for development of new technologies which would enable safe airspace integration. Fig. 5 Example quad-rotor design that offers simple dynamics, stability and agility 5

6 Marijan Andrić Innovations Trough History of UAS REFERENCES [1] Valavanis, K. P., Advances in unmanned aerial vehicles: state of the art and the road to autonomy, Springer [2] Rosheim, M. E., Leonardo s Lost Robots, Springer [3] Slogget, D., Drone Warfare: The Development of Unmanned Aerial Conflict, Skyhorse Publishing [4] Gundlach, J., Designing Unmanned Aircraft Systems - A Comprehensive Approach, American Institute of Aeronautics and Astronautics, [5] Barnhart, R. K., Hottman, S. B., Marshall, D. M., and Shappee, E., Introduction to Unmanned Aircraft Systems, CRC Press (Taylor & Francis Group) Defined by Marijan Andrić: Delivered to Kalman Žiha Marijan Andrić, andric343@gmail.com ANDEL d.o.o., Majstorska 1G, Zagreb 6