PROPULSION INTEGRATION CHALLENGES- Lecture to DGLR

05th July 2007 Vincent RIVOIRE PROPULSION INTEGRATION CHALLENGES- Lecture to DGLR Hamburg, July 5th 2007 Lecture to DGLR- Propulsion Integration Challenges Download this presentation from http://hamburg.dglr.de

TABLE OF CONTENTS 1-1-INTRODUCTION 2-2-INDUSTRIAL LIFE-CYCLE AND AND COOPERATION 3-3-AN INTEGRATED DESIGN PROCESS 4-4-PERSPECTIVES AND AND NEW NEW CONCEPTS Lecture to DGLR- Propulsion Integration Challenges 05th July 2007 Page 2

TABLE OF CONTENTS (1) 1-1-INTRODUCTION 2-2-INDUSTRIAL LIFE-CYCLE AND AND COOPERATION 3-3-AN INTEGRATED DESIGN PROCESS 4-4-PERSPECTIVES AND AND NEW NEW CONCEPTS Lecture to DGLR- Propulsion Integration Challenges 05th July 2007 Page 3

MAJOR STAKES : HISTORICAL EXAMPLES PERFORMANCE 1962 : CONVAIR 990 Coronado programme endangered severe cruise performance deficit during flight tests. Complete reshaping of wing/engine integration (6 fairings/engine!) to recover guaranteed performance and General Dynamics program viability Source : AIAA paper n 63-276, summer meeting June 17-20, 1963 (J Kutney, S Piszkin) 1991-1992 : two B747 crashes caused by engine separation structural design modification of pylon to wing attachment requested by FAA (June 1995). More than 1000 B747 concerned. Retrofit costs 10000 to 15000 man-hour per A/C Source : Aircraft Economics n 28, Nov/Dec 1996 SAFETY ENVIRONMENT 2000 : A380 launch customer demands QC2 noise level compliance major engine and A/C configuration adaptations required to fulfill stringent noise guarantee, quite late in A/C development Lecture to DGLR- Propulsion Integration Challenges 05th July 2007 Page 4

STAKEHOLDERS AIRCRAFT MANUFACTURER - Technical specifications - Perfos guarantees - Purchasing contract ENGINE MANUFACTURER - engine selection process - guaranteed perfos (all flight phases) - safety requirements (fire, engine burst ) - environmental factors AIRLINE compliance (our customer) Overhaul + Spare parts policy AIRWORTHINESS AUTHORITIES - ETOPS licensing - Maintenance compliance - Local noise/emissions/ operations regulations - Field length requirements AIRPORTS Design options influenced by complete network Lecture to DGLR- Propulsion Integration Challenges 05th July 2007 Page 5

A CHALLENGE FOR FUTURE ADVANCED POWERPLANTS need for thrust capabilities high capacity A/C or large twin-engined A/C) fuel burn noise levels present trend bypass ratios fan diameters nacelle length Integration challenges engine/airframe interference engine weights/loads ground clearances environmental compliance issues (Source: General Electric 2002-03) BPR = 4 to 6 BPR = 6 to 9 Need for new integration concepts (close-coupling, noise-shielding...) Lecture to DGLR- Propulsion Integration Challenges 05th July 2007 Page 6

TABLE OF CONTENTS (2) 1-1-INTRODUCTION 2-2-INDUSTRIAL LIFE-CYCLE AND AND COOPERATION Engines Engines selection selection International International cooperation cooperation Industrial Industrial responsibilities responsibilities- -Work sharing sharing 3-3-AN INTEGRATED DESIGN PROCESS 4-4-PERSPECTIVES AND AND NEW NEW CONCEPTS Lecture to DGLR- Propulsion Integration Challenges 05th July 2007 Page 7

FROM SELECTION OF CANDIDATE TECHNOLOGIES design complexity Low Noise 6 Low Noise Low Fuel Burn 5 Low Fuel Burn 3 G/B 2-stage HPT ContraFan Geared Turbo Fan Low Cost 1 2 4 Advanced Turbo Fans (Exemples of candidate engine architectures) 3-stage HPT GUIDELINES : Thrust, Noise, Operational requirements New technologies assessment. Benefits / risks tradeoff Suppliers market situation : adapted or new engine Airline demands and economics : low design/maintenance cost (regional) vs low fuel consumption (long range) Political/strategical considerations (alliances, competitors projects...) Not always a straighforward decision (cf. A400M military cargo) Not only technical drivers Lecture to DGLR- Propulsion Integration Challenges 05th July 2007 Page 8...

... TO COMMITMENTS FOR COOPERATION Two industrial partners with respective business standpoints, sharing risks ENGINE MANUFACTURER : One engine program for several A/C (optimize business case) Eg : GE CF6-80C2 DOUGLAS MD11 AIRBUS A310 AIRFRAME MANUFACTURER : Same A/C with different engines (with max. commonality) Eg : A320 CFM 56-5 IAE V2500 A330 GE CF6-80 E1 PW 4164/68 RR TRENT772 Capability to get commitments for best adapted engines is of prime importance in competitive environment Engine manufacturers run their own A/C market forecasts! A/C manufacturers must audit engine manufacturers proposals Lecture to DGLR- Propulsion Integration Challenges 05th July 2007 Page 9

INDUSTRIAL RESPONSABILITIES - INTERFACES Fan cowls Bare engine Inlet cowl Exhaust nozzles Thrust reverser Clear workshare required for specification, design and manufacture of Powerplant interface components Boeing and more recently Airbus tend to retain nacelle responsibility. To save significant leadtime, Airframer must ensure development plans coordination with Engine and Nacelle suppliers. Lecture to DGLR- Propulsion Integration Challenges 05th July 2007 Page 10

TABLE OF CONTENTS (3) 1-1-INTRODUCTION 2-2-INDUSTRIAL LIFE-CYCLE AND AND COOPERATION 3-3-AN INTEGRATED DESIGN PROCESS Feasibility Feasibilityphase Concept Concept phase phase Definition Definitionphase Design Design logic logic Design Design requirements 4-4-PERSPECTIVES AND AND NEW NEW CONCEPTS Lecture to DGLR- Propulsion Integration Challenges 05th July 2007 Page 11

FEASIBILITYPHASE : BASIC OPTIONS Example : Rear Fuselage mount compared to Wing mount Advantages Drawbacks No adverse interference on the wing (better CD and Clmax) Better lateral control in case of one engine failure Relaxed nacelle ground clearances Engine noise shielding benefit Safety compliance in case of engine burst More restricted A/C loading /CG travel Rear doors arrangement on fuselage Weight penalty : fuselage, empennage Air inlet behaviour at high angle of attack Rear fuselage aerodynamic interference Poor engine accessibility/maintainability Need to mitigate configuration risk for noise advantage Lecture to DGLR- Propulsion Integration Challenges 05th July 2007 Page 12

CONCEPT PHASE : A MULTIDISCIPLINARY BALANCE Propulsion system installation impacts largely A/C configuration Basic options must always be balanced on a multidisciplinary basis : sensitivity factors for quick comparisons and decisions integrated sizing tools for preliminary General Arrangement set-up Exemples of sensitivity factors Short Range eg A320 Long Range eg A340 Large Aircraft eg A380 drange/dmwe -220 nm/t -90 nm/t -50 nm/t drange/(dcd/cd) -35 nm/% - 70 nm/% - 75 nm/% drange/dsfc -32 nm/% -77 nm/% -85 nm/% MWE : A/C empty weight ; CD: drag coefficient SFC : engine specific fuel consumption Cumulative Margin [EPNdB] 32 30 28 26 24 22 20 GTF 2-stage HPT At fixed design range and max payload. Advanced TurboFans ContraFan 18-4% -3% -2% -1% 0% 1% 2% 3% 4% 5% 6% BF - 500NM vs Status 8 [%] Block Fuel Lecture to DGLR- Propulsion Integration Challenges 05th July 2007 Page 13 Operational Costs ($/trip)) Exemple of Wing area / Engine thrust trade-off Wing area -60 m +60 m 2 2 +40 m 2-40 m 2 +20 m 2 S ref -20 m 2 Optimum (under constraints) Time to Climb Initial Take-off field length Fuel volume +4% +2% Fn ref -2% -4% -6% Engine Thrust

DEFINITION PHASE : THE OPTIMISATION LOGIC Detailed propulsion system integration is a highly iterative process, involving many engineering and non-engineering functions. We can differentiate : The degrees of freedom available The target function to be minimised The requirements to comply with Such design process can therefore be considered as A CONSTRAINED OPTIMISATION Lecture to DGLR- Propulsion Integration Challenges 05th July 2007 Page 14

DEGREES OF FREEDOM : POSITIONS and SHAPES no-enveloping pylon AXIAL (X) POSITION PITCH ANGLE semi-enveloping pylon VERTICAL (Z) POSITION TOE ANGLE enveloping pylon SPANWISE (Y) POSITION Engine position on wing Pylon and nacelle external shapes Lecture to DGLR- Propulsion Integration Challenges 05th July 2007 Page 15

THE TARGET FUNCTION The design process aims at minimising a combination of : Manufacturers costs : recurring and non-recurring Operators cost : fuel burn, maintenance, airport fees Community cost : sustainable growth aspects, environmental factors This target is not a direct computed function of the degrees of freedom. It must be approached qualitatively, with basic decisions at every step Engineering driven cost targets often relate to few basic drivers : weight, drag, engine SFC, noise dbs. They lead to Fuel Burn and Cash-Operating-Costs models BF - 500NM Block vs Fuel Status 8 [%] 6% 5% 4% 3% 2% 1% 0% -1% -2% GTF -3% -4% 3-shaft engine??? At fixed design range and max payload. Advanced TurboFans 2-stage HPT Engine maintenance Cockpit Crew Airframe maintenance Landing fees Navigation charges -20% -10% 0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100% Engine Direct Maintenance DMC vs Status Cost 8 [%] Lecture to DGLR- Propulsion Integration Challenges 05th July 2007 Page 16 Fuel

WEIGHT DRIVER : LOADS & DESIGN PRINCIPLES Structural sizing of engine/pylon/wing interfaces for certification requirements : reaction to gusts and windshears wheels-up landings (landing gear extension failure) fan blade off (engine failure) and windmilling (cf Cathay Pacific B747 incident, Nov. 1993) Most loads cases depend closely on engine location on the wing. Sizing of engine/pylon/wing attachements, with various concepts, may impact space allocation and minimum pylon width. YZ X Z Y X Y Z X Fan mount Core mount Thrust bars Some load cases, like Fan Blade Off, requires complex FEM computational models Affects engine position and pylon primary structure sizing Sometimes trade-off between contradictory engine/airframe benefits Lecture to DGLR- Propulsion Integration Challenges 05th July 2007 Page 17

DRAG DRIVER : INSTALLATION DRAG DEFINITION Installation drag = interference penalties between propulsive system and airframe Order of magnitude : 2 to 6% of A/C overall drag 1% drag reduction for long range A340 is : 800 kg of extra payload 100 keuros savings for 1 year exploitation Wing+Pylon+Nacelle (thrust + drag) Wing alone (drag only) Precise thrust / drag bookkeeping system to be agreed between engine / airframe manufacturers to assess respectives shares in A/C performance Isolated nacelle net thrust & nacelle+pylon skin friction Lecture to DGLR- Propulsion Integration Challenges 05th July 2007 Page 18

ENVIRONMENTAL DRIVER : OVERVIEW Main factors : GAZEOUS EMISSIONS (indirect long term harm, pollution) NOISE (immediate harm) HAZARDOUS MATERIALS (restrictions on certain materials/manufacturing process) Regulating process : Airworthiness requirements (ICAO - Chicago Agreement / FAR36) National laws (eg : French landing tax for noisy A/C) Airport local restrictions (eg : Heathrow, Washington National, Orly...) Airline demands ( Green brand image) Affects : Engine design and integration on the Aircraft Operational handling of the Aircraft (take-off and landing procedures) Growing consideration for Aerospace Industry due to : increase of Air Traffic increase of Environmental preoccupation in public opinion Lecture to DGLR- Propulsion Integration Challenges 05th July 2007 Page 19

DESIGN REQUIREMENTS : GENERAL Propulsion system integration must fulfill various design requirements. These an be split in different classes : Safety and Airworthiness, normal of failure modes Operations, in-flight, on ground and overhaul procedures Space allocation, for initial and future growth versions Compliance to requirements reduces drastically the optimisation window. Requirements can sometimes be challenged with innovative solutions Bounds the optimisation window Must consider and protect full A/C family concept Lecture to DGLR- Propulsion Integration Challenges 05th July 2007 Page 20

SAFETY REQts : ENGINE BURST- (FAR/JAR 25.903) Systems segregation Configuration driver 5 5 Safe zone if required for systems installation No engine to engine damage Affects engine position or engine size envelops Lecture to DGLR- Propulsion Integration Challenges 05th July 2007 Page 21

SAFETY REQts : EMERGENCY EVACUATION ESCAPE SLIDE & HAZARD ZONE Slide deployment not always in ideal conditions (A310 -Vienna -10 July 2000) Affects engine position or engine size envelops, (traded with doors location and slide cant angle) Lecture to DGLR- Propulsion Integration Challenges 05th July 2007 Page 22

AIRWORTHINESS REQts : ENGINE FAILURE Rudder action Windmilling drag Inoperative engine Engine lever arm Fin lever arm Thrust LATERAL CONTROL, ONE ENGINE FAILURE CASE Trade-off fin size & rudder efficiency vs wing bending relief Lecture to DGLR- Propulsion Integration Challenges 05th July 2007 Page 23

AIRWORTHINESS REQts : WATER SPRAY FLOODED RUNWAY SPRAY INGESTION FROM LANDING GEAR May limit engine location window or require deflector on nose landing gear Lecture to DGLR- Propulsion Integration Challenges 05th July 2007 Page 24

OPERATIONAL REQts : GROUND CLEARANCE Nacelle damage acceptable if engine fan case protected COLLAPSED NOSE GEAR Bank angle computed with dynamic landing simulation at given cross-wind BANK ANGLE (CROSS-WIND LANDINGS) Affects engine position or engine size envelops Lecture to DGLR- Propulsion Integration Challenges 05th July 2007 Page 25

OPERATIONAL REQts : GROUND CLEARANCE Rejected Approach, side wind-tap_321_ventos_fortes.asx Engine STRIKE (CROSS-WIND LANDINGS) Lecture to DGLR- Propulsion Integration Challenges 05th July 2007 Page 26

OPERATIONAL REQts : RAMP-HANDLING Easy access of Ground Service Equipements, to avoid damage to A/C structure Affects engine position relative to fuselage doors Lecture to DGLR- Propulsion Integration Challenges 05th July 2007 Page 27

OPERATIONAL REQts : MAINTENANCE ASPECTS ENGINE ACCESS OPEN COWLS No clash between extended high lift devices and open engine cowls Dp Ds ENGINE HOISTING GROUND CART Minimum ground clearance for safe transportation & hoisting of spare engine Affects engine position relative to Wing and Ground Lecture to DGLR- Propulsion Integration Challenges 05th July 2007 Page 28

SPACE ALLOCATION REQts : SYSTEMS ROUTING Space allocation for the various systems interfacing the engine and the airframe, with segregation requirements BLEED AIR SYSTEM ELECTRICS, HYDRAULICS Affects : minimum pylon width and crest line for secondary shapes aerodynamic design Lecture to DGLR- Propulsion Integration Challenges 05th July 2007 Page 29

DESIGN DRIVERS : A DIFFICULT LIVING TOGETHER! To satisfy following criteria Engine should Ground clearance...... Static and dynamic loads..... Turbine burst..... Wing bending relief. Lateral control (engine failure).. Noise reduction..... Drag minimization... Move upward Move backward Move forward Move outboard Move inboard Long cowl design Move downward and forward ; Short cowl design? Lecture to DGLR- Propulsion Integration Challenges 05th July 2007 Page 30

TABLE OF CONTENTS (4) 1-1-INTRODUCTION 2-2-INDUSTRIAL LIFE-CYCLE AND AND COOPERATION 3-3-AN INTEGRATED DESIGN PROCESS 4-4-PERSPECTIVES AND AND NEW NEW CONCEPTS Lecture to DGLR- Propulsion Integration Challenges 05th July 2007 Page 31

ENVIRONMENTAL ISSUES RECOGNISED DC8 1 st Flight May 1958 Quality and Affordability Safety Environment : Reduction of CO2 by 50% Reduction of NOx by 80% Reduce perceived external noise by 50% Substantial progress towards Green MMD Air Transport Effectiveness The age of sustainable growth The commercial age Efficiency Security The pioneering age 1900 s 1950 s 2000 s 2050 s Vision 2020 European Aeronautics January 2001 Evolutionary, or Revolutionary scenarios Lecture to DGLR- Propulsion Integration Challenges 05th July 2007 Page 32

GREENER AIRCRAFT CONCEPT Pros Shielding of engine noise Lower fuel burn from High aspect ratio wing Open issues Engine integration (certification, structural concept, aerodynamics interactions) Accessibility & Maintainability of Engine trade-off on cruise Mach number Lecture to DGLR- Propulsion Integration Challenges 05th July 2007 Page 33

The predictable issue : oil shortage Alternative fuels options : Synthetic kerosene From Coal From Natural Gaz From Methan Hydrates? Tu-155 with NK-88 engine Bio-fuels Methyl Esthers Cryogenic fuels Liquid Natural Gaz (LNG) Liquid Hydrogen (LH2) A possible scenario : cryogenic Hydrogen Synthetic, methan based kerosene Synthetic, gaz based kerosene? Oil based kerosene (current) + bio-fuel addition? 2000 2010 2020 2030 2040 2050 Lecture to DGLR- Propulsion Integration Challenges 05th July 2007 Page 34??

TABLE OF CONTENTS (5) ILLUSTRATIONS The Unconventional ones Lecture to DGLR- Propulsion Integration Challenges 05th July 2007 Page 35

ANTONOV 70 High speed propellers Lecture to DGLR- Propulsion Integration Challenges 05th July 2007 Page 36

ANTONOV 225 (wing root insert with additional engines derivated from An 124) Lecture to DGLR- Propulsion Integration Challenges 05th July 2007 Page 37

VFW 614 (mid-70s) research platform ATTAS in flight Overwing engine configuration Lecture to DGLR- Propulsion Integration Challenges 05th July 2007 Page 38

BERIEV 200 Lecture to DGLR- Propulsion Integration Challenges 05th July 2007 Page 39

PW 6000 Flight test bed on B720 Lecture to DGLR- Propulsion Integration Challenges 05th July 2007 Page 40

TR 900 Flight test bed on A340-300 Lecture to DGLR- Propulsion Integration Challenges 05th July 2007 Page 41

A380 - RR Trent 900 engines - Lecture to DGLR- Propulsion Integration Challenges 05th July 2007 Page 42

Guess what! Spare engine ferried to Heathrow, mounted on B747 wing (without reconfiguration) Lecture to DGLR- Propulsion Integration Challenges 05th July 2007 Page 43

KM«Caspian Sea Monster», experimental transport Wingspan: 40 m Length: 106 m Height: 22 m MTOW: 550 t Max speed: 500 km/h Produced: 8 (1965-1978) Lecture to DGLR- Propulsion Integration Challenges 05th July 2007 Page 44

New challenges? Lecture to DGLR- Propulsion Integration Challenges 05th July 2007 Page 45

Thank you for your attention! Lecture to DGLR- Propulsion Integration Challenges 05th July 2007 Page 46

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