DESIGNING THE DESIGNING THE HEAVYWEIGHTSHEAVYWEIGHTS
TECHNIQUES AND APPROACHES FROM THE WORLD OF AIRLINERS
TRANSTRANS--NATIONALMANUFACTURINGNATIONALMANUFACTURING
The Airbus Way Page 24© A
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The A380 is taking shape March 2004(Example A380)
Wing, Broughton
AirbusUK
AirbusSpain
Horizontal Tail Plane & Tail Cone, Getafe
Vertical Tail Plane, Stade
Section 13, Hamburg
Section 18,Hamburg
Flaps & SlatsBremen
Cabin,Hamburg
Airbus Germany
Airbus France
Sub-assembly ofSection 11/12, Méaulte
Cockpit-Section, Méaulte
Section 15, St. NazairePylons,Toulouse
AIRBUS A380
TACKLING TRANSTACKLING TRANS--NATIONAL DESIGNNATIONAL DESIGNMany Countries
Many Languages
Many Design Offices
Sub-Contracted Design
Separation of Design and Test
Remote Manufacturing
But One Final Certifying Signature
KEEPING IT ALL TOGETHERKEEPING IT ALL TOGETHERAll Use the same Load Cases
All Use the same Hardware
Common Design Features
But Using New Technologies in Ever More Rapid Development Programs
EVEN THE SIMPLE BITS ARE EVEN THE SIMPLE BITS ARE COMPLICATEDCOMPLICATED
WING TIP ASSEMBLY
FUEL TANK VENT
EVERY STEP OF THE DESIGN HAS EVERY STEP OF THE DESIGN HAS A CONTROLLED METHODA CONTROLLED METHOD
STEP-BY-STEP INSTRUCTIONS
ALL CONTAINED IN A HUGE ON-LINE DESIGN MANUAL
FLOWFLOW--CHARTS FOR THE WHOLE CHARTS FOR THE WHOLE CALCULATION PROCESSCALCULATION PROCESS
e.g. BOLT BEARING/BYPASS FAILURE CALCULATION
PROBLEMS TO CONTROLPROBLEMS TO CONTROL
Limitations of each “Method” may not be appreciated when a particular instance is not exactly as idealised .Some configuration feature may change the way the structure is loaded, rendering Methods obsolete. e.g. “Gull-Wing” on A380 reverses normal Brazier loading on ribs.Leads to “Small-Picture” thinking – concentrating on a local feature with no regard to what it does or how it works.Leads to a class of engineer who are content to do “data-entry” and not develop the skills or experience to solve problems from “first principals”.
FUTURE AIRLINERSFUTURE AIRLINERS
FUTURE AIRLINER TARGETFUTURE AIRLINER TARGET
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
1950 1960 1970 1980 1990 2000 2010 2020
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Rolls-Royce engine SFC
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ENGINE FUELCONSUMPTION
ACARE aircraft fuel burn target
AIRCRAFT FUELBURN PER SEAT
The Target Does Not Lie on Current Trend Lines
THE NEED FOR RADICAL CHANGETHE NEED FOR RADICAL CHANGEContributions to CO2 Reduction
-50%
-40%
-30%
-20%
-10%
0%
Engines Airframe Air traffic management
and operations
Possible design solutions
Change in All Areas to Accommodate and Exploit New Developments and Technologies
FUNDAMENTAL PRINCIPALSFUNDAMENTAL PRINCIPALSThe Fundamental Engineering Principals Still Apply.
e.g. The classical Breguet range equation for jet aircraft;
Range = (airspeed/sfc) x (Lift/Drag)R x loge(W0/We )
Engine Efficiency
Aerodynamic Efficiency
Weight Efficiency
THE DRAG EQUATIONTHE DRAG EQUATIONFuel is Mainly Used to Overcome Drag.Only a Big Change Somewhere in the Design Will Create a Big Reduction in Drag
Drag = q.S.CD0 + k.(W/b)2/(Π.q) + q.Aw.CD.fric
Wing Profile DragReduce CD by Better Airfoil Design.Increase CL to Reduce “S” (Better L/D).Reduce Weight to Reduce “S”.
Parasite DragReduce Wetted Area.Reduce Friction (Laminar Flow).Reduce Leaks, Gaps and Obstructions.Eliminate Systems Losses
Induced DragIncrease Wingspan.Reduce Weight.
STATE OF THE ART STATE OF THE ART –– A320A320
Cruise Mach 0.78
Cruise Altitude 36,000 ft
Range 2,600 n.m
Wing Sweep 25o
Passengers 150 -180
MTOW 73.5 – 77 Tonnes
CHANGING PARAMETERSCHANGING PARAMETERSReducing Cruise Mach from 0.78 to 0.65
Wing sweep eliminated to reduced weight.Cruise Lift Coefficient CL increases by 10% for same CD
Dynamic Pressure “q” reduces by 30%Wing Area increases by 30%Same length wing but not swept increases span by 10%Induced Drag increases by 19% due to q less span increaseLanding CL.MAX reduces by 30% giving lighter and simpler flap system.
Increase Span by 10% for a further 17% reduction in Induced DragReduced weight due to 20% reduced fuel load.3 hour journey now takes 3 ½ hours.
Total Drag/Fuel Reduction about 25%
REDUCED CRUISE SPEED REDUCED CRUISE SPEED CONFIGURATIONCONFIGURATION
Increased Span
Increased t/cNo Sweep
Lower CD
Geared Fans Reduced Weight
CHANGING CONFIGURATIONCHANGING CONFIGURATIONBlended Wing-Body Concept
‘Aft fan’ ‘Driven fan’
BLENDED WINGBLENDED WING--BODYBODYOptimum for large, Long range aircraft.Cruise at Mach .85 for 4,200 n.m.33% reduction in wetted areaSpan load distribution reduces wing and fuselage bending loadsIncreased span with little weight penaltyDeeper structural wing boxAerodynamic interferences reduced at high Mach cruiseHeavier pressure vessel offset by better integrationSimpler and lighter landing gear installation
Cabin evacuation and emergency exit issues to be resolved
Total Drag/fuel Reduction About 20% Attributable to Airframe, up to 40% Claimed Including Engine
Ref: AIAA 2003-2503
BOEING BWB FREIGHTER BOEING BWB FREIGHTER PROPOSALPROPOSAL
OTHER WAYS WE MIGHT SAVE FUELOTHER WAYS WE MIGHT SAVE FUEL
Fly in formation to reduce induced drag.Buy duty-free goods at arrival airport.Lighter suitcases.Air-to-Air or en-route refuelling to reduce fuel load and take off weight.Solar panels on wings to reduce parasitic power load.Pulsed laser power for take-off or other external powering system that doesn’t need to be carried on the aircraft.Water recovery from exhaust or air to reduce water tank requirement.Reduce energy required in manufacture, maintenance and support.
The end The end –– discussion?discussion?
On a lighter note – this is my FLS Sprint 160 aerobatic aeroplane featured in October’s “Flyer” magazine and “Loop”.
AIRCRAFT DATA From CAA Approved Pilot’s Operating Handbook
SEATING: 2 seats, side-by-side. Dual controls. 5-point harnesses.
TRIM: Leather Seats and Side Panels Standard.
CABIN: 1.1m (43 inches) wide. 100 lb (45 kg) baggage.
ENGINE: Lycoming AEIO-320-D1B 160 h.p. Fuel-injected.
PROPELLER: Hoffmann HO-V72L-V180 composite, constant-speed.
ELECTRICAL SYSTEM: 24 V d.c. (12 V option). 70 amp alternator.
MAXIMUM WEIGHT: 2050 lb Maximum Take Off Weight.
AEROBATIC WEIGHT: 1920 lb Maximum Weight for Aerobatics.
EMPTY WEIGHT: 1375 to 1425 lb depending upon equipment.
FUEL CAPACITY: 114 litres (30 US gal) Total in two tanks in wings.
RANGE: 500 nm (900 km). ENDURANCE: 3 hours typical
AEROBATIC “G” LIMITS: +6g / -3g Including inverted flight and spinning.
SPEEDS: Never Exceed Speed; VNE = 181 knots.
Maximum Speed; VH = 140 knots.
Cruising Speed (75% power) = 126 knots
Stall Speed, flaps extended; VS1 = 50 knots.
TAKE OFF DISTANCE: 200m Ground Roll, 500m to 15m (50ft) height.
RATE OF CLIMB: 1000 ft/min at 1920 lb at 80 knots.
DIMENSIONS: Wing span 30.7 ft (9.36 m). Length 22 ft (6.7 m)
APPROVED OPERATIONS: [European (UK) Type Certificated to JAR-23]
Daytime VFR – all aircraft
Night – when suitably equipped (Not UK “Permit” aircraft)
IMC – when suitably equipped (Not UK “Permit” aircraft)
IFR - when suitably equipped (Not UK “Permit” aircraft)
COMPONENT TBO: Engine 1,600 hr. Propeller 1,000 hr (500 hr aero).
LIFE: Wing spar 6,500 hr aerobatic life, replace lugs at 2,650 hours.
SPRINT 160AeroElvira.com
TAKE YOU SKILLS TO REAL AEROBATICS, SPINNING AND INVERTED FLIGHT
IN A SAFE AND COMFORTABLE AEROPLANE YOU CAN LIVE WITH
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