DESIGNING THE DESIGNING THE HEAVYWEIGHTSHEAVYWEIGHTS

TECHNIQUES AND APPROACHES FROM THE WORLD OF AIRLINERS

TRANSTRANS--NATIONALMANUFACTURINGNATIONALMANUFACTURING

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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

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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