Aeroplane Interdependencies & TradeoffsIndependent Experts Integrated Review (IEIR)

Rainer von Wrede10 May 2017

TECHNOLOGY MEETING: CO2 mitigation technology Workshop 10th & 11th May 2017 in Reims, France

Overall Schedule for IE Process

• 24-28 APR 2017: Conduct IE Panel Review Session #1 (Washington).

Focus on noise & pollutant emissions; introduction to CO2

• 16-20 OCT 2017: Conduct IE Panel Review Session #2 (Berlin)Focus on CO2 and integration

• April 2018: Complete draft report to WG1/3 for comments.

• June 2018: Present draft final report to the 2018 Steering Group.

• October 2018: Complete final report and submit for CAEP/11.

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Industry OutlookTechnology OutlookInterdependencies & Tradeoffs

Outline

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5

High Production Rate Required

This means 4-5 aircraft per day need to be produced for the next 20 years

Manufacturers cannot take industrial risks, so tube & wing architecture will predominate

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Technology OutlookAerodynamics Fuel Burn Technologies

Skin-Friction Drag Reduction

Separation Flow Control

Vortex-Drag Reduction

Confidential – For use by participants of CAEP11 Independent Experts Integrated Review 6

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Technology OutlookStructures/Materials Fuel Burn Technologies

Advanced MetallicTechnologies

Advanced CompositesTechnologies

MultifunctionalDesign / Materials

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Design Constraints:

Aircraft design has to conform with a large number of constraints coming from requirements for:

Safety, Laws & Regulations, Airport and Airspace Infrastructure, Market, Economics...

There will be no new aircraft if one of these is not fulfilled, and any change of one of them will also result in a change of the design of a new aircraft.

A step change in environmental performance will require time to mature technologies for improvements within these design constraints, or/and requires a change of one or several of these constraints.

Any strengthening of regulations increases the time for improvement potential and the emergence of a new aircraft.

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How Design Requirements are Set

AirlineRequirements

Regulatory RequirementsCurrent and Future

Local AirportRestrictions

Direct PublicPressure

Anticipatedroutes

Airplane LevelTrade-off Review

Current and AnticipatedLocal AirportRequirements

SupplyChain

CompetitivePressures

AvailableTechnology Airplanes

“Family”

Airplane LevelDesign

Requirement

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Interdependencies and Trade-Offs

New technologies bring benefits. For a new aircraft design these are used to improve as many aspects as possible without degrading any of them compared to previous generation of aircraft.

• INTERDEPENDENCIES:Technologies are very often inter-dependent and need to be compatible, the choice of one conditions or forbids the use of others. Such combinations of compatible technologies impact all design parameters including the ones for environment, some positively, some negatively.

• (environmental) TRADE-OFFs:The choice of technologies and their interdependencies leads inevitably to trade-offs. In most of the cases, the design for strong improvement or optimization of noise or pollutant emissions leads to increased fuel burn and CO2 emissions.

No integrated aircraft design can deliver the optimum improvement individual technologies could bring

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Airplane Design Is Always a Balanceof Various Requirements and Objectives

Fuel Economy

Maintainability

Payload(Passengers and Cargo) C

ruiseA

ltitude

Time to climb: changes mainly with thrust (via

increases in climb angle at a given speed), plus an effect from wing size

based on weight and L/D in climb

Approach speed: changes mainly with wing

area, there is an effect from engine size mainly based on

weight

Page XIII.12

Ordinate (figure of

merit):

Fuel efficiency

NOTIONAL CHART

(airport wing span code…)Geometric limits(airport wing span code…)

Take-off field length: changes with both wing area and thrust compliance

Noise Ch. 14 compliance

DESIGN SPACE

OPTIMUM FUEL EFFICIENCY

Overall aircraft optimization carpet plot (2D representation of a 3D space)

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Propulsion-level Decisions: Cycle Trades

Design targeted min Fuel Burn – Good for Noise in General, Trade with NOx

-1.0

0.0

1.0

2.0

3.0

4.0

5.0

6.0

70 75 80 85 90 95 100 105 110 115 120 125

Min

Fu

el B

urn,

%

Absolute LTO NOx, %kg

Lines of Const OPR

Lines of Const FPR

Incr OPR/T3(~FB(OPR)) T3 RLmax

(Max OPR)Technology

For improved FB

Min OPR

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Under-wing Propulsion Trades

Installation Constraints

Propulsion Trends• Higher BPR – propulsive efficiency• Highly integrated propulsion• Short Inlets and Thrust Reversers

• Light weight and Low drag nacelles

Noise Margin

Acoustics Considerations• Distortion Tolerant Fan and LPC• Aero-acoustic Fan-OGV Design• Jet Installation Effects• Noise suppression per unit treatment area

• Innovative liner concepts• Other noise sources (Combustor, LPT, Bleeds etc.)

Fuel Burn and NOx Considerations• Propulsive efficiency (OPR)

• sfc and NOx trades• Combustor design

• Nacelle Diameter – Drag and Weight• Nacelle Installation

Other design considerations include: Accessibility, Maintainability, Repairability etc.

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InterdependenciesMass/Mission loop (snowballing) effect on aircraft weights

NOTIONAL CHART

A configuration decision lasts for the life of a type (can be 30+ years).Each imposes its own constraints on installations and design changes.

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Configurations Balance Requirements

Business jetsShort range regional (turboprop)

Single-aisleTwin-aisle

Medium range regional (jet)

Some of the most recent airplanes per category (certified or in development):

Very large

Thank you