Team 2Team 2 AAE451 System Definition ReviewAAE451 System Definition Review

OutlineOutline Mission Statement Major Design Requirements Concept Selection

• Overview• Pugh’s method

Advanced Technologies• Technologies incorporated• Impact on sizing

Constraint Analysis• Major performance constraints• Basic Assumptions• Constraint diagrams

Sizing Studies• Design Mission• Current sizing approach

Propulsion Selection

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Mission StatementMission StatementTo be the primary systems

integrator of a high speed, long range executive transport system with unprecedented efficiency and minimal environmental impact.

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Major Design Major Design RequirementsRequirementsDesign Target Goals

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Design MissionDesign Mission

0-1: Take off to 50 ft. 5-6: Climb to 5000 ft. (Best Rate)

1-2: Climb to 42000 ft. (Best Rate) 6-7: Divert to Alternate 200 nm

2-3: Cruise at Mach 0.85 7-8: 45 minute Holding Pattern

3-4: Decent to Land (No Range Credit) 8-9: Land

4-5: Missed Approach (Go Around)

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0 1

2

4 5

6 7

8 97100 nm 200 nm

Los Angeles Hong Kong Alternate

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Pugh’s Method ProcessPugh’s Method Process Eight initial designs were presented and discussed A concept was chosen for baseline comparisons Each design was evaluated for each criterion

• Every design was assigned a +, -, or S

• All criteria are equally weighted All +, -, and S ratings were individually totaled for each design

• In Pugh’s method, each aircraft’s ratings are not summed Positives and negatives were investigated

• Positives were applied to other designs Designs were narrowed to four, and a new baseline was chosen All criteria were re-evaluated with the new baseline After iterating, two designs were chosen for further investigation

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Concepts OverviewConcepts Overview

Concept 1 Concept 2 Concept 3

Concept 4 Concept 5 Concept 6

Concept 7 Concept 87

Design Number 

1 2 3 4 5 6 7 8

 Criteria       Baseline        Cruise Drag + + s s + + + +

Weight - s s s s - - -Ability to

accommodate UDF- s - s s s s s

Cabin Noise s s - s s s s sEnvironmental

Noise+ s s s s s + +

Landing Gear s s - s s s s +Window Placement + + - s + s + -

Attractiveness s + - s - + + +Pressurization s s s s s s s -Static Margin - - s s - + - -

 total S's 4 6 5 10 6 6 4 2total +'s 3 3 0 0 2 3 4 4total -'s 3 1 5 0 2 1 2 4

Pugh’s Method Round 1

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Design Number

2 4 6 7

     

Cruise Drag + - s +

Weight - + s -

Ability to accommodate PF - s s s

Cabin Noise s s s s

Environmental Noise + s s +

Landing Gear + - s +

Window Placement s s s +

Attractiveness - - s +

Pressurization s s s s

Cost - + s -

Static Margin - + s -

 

total S's 3 5 11 3

total +'s 3 3 0 5

total -'s 5 3 0 3

Pugh’s Method Round 2

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Concept 1Concept 1

Rear fuselage mounted engines T-tail

Low wing

Circular Fuselage

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Concept 2Concept 2

•Vertical stabilizer

• Lifting Canards

•Rear mounted engines

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Advanced TechnologyAdvanced TechnologyUnducted PropfanComposite Materials

http://www.aviation.ru/jno/MACS97/An-70-engine.jpg

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Unducted Propfan Unducted Propfan Unducted Fan shows promise to reduce

emissions and fuel consumption “ERA is focused on the goals of NASA’s N+2, a

notional aircraft with technology primed for development in the 2020 time frame as part of the agency’s subsonic fixed wing program”Aviation Week Dec 14, 2009 on the development

of UDF

13http://f00.inventorspot.com/images/Test%20Prop.jpg

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Benefits of UDFBenefits of UDFRelative to 1998 levels, NASA plans to

reduce cumulative noise levels to 42 dB below stage 4, 75% lower NOx emissions, and reduce fuel burn by 40%◦ Aviation Week onN+2 goals regardingUDF

1414

How to Model UDF?How to Model UDF?According to Aviation Week Current

UDF Tests State that the UDF is Capable of: 25%-30% better fuel burn than

current engines 20% lower NOx emissions than

current engines Good probability of meeting N+2

goals by 2020

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How to Model UDF?How to Model UDF?Use a benchmark engine built on

or before 1998Calculate fuel burn and emissions

via projected N+2 percentagesAssume Stage 4 noise

complianceUse GE36 blade diameter with a

thrust scale factor for engine diameter

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Composite MaterialsComposite MaterialsSignificant Empty Weight SavingsProven TechnologySignificant Savings in Production CostUp to 50% of Structure Could Be

Constructed from Composite Materials Based on Historical Aircraft

http://www.comglasco.com/product_line/automotive/aluminun/comglasco0072.jpg

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How to Model Composite How to Model Composite MaterialsMaterials

Initial Plan Was to Use Database of Weight Fraction of Composite Hawker 4000 With Comparable Designs

*All Weights Courtesy of Jane’s All The World’s Aircraft

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New Method to Model New Method to Model CompositesComposites

No Significant Weight Fraction Difference With Hawker 4000

Hawker used weight savings from composites to increase cabin volume for a very comfortable ride for aircraft category weight

New Method is to Use a 20% Empty Weight Reduction*

*based of historical estimates from http://www.aviation-history.com/theory/composite.htm

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Constraint DiagramsConstraint DiagramsBasic assumptions and initial

estimates for aircraft concepts • (CL)maxT/O = 1.5• (CL)maxLanding = 2.0• CD0 = .0180• e = .8• Mcruise = .85• Cruise Altitude = 42,000 ft• AR = 10.5 (canard)• AR = 8 (conventional)• No thrust reversers

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Constraint Diagram of Conventional Aircraft

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Landing ground roll 2600 ft

Constraint Diagram of Canard Pusher

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Sizing CodeSizing CodeCurrent status:

• MATLAB script Inputs: ~100 variables describing each aircraft Fuel Weight

Engine Model (flight profile analysis) Drag Prediction (component buildup)

Empty Weight (component buildup) Correlation Factors (to similar aircraft) Technology Factors (engines) Calculates gross weight

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MATLAB Code FlowchartMATLAB Code FlowchartInitial Guess

Wo

Geometry Calculatio

ns

We Prediction

Engine Model

Drag Calculation

Wfuel Prediction

W0 Calculation

W0 = W0 calc

Set W0 guess to W0 calc

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Input VariablesInput VariablesFrom constraint diagram

• W0/S = 76 (conventional), 84 (canard)• TSL/W0 = .33

Wing, Canard, and Tail• Geometric variables (AR, Taper ratio, sweep,

etc)Fuselage

• Dimensions, shape, etc.Engines

• Weight, number, size, etc.Mission Variables

• Range, Cruise Mach, etc.Location of components (for xcg

calculuation)25

AssumptionsAssumptionsFlight conditions are constant

over 500 ft altitude intervals during climb and descent.

Engine data is scalableIt was assumed that the

equations in Daniel Raymer’s textbook were accurate

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ValidationValidationCorrelated Conventional design

to G550 and Canard design to Beechcraft Starship

Conventional

Canard

Fuel Weight 0.77 0.77

Empty Weight

1.28 1.33

Gross Weight

1.01 1.05

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Estimated Weight TableEstimated Weight Table

Conventional Canard

Empty Weight (lbs) 47200 48800

Fuel Weight (lbs) 24100 23100

Weight of Crew (lbs)(200 per)

800 800

Weight of Passengers(lbs)

(220 per)3960 3960

Gross weight (lbs) 73100 75100

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Drag PredictionDrag PredictionUsed to help predict:

• Engine size• Amount of fuel• Coast of aircraft

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How to model Drag?How to model Drag?Component build up of different

types of drag:• Parasite drag

• Skin friction• Pressure drag• Interference drag

• Induced drag• Miscellaneous rag• Wave drag

• Assumed 20 counts of drag

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Skin FrictionSkin FrictionAssumed turbulent flow for

conceptual design.• Schlicting Formula

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Pressure DragPressure DragBody component shape dependant

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Interference DragInterference DragDrag from different components

interacting with each other

Q = 1

Q = 1.2

Q = 1

Q = 1.5

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Parasite Drag Build-upParasite Drag Build-up

Component Conventional Canard

Fuselage 0.00520 0.00567

Wing 0.00692 0.00739

H-Tail 0.00219 0.00171

V-Tail 0.00137 0.00268

Nacelle 0.00184 0.00161

Pylon 0.00016 0.00018

* All values are at Cruise Conditions

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Benchmark EngineBenchmark Engine Rolls Royce BR700 Series First Production Run in 1994 The BR700 Series has a thrust range of 14,750 lbf -

22,000 lbf range to allow for “rubber engine” design

http://de.academic.ru/pictures/dewiki/69/Engine_BR710-1.jpg35

Fuel Weight PredictionFuel Weight Prediction Imported engine

data curvesCurves were scaled

based on the sea-level static thrust

Interpolated to find points not on curves

Calculated TSFC for different segments of the design mission

Fuel weight predicted for each segment

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Engine SelectionEngine Selection

Unducted Propfan Modeled Off of Previous Data and N+2 Goals, as Stated Before

Geared Turbofan Stated to Start Production Between Now and 2020

http://www.flug-revue.rotor.com/FRHeft/FRHeft07/FRH0702/FR0702c1.JPGhttp://bryanandhannah.net/assets/

clip_image002.jpg

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Geared TurbofanGeared Turbofan

Uses a gear to decouple the fan from the low pressure turbine, thus allowing a large fan to spin slowly and a small turbine to spin quickly increasing efficiency

http://www.profeng.com/NR/rdonlyres/B0A36366-BDBD-49EF-8C87-ACA1E3630B03/0/211300212.jpg

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Pratt & Whitney PurePower Pratt & Whitney PurePower PW1000PW1000

First ultra-high bypass ratio turbofan engine

Light-weight, low pressure fan design20 dB Quieter than current enginesProven Efficiency with No life-limited

partsReduce NOx emissions (50% margin to

CAEP/6)13,000-17,000 lbf Thrust for 1215G or

21,000-24,000 lbf Thrust for 1524G15% Reduction in Fuel Burn

http://www.purepowerengine.com.html 39

UDF UDF PurePowerPurePowerPros

Very Efficient N+2 goals likely

met Light Weight

(direct drive)Cons

Noise Technology Still in

Devlopment Large Diameter

Pros Reasonably Efficient Quiet In Production by

2016 Low Emissions

Cons Large Diameter

Casing (70in) Not a lot of Data Heavy (gearing)

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Static Margin(SM)Static Margin(SM)Conventional

• CG = 51% of fuselage length• SM = 37% of Cmac

Canard• CG = 74% of fuselage length• SM = 29% of Cmac

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Requirements Compliance MatrixRequirements Compliance MatrixPerformance

CharacteristicsTarget Threshold Current

Range (60 kt headwind)

7100 nm 6960 nm 7100 nm

MTOW Balanced T/O Field Length

(Takeoff Ground Roll)

6000 ft(4000 ft)

7000 ft(5000 ft)

6000* ft(3500 ft Concept 1)( 3400 ft Concept 2)

Max. Passengers 17 8 16

Volume per Passenger per Hour (Design)

13.3 ft3/(pax⋅hr) 2.28 ft3/(pax⋅hr) 13.3 ft3/(pax⋅hr)

Cruise Mach 0.85 0.8 0.85

Initial Cruise Altitude 42000 ft 40000 ft 42000 ft

Cabin Noise 60 dB 70 dB65 dB*

(will differ among concepts)

LTO NOx Emissions CAEP 6-75% CAEP 6-60% CAEP 6-70%*

Cumulative Certification Noise Limits

232 dB 274 dB 274 dB*

Cruise Specific Range 0.3 nm/lb 0.26 nm/lbConcept 1: 0.29 nm/lb*Concept 2: 0.31 nm/lb*

Loading Door Sill Height 4 ft 5 ft 4 ft*

Variable Costs $4100/hr* $4300/hr $4100/hr*

* Value estimated at current stage in analysis 42

Summary & Next StepsSummary & Next Steps

Summary◦ Two concepts selected for detailed analysis◦ Sizing improved using component based method and

engine model◦ Early stability and control estimates developed

Next Steps◦ Select final engine classification (GTF or UDF)◦ Detailed aerodynamic analysis (airfoil selection, etc)◦ Detailed stability analysis◦ Refine sizing code

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Questions and CommentsQuestions and Comments

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