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Conceptual Design Review

Dean Jones

Dustin Souza

Anthony Malito

Ricardo Mosqueda

Alex Fickes

Keyur Patel

Matt Dienhart

Danielle Woehrle

Nayanapriya Bohidar

N.E.R.D.New Environmentally Responsible Design

• Project Mission and Target Market

• Design Mission and Requirements

• Walk-around

• Sizing code Description

• Carpet Plots

• Aircraft Description

• Aerodynamic details

• Performance

• Propulsion

• Structures

• Weights and Balance

• Stability and Control

• Noise

• Cost

• Summary

Outline

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• Mission Statement

– “To design an environmentally responsible aircraft for the twin aisle

commercial transport market with a capacity of 300+ passengers, NASA’s

N+2 capabilities, and an entry date of 2020-2025.”

– NASA’s N+2 technology requirements include:

1. Reducing cumulative noise by 42dB below Stage 4

2. Reducing take-off and landing NOx emissions to 75% below CAEP6 levels

3. Reducing fuel burn by 50% relative to “large twin-aisle performance” (777-200LR)

4. Reducing field length by 50% relative to the large twin-aisle

Project Mission

3

• Mission Statement

– A high-capacity, short- to

medium-haul aircraft

– Primarily servicing Asia-

South Pacific region

Target Market

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Target Market

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Design Mission

6

• Design Mission

– 400 Passengers

– 4,000 nmi Range (Honolulu, HI to Osaka, Japan: 4,000nmi)

6500 ft 6500 ft

Design Requirements

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Requirements Threshold Target

Cruise Mach 0.75 0.80

Range 3,000 nmi 4,000 nmi

Field Length(at sea level, MTOW) 8,800 ft 5,800 ft

Field Length(@ 14K ft, +15°F) 18,000 ft 9,000 ft

Fuel Burn* 33% reduction 50% reduction**

NOx Emissions 50% below CAEP 6 75% below CAEP 6**

Noise Reduction 32 EPNdB cum. below Stage 4

42 EPNdB cum. below Stage 4**

Passenger Capacity 350 400

Direct Operating Cost* 10% Reduction 15% Reduction

*Relative to B777-200LR** NASA ERA goal

Walk-Around

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*Liebeck, R.H., “Design of the Blended Wing Body.” The Boeing company, 01/02/2004, Web, 20/04/2011

Design Parameters

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Parameters Value Units

Wing Loading 87 lb/ft2

Wing Aspect Ratio 11 -

Wing Span 203 ft

Wing Sweep 40⁰ degrees

Thrust-Weight ratio 0.226 -

Reference Area 3775 ft2

Technologies

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Requirements GTF Composites

WingtipTechnolo

gy

FlyBy

Wireless

TrailingEdge

Brushes

ElectricActuator

s

LaminarFlow

Control

Active Noise

Cancellation

Fuel Burn + + + + - + +

Exterior Noise + + + + +

NOX +

Field Length

Empty Weight - + - + - + - -

Cruise Speed

Manufacturing Cost - - - - - -

Maintenance Cost - - + - + - -

Pax/Crew Comfort + +

Layout Complexity - - - -

Stability & Maneuverability

Minimum Ground Time

Aesthetics + + - -

Sigma 1 1 0 2 -4 3 -2 -3

Aircraft Sizing

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• Best Description of Sizing Code

– Uses Matlab script provided that iterates for an initial TOGW to a

converged value

– Uses inputs from trade studies and calculates aircraft geometry and thrust

requirements

– Incorporates component weight and drag buildup technique

– Aircraft is treated as a complete wing for drag buildup.

but broken up into centerbody, aft and wing for weight buildup

Aircraft Sizing

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• Fixed Design Parameter Values

Parameter Value Units

1. Taper ratio 0.27 -

2. Sweep 40 degrees

3. CLmax 1.4 -

4. Vpr 85,500 ft3

5. Max Landing weight fraction 0.9 -

6. Passenger weight 88000 lbs

7. Crew weight 1400 lbs

Aircraft Sizing

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• Modeling Approaches– Weight Equations: Raymer’s Transport equations + NASA Sizing

Methodology for the Conceptual Design of BWB, by Kevin R. Bradley

Wfuse = 5.698865*0.316422(TOGW)0.16652(Scabin)1.061158

Waft = (1 + 0.05*NEng)*0.53*Saft*(TOGW)0.2*(λaft + 0.5)

Component Weight lbs1. We 17,7210

2. Wfuel 61,800

3. Wengine 7,220

4. Wcenterbody 83,910

5. Wwing 88,000

6. WVT 1,400

7. Wavionics 1,840

Aircraft Sizing

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• Modeling Approaches (contd.)– Drag prediction equations: Raymer’s component drag buildup method

using a transonic Re cutoff, flat plate skin friction coefficient and component form factors.

– Tail sizing: Raymer’s equations + cross-wind and one-engine out conditions

Component Parasite Drag1. Cdo,wing 0.0117

2. Cdo,VT 0.0003

3. Cdo,pylons 0.0001

4. Cdo,nacelles 0.0003

Component Parasite Drag ft2

1. Sref 163

Aircraft Sizing

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Sized Parameter Unit

1. SFCmaxthrust 0.1108 1/hr

2. SFCcruise 0.416 1/hr

3. Thrustcruise 11,000 lb

4. Weight 4,815 lb

5. Length 12 ft

6. Diameter 11.8 ft

• Modeling Approaches (contd.)

– Engine deck using Raymer’s equations and optimized T/W

Aircraft Sizing

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• Modeling Assumptions

– From new technologies

Technology Variable(s) Affected Amount Affected

1. CompositesOEW -20%

Cdo -6%

2. GTF Wfuel -12%

3. Fly by wireless Welectronic -50%

4. Airfoil (passive laminar control) % laminar flow +50%

5. Active laminar flow controlD -20%

Wwing +5%

6. Electric actuators Wfuel -9%

Aircraft Sizing

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• Validation

– Using current aircraft in the industry

3,000 3,500 4,000 4,500 5,000 5,50020,000

40,000

60,000

80,000

100,000

120,000

140,000

160,000

Pocket Protector

B737-700

B767-200

B777-200

Range Comparison

Current Aircraft Range Linear (Current Aircraft Range)Pocket Protector Range

Range (nmi)

Fuel

wei

ght(

lb)

100 150 200 250 300 350 400 45020,000

40,000

60,000

80,000

100,000

120,000

140,000

160,000

Pocket ProtectorB737-700

B767-200

B777-200

Pax Comparison

Current Aircraft Pax Polynomial (Current Aircraft Pax)Pocket Protector Pax

No. of passengers

Fuel

wei

ght(

lb)

Carpet Plot Constraints

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Constraint Parameter Value Units

Take off Ground Roll 3500 ft

Landing Ground Roll 4400 ft

Specific Power 100 ft/sec

Fuel Weight 63000 lbs

2g Maneuver 50 ft/sec

2nd Seg. Climb 2.5 %

Sref 3762.5 ft2

Carpet Plot

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3.10E+05

3.20E+05

3.30E+05

3.40E+05

3.50E+05

3.60E+05

3.70E+05

D_l≤ 4400[ft]

dh/dt≤ 50

Ps> 100 [ft/min]

CGRs> 2.5%

Sref > 3760[ft^2]

Carpet Plot Results

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Parameter VALUE Comparison NASA ERA Goals

TOGW 328410 lb -

We 177210 lb -

Wfuel 61799 lb 51% Decrease

AR 11 -

T/W 0.226 -

W/S 87 -

Cdo 0.0131 -

Sref 3775 ft2 -

Field Length 8,670 ft Does not meet NASA Field Length goals

Aircraft Description

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Aircraft Description

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• 400 Passengers • 1-Class configuration

Aerodynamic Design Details

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• Difficult to put flaps on a HWB design– must make due with leading edge high-lift devices

– Choose airfoils with high camber/high CLmax

• To reduce fuel burn, airfoil should offer minimum drag– Laminar flow airfoils (eg. NACA 6-series)

– Smooth fabrication to reduce skin friction

• Airfoil thickness chosen with respect to laminar flow properties

and structural considerations– HWB must fit entire cabin volume within the wing section

– t/c >14% desirable for good performance (gradual stall)

• Design lift coefficient is a function of wing loading 10.385L design

WC

q S

Aerodynamic Design Details

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-6 -4 -2 0 2 4 6-0.5

0

0.5

1

1.5

2

Lift Curve Slope for NACA 632-415 a=50

CleanTakeoffLandingCleanLogarithmic (Clean)TakeoffLanding

α (degrees)

Cl

Aerodynamic Design Details

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0 0.01 0.02 0.03 0.04 0.05 0.06 0.07 0.08 0.09-0.5

0

0.5

1

1.5

2

Drag Polar for NACA 632-415 a=50

CleanTakeoffLandingCleanTakeoffLanding

Cd

Cl

Performance

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• V-n diagram with gust loading

Performance

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• Performance Summary

Parameter Value Units

Maximum load factor 2.76 -

Stall speed at sea level 195 ft/s

Landing speed at sea level 220 ft/s

Takeoff speed at sea level 213 ft/s

Cruise speed 782 ft/s

Loiter speed 340 ft/s

Takeoff field length 5640 ft

Landing field length 8670 ft

Propulsion

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• Geared Turbofan Engine

– Cycle Type: High-bypass turbofan

– By-pass Ratio: 15:1

– SLS Thrust: 39110 lbs.

– Overall Pressure Ratio: 50:1

– Fan Pressure Ratio: 3:1

– Stage Count: 1-G-3-8-2-3

Propulsion

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• Engine Size & Assumptions

– Length = 15.99 ft Diameter = 9.14 ft Weight = 7223.35 lbs.

– Smaller in length due to less stages

– Less maintenance due to fewer stages

– Negligible losses upon installation, on top mounting and no integration

into airframe.

– -20 decibels below Stage 4

– 15% Reduction on fuel consumption

– Less air needed to cool the turbine

– 75% Reduction in NOx emissions

Propulsion

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• Engine Performance

Propulsion

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• Engine Performance (cont’d)

Important Altitudes

Velocity Desired (ft/s)

Thrust Required (lbs)

Thrust Available (lbs)

SLS – 0 ft 213 20106.9 78220High Hot – 14,000 ft 265 22417.7 32003.5

Cruise – 34,000 ft 780.104 14409.6 22994.940,000 ft 776.048 12050.6 20019.1

Single Engine PerformanceSFC at Tmax 0.111

Thrust at Cruise 11002.68SFC at Cruise 0.416

Structures

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Spars

RibsLanding gear

Vertical stabilizers

• Center spars in pressurized vessels separate cargo area from passenger seating area.

Structures

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Composites with conductive layersAluminumTitaniumCarbon Fiber Reinforced PlasticCopper-aluminum-zinc alloy (SMAs)*

*Barbarino, Silvestro, “Morphing trailing edges with shape memory alloy rods”, 21st International Conference on Adaptive Structures and Technologies, Oct 4th 2010, Web, 20/04/2011

Material Justification

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• Composites with conductive layers– This is used as the skin of the aircraft. Incorporates potential for

lightning strikes with conductive layers.

• Aluminum– Placed at leading edges due to higher heat resistance as compared to

composites and less prone to damage on impact.

• Titanium– Used in landing gear, for high strength

• Carbon Fiber Reinforced Plastic– Used on ribs, spars and stringers because of high strength-to-weight

ratio

• Copper-Aluminum-Zinc Alloy (Smart Material Alloy)– Used in the morphing trailing edges. They are able to sustain external

loads while allowing controlled shape modification

Weights & Balance

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• Free Body Diagram

Weights & Balance

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• Load Routing

Weights & Balance

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• Empty Weight BreakdownWeight [lb] Weight [lb]

Structures

Wing 32441.00

Equipment

APU 2800.00

Vertical Tail 4698.00 Flight Controls 7088.40

Center Body 83910.00 Instruments 1772.10

Main Landing Gear 7766.90 Hydraulics 5316.30

Nose Landing Gear 1412.16 Electrical 8860.50

Engine Mounts 2889.36 Avionics 2362.80

Nacelles 1772.10 Furnishings 17721.00

Misc. Systems 5316.30

Propulsion

Fuel System/Tanks 2889.36

Engine Cooling 2167.02

Useful Load

Crew 1400.00

Exhaust System 1011.28 Fuel 61799.00

Starter 577.87 Oil 722.34

Passengers 72000.00

Payload 16000.00

Weights & Balance

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• Center of Gravity Location

Aerodynamic Center 73.6 ft from nose

CG Location 63.3 ft from nose

Static Margin 7.78 %Cmac

Stability & Control

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• Lateral trim for one engine out @ V = 1.1Vstall

• Rudder deflection angle δ = 16 degrees

• Cross wind landing condition @ V = .2 VTO

• Sideslip angle β = 5 degree

Tail Surface area Tail height Rudder height Rudder width

163 ft2 each326 ft2 total 25.5 ft 15.3 ft 4.2 ft

Aileron Surface area Aileron span Aileron length

165.8 ft2 each331.70500 ft2 total 81.5 ft 2 ft

Noise

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• Approach

– Choose baseline engine

– Adjust engine PNdB level based on:

• Distance

• Maximum thrust

• Partial throttle

• Engine technologies

– Calculate airframe noise for landing

• Function of aircraft weight

Noise

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Noise Level BreakdownBasis of Change Change in dB

Number of engines +3.0

Maximum thrust -4.7Partial throttle during

landing -6.9

Distance during takeoff measurement -12.8

Distance during sideline measurement -5.5

Distance during approach measurement +8.8

Takeoff EPNdB adjustment -4.0

Landing EPNdB adjustment -5.0

Engine Technology -15

Baseline Engine

GE90-115B

Thrust 115,000 lbs

Noise 103 PNdBDistance to

measurement 1,107 ft

Noise

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• FAR Noise Thresholds & Design Noise Level

Condition Stage 3 Requirement (EPNdB)

Design Noise Level (EPNdB) Margin (EPNdB)

Takeoff 95.5 69.5 26.0

Sideline 99.4 76.8 22.6

Approach 102.9 95.4 7.4

Sum 56.1

Below Stage 4 46.1

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Cost Analysis

• Estimated Development and Manufacturing Cost

• Estimated number of aircraft in production run– Approximately 400 airplanes for the first 5 years due to the learning curve

– Targeting production of 2000 aircrafts in the production run

• Estimated Direct Operating Cost

Airframe Cost $ 52,742,862.01

Engine Cost (1) $ 6,464,986.58

Total DOC+I

$ 69,689.74 $/trip

$ 7,461.43 $/hour

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Cost Analysis

• DOC + I Method

– Fuel Cost

– Flight Deck Crew Cost

– Airframe Maintenance Cost

– Engine Maintenance Cost

– Depreciation

– Interest

– Insurance

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Cost Analysis

• Method Used (Production and Manufacturing Cost)

– Using a modified version of Raymer’s Eq. 18.9 for airframe and

• Pay (Rx ) were changed to 2011 dollars from 1999 dollar by accounting for

inflation

• The hours were also adjusted for based on the production complexity

– Using Raymer’s Equation 18.8 for engine cost

• Tmax of 39110 lbs was obtained from the sizing code while Mmax, and

Tturbine inlet were assumed to be 0.85 and 2560 R, respectively

Summary

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Compliance Matrix

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Requirements Threshold Target Current Values

Cruise Mach 0.75 0.80 0.80

Range 3,000 nmi 4,000 nmi 4,000 nmi

Field Length(at sea level, MTOW) 8,800 ft 5,800 ft 8,670 ft

Field Length(@ 14K ft, +15°F) 18,000 ft 9,000 ft 10,500 ft

Fuel Burn* 33% reduction 50% reduction** 51% reduction

NOx Emissions 50% below CAEP 6 75% below CAEP 6** 50% reduction

Noise Reduction 32 EPNdB cum. below Stage 4

42 EPNdB cum. below Stage 4**

46.1 EPNdB cum. below Stage 4

Passenger Capacity 350 400 400

Direct Operating Cost* 10% Reduction 15% Reduction 79% Increase

*Relative to B777-200LR** NASA ERA goal

Future Work

• NOx Prediction

• Structural Refinement

• Design & Development Work

Summary

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