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Systems DesignReview

Dean JonesDustin Souza

Anthony MalitoRicardo Mosqueda

Alex FickesKeyur PatelMatt DienhartDanielle WoehrleNayanapriya Bohidar

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

• Mission Statement

• Design Requirements

• Aircraft Concept Selection

• Advanced Technologies / Concepts

• Engine / Propulsion Modeling

• Constraint Analysis / Constraint Diagram

• Sizing Studies

• Initial Center of Gravity, Stability and Control Estimates

• Summary of Aircraft Concepts

Outline

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To design an environmentally responsible aircraft for the twin aisle commercial transport market with a capacity of 400 passengers, NASA’s N+2 capabilities, and an entry date of 2020-2025.

NASA’s N+2 technology benefits include:

• Reducing cumulative noise by 42 dB below Stage 4• Reducing take-off and landing NOx emissions to 75% below CAEP6 levels• Reducing fuel burn by 50%

– relative to “large twin-aisle performance” (777-200LR)• Reducing field length by 50% relative to the large twin-aisle

Mission Statement

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• Requirements• Threshold

Design Requirements

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Requirements Threshold Target Current

Cruise Mach 0.75 0.80 0.80

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

Field Length(at sea level, MTOW) 8,300 ft 5,800 ft 6,500 ft

Field Length(@ 14K ft, +15°F) 18,000 ft 9,000 ft 11,100 ft

Fuel Burn* 33% reduction 50% reduction** -

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

Noise Reduction 32 dB cum. below Stage 4

42 dB cum. below Stage 4** -

Passenger Capacity 350 400 400

*Fuel burn reductions relative to B777-200LR** NASA ERA goal

Aircraft Concept Selection

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The “Pocket Protectors” (2 Variations UDF or GTF)

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Aircraft Concept Selection

Pros

• Increased aerodynamic efficiency for lower drag

• Decreased noise with engines mounted on top

• Lighter structure

Cons

• Increased manufacturing complexity

• Increased maintenance costs

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Aircraft Concept Selection

The “Side Part”

Pros

• Conventional design

• Decrease manufacturing cost

• Decrease maintenance cost

• Increase noise shielding

Cons

• Not as efficient as a Blended Wing Body design

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Aircraft Concept Selection

The “Suspenders”

Pros

• Semi-blended wing design

• Circular pressure vessels

• Maintenance and manufacturing complexity not as high as a BWB design

Cons

• Higher drag from increased surface area

Cabin Layouts

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The “Pocket Protectors”

The “Side Part” The “Suspenders”

Advanced Technologies

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Requirements UDF GTF Composites Wingtip Technology

Fly By Wireless

Trailing Edge Brushes

Electric Actuators

Laminar Flow 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 -3 1 1 0 2 -4 3 -2 -3

Un-Ducted Fan (UDF)

• Offering minimal fuel consumption• Double digit SFC• 30% Reduction in fuel consumption and greenhouse gases• Offering speed and performance of a turbofan• Bigger in size, noisy, safety issues

Geared Turbofan (GTF)

• 12% reduction in fuel consumption• 35-50% reduction in CO2 and NOx• 50% reduction in noise• Bigger in size• Fuel consumption is an issue

Engine Concepts

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Rubber Engine Sizing

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Concepts T/TOGW Thrust Required TOGW EnginesRequired

Direct-Drive Engines

Required

Pocket ProtectorsWith UDF Engine 0.36 84837.6 235660.00 2.31 0.735798786

Pocket ProtectorsWith GTF Engine 0.28 75633.6 270120.00 2.06 0.655972246

Side Part UDF Engine 0.335 84406.6 251960.00 2.29 0.732060711

Suspenders UDF Engine 0.317 76977.1 242830.00 2.09 0.667624545

GTF(PW1400G @ 32K)

UDF(same as GTF)

Direct-Drive(GE90-115B)

36800 36800 115,300

50 60 70 80 90 100 110 120 130 140 1500

0.1

0.2

0.3

0.4

0.5

0.6

top of climb (1g steady, level flight, M = 0.8 @ h=34K, service ceiling)

sustained subsonic 2g manuever, 250kts @ h =10K

takeoff ground roll 4500 ft @ h = 5K, +15° hot day

landing braking ground roll 2000 ft @ h = 5K, +15° hot day

second segment climb gradient above h = 5K, +15° hot day

W0/S [lb/ft2]

TSL/

W0

Constraint Analysis

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Constraint assumptions

L/D = 23.9CL max = 2.16CD0 = 0.0075

e = 0.9AR = 12

αcruise = 0.322αloiter = 0.739Vcruise = 0.8 M

VTO = 256.9 ft/sVapproach = 283.1 ft/s

Pocket Protector

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Altitude (ft) Mach Aspect

RatioTO Ground

Roll (ft)Braking Ground Roll (ft)

34000 0.8 12 4500 200034000 0.8 12 4000 200034000 0.8 12.5 4000 2000

Wo/S(lb/ft2) TSL/Wo

115 0.27105 0.27100 0.26

Altitude(ft) Mach Aspect

RatioTO Ground

Roll (ft)Braking Ground Roll (ft)

34000 0.8 12 4500 200034000 0.8 12 5800 250034000 0.8 12.5 6000 2500

Wo/S(lb/ft2) TSL/Wo

90 0.36108 0.36115 0.35

Pocket Protector

High Hot Operating Conditions : H = 14K + 15°

Constraint Analysis

Normal Operating Conditions

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Constraint assumptions

L/D = 19.7CL max = 1.8CD0 = 0.015

e = 0.8AR = 9

αcruise = 0.322 αloiter = 0.838 Vcruise = 0.8 M

VTO = 240.6 ft/sVapproach = 265.05 ft/s

50 60 70 80 90 100 110 120 130 140 1500

0.1

0.2

0.3

0.4

0.5

0.6

top of climb (1g steady, level flight, M = 0.8 @ h=34K, service ceiling)sustained subsonic 2g manuever, 250kts @ h =10Ktakeoff ground roll 5800 ft @ h = 5K, +15° hot daylanding braking ground roll 2000 ft @ h = 5K, +15° hot daysecond segment climb gradient above h = 5K, +15° hot day

W0/S [lb/ft2]

TSL/

W0

Constraint AnalysisSide Part

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Altitude(ft) Mach Aspect

RatioTO

Ground Roll (ft)

Braking Ground Roll (ft)

34000 0.8 9 4500 2000

34000 0.8 9 4500 2300

34000 0.8 9.5 4500 2000

Wo/S(lb/ft2) TSL/Wo

108 0.33

120 0.33

115 0.32

Altitude(ft) Mach Aspect

RatioTO

Ground Roll (ft)

Braking Ground Roll (ft)

34000 0.8 9 4500 2000

34000 0.8 9 6000 2500

34000 0.8 9.5 6000 2800

Wo/S(lb/ft2) TSL/Wo

84 0.43

108 0.43

118 0.41

Side Part - Normal Operating Conditions

High Hot Operating Conditions- H = 14K +15°

Constraint Analysis

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50 60 70 80 90 100 110 120 130 140 1500

0.1

0.2

0.3

0.4

0.5

0.6

top of climb (1g steady, level flight, M = 0.8 @ h=34K, service ceiling)sustained subsonic 2g manuever, 250kts @ h =10Ktakeoff ground roll 4500 ft @ h = 5K, +15° hot daylanding braking ground roll 2000 ft @ h = 5K, +15° hot daysecond segment climb gradient above h = 5K, +15° hot day

W0/S [lb/ft2]

TSL/

W0

Constraint assumptionsL/D = 21.8CL max = 2.45CD0 = 0.0138e = 0.75AR = 10.5αcruise = 0.323αloiter = 0.739Vcruise = 0.8 MachVTO = 260.9 ft/s @ sea levelVapproach = 268.1 ft/s @ sea level

Constraint AnalysisSuspenders

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Altitude(ft) Mach Aspect

RatioTO

Ground Roll (ft)

Braking Ground Roll (ft)

34000 0.8 10.5 4500 2000

34000 0.8 10.5 4000 2300

34000 0.8 12.5 4500 2000

Wo/S (lb/ft2)

TSL/Wo

117 0.32

105 0.32

107 0.28

Altitude(ft) Mach Aspect

RatioTO

Ground Roll (ft)

Braking Ground Roll (ft)

34000 0.8 10.5 4500 2000

34000 0.8 10.5 6000 4000

34000 0.8 12.5 4500 2000

Wo/S(lb/ft2) TSL/Wo

92 0.41

125 0.41

85 0.35

Suspenders - Normal Operating Conditions

High Hot Operating Conditions- H = 14K +15°

Constraint Analysis

Sizing Study

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• Simple to Initial• L/D calculations implement results from trade studies• Component weight build-up method included in code

(Raymer, eqs.15.46 – 15.59)

• Component build-up technique underway for drag prediction

(Raymer, eq. 12.24)

• Best current predictions

Concepts TOGW (lb) OEW (lb) Wfuel (lb)

The “Pocket Protectors” 235,660 91,540 54,720

The “Side Part” 251,960 97,480 65,070

The “Suspenders” 242,830 94,160 59,270

•Validation

Sizing Study

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2,500 3,000 3,500 4,000 4,500 5,000 5,500100000.00

150000.00

200000.00

250000.00

300000.00

350000.00

400000.00

450000.00

500000.00

550000.00

600000.00

B737-700

B767-200

B777-200

Range Comparison

RangeLinear (Range)Pocket ProtectorsSide PartSuspenders

Range (nmi)

TOGW

(lb)

100 150 200 250 300 350 400 450 5000.00

100000.00

200000.00

300000.00

400000.00

500000.00

600000.00

B737-700

B767-200

B777-200

Passenger Comparison

PaxLinear (Pax)Pocket ProtectorsSide PartSuspenders

Pax

TOGW

(lb)

Center of Gravity Estimates

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Concept Center of Gravity (% a/c length)

Static Margin Threshold

Static MarginTarget

Pocket Protector 53% 5% 8%

Side Part 61% 5% 8%

Suspenders 59% 5% 8%

Control Sizing Approach

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• Tailless Concepts– Aerodynamic Center Location– Wing Sweep Tradeoffs

• Traditional Tail Concepts– Tail Area

• Implementing New Technologies

• Geometry Sizing

- Component weight distribution

- Drag build-up

• Stability Analysis

• Internal layout and subsystems

• Noise prediction

• Concept refinement

Next Steps

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