ASGARD AVIATION CONCEPTUAL DESIGN

REVIEWLogan WaddellMorgan BuchananErik SusemichelAaron Foster

Craig WikertAdam AtaLi TanMatt Haas

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Outline1. Project mission2. Selected concept3. Sizing code results

• Modeling assumptions4. Major Design Tradeoffs

• Carpet plots5. Aircraft description6. Aerodynamics

• Airfoil selection• High-lift devices

7. Performance• V-n diagram

8. Propulsion• Engine description

9. Structures• Configuration layout

10.Weights and Balance• Center of gravity location

11.Stability and Control12.Noise13.Cost14.Summary

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Mission Statement

To design an environmentally responsibleaircraft that sufficiently completes the “N+2” requirements for the NASA green aviation challenge.

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Major Design Requirements

Noise (dB) 42 dB decrease in noise

NOx Emissions 75% reduction in emissions below CAEP 6

Aircraft Fuel Burn 50% Reduction in Fuel Burn

Airport Field Length 50% shorter distance to takeoff

*

*ERA. (n.d.). Retrieved 2011, from NASA: http://www.aeronautics.nasa.gov/isrp/era/index.htm

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Selected Concept

Twin-aisle configuration, ~250 passengers with a two-class configuration

Wing loading: 108 lb/ft^2

Wing AR: 7.8

Wing sweep: 31˚

T/W: 0.32

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Aircraft Concept Walk-around

Spiroid Winglets

Technology Suite

Geared Turbo Engines

Scarf Inlets

Chevron Nozzle

Landing Gear Fairings

Advanced Composites

Spiroid Winglets

Hybrid Laminar Flow ControlConventional VerticalStabilizer

Advanced Composite Materials

Wing Mounted Engines

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Sizing Code Using MATLAB

software, first order method from Raymer

Used inputs to determine the size of pre-existing aircraft for validation

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Incorporating Drag Drag values affect

fuel fraction weights which affect the fuel weight

Drag buildup equation used to predict drag

Wave drag uses Lock’s fourth power law

Included in the equation are the parasitic, induced, and wave drag

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Component Weights

Component Weight (lb)

Fuselage 45,723

Wings 51,396

Vertical Tail 2,224

Horizontal Tails 5,494

Engines 25,200

Main Landing Gear 14,972

Nose Landing Gear 2,641

Empty weight buildup from Raymer text.

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Validation Boeing 767-200ER

Passenger Capacity: 224

Range: 6,545 nmiCrew: 2Cruise Mach: 0.8Max Fuel Capacity:

16,700 gal

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Validation continuedActual Prediction %

Error

Gross Takeoff Weight

395,000 [lb] 426,560 [lb] 7.99

Empty Weight Fraction

.46684 .45765 1.97

The sizing code predictions are accurate

The error factor for the takeoff weight is:

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Selected Concept Predictions

Take Off Gross Weight [lb]

Empty Weight Fraction

Wempty [lb] Wfuel [lb] Wpayload [lb] Wcrew [lb]

309050 .478 147650 105000 55000 1400

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Fixed Design Parameter ValuesParameter Value

Cd0 0.0198

Cl (cruise) 0.5185

L/D (cruise) 15.4654

Thickness to Chord Ratio

Sweep angle 31

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Engine Modeling

ሺ𝑻𝑺𝑳𝑺ሻ𝒓𝒖𝒃𝒃𝒆𝒓 = (𝑾𝟎 )𝒓𝒖𝒃𝒃𝒆𝒓 [ሺ𝑻𝑺𝑳𝑺ሻ(𝑾𝟎 ) ]𝒏𝒆𝒏𝒈𝒊𝒏𝒆 𝑺𝑭= 𝑻𝑺𝑳𝑺ሺ𝑻𝑺𝑳𝑺ሻ𝒃𝒂𝒔𝒆𝒍𝒊𝒏𝒆

Used NASA Geared Turbofan tabular data to scale engine to desired propulsion characteristics

Scale factor is based on SLS thrust from tabular data Scale factors also implemented for technologies

Concept AircraftMTOW

(lbs)TSL/W0

# of engines

Max SLS Thrust (lbf)

Scale Factor

Baseline CS300ER 139600 0.335 2 23369 n/a

1Conventional

w/tech 309050 0.32 2 49448 2.116

2 H-Tail 316240 0.35 2 55342 2.368

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Engine Modeling Scale Factor used to size up all

performance data in NASA fileEx.

Technology Data AdjustmentOrbiting Combustion Nozzle

Performance Characteristic Adjustment FactorNOx Emissions 0.75Fuel Burn 0.85

𝑺𝑭𝑪𝒓𝒖𝒃𝒃𝒆𝒓 = 𝑺𝑭𝑪𝒃𝒂𝒔𝒆𝒍𝒊𝒏𝒆(𝑺𝑭)−.𝟏

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Design Mission

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Typical Design Mission Average flight in the continental United

States is 650 nm Typical design mission

Chicago to New YorkApproximately 618 nmConnects two major citiesTypical route carries 212 passengers

○ 85% load factor

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“Basic” Carpet Plot

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Constraint Cross PlotsTakeoff Ground Roll(dTO < 5000 ft) Cross Plot

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Constraint Cross PlotsLanding Braking Ground Roll(dL < 2000 ft) Cross Plot

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Constraint Cross PlotsTop Of Climb (TOP >= 100 ft/min) Cross Plot

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Final Carpet Plot

Design Point W/S[lb/ft^2] T/S W0

108 0.32 309050

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Other Trade-offs

Geared Turbofan: Less Fuel Weight vs. More Drags

Hybrid Laminar Flow Control: 12-14% Less Drags vs. 2.8% More Cost

Landing Fairing: Reduce noise vs. More Weight

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•Length: 180’ 186’•Wing Span: 167’ 197’•Height: 51’ 56’•Fuselage Height: 17’ 19’ 7’’•Fuselage Width: 16’ 18’ 11’’

787-8Our concept

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Two Class System

Seating4 rows 1st Class34 rows Economy Class250 passengers

Seat Pitch39 inches 1st Class34 inches Economy

Class Seat Width

23 inches 1st Class19 inches Economy

Class

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One Class System Seating

No First Class (Low Cost Carriers)44 rows Economy

Class303 passengers

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Airfoil Selection Supercritical airfoils to be used for all

wing and stabilizer sectionsStill used for transonic aircraft*Reduce wave dragIncrease fuel storage space

Airfoil would be designed to meet design goalsCruise CL = 0.5185, L/D = 15.4654

*http://adg.stanford.edu/aa241/intro/futureac.html

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Divergent Trailing Edge Airfoil

Separation bubble employed to generate more lift at trailing edge

New technology being developed with advances in CFD Not much concrete data at this time

Potentially plausible for N+3 goals

http://adg.stanford.edu/aa241/intro/futureac.html

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High-Lift Devices

Slats, Triple-slotted flapsUsed for reliability

Lift coefficients for different configurationsTakeoff CL = 1.3Landing CL = 2.5

Landing and takeoff speeds set at 175 mph (152 kts), 15% faster than stall

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Performance

V-n (Loads) DiagramPerformance Summary

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V-n (Loads) Diagram

n=+2.11n=-1

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Performance Summary

Performance Summary Values

Best Range Velocity 473 knots

Best Endurance Velocity 412 knots

Stall Speed 132 knots (no flaps)

Maximum Speed during Climb

191 knots

Maximum Speed during Cruise

M = 0.8

Takeoff Distance (ground roll)

4,500 ft

Landing Distance (ground roll)

1700 ft

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Propulsion Engine type: High-Bypass Geared Turbofan

Bypass Ratio: 14.5-14.7 Fan Pressure Ratio: 1.4-1.6 Overall Pressure Ratio: 42 SLS Thrust: 49,450 lbs Dry Weight: 9590 lbs

Improvement Technologies Orbiting Combustion Nozzle

Improves fuel burn/reduces emissions Scarf Inlet

Redirects/Decreases fan noise Chevron Nozzle

Reduces low frequency exhaust noise

Courtesy of Airliners.net

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Other Technology Effects Chevron Nozzle

Mixing flows can have adverse effect on thrust Scarf Inlet

Greatly increases engine nacelle weight Reduces inlet efficiency

Orbiting Combustion Nozzle Thrust does not take a huge hit due to

converging/diverging exit Lack of need for diffusers and stators on either

end of compressor reduce weight of engine

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Engine Performance Specific Fuel Consumption

0 0.1 0.2 0.3 0.4 0.5 0.60

0.050.1

0.150.2

0.250.3

0.350.4

0.450.5

Full Throttle Sea Level SFC

NASA DataRubber EngineRubber w/Tech

Mach Number

SFC

(1/h

r)

0.5 0.55 0.6 0.65 0.7 0.75 0.8 0.850.3

0.35

0.4

0.45

0.5

0.55

Partial Throttle Cruise SFC

NASA DataRubber EngineRubber w/Tech

Mach Number

SFC

(1/h

r)

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Engine Performance

500.00 550.00 600.00 650.00 700.00 750.00 800.000.00

2000.004000.006000.008000.00

10000.0012000.0014000.0016000.0018000.00

Available vs. Required Thrust (35k feet)

Thrust AvailableThrust RequiredPolynomial (Thrust Required)

Velocity (ft/s)

Thru

st (l

bf)

450.00 550.00 650.00 750.00 850.000.00

5000.00

10000.00

15000.00

20000.00

25000.00

Available vs. Required Thrust (30k feet)

Thrust AvailableThrust RequiredPolynomial (Thrust Required)

Velocity (ft/s)

Thru

st (l

bf)

0.00 100.00 200.00 300.00 400.00 500.00 600.000.00

10000.0020000.0030000.0040000.0050000.0060000.0070000.0080000.0090000.00

100000.00

Available vs. Required Thrust (Takeoff)

Thrust AvailableThrust Required

Velocity (ft/s)

Thru

st (l

bf)

0.00 100.00200.00300.00400.00500.00600.000.00

50000.00

100000.00

150000.00

200000.00

250000.00

Available vs. Required Thrust (Landing)

Thrust AvailableThrust Required

Velocity (ft/s)

Thru

st (l

bf)

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Engine Performance Emissions Reduction/Fuel Burn Savings

LTO NOx Emissions

CAEP 6 Standard 83 g/kN

75% below CAEP 6 20.75 g/kN

Original Engine Deck 54 g/kN

% Improvement 34.9%

Rubber Engine 21.1 g/kN

% Improvement 74.6%

Fuel Burn (Cruise)

RB-211 (757) 7023 lb/hr

Rubber GTF Engine 3841 lb/hr

% Reduction 45.31%

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Structures: Load Paths•Wing-fuselage intersection (Wing box)

•Pylons

•Tail Intersections

•Fuselage

•Landing gear

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Structures: Wing Box

Wing-fuselage intersection (Wing box)

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Structures: Engine Pylons

Engine pylons

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Structures: Landing GearLanding Gear Integration

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Structures: Material Selections Composite Fuselage (Carbon Laminate)

Composites on leading edges for laminar flow

Aluminum and Fiberglass wings Titanium for pylons

Steel for elevator, rudder, and landing gear

Total MaterialsCompositesAluminumTitanium Steel

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Weights and Balance

Aircraft Group Weights Statement

Description of Empty Weight Prediction

Location of Center of Gravity

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Empty Weight Prediction Method Equations for a/c components from

Raymer Each component function of designed

gross weight Summation of component weights

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CG and Neutral Point Center of Gravity: Components included in CG calculation

Fuselage, wing, horizontal tail, vertical tail, nacelles, engines, and landing gears

Other weights put in center of vehicle Crew, passengers, payload, furnishings,

etc. Neutral Point: 87.6 ft from nose

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Center of Gravity Travel

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Stability and Control

Static Longitudinal Stability Lateral Stability

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CG and Longitudinal Stability

CG from Nose [ft] Weight [lb] Static Margin

EW 84.32 147650 14.6%

OEW 84.0 214550 16%

OEW+fuel 82.18 254050 24.1%

MTOW 83.30 309050 19.1%

MTOW-fuel 85.46 204050 9.5%

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Tail Sizing Current Approach

Using Raymer Equations (6.28) and (6.29)

Concept 1

Tail area 815 ft2

Vertical Tail area 660 ft2

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Control Surface Sizing

Control Surface

Surface Area [ft2]

Aileron 476

Elevator 149

Rudder 198

Raymer Figure 6.3 – Aileron Sizing Raymer Table 6.5 – Elevator Sizing

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Noise Reduction Technologies

Geared turbofan engine Approximate 20% in noise Engine developed twice as powerful as anything presently built,

10% reduction in noise used Compared to Boeing 777-200ER with GE 90-90B engines, this is

a 9 dB decrease Chevron nozzle

Reduces noise up to 2.5 dB Due to engine size, reduction assumed to be 1 dB

Scarf Inlet No concrete data could be found, noise reduction assumed to be

1 dB Landing Gear Fairings

Reduce noise by 2 dB

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Boeing 777-200LR Noise Data

http://adg.stanford.edu/aa241/noise/noise.html

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Conclusion on Noise For Stage 4 standards, noise generated must be

less than 90 dB in any given test. To meet N+2 requirements, the cumulative margin

between the noise generated and 90 dB must be at least 42 dB.

Estimates give a 9 dB deficit from Stage 4, with a cumulative noise reduction of 27 dB. Goal is NOT met.

Plenty of noise reduction technology is in development, but none would be ready by 2025.

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Cost Prediction* the accuracy of results obtained with these models for commercial aircraft is questionable

0 50 1001502002503003504004500

1000

2000

3000

4000

5000

6000

Airframe cost (RDT&E)

Airframe cost (RDT&E)

Number of aircraft produced

Cost

per

Airc

raft

(Mill

ions

)

Non-Recurring Costs• Engineering• Tooling• Development support• Flight tests

Recurring Costs• Engineering• Tooling• Manufacturing• Material• Quality Assurance

•Increase cost by ~ 20% to account for all new technologies

* Analysis from NASA Airframe cost model

Airframe cost in 2011$, millions

# A/c Non-recurringRecurring cost Total Cost Cost per A/C

1 4495.35 1147.7 5643.05 5643.0510 4495.35 3561.55 8056.9 805.6950 4495.35 7981 12476.35 249.527

100 4495.35 11382.7 15878.05 158.7805200 4495.35 16350.7 20846.05 104.23025400 4495.35 23703.8 28199.15 70.497875

1000 4495.35 39477.2 43972.55 43.97255

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Cost PredictionExample case if producing 200 A/C

Would have to sell each aircraft for $104M to break even

Using the modified DAPCA IV Cost Model (costs in 2011 dollars)*Increased cost by 20% to account for technologies

•Production of 200 aircraft

•RDT&E + Flyaway = $34.1208 B

•Would have to sell 200 aircraft for $170.6 M each to breakeven

Airframe cost

# A/c Non-recurringRecurring cost Total Cost Cost per A/C

1 4495.35 1147.7 5643.05 5643.0510 4495.35 3561.55 8056.9 805.6950 4495.35 7981 12476.35 249.527

100 4495.35 11382.7 15878.05 158.7805200 4495.35 16350.7 20846.05 104.23025400 4495.35 23703.8 28199.15 70.497875

1000 4495.35 39477.2 43972.55 43.97255

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Cost: Operations and Maintenance

• Fuel costs Price: ~$5.50 / gallon Jet A (2011 price)

•Crew Salaries

•Maintenance

•InsuranceCommercial: add approx. 1-3% to cost of operations *Raymer

•Depreciation~ 4.0% total value per year

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Cost: Operations and MaintenanceIn 2011$

Cockpit Crew: $912.66 /block hour (domestic) $1003.15 / block hour (international)

Cabin crew: ~$647.14 /block hour (domestic) ~$841.07 / block hour (international)

Landing fee: $679.5 / trip

Maintenance labor: 3.64 MMH/FH airframe 6.84 MMH/TRIP Engine

Maintenance material: $85.74/ flight hour airframe $1416.12/trip Engine

* Advanced subsonic Airplane design & Economic Studies (NASA)

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Summary of Final Design

•Tube and Wing design with advanced technologies•Swept back wings• Technologies

• Spiroids• Laminar Flow• Geared Turbofan• Composite Materials

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Compliance MatrixDesign

Requirements Units Target Threshold Final Design Compliant

Range Nautical Miles

4,000 3,600 4,000 Yes

Payload Passengers 250 230 250 Yes

Cruise Mach # - 0.8 0.72 0.8 Yes

Takeoff Ground Roll

ft 7,000 9,000 4,500 Yes

Landing Ground Roll

ft 6,000 6,500 1,700 Yes

Fuel Burn lb/hr 4,250 4,500 3,841 Yes

Emissions(NOx) g/kN thrust 15 (-75%) 22 21.1(-74.6%) No

Noise (Cumulative)

dB -42 -32 -27 No

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Design Requirements Plausible? Fuel Burn ~ Possible Field Length ~ Possible Emissions ~ Very difficult but can be

possible Noise ~ Not possible for N+2

Noise shieldingEngine configuration

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Future Work More detailed sizing code/calculations

Aircraft ModelBuild 3-D model

Work with airlines to receive feedback

Enter NASA competition