ConceptualDesignReview

• XG International

presented by:

Gihun Bae - Joe Blake - Jung Hoon Choi - Jack Geerer - Jean Gong – Sang Jin Kim - Mike McCarthy - Nick Oschman - Bryce Petersen - Lawrence Raoux - Hwan Song

Outline of Contents

I. Mission StatementII. Design Mission/

RequirementsIII. “Best” Aircraft ConceptIV. Sizing, Carpet PlotsV. Design Trade-offsVI. AerodynamicsVII. Performance

VIII. PropulsionIX. StructureX. WeightsXI. Stability/ControlXII. NoiseXIII. CostXIV. Summary

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Mission Statement

Develop an environmentally-sensitive aircraft which will provide our customers with a 21st-century

transportation system that combines speed, comfort, and convenience while meeting NASA’s N+2 criteria.

3

Design Requirements

4

• Noise (dB)– 42 dB decrease in noise

• NOx Emissions– 75% reduction in emissions

• Aircraft Fuel Burn– 40% lower TSFC

• Airport Field Length– 50% shorter distance to

takeoff

**Values for NASA N+2 protocol are found in the Opportunity Statement**

NASA ‘s Subsonic Fixed Wing Project Requirements.

Previous vs. Final Models

Previous Final

5

Previous vs. Current

Previous• 2 Turboprops/UDF• 1 Turbofan• Canard• T-Tail

Current• 3 Turbofans• No Canard• Cruciform Tail

6

Previous Current

Wing Loading 82 97.5

Aspect Ratio 9 7.8

Thrust-to-Weight 0.3 0.33

Wing Sweep Angle 35° 28.13°

2

lbf

ft2

lbf

ft

Previous vs. Current - Justification

• Removal of UDF: Lack of historical dataNoise will exceed regulations

• Turbofan vs. Turboprop: Faster speed• Cruciform vs. T-tail: Reduce structure weight• Engine placement: Reduce structure weight

(pylons, nacelles)• Removal of Canard: Weight increase overrides

the benefits7

8

“Best” Aircraft Concept

Solar Films

Cruciform Tail

Winglet

Turbofan

Engine Duct

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“Best” Aircraft Concept

3rd Engine

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“Best” Aircraft Concept

• 3 Turbofan engines• 2 Outer engines for cruise• Cruciform Horizontal Stabilizer• Dropped canard configuration

Important Specifications

Wing Loading 97.5

Aspect Ratio 7.8

Thrust-to-Weight 0.33

Wing Sweep Angle 28.13°

2

lbf

ft

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“Best” Aircraft Concept

Advanced Conceptsa. Solar Panels – Powers cabin electronicsb. 3 Engines – Maximizes fuel efficiency during cruise

– Reduces takeoff distance – Safer for 1-engine-out condition

c. Closable duct – Reduces drag of the duct that might be produced when the engine is not used.

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Sizing Code

• Used Cargo/Transport Weights from Raymer’s

• Used Excel Spreadsheet• 6 Different Sections

a) Maini. Fuselageii. Wingiii. Engine

b) Geometryc) Constraint Diagramd) Weighte) Airfoilf) Mission Detail

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Sizing - AssumptionsPerformance Specs Value

CLmax 1.6(L/D)max 9.3We/WO 0.714SFCcruise 0.5 /hrSFCloiter 0.4 /hr

t/c 0.0158Sweep Angle (Λ) 28.13°Taper Ratio (λ) 0.5

e 0.8Vcruise 710 ft/sVstall 223 ft/s

Vtake-off 245 ft/sVapproach 280 ft/s

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Sizing – Drag Prediction

• CD = CDP + CDi + Cmisc + Cw

• CD = Parasite Drag Coefficient +

Induced Drag Coefficient• CDmisc and CDw are assumed to be zero.

• CDi = Induced drag coefficient = • Parasite drag calculated from sizing code

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Sizing – Tail

The rudder and ailerons are based on conventional business jet values (Raymer).

Rudder Dimensions Aileron Dimensions

Span 4.95 ft Span 9.6 ft

Chord 2.12 ft Chord 1.33 ft

Planform Area 10.5 ft2 Planform Area 12.73 ft2

Aspect Ratio 2.33 Aspect Ratio 7.22

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Sizing - Validation

Bombardier Challenger 300 Specification (XG Endeavour)• Range : 3560 nmi (3700 nmi)• Passenger number: 9 (9)• Crew Number : 2 (2)• Cruise Mach Number : 0.8 (0.8)• Service Ceiling : 45000 ft (45000 ft)

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Sizing - Validation

• Weights based on the sizing codea) Empty Weight = 17500lbb) Fuel Weight = 14000lbc) Total Weight = 34400lb

• Actual Weights of Bombardier Challenger 300a) Empty Weight = 18500b b) Fuel Weight = 14100lbc) Total Weight = 35400lb

• Fudge Factor

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Design Trade-offs

• Based off of calculations in the constraint diagram• Constraints vs. Wing Loading

1. Gross Weight2. 2g Maneuver3. Takeoff Ground roll4. Landing Ground roll

Carpet Plot

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Design Trade-offs

70 75 80 85 90 95 100 105 110 115 12020000.00

20200.00

20400.00

20600.00

20800.00

21000.00

21200.00

21400.00

21600.00

21800.00

22000.00

Carpet Plot

T/W=0.3T/W=0.4T/W=0.5W/S=70W/S=80W/S=902g maneuvertakeoff ground rollLanding ground roll

Wing Loading

Gros

s Wei

ght

Carpet Plot

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Design Trade-offs

Pros Cons

Cruciform Tail Aft fuselage engine Increase weight

Solar Film More Engine Efficiency Increase empty weight

3 Engines Safer 1 engine-out situation Heavier empty weight

3 Engines Cont’d Better fuel efficiency at cruise More maintenance cost

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Design Trade-offs

7 ft Cabin 6.5 ft Cabin

Increase in DragMore head Room

Less Drag

Cabin Layout

Three Views

Dimensions

22”Wing Leading Edge

36”Tail leading edge

37”Vertical Stabilizer

38”Tail Mounted Engine

40”Center Engine

50”Total aircraft length

Internal Layout

Fuel Tank

Wheel housing

Equipment compartment

Avionics compartment and nose landing gear housing

Enlarged equipment compartment:Fuel pump and reservoirDuctEngineEquipment (APU, AC, etc.)

Cabin Layout

Airfoil Selection

Drag Polar Shape

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NACA 2414

www.worldofkrauss.com

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Airfoil Selection

www.worldofkrauss.com

Parameter Values

CLmax 1.276

Angle CLmax 15°

(L/D)max 48.157

Angle (L/D)max 6.5°

Angle Stall 6.5°

Angle Zero-lift -2°

NACA 2414

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Drag Polar

0.04 0.05 0.06 0.07 0.08 0.09 0.1 0.11

-1.5

-1

-0.5

0

0.5

1

1.5

Drag Polar

CruiseTakeoffLanding

Coefficient of Drag

Coeffi

cient

of L

ift

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Performance

• Diagram provides visualunderstanding of wing loading with increasing velocity.

• Created V-n diagram using maximum wing loading of +3.333Gs and -1G (using a 1.5 SF).

• V is velocity represented in ft/s.• n is load factor in Gs.

0 200 400 600 800 1000 1200

-2

-1

0

1

2

3

4V-n Diagram

V

n

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Performance

Performance Specification Values (units)

Take Off Distance 4000 (ft)

Landing Distance 2500 (ft)

Best Range 3700 (nmi)

Best Endurance Velocity 710 (ft/s)

Stall Speed 220 (ft/s)

Stall Speed @ Max. (+) Load Factor 400 (ft/s)

Stall Speed @ Max. (-) Load Factor 220 (ft/s)

Dive Speed 1020 (ft/s)

Cruise Speed 710 (ft/s)

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Propulsion

Engine Description• For the final design 3 turbofan engines will be used, one capable of producing

6,800 pounds of thrust, and two that produce 2,000 pounds of thrust.• These engines are modeled from the HF120 turbofan which is manufactured

by GE Honda Aero Engines.• Below are a picture of the engine, and a schematic showing dimensions. Both

are for the 2000 pound thrust version.

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Propulsion

• The 2000 pound thrust model has the following characteristics:– Bypass Ratio=– Takeoff Thrust=2050 lbs– Compressor pressure ratio=24

• The 6800 pound thrust model has the following characteristics:– Bypass Ratio=– Takeoff Thrust =6800 lbs– Compressor pressure ratio=26

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Propulsion

• Assumptions for Engine Modeling:– The baseline model was scaled to meet the mission’s

thrust requirements using an Excel sizing routine.– Technological improvement factors were used to

determine performance in 2020. – Since the 2000 pound thrust model did not need to be

scaled, available data was used in calculations and no efficiencies were needed. To scale the larger engine the sizing routine was used to determine the appropriate weight given the thrust required.

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Propulsion

1. The following graphs show the thrust available from the engines and the thrust required to power the aircraft versus velocity for several altitudes :

0 20 40 60 80 100 120 1400

2,000

4,000

6,000

8,000

10,000

12,000

Thrust vs Velocity at Takeoff

Thrust AvailableThrust Required

Velocity (mph)

Thru

st (l

b)

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Propulsion

0 100 200 300 400 500 6000

2000400060008000

1000012000

Thrust vs. Velocity (15000 ft, climbing)

Thrust AvailableThrust Required

Velocity (mph)

Thru

st (l

b)

0 100 200 300 400 500 6000

2000400060008000

1000012000

Thrust vs. Velocity (25000 ft, climbing)

Thrust AvailableThrust Required

Velocity (mph)

Thru

st (l

b)

0 100 200 300 400 500 6000

2000400060008000

1000012000

Thrust vs. Velocity (35000 ft, climbing)

Thrust AvailableThrust Required

Velocity (mph)

Thru

st (l

b)

0 100 200 300 400 500 600 7000

2000400060008000

1000012000

Thrust vs. Velocity (45000 ft, cruise)

Thrust AvailableThrust RequiredThrust Available (2 engines)

Velocity (mph)

Thru

st (l

b)

Load path overview

Load path estimation

Load path overview

• Main formers, ribs, stringers and longerons made of TiAl

• Additional components added to re-enforce strength of the structure.

A closer inspection

Main supports

Additional components

Wing intersection

• Wings – Common Low Mount– Through fuselage for stability– Uses two main aft formers of the aircraft

• Stabilizers – High mount

Engines

• Innovative locations of engines • Tail mounted Engines.

– Requires that the tail be mountto the fuselage

• The ‘3rd’ Engines – Placed in line with the

centerline of the aircraft to avoid pitching moment.

Landing Gear

• Retracts inward and is stored under the fuselage and wing when in flight.

• Placed on wings to increase yaw stability during taxi

Side retracting landing gear.

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• Located on the intersection of the main stringer and a rib.

• Stringer is supported on the frame of the craft where the CG is located.

Landing Gear

Far right, side view of landing gear relative to location of center of gravity. Near right, view from below the craft.

Material Selection

• Fiber Glass• Composites• Thermoplastics• Aluminum based

Alloys

GE’s, GEnx engine currently uses an lightweight Aluminum based alloy, Gamma Titanium Aluminide.

• Nickel Aluminide– Extremely high strength to weight ratio– Ductile– Common in gas turbines and get engines

• Titanium Aluminide– Intermetallic chemical compound– Resistant to oxidation and heat– Low ductility

• Gamma Titanium Aluminides – Currently focused on use in engines.– Can withstand temperatures from 600oC and higher– Half the density of steel or nickel based alloys

Material Selection Aluminum based Alloys

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Structures Weight (lb) Loc (ft) Mom (ftlb) Equipment Weight(lb) Loc (ft) Mom (ftlb)

Wing 1150 31.1 36044 Flight Cont 460 11 5016

Horizontal Tail 440 40.7 18180 APU Installed 200 43 8510

Vertical tail 400 38.8 15950 Instruments 110 11 1160

Fuselage 4100 44.5 184664 Hydraulics 100 31.1 3200

Main Landing 800 34.1 27250 Electrical 590 31.1 18260

Nose Landing 210 11 2355 Avionics 1200 7.3 8470

Propulsion Weight (lb) Loc (ft) Mom (ft-lb)Furnishing 270 31.1 8395

A/C 200 40.7 8470

Engine 1800 43 80060 Anti-ice 60 31.1 1860

Engine Cont 40 43 1740 Handling Gear 9 31.1 280

Starter 85 43 3640 Cargo / Seats 700 31.1 21800

Fuel System 280 31.1 8830 Total Wempty 16,800

Loads Weight (lb) Loc (ft) Mom (ftlb) Loads Weight (lb) Loc (ft) Mom (ftlb)

Pilots 240 20 4680 Luggage 240

Passengers 1600 N/A N/A TOGW 29,800

Weights

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CG Travel

25 27 29 31 33 35 37 3917000

18000

19000

20000

21000

22000

23000

24000

25000

26000

27000

CG Travel

Location

Wei

ght

Take Off Gear up Fuselage Tank

Wing Tank

Gear Down Land Reserve

Fuel Passenger

Off Crew Off Add Fuel Add Crew Add Passenger Min Max

CG 27.97 28.13 31.18 31.89 31.93 31.93 35.41 36.51 36.97 28.49 28.21 27.97 27.97 36.97Weight 26163 26011 23468 22951 22916 22916 20669 18680 18446 23940 24174 26163 18446 26163

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Stability/Control

• Control surfaces are sized to minimize weight and drag while ensuring stability of the aircraft.

• Static Longitudinal Stability:– 4% static margin calculated from the sizing code. This

makes the aircraft more responsive to pilot inputs.– The center of gravity was determined to be positioned at

33 feet from the nose of the fuselage.– The neutral point is thus 0.266 feet behind the c.g. (wing’s

mean chord length is 6.644 ft.)

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Stability/Control

• Based on conventional business jet sizing values (Raymer), we designed the elevator to be about 90% of the tail span and 32% of the tail chord. Each elevator thus has a chord length of 1.43 ft, a span of 10 ft, planform area of 14.3 ft2, and an aspect ratio of about 7.

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Stability/Control

Trim Diagrams

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Stability/Control

• Potential Issues:– ‘One-engine out’: In case one of the two aft-

fuselage engines were to go out, the turbofan at the end of the fuselage can be turned on to provide enough thrust to maintain cruise flight.

– ‘Cross-wind landing’: Sideslip technique used (i.e. rudder/ailerons adjust aircraft’s heading in order to keep the aircraft lined up with the runway until touchdown).

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Noise

• Smaller HF120 turbofan engines designed to be fully stage IV compliant

51

Noise

• Larger 3rd engine housed in the aircraft body reduces external noise

• Future propfan integration to feature Active Vibration Control System, reduces internal noise

– Deemed unnecessary for turbofan platform• External noise is estimated using

combination of scaled engine and historical data

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Noise

• Aerodynamic noise comparable to similarly-sized current aircraft

• Decreased timeto climb reducesground signatureduring flyover stage

Noise Certification Values according to ICAO Annex 16, Volume I, Chapter 3

53

Cost Prediction

• Calculated using Rand DAPCA IV model along with information from Raymer’s text.

Type Price

RTD&E + Flyaway Cost $2.4 Billion

Production Cost $15 Million

Profit Per Aircraft $750,000

Breakeven Point 20 aircrafts

Production Run 160 in 5 years

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Cost Prediction

Rates Values

Depreciation 6.6% / year

Insurance $30,000 / year

Crew $230 / block hour

Fuel/Oil $1158/flight hour

Maintenance $764 / flight hour

DOC $2274 / flight hour

DOC/Seat-Mile $0.22

55

Cost Prediction

• Miscellaneous Customer Costs

Type Cost

Hangar $80,000 / year

Training $40,000 / year

Landing $386 / landing

56

Summary

• Trans-Atlantic flight• 12 Passenger luxury cabin• 3 Turbofan Engines

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Summary

Requirement Target Threshold Endeavour XG CompliantMaximum Mach Number 0.85 0.8 0.8 Yes Empty Weight (lb) 18,500 20,000 11,714 YesGross Weight (lb) 28,000 32,000 22,116 YesTakeoff Distance (ft) 3,400 3,800 4,000 No Maximum Range (nmi) 3,700 3,600 3,700 YesDesign Mission Range (nmi) 3,700 3,600 3,700 YesNoise (dB) 42 50 <48 YesSeats 10 8 9 YesVolume Per Passenger (ft^3) 65 60 60 YesTSFC (% of avg) 55 65 65 Yes N0x Emissions (% of avg.) 25 50 50 Yes

Charge Time - 220V 80A* (hr) 2 4 1.5 Yes

Charge Time - 125V 15A** (hr) 3 5 4 Yes

Internal Systems Power (kWh) 5 6.5 8 No

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Summary

Environmentally-sensitive business aircraft concept is a plausible opportunity. However:

a) Meeting 40% reduction of fuel consumption is still a big challenge

b) Difficult to meet all of NASA’s N+2 goals at oncec) With further research on UDF conducted to meet the

noise requirement , 40% reduction in fuel consumption may be possible.

59

Summary

Areas in need of further research:

a) Catalytic reduction technology on the aircraftb) Shorten takeoff distance c) Reduce empty weight to increase fuel efficiency

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Thank you

Sources• ___ Gas Turbine Engines. Aviation Week & Space Technology Source Book 2009. p 118

• ___ GE Aviation. The GEnx Engine Family. Available online [http://www.geae.com/engines/commercial/ genx/combustor.html], 2010

• ___ GE Honda Aero Engines. Available online [http://www.gehonda.com], 2010

• ___ Calculating noise ICAO Annex 16, Volume I, Chapter 3.

• Campbell, G.S., and Lahey, R.T.C., A survey of serious aircraft accidents involving fatigue fracture, Vol. 1 Fixed-wing aircraft, National Aeronautical Establishment, Canada. 1983

• Christensen, R.M. Mechanics of Composite Materials. New York, John Wiley & Sons, 1979

• Hoskin, B.C., and Baker, A.A., eds. Composite Materials for Aircraft Structures, New York: American Institute of Aeronautics and Astronautics, Inc., 1984.

• Martin, Christopher L.; Goswami, D. Yogi (2005). Solar Energy Pocket Reference. International Solar Energy Society

• Megson, T.H.G. Aircraft Structures for engineering students. Burlington MA: Butterworth-Heinemann. 2001

• Kroo, Ilan. Stanford university. “Aircraft Structural Design”. Available online [http://adg.stanford.edu/aa241/structures/structuraldesign.html] 2010.

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