Conceptual Design Review

1. Conceptual Design Review presented by: • XG International GihunBae - Joe Blake - Jung HoonChoi - Jack Geerer - Jean Gong – Sang Jin Kim - Mike McCarthy - Nick Oschman - Bryce Petersen - Lawrence Raoux - Hwan Song

2. Outline of Contents VIII. Propulsion Structure Weights Stability/Control Noise Cost Summary • Mission Statement • Design Mission/ Requirements • “Best” Aircraft Concept • Sizing, Carpet Plots • Design Trade-offs • Aerodynamics • Performance

3. 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.

4. Design Requirements • 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.

5. Previous vs. Final Models Previous Final

6. Previous vs. Current Previous Current 3 Turbofans No Canard Cruciform Tail • 2 Turboprops/UDF • 1 Turbofan • Canard • T-Tail

7. Previous vs. Current - Justification • Removal of UDF: Lack of historical data Noise 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 benefits

8. “Best” Aircraft Concept Cruciform Tail Turbofan Engine Duct Winglet Solar Films

9. “Best” Aircraft Concept 3rd Engine

10. “Best” Aircraft Concept • 3 Turbofan engines • 2 Outer engines for cruise • Cruciform Horizontal Stabilizer • Dropped canard configuration

11. “Best” Aircraft Concept Advanced Concepts • Solar Panels – Powers cabin electronics • 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.

12. Sizing Code • Used Cargo/Transport Weights from Raymer’s • Used Excel Spreadsheet • 6 Different Sections • Main • Fuselage • Wing • Engine • Geometry • Constraint Diagram • Weight • Airfoil • Mission Detail

13. Sizing - Assumptions

14. 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

15. Sizing – Tail The rudder and ailerons are based on conventional business jet values (Raymer).

16. 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)

17. Sizing - Validation • Weights based on the sizing code • Empty Weight = 17500lb • Fuel Weight = 14000lb • Total Weight = 34400lb • Actual Weights of Bombardier Challenger 300 • Empty Weight = 18500b • Fuel Weight = 14100lb • Total Weight = 35400lb • Fudge Factor

18. Design Trade-offs Carpet Plot • Based off of calculations in the constraint diagram • Constraints vs. Wing Loading • Gross Weight • 2g Maneuver • Takeoff Ground roll • Landing Ground roll

19. Design Trade-offs Carpet Plot

20. Design Trade-offs

21. Design Trade-offs Cabin Layout

22. Three Views

23. Dimensions 22” Wing Leading Edge 36” Tail leading edge 37” Vertical Stabilizer 38” Tail Mounted Engine 40” Center Engine 50” Total aircraft length

24. Internal Layout Avionics compartment and nose landing gear housing Fuel Tank Wheel housing Enlarged equipment compartment: Fuel pump and reservoir Duct Engine Equipment (APU, AC, etc.) Equipment compartment

25. Cabin Layout

26. Airfoil Selection NACA 2414 Drag Polar Shape www.worldofkrauss.com

27. Airfoil Selection NACA 2414 www.worldofkrauss.com

28. Drag Polar

29. Performance • Diagram provides visual understanding 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.

30. Performance

31. 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.

32. 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

33. 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.

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

35. Propulsion

36. Load path overview Load path estimation

37. Load path overview A closer inspection Main supports • Main formers, ribs, stringers and longerons made of TiAl • Additional components added to re-enforce strength of the structure. Additional components

38. Wing intersection • Wings • Common Low Mount • Through fuselage for stability • Uses two main aft formers of the aircraft • Stabilizers • High mount

39. Engines • Innovative locations of engines • Tail mounted Engines. • Requires that the tail be mount to the fuselage • The ‘3rd’ Engines • Placed in line with the centerline of the aircraft to avoid pitching moment.

40. 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.

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

42. Material Selection • Fiber Glass • Composites • Thermoplastics • Aluminum based Alloys GE’s, GEnx engine currently uses an lightweight Aluminum based alloy, Gamma Titanium Aluminide.

43. Material Selection Aluminum based Alloys • 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

44. Weights

45. CG Travel

46. 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.)

47. 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.

48. Stability/Control Trim Diagrams

49. 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).

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