Philip Halsmer Kwan Chan Tyler Hall Sirisha Bandla Adam Edmonds Chris J. Mueller Stephen Haskins

1. Philip Halsmer Kwan Chan Tyler Hall SirishaBandla Adam Edmonds Chris J. Mueller Stephen Haskins Shaun Hunt Jeff Intagliata

2. Outline • Mission Statement • Design Requirements • Concept Selection • Advanced Technologies and Concepts • Engine Modeling • Constraint Analysis • Most Recent Sizing Studies • Center of Gravity and Stability Estimates • Summary

3. Mission Statement • Bring aircraft developments into the modern age of environmental awareness by means of innovative design and incorporating the next generation of technologies and configurations to meet NASA’s ERA N+2 guidelines. • Reduce operating cost in face of rising fuel prices and consumer pressures to reduce fares. New ERA Technologies

4. Design Requirements

5. Concepts Overview • Conventional with improvements • Tube & Wing • Hybrid Blended Body • Fuselage-Wing Fairing • Asymmetric Twin Fuselage • Two Tubular Fuselages

6. Concept Generation

7. Concept Selection

8. Concepts for Further StudyHybrid Blended Body (HBB) • Advantages • Increased aerodynamic efficiency • Increased enclosed volume • Shorter take-off capabilities • Increased noise shielding • Disadvantages • Manufacture cost • Development cost • Increased maintenance cost from engine support equipment

9. Concepts for Further StudyAsymmetric Twin Fuselage • Advantages • Increased passenger comfort • Increased airliner options for passengers • High aspect ratio without weight penalty • More engine placement options • Fuselage noise shielding • Disadvantages • Increased wetted area • Asymmetric aerodynamic loading • Airport adaptability

10. Hybrid Blended Body Dimensions and Layout Dimensions Total Length: 120 ft Total Width: 18.6 ft Cabin Length: 87 ft Cabin Width: 18 ft 21 First Class Passengers 190 Economy Class Passengers 4 in 98 in 118 in 98 in 216 in Reference: www.seatguru.com

11. Twin Body Dimensions and Layout Dimensions Large: Small: Total Length: 143.4 ft Total Length: 75 ft Total Width: 11.08 ft Total Width: 9.08 ft Cabin Length: 98 ft Cabin Length: 23 ft Cabin Width: 10.42 ft Cabin Width: 8.42 ft 180 Economy Class Passengers 15 First Class Passengers Storage / Cargo Space Large Body Reference: www.seatguru.com

12. New Technologies • Composites • Engine Selection • Propfan • Geared Turbofan • Electric Assisted Take-Off • Hybrid Laminar Flow Control • Boundary layer control • Engine-Air Brake / Quiet Drag Applications

13. Laminar Flow Technologies Source: http://www.nasa.gov/centers/dryden/pdf/88792main_Laminar.pdf Source: http://www.aviationweek.com/media/images/awst_images/large/AW_09_20_2010_3506A.html

14. Laminar Flow Technologies • -Effects • --Researchers at Langley Research Center calculated that implementing Hybrid Laminar Flow Control to a 300 passenger twin-engine subsonic aircraft to allow for 50% laminar flow on the top of the wings and on both sides of the tail. • -15% reduction in block fuel • -50% laminarity translates to 5-7% total drag reduction Source: http://www.nasa.gov/centers/dryden/pdf/88792main_Laminar.pdf

15. Engine Air Brake Integrate swirl vanes into the mixing duct • Swirling exhaust flows can generate drag quietly – demonstrated drag coefficient near one at ~44 dBAfull-scale • Engine air-brake application for quiet, slow / steep approach profiles (estimate up to 6 dB for 3 degree change in glideslope) Source: http://ns1.nianet.org/workshops/docs/QA/presentations/FSIS/Spakovsky.pdf

16. Induced Drag Management Source: http://ns1.nianet.org/workshops/docs/QA/presentations/FSIS/Spakovsky.pdf

17. Engine Types Compared to a High Bypass Turbofan Geared Turbofan with Electric Assist Contra-Rotating Propfan with Electric Assist • Advantages • Decrease fuel consumption by 16% gate to gate • Decreased Nox Emissions by 50% • Reduced Noise by 15dB • Multiple Energy Storage Options • Disadvantages • Increased Weight due to gearbox • Advantages • Increased Fuel Efficiency 30% • Decreased Emissions • Multiple Energy Storage Options • Disadvantages • Increased Noise Reference: memagazine.asme.org and Pratt & Whitney Dependable Engines Reference: airforceworld.com

18. Propulsion Modeling • Thrust is dependent upon • Engine size • Mach • Altitude • Throttle Position • Process • Determine Required Engine size – Rubber Engine • From Take-off or Climb Constraint • Fit Altitude and Mach Curves • From NASA’s EngineSim 1.7 • Interpolate between Curves to find SFC

19. Engine Size • -Turbofan engine empirical data • -Engine weight, length, diameter and fan diameter versus dry thrust. • -Curve fit function Data from http://www.jet-engine.net/civtfspec.html

20. Engine dimension Data from http://www.jet-engine.net/civtfspec.html

21. Determining SFC • NASA’s Engine Sim Interpolations at 25,000’

22. Electric Assisted Take-OffAn Energy Approach • Energy Density Variance • Jet-A: 18700 BTU/lbm • Lithium Polymer: 336 BTU/lbm • Total Take-Off Kinetic Energy Constant • Substitute Turbine Energy with Electric Energy • Smaller Turbine Engine may be obtained • This Technology dependent on Constraint Diagram • Mechanics and Thermodynamics of Propulsion 2nd ed. Hill, P. and Peterson, C. • Emerging Power Batteries

23. Constraint Analysis & Diagrams • Performance Constraints • Basic Assumptions • Constraint Diagrams Constraint Analysis performed on: • Boeing 757 • Hybrid Blended Body Concept • AsymmetricTwin Fuselage Concept

24. Major Performance Constraints • Top of Climb • Drag of Aircraft, AR • Sustained Subsonic 2G Maneuver • Drag of Aircraft, AR • Takeoff Ground Roll • CL Max for Takeoff, AR, Drag of Aircraft, Takeoff Distance • Second Segment Climb • CL Max for Takeoff, AR, Drag of Aircraft • Landing Ground Roll • CL Max for Landing, Landing Distance

25. Datum Basic Assumptions • Boeing 757 Datum: TSL/W = 0.33 & WO/S = 135.18

26. Datum Constraint Diagram

27. Constraint Diagram Observations

28. Resulting Feasibility • Increasing CL Landing, Ground Roll, e improve upon datum • Blended Wing Body Concept • Setting computed AR, T/W increases, W/S increases • Twin Fuselage Concept • Setting computed AR, T/W decreases, W/S decreases

30. Significant Differences Between Assumptions and Technology Factors • Twin Fuselage Concept • With larger AR and wetted area, larger CL Takeoff & Landing required and increased CDO • Alternatively, extend runway limitations • Blended Wing Body Concept • With top-sided engine placement, increased CL because of disturbances from engine • With lower AR, can make up efficiency with higher Oswald efficiency factor • Smaller Parasite Drag leads to smaller CDO

32. Aircraft Sizing Capabilities • Status: Working • Weight Build-Up Complete • Simple Drag Polar • Mission Profile • Engine Modeling • Concept Application • 3 variations of Sizing Algorithms • 757-200, Hybrid Blended Body, Asymmetric Twin Fuselage

33. Structures Build Up • Empty Weight Estimates – Wing, Vert/Horiz Tail, Fuse, Engines, Nacelles, Landing Gear, Avionics, Control Systems, etc. • Composite structure was taken into account with a ‘fudge’ factor (Raymer) • 0.9 for wing • 0.88 for tails • 0.95 for fuselage • Twin Fuselage Considerations: • Distribution of weight between fuselages • Passenger weight is also taken into account Large Fuselage: 41000 lbs Small Fuselage: 51000 lbs Without passengers This output compared to the actual EOW of 127520 lbs results in a difference of ~1%. *airliners.net

34. Drag Estimate Results for Concept Comparison Twin Fuselage 757 Hybrid Blended Body 21400 lbf 17400 lbf 14900 lbf -Values represent the drag estimate based on the parameter files with cruise conditions for each individual case - Plan to obtain more accurate results when the Drag Code is changed to accommodate for more Geometry and Sizing Variables using the Component Buildup Method

35. Current Weight Conclusions • HBB modeled as having a lower AR, and lower Swet/Sref which is equivalent to a lower skin friction drag • Two fuselage modeled as higher AR and higher wetted area. • Both propulsion models have a 16% decrease in SFC.

36. Concept Geometry Inputs In addition to the component weight buildup, the aerodynamics were modified to reflect the different concepts. This is summarized by the above table.

37. Location of c.g. estimation From Boeing.com B757-200 as an example Only some major parts of the aircraft that significantly affect the c.g. location are considered More parts will be added to our calculation of c.g in the future.

38. Calculation of c.g. c.g. travel diagram Weight Take Off Minimum allowable SM Gear up Wo Forward tank 3 fuel tanks: forward(fuselage), aft and wing tanks. c.g. shifting in flight Distance within forward and aft c.g. limit for 10% of the mean aerodynamic chord. Forward c.g. limit Aft tank Aft c.g. limit Fuel refilling Wing tank SM Gear down Stick fixed neutral point Wland nose CG location From Raymer

39. Static Margin *consider only wing and horizontal tail Static margin positive for stability Use the lift curve slope of the wing and the horizontal tail. Lift coefficient equation to find the neutral point of the aircraft. Two categories, fixed parts (i.e. wing, fuselage…)and moveable parts(i.e. furnishing, payload…) Target static margin about 15%. Adjust the moveable parts to allow SM reaches our desire value.

40. Tail sizing For jet transport aircraft: cht=1, cvt=0.09

41. Concept Summary Hybrid Blended Body Asymmetric Twin Fuselage

42. Next Steps • Carpet Plots • Final Concept Decision • Cost Estimate • Add details to Final Concept Sizing

43. Philip Halsmer Kwan Chan Tyler Hall SirishaBandla Adam Edmonds Chris J. Mueller Stephen Haskins Shaun Hunt Jeff Intagliata