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Outline I. Mission Statement II. Design Requirements III. Concept Selection IV. Advanced Technologies and Concepts V. Engine Modeling VI. Constraint Analysis VII. Most Recent Sizing Studies VIII. Center of Gravity and Stability Estimates IX. Summary 2

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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 NASAs ERA N+2 guidelines. Reduce operating cost in face of rising fuel prices and consumer pressures to reduce fares. 3

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Design Requirements 4

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

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Concept Generation 6

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Concept Selection 7

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Concepts for Further Study Hybrid 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 8

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Concepts for Further Study Asymmetric 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 9

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

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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 Reference: www.seatguru.com 180 Economy Class Passengers 15 First Class Passengers Storage / Cargo Space Large Body 11

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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 12

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Laminar Flow Technologies Source: http://www.nasa.gov/centers/dryden/pdf/88792m ain_Laminar.pdf Source: http://www.aviationweek.com/media/images/ awst_images/large/AW_09_20_2010_3506A.ht ml 13

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-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 Laminar Flow Technologies 14

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

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

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

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Propulsion Modeling Thrust is dependent upon Engine size Mach Altitude Throttle Position Process 1.Determine Required Engine size Rubber Engine From Take-off or Climb Constraint 2.Fit Altitude and Mach Curves From NASAs EngineSim 1.7 3.Interpolate between Curves to find SFC 18

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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 19

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Engine dimension DimensionsEstimation Engine Weight7530 lb Engine Length145 in Engine Diameter83 in Fan Diameter80 in Data from http://www.jet-engine.net/civtfspec.html 20

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Determining SFC NASAs Engine Sim Interpolations at 25,000 21

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Electric Assisted Take-Off A n 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 2 nd ed. Hill, P. and Peterson, C. Emerging Power Batteries 22

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

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

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Datum Basic Assumptions Datum ConstraintsDatum Results C L Max Takeoff1.5 C L Max Landing1.6 Max Cruise0.75 Induced Drag Coefficient0.015 Oswald Efficiency0.8 Aspect Ratio7.8 Takeoff Ground Roll6,000 ft. Landing Ground Roll3,000 ft. Cruise Altitude32,000 ft. Boeing 757 Datum: T SL /W = 0.33 & W O /S = 135.18 25

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Datum Constraint Diagram 26

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Constraint Diagram Observations *T/W NegativeW/S (lb/ft2) Positive T/W PositiveW/S (lb/ft2) Negative IncreaseDecreaseAffects CL Takeoff T/W W/S T/W W/S Aerodynamics, Structures, Propulsion CL LandingW/S W/S Aerodynamics, Structures Take off Ground Roll Distance W/S W/S Structures Landing Ground Roll Distance W/S W/S Structures Oswald EfficiencyT/W T/W Aerodynamics, Structures 27

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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 28

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Significant Differences Between Assumptions and Technology Factors Twin Fuselage Concept With larger AR and wetted area, larger C L Takeoff & Landing required and increased C DO Alternatively, extend runway limitations Blended Wing Body Concept With top-sided engine placement, increased C L because of disturbances from engine With lower AR, can make up efficiency with higher Oswald efficiency factor Smaller Parasite Drag leads to smaller C DO T/W W/S (lb/ft 2 ) C L Landing C L TOAR Ground Roll (TO/Land) e C DO Hybrid Blended Body 0.341201.651.556.95000/3000 ft.0.850.01 Twin Fuselage0.331252.42.1 10.2 2 4000/2000 ft.0.80.02 30

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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 32

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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 757-200HBB2 Fuse Operating Empty Weight [lbs] 126,000110,000154,000 This output compared to the actual EOW of 127520 lbs results in a difference of ~1%. *airliners.net Large Fuselage: 41000 lbs Small Fuselage: 51000 lbs Without passengers 33

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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 34

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Current Weight Conclusions HBB modeled as having a lower AR, and lower S wet /S ref 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. 35 757-200HBB2 Fuse OEW (lbs) 130,000116,500154,000 Wfuel (lbs) 72,50058,90066,900 GTOW (lbs) 252,000225,500271,000

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Concept Geometry Inputs 36 Boeing 757HBBTwin Fuselage AR7.86.98.5 Swet/Sref5.735.376.22 e.81.84 In addition to the component weight buildup, the aerodynamics were modified to reflect the different concepts. This is summarized by the above table.

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Location of c.g. estimation 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. From Boeing.com 37

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Calculation of c.g. 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. Take Off Gear up Forward tank Aft tank Wing tank Gear down Fuel refilling CG location Weigh t Wo Wland Forwar d c.g. limit Aft c.g. limit Stick fixed neutral point SM nose Minimum allowable SM c.g. travel diagram From Raymer 38

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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. Xcg from nose (ft) Xn from nose (ft)Static Margin (%) 73.476.416.5 39

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Tail sizing For jet transport aircraft: cht=1, cvt=0.09 Blended Body Hybrid Asymmetric double fuselage V Tail Area (ft^2)810- Horizontal Tail Area (ft^2) -487 Vertical Tail Area (ft^2) -325 40

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Concept Summary 41 Hybrid Blended BodyAsymmetric Twin Fuselage

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

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