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Project Mission and Target Market Design Mission and Requirements Walk-around Sizing code Description Carpet Plots Aircraft Description Aerodynamic details Performance Propulsion Structures Weights and Balance Stability and Control Noise Cost Summary 2
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Mission Statement – “To design an environmentally responsible aircraft for the twin aisle commercial transport market with a capacity of 300+ passengers, NASA’s N+2 capabilities, and an entry date of 2020-2025.” – NASA’s N+2 technology requirements include: 1. Reducing cumulative noise by 42dB below Stage 4 2. Reducing take-off and landing NOx emissions to 75% below CAEP6 levels 3. Reducing fuel burn by 50% relative to “large twin-aisle performance” (777-200LR) 4. Reducing field length by 50% relative to the large twin-aisle 3
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Mission Statement – A high-capacity, short- to medium-haul aircraft – Primarily servicing Asia- South Pacific region 4
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6 Design Mission – 400 Passengers – 4,000 nmi Range (Honolulu, HI to Osaka, Japan: 4,000nmi) 6500 ft
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7 RequirementsThresholdTarget Cruise Mach0.750.80 Range3,000 nmi4,000 nmi Field Length (at sea level, MTOW) 8,800 ft5,800 ft Field Length (@ 14K ft, +15°F) 18,000 ft9,000 ft Fuel Burn*33% reduction50% reduction** NOx Emissions50% below CAEP 675% below CAEP 6** Noise Reduction 32 EPNdB cum. below Stage 4 42 EPNdB cum. below Stage 4** Passenger Capacity350400 Direct Operating Cost*10% Reduction15% Reduction *Relative to B777-200LR ** NASA ERA goal
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9 ParametersValueUnits Wing Loading87lb/ft 2 Wing Aspect Ratio11- Wing Span203ft Wing Sweep40⁰degrees Thrust-Weight ratio0.226- Reference Area3775ft 2
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10 Requirements GTF Composites Wingtip Technology Fly By Wireless Trailing Edge Brushes Electric Actuators Laminar Flow Control Active Noise Cancellation Fuel Burn ++++-++ Exterior Noise + ++++ NOX + Field Length Empty Weight -+-+-+-- Cruise Speed Manufacturing Cost -- ---- Maintenance Cost -- +-+-- Pax/Crew Comfort + + Layout Complexity --- - Stability & Maneuverability Minimum Ground Time Aesthetics ++ -- Sigma 1102-43-2-3
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11 Best Description of Sizing Code – Uses Matlab script provided that iterates for an initial TOGW to a converged value – Uses inputs from trade studies and calculates aircraft geometry and thrust requirements – Incorporates component weight and drag buildup technique – Aircraft is treated as a complete wing for drag buildup. but broken up into centerbody, aft and wing for weight buildup
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12 Fixed Design Parameter Values ParameterValueUnits 1.Taper ratio0.27- 2.Sweep40degrees 3.C Lmax 1.4- 4.V pr 85,500ft 3 5.Max Landing weight fraction0.9- 6.Passenger weight88000lbs 7.Crew weight1400lbs
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13 Modeling Approaches – Weight Equations: Raymer’s Transport equations + NASA Sizing Methodology for the Conceptual Design of BWB, by Kevin R. Bradley W fuse = 5.698865*0.316422(TOGW) 0.16652 (S cabin ) 1.061158 W aft = (1 + 0.05*NEng)*0.53*S aft *(TOGW) 0.2 *(λ aft + 0.5) Component Weightlbs 1.WeWe 17,7210 2.W fuel 61,800 3.W engine 7,220 4.W centerbody 83,910 5.W wing 88,000 6.W VT 1,400 7.W avionics 1,840
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14 Modeling Approaches (contd.) – Drag prediction equations: Raymer’s component drag buildup method using a transonic Re cutoff, flat plate skin friction coefficient and component form factors. – Tail sizing: Raymer’s equations + cross-wind and one-engine out conditions Component Parasite Drag 1.C do,wing 0.0117 2.C do,VT 0.0003 3.C do,pylons 0.0001 4.C do,nacelles 0.0003 Component Parasite Drag ft 2 1.S ref 163
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15 Sized ParameterUnit 1.SFC maxthrust 0.1108 1/hr 2.SFC cruise 0.416 1/hr 3.Thrust cruise 11,000 lb 4.Weight4,815lb 5.Length12ft 6.Diameter11.8ft Modeling Approaches (contd.) – Engine deck using Raymer’s equations and optimized T/W
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16 Modeling Assumptions – From new technologies TechnologyVariable(s) AffectedAmount Affected 1.Composites OEW-20% C do -6% 2.GTFW fuel -12% 3.Fly by wirelessW electronic -50% 4.Airfoil (passive laminar control)% laminar flow+50% 5.Active laminar flow control D-20% W wing +5% 6.Electric actuatorsW fuel -9%
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17 Validation – Using current aircraft in the industry
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18 Constraint ParameterValueUnits Take off Ground Roll3500ft Landing Ground Roll4400ft Specific Power100ft/sec Fuel Weight63000lbs 2g Maneuver50ft/sec 2 nd Seg. Climb2.5% S ref 3762.5ft 2
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20 ParameterVALUEComparison NASA ERA Goals TOGW328410 lb- WeWe 177210 lb- W fuel 61799 lb51% Decrease AR11- T/W0.226- W/S87- C do 0.0131- S ref 3775 ft 2 - Field Length8,670 ftDoes not meet NASA Field Length goals
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22 400 Passengers 1-Class configuration
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23 Difficult to put flaps on a HWB design – must make due with leading edge high-lift devices – Choose airfoils with high camber/high CLmax To reduce fuel burn, airfoil should offer minimum drag – Laminar flow airfoils (eg. NACA 6-series) – Smooth fabrication to reduce skin friction Airfoil thickness chosen with respect to laminar flow properties and structural considerations – HWB must fit entire cabin volume within the wing section – t/c >14% desirable for good performance (gradual stall) Design lift coefficient is a function of wing loading
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26 V-n diagram with gust loading
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27 Performance Summary ParameterValueUnits Maximum load factor2.76- Stall speed at sea level195ft/s Landing speed at sea level220ft/s Takeoff speed at sea level213ft/s Cruise speed782ft/s Loiter speed340ft/s Takeoff field length5640ft Landing field length8670ft
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28 Geared Turbofan Engine – Cycle Type: High-bypass turbofan – By-pass Ratio: 15:1 – SLS Thrust: 39110 lbs. – Overall Pressure Ratio: 50:1 – Fan Pressure Ratio: 3:1 – Stage Count: 1-G-3-8-2-3
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29 Engine Size & Assumptions – Length = 15.99 ft Diameter = 9.14 ftWeight = 7223.35 lbs. – Smaller in length due to less stages – Less maintenance due to fewer stages – Negligible losses upon installation, on top mounting and no integration into airframe. – -20 decibels below Stage 4 – 15% Reduction on fuel consumption – Less air needed to cool the turbine – 75% Reduction in NOx emissions
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30 Engine Performance
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31 Engine Performance (cont’d) Important Altitudes Velocity Desired (ft/s) Thrust Required (lbs) Thrust Available (lbs) SLS – 0 ft21320106.978220 High Hot – 14,000 ft26522417.732003.5 Cruise – 34,000 ft780.10414409.622994.9 40,000 ft776.04812050.620019.1 Single Engine Performance SFC at Tmax0.111 Thrust at Cruise11002.68 SFC at Cruise0.416
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32 Center spars in pressurized vessels separate cargo area from passenger seating area.
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34 Composites with conductive layers – This is used as the skin of the aircraft. Incorporates potential for lightning strikes with conductive layers. Aluminum – Placed at leading edges due to higher heat resistance as compared to composites and less prone to damage on impact. Titanium – Used in landing gear, for high strength Carbon Fiber Reinforced Plastic – Used on ribs, spars and stringers because of high strength-to-weight ratio Copper-Aluminum-Zinc Alloy (Smart Material Alloy) – Used in the morphing trailing edges. They are able to sustain external loads while allowing controlled shape modification
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35 Free Body Diagram
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36 Load Routing
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37 Empty Weight Breakdown Weight [lb] Structures Wing 32441.00 Equipment APU 2800.00 Vertical Tail 4698.00 Flight Controls 7088.40 Center Body 83910.00 Instruments 1772.10 Main Landing Gear 7766.90 Hydraulics 5316.30 Nose Landing Gear 1412.16 Electrical 8860.50 Engine Mounts 2889.36 Avionics 2362.80 Nacelles 1772.10 Furnishings 17721.00 Misc. Systems 5316.30 Propulsion Fuel System/Tanks 2889.36 Engine Cooling 2167.02 Useful Load Crew 1400.00 Exhaust System 1011.28 Fuel 61799.00 Starter 577.87 Oil 722.34 Passengers 72000.00 Payload 16000.00
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38 Center of Gravity Location Aerodynamic Center 73.6 ft from nose CG Location 63.3 ft from nose Static Margin 7.78 %Cmac
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39 Lateral trim for one engine out @ V = 1.1V stall Rudder deflection angle δ = 16 degrees Cross wind landing condition @ V =.2 V TO Sideslip angle β = 5 degree Tail Surface areaTail heightRudder heightRudder width 163 ft 2 each 326 ft 2 total 25.5 ft15.3 ft4.2 ft Aileron Surface areaAileron spanAileron length 165.8 ft 2 each 331.70500 ft 2 total 81.5 ft2 ft
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40 Approach – Choose baseline engine – Adjust engine PNdB level based on: Distance Maximum thrust Partial throttle Engine technologies – Calculate airframe noise for landing Function of aircraft weight
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41 Noise Level Breakdown Basis of ChangeChange in dB Number of engines+3.0 Maximum thrust-4.7 Partial throttle during landing -6.9 Distance during takeoff measurement -12.8 Distance during sideline measurement -5.5 Distance during approach measurement +8.8 Takeoff EPNdB adjustment-4.0 Landing EPNdB adjustment-5.0 Engine Technology-15 Baseline Engine GE90-115B Thrust115,000 lbs Noise103 PNdB Distance to measurement 1,107 ft
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42 FAR Noise Thresholds & Design Noise Level Condition Stage 3 Requirement (EPNdB) Design Noise Level (EPNdB) Margin (EPNdB) Takeoff95.569.526.0 Sideline99.476.822.6 Approach102.995.47.4 Sum56.1 Below Stage 446.1
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43 Estimated Development and Manufacturing Cost Estimated number of aircraft in production run – Approximately 400 airplanes for the first 5 years due to the learning curve – Targeting production of 2000 aircrafts in the production run Estimated Direct Operating Cost Airframe Cost $ 52,742,862.01 Engine Cost (1) $ 6,464,986.58 Total DOC+I $ 69,689.74 $/trip $ 7,461.43$/hour
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44 DOC + I Method – Fuel Cost – Flight Deck Crew Cost – Airframe Maintenance Cost – Engine Maintenance Cost – Depreciation – Interest – Insurance
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45 Method Used (Production and Manufacturing Cost) – Using a modified version of Raymer’s Eq. 18.9 for airframe and Pay (R x ) were changed to 2011 dollars from 1999 dollar by accounting for inflation The hours were also adjusted for based on the production complexity – Using Raymer’s Equation 18.8 for engine cost T max of 39110 lbs was obtained from the sizing code while M max, and T turbine inlet were assumed to be 0.85 and 2560 R, respectively
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47 RequirementsThresholdTargetCurrent Values Cruise Mach0.750.80 Range3,000 nmi4,000 nmi Field Length (at sea level, MTOW) 8,800 ft5,800 ft8,670 ft Field Length (@ 14K ft, +15°F) 18,000 ft9,000 ft10,500 ft Fuel Burn*33% reduction50% reduction**51% reduction NOx Emissions50% below CAEP 675% below CAEP 6**50% reduction Noise Reduction 32 EPNdB cum. below Stage 4 42 EPNdB cum. below Stage 4** 46.1 EPNdB cum. below Stage 4 Passenger Capacity350400 Direct Operating Cost*10% Reduction15% Reduction79% Increase *Relative to B777-200LR ** NASA ERA goal
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Future Work NOx Prediction Structural Refinement Design & Development Work 48
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