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1. Outline Mission Statement and Design Mission Best Aircraft Selection Aircraft Sizing, Carpet Plots, and Performance Aerodynamic Design Details 2.

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Presentation on theme: "1. Outline Mission Statement and Design Mission Best Aircraft Selection Aircraft Sizing, Carpet Plots, and Performance Aerodynamic Design Details 2."— Presentation transcript:

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2 Outline Mission Statement and Design Mission Best Aircraft Selection Aircraft Sizing, Carpet Plots, and Performance Aerodynamic Design Details 2

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. 3

4 Compliance Matrix 4

5 Mission Specific Parameters Boeing 737-900 1 Boeing 757-200 1 Boeing 777-200LR 1 MD-83 1 A321- 200 2 A330- 300 2 Threshold Cruise Mach0.7850.80.850.760.780.82>0.7 Maximum Passenger Capacity 215234440172220335>200 MTOGW w/ 200 passengers (lb) 174200255000766000160000200000460765- Max Range at MTOGW w/ 200 pax (nm) *n/a36009200*n/a25005800>3500 Take-Off Length at Sea Level at MTOGW (ft) *n/a950014200*n/a75006800<7000 *cannot exceed 200 passengers w/o exceeding MTOGW Requirement Benchmarking Matrix 1 Courtesy of Boeing online documentation 2 Courtesy of Airbus online documentation

6 Land and TaxiMissed ApproachLand and Taxi DescentClimb Cruise Design Range Taxi and Take Off Loiter Direct ≈ 3300 nmi≈ 200 nmi (0) -> (4) : ‘Basic Mission’(5) -> (9) : ‘Reserve Segments’ Design Mission Concept 1 1 Extrapolated from Raymer, Daniel Aircraft Design: A Conceptual Approach Fig. 3.2 <7000 ft > 0.7 M

7 Market Opportunity Market niche Creating an aircraft that can replace large portions of major airlines’ aging fleets such as MD-80, Boeing 757, 767 due to evolving market and economic needs Potential customers include airlines such as Delta, American, and Continental 7

8 Target Markets North America Predicted second most in demand of new aircraft between 2010-2029 *(7200 new a/c) 78% of single aisle purchases are for airline fleet replacement Single aisle a/c market is predicted to grow from 56% to 71% in next 20 years * Airlines in both the North American and European markets are looking for more fuel efficient and less pollutant a/c. Europe Predicted third most in demand of new aircraft between 2010-2029 *(7190 new a/c) Single aisle a/c are forecasted to make up 75% of new purchases in next 20 years According to Boeing market forecast, only 4% of current a/c in current use will still be flying in 2029 The European domestic air routes are all short enough that our a/c can cover them *References: Boeing future market forecast, Airbus future market forecast 8

9 Walk around Advanced Features 9

10 Final Concept Trade Studies on Final Design Eliminated Twin Fuselage – Too Heavy – Extra Parasite Drag HBB - During the trade study of sizing the body, justification of the faired wing-fuselage intersection was lacking. (In the process of deciding how big the fairings should be, we discovered errors in our prior reasoning. We could not fully justify having such large fairings.) 10

11 Technologies Majority Composite Construction Engine Selection Geared Turbofan Aerodynamics Passive Laminar Flow Control Boundary layer control Noise Reductions Engine-Air Brake / Quiet Drag Applications Pratt & Whitney PurePower 11







18 Dimensions Total Length: 150 ft Total Width: 10.4 ft Cabin Length: 118 ft Cabin Width: 11.1 ft 180 Economy Class Passengers 20 First Class Passengers Cabin Dimensions and Layout 18 125 in 78 in 47 in 67 in 4 in Reference:

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20 Sizing Approach Based on Raymer’s sizing approach Empty Weight Buildups Mission Segment Fuel Weight Buildups Drag breakdown C DO + C DI approach Curve fits for engine data Carpet plots to optimize W/S and T/W 20

21 Engine Modeling Partial Power Model is Semi-Empirical Verify Model with NASA EngineSim 1.7a Use General Electric CF6 as baseline engine Partial Power Model with new Coefficients fitted Apply New Technology to Partial Power Model 21 Daniel Raymer Aircraft Design: A Conceptual Approach. p378. Courtesy NASA.

22 Cruise Performance

23 Tail sizing strategy Using B757 as a reference Calculate Tail volume coefficient Compare to Raymer

24 Tail sizing strategy One engine out and crosswind: Vertical tail large enough to provide side force with rudder deflection less than 20 deg Consider crosswind about 20% Vto Rotation authority: Calculate moment of horizontal tail when take off Compare with moment of c.g. Main landing gear is the moment reference point

25 Tail sizing strategy Tail volume coefficients: Cht = 1.02 Cvt = 0.11 Moment arm about 50% of fuselage length Vertical TailHorizontal Tail Area (ft^2)348414

26 Effect of tail configuration T-tail, V-tail and cruciform tail (mid-tail) were considered. Avoid engine exhaust Cruciform tail: Reduce weight penalty to the vertical tail Reduce chance of flutter Heavier than V-tail Will not provide a tail-area reduction due to endplate effect as will a T-tail

27 BFL Constraint Crossplots 27 The W/S that that violates the constraint is recorded and plot on the final sizing plot.

28 Sizing Plot 28 Minimum TOGW occurs at W/S = 128 lb/ft^2, T/W =.31, TOGW = 224,000 lbs

29 Sizing Plot Constraints Balanced field length for takeoff 7800 ft Second segment climb Gamma >.024 Landing Ground Roll d Land < 5800 ft Not a function of T/W Found the max W/S to be 129 lb/ft^2 29

30 Current Weight Conclusions SFC –  16% C D0 –  10% Laminar Control Composites Higher AR Reductions in various component weights Bench mark New EraSavings OEW131,200123,0006% Wfuel79,30051,00036% GTOW260,300224,00014% 30

31 V N Diagram Used to show the limitations with regard to speeds/acceleration Shows the amount of positive or negative lift that can be generated while showing maximum G the aircraft can sustain. N+ = 2.5 N- = -1 V S – 130 kts V A – 166 kts V NO – 469 kts V NE – 522 kts Normal Operating Range Never Exceed Speed n Indicated Airspeed Structural Damage VSVS VAVA V NO V NE Acceleration Stall CAUTIONCAUTION Stall SpeedManeuver SpeedMax Structural Cruise Speed Max Speed

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33 Drag Prediction Describe Approach Component Build-up Method (CDo) Sum of the subsonic parasite drag from each component Skin Friction, Form Factor, Interference Scaling Factor, and Wetted Area CDmisc added: upsweep, landing gear, leaks/protuberances CLalpha estimation (K*CL^2) Based on Aspect Ratio, Sweep, Mach Number, Airfoil Efficiency, and Fuselage Lift Factor Transonic Wave Drag (CDwave) Divergence Mach Number, Crest Critical Mach Number, Critical Pressure Coefficient, Sweep Angle Mostly Empirical Data

34 Airfoil Selection Wing - DBLA 238 Checked Empirical Data based on t/c ratio, Mach design range, max thickness location, and Supercritical effects Tail – NACA 64-012 Checked Empirical Data based on Stall angle and Zero-Lift angle

35 High-Lift Devices Slotted Leading Edge Flap (Slat) Double Slotted Flaps CLmax Cruise:.95 Takeoff: 2.3 Landing: 3.1

36 Drag Polars Estimated by changing Mach, Angle of Attack, and Effective Wetted Area for each different segment CD values were then found as a function of a range of CL values

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38 Propulsion Overview Geared Turbofan Technology Readiness Requires Producibility Stabilized Performance Supportability P&W PurePower Specs Reduced SFC by 16% High BPR of 12:1 NOx emissions 55% below CAEP/6 Reduced Carbon Emissions PureSolution MRO services MRO - (Maintenance, Repair, and Overhaul) John W. Lincoln – Technology Transition to New Aircraft. 1987 Courtesy: Pratt & Whitney

39 Installed Performance Assumptions Future Technology 32% percent SFC reduction 50% reduction in NOx Neglect Subsonic Inlet and Nozzle Pressure Losses Inlet Drag Estimation* (per engine) Bleed Power Loss Estimation* (per engine) Assume Bleed Mass Flow 3% of engine mass flow *Daniel Raymer Aircraft Design: A Conceptual Approach. p374 & p377.

40 Engine Size -Turbofan empirical data -Engine weight, length, diameter and fan diameter versus dry thrust. -Curve fit function Data from 40

41 Engine Dimension Dry Thrust 40k GE CF6-6Estimation Weight (lb)73507090 Length (in)173143 Diameter (in)8778 Fan Diameter (in) 9280 Data from 41

42 Engine Emissions 42


44 Important Load Paths Lift Drag Thrust Weight Items considered when designing the structure: Bending and Torsion Loads Pressure Loads Buckling of the wing

45 Internal Structure Wing: -Ribs will maintain shape of the wing. -Ribs will be supported by spars. -Skin of the wing will carry the pressure loads. -Torsion box structure (not pictured) will be incorporated into wing design Fuselage: -Semi-Monocoque construction consisting of stressed skin with stringers and longerons attached to hoop-shaped frames Engine Pylons: -Bulk head will reinforce engine mounts in the wing. -Rib and spar design will be implemented in the pylons, constructed of higher strength material. Windows/Doors: Windshield, doors and windows will have a frame around them to increase the strength in that particular area.

46 Special Considerations Wing box has a carry through section in the lower part of the fuselage Landing gear to fuselage intersection will be reinforced with a stiffener made with higher strength material Flat disk Pressure bulkheads will close the cabin on both ends and carry the loads induced by pressurization

47 Material Selection Composites 50% Light weight Strong Higher resistance to corrosion Costly Increased options during the lay-up process Advanced Aluminum Alloys 25% CentrAl - Fiber metal laminate reinforced by high-quality aluminum Alleviate fatigue issues Reduce maintenance costs Less sensitive to damage caused by Titanium 10% Steel 10% Other 5%

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49 Empty Weight Components Component build up method (Raymer) Wing, Horizontal Tail and Vertical tail are dynamic Composite structure was taken into account with a ‘fudge’ factor (Raymer) 0.9 for wing 0.88 for tails 0.95 for fuselage ComponentWeight (lbs) Wing 28063 Horizontal Tail 1100 Vertical Tail 1948 Fuselage 22572 Nacelles 5073 Landing Gear 1272 Landing Gear 7955 Engine 23746 Engine Controls 51.36 Starter 312 Fuel System 1714 Flight Controls 2133 Aux Power Unit 1521 Instruments 360 Hydraulics 262 Electrical 2860 Avionics 1962 Furnishings 16725 Air Conditioning 3300 Anti-Ice 560 Handling Gear 84 Total Weight123573.36

50 Location of center of gravity Weight of parts from empty weight function Location of all the parts

51 Location of center of gravity Four fuel tanks C.G. shift during flight Depends on fuel tanks position. Location of C.G.Most forwardMost aft 64.6ft63.7ft65.5ft * From nose

52 Longitudinal stability Neutral point and static margin Static margin about 15% of the mean aerodynamic chord Neutral pointStatic margin 67.3ft15%

53 Control surface size Elevator: Begin from the side of the Vertical tail extend to 90% of the horizontal tail span. 40% of the tail chord Aileron: Outboard – low speed Inboard – high speed From 50% to 90% of wing span 20% of the wing chord * Avoid aileron reversal

54 Control surface size Rudder: One engine out and cross wind Calculate rudder size based on yawing moment from one engine at full thrust and crosswind of 20% Vto. Begin from fuselage 50% of vertical tail span 40% of tail chord

55 55

56 Means of Aircraft Noise Reduction Pratt & Whitney PurePower 1 Geared Turbofan Engine Engine Air Brake 2 Engine Placement (Due to the Noise Shielding form the Body Itself) 56

57 Engine Air Brake Source: 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) 57

58 Method of Calculation 58 Pratt & Whitney PurePower 1 Geared Turbofan is projected at 20 dB below the Stage 4 noise limit The Engine Air Brake 2 is proposed to reduce approach noise by 6 dB Corrections for sound propagation, engine effect, and airframe effect using an estimation method proposed by Stanford professor Ilan Kroo The sound propagation is attributed to the altitude at flyover and the distance from the sideline

59 Noise Levels 59 Takeoff [dB]Sideline [dB] Approach [dB]Total [dB] Stage 4 909598283 Current Design 77.479.986.5243.8 Current Design (with Engine Air Brake) 77.479.980.5237.8 NASA N+2 : 241 dB Current Design: 237.8 dB

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61 Cost Methods Used to Estimate Cost Number of Aircraft in Production Run Estimated Cost of Development, Manufacturing, and Purchase Estimated Operating Cost

62 Cost Estimation Method RAND DAPCA IV Model used from Raymer’s text. Estimates Development and Procurement costs. Includes hours required and wrap rates for labor costs. Technology Factoring. Accounts for increases in Development and Manufacturing costs for new technologies. Also includes reductions for Operating Costs. Empty Weight, Quantity in Production Run, and Velocity were major contributors.

63 Cost Assumptions From market analysis, 2000 a/c are expected to be produced to supply the Asia Pacific and American markets. 200 a/c for first 5 years production is needed for the DAPCA IV Model. 5 test aircraft to be produced. Aircraft assumed to fly 3500 block hours. 2 pilot crew and 4 flight attendants. Cost of Jet-A fuel estimated at.76¢/lb. From IATA estimations on weekly price average. Insurance rate: 1.5%

64 Development Cost Analysis Development Cost Breakdown2011 Dollars Development Support Cost354,000,000 Flight Test Cost112,000,000 Manufacturing Materials Cost3,215,000,000 Engine Production Cost6,630,000 Avionics700,000,000 Interior Furnishings500,000 Hourly Rates1999 $2011 $ Engineering86115 Tooling88118 Quality81109 Manufacturing7398 *Wrap rates from Raymer 18: Increased 34% for inflation from United States Department of Labor. Interior costs estimated at $2500 per passenger from Raymer

65 RDT&E and A/C Cost The total cost of the RDT&E + Flyaway cost is: The cost per aircraft comes to: This is with the inclusion of inflation rates from 1999 to 2011 and an investment rate of 10%. For our project to reach the breakeven point, 150 a/c will need to be sold. RDT&E + Flyaway Cost$19.7 Billion Cost of A/C$131 million Depreciation/year$8.9 million Insurance/year$1.8 million

66 Operating Cost Estimates Operating Cost BreakdownValue ($) Total Direct Operating Cost8350/BH Variable Cost6000/BH Fuel Consumption4600/BH Tax200/BH Landing Fee1200/BH (avg) *based on MTOW Fixed Cost2350/BH Crew and Attendants717/BH Maintenance1600/BH Hangar/Training Fees35/BH *All calculations done for design mission (3000 nm.)

67 Conclusion Thank you Professor Crossley and Stephan Lehner Thank you Boeing for your feedback and time Next, NASA’s Environmentally Responsible Aviation Challenge Gained valuable experience and knowledge Questions? 67

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