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Wingman -22

Wingman -22. Qi Chengzi Arnab Roy Trevor Steiner. Improved fuel weight method. As the PI includes the max range of the missions, an improved method with integrating the Weight decreasing of the fuel burn is introduced, so that the PI can be increased.

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Wingman -22

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  1. Wingman -22 Qi Chengzi Arnab Roy Trevor Steiner

  2. Improved fuel weight method As the PI includes the max range of the missions, an improved method with integrating the Weight decreasing of the fuel burn is introduced, so that the PI can be increased. First begin with the differential equation: And then the equation at constant velocity and constant altitude would be:

  3. Improved fuel weight method Let : A=; B= Therefore: Separated into 2 parts: and Would give:

  4. Improved fuel weight method As the initial weight of the wing would decrease due to the change of the fuel burn by part B (parasite), the is expect to be lower than the original weight.

  5. Improved fuel weight method It is almost a linear relation, so the initial weight is calibrated by using halfway aircraft weight. Which make the fuel requirement from induced drag 5% less and is around 1.5 % (can be more if separate into more parts)of the total fuel requirement. And the fuel calculation method is therefore more accurate.

  6. Mission 2 Profile:

  7. Aspect Ratio (AR) • Altitude: 6000 meters • Speed: 240 knots • Clcruise = .9

  8. AR of around 20 will give us the lowest power and best L/D

  9. AR & Clcruise calculation: • AR of low subsonic transport vehicle: 6-9 (Ref 3) • AR of V-22 = 6.97 , Clcruise of V-22 = .79 • But, the span of the V-22 was restricted by the Marine requirements. • High AR is desirable to reduce Cdinduced • We can’t have too large AR because of structural capabilities and Whirl Flutter. • At this point without structural analysis of the wing it is hard to measure the maximum limit.

  10. Whirl Flutter Whirl flutter occurs due to the result of interactions between aerodynamics, stiffness, and inertial forces on the structures. The topic is not possible to covered for the given time. But, NASA did plenty of whirl flutter experiments on VTOL aircrafts. - LCTR (large Civil Tilt-rotor) - LCTC (large Civil Tandem Compound) These articles can be used to optimize the design of the aircraft: PI - Stabilizing effect on Whirl Flutter (Ref 1) - offset of coning-hinge, rotor precone - reduction of pitch-flap coupling - Reduction of airfoil thickness on tilt-rotor aircrafts by using composite materials (Graphite Epoxy) (Ref 2)

  11. Aspect Ratio Analysis Higher AR gives us lower power. But the power saving for every .5 AR increase is decreasing. So, when do we limit the increase of AR?

  12. We turned to Dave to find a limit through weight calculation. Wing Weight Equation Cw=0.0215 kuc=1.002 ksl=1.004 ksp=1 kre=0.98 Typical range of % weight for the wing is 15-25% of empty weight.

  13. Wingman-22 Wing weight calculation: Empty Weight: 19 841.6 lbs Typical range of % weight for this wing: (2976.24 lbs – 4960.40 lbs) Employing Dave’s equation AR of 7-9 gives wing weight: 1996 lbs – 2667 lbs (This does not include the weight of the drive shaft and other mechanisms inside the wing)

  14. Reviewing Power Vs. Cl After AR of 8 the power saving does not decrease as rapidly. AR of 8 also gives 2282 lbs for wing weight. This also allows to implement outboard section of the wing, where winglets, twist, sweep can be optimized. (Span longer than just rotor blade)

  15. Airfoil Selection (Ref 4)

  16. NACA 65(3)218 (Ref 4)

  17. Wing Design • At this point the wing does not include any sweep, twist or taper. • These aspects will be visited to optimize the wing • Winglets at the outboard section will improve Oswald’s efficiency = CLα = lift curve slope of the entire wing Clα = lift curve slope of the airfoil Clmax = 1.3 CLmax = 1.24 CLmax = CL at which the wing stalls Clmax= CL at which the airfoil Vstall6000meters = 205 knots Vstall2000meters = 165 knots

  18. Now going back to find best Clcruise The reduction of power is very small for Clcrusie = .9-1.0 We want the smaller value of Clcruise which will keep us Further away from Clmax for maneuver and safety. This gives us a wing area for flying at 6000 meters. S = 349 ft2

  19. Best Cruise speed to climb NOT CORRECT We can’t fly at 125 knots because the wings will stall at this speed. We must fly around stall speed during climb, which changes as altitude increase. For safety purposes the Cruise speed should be around 210 knots

  20. References • 1: PiaTak, David, Mark Nixon, and Mark Bennet. "A Wind_tunnel Parametric Investigation of Tiltrotor Whirl-Flutter Stability Boundaries." (2008): 1-12. Print. • 2:Acree, C.W., R.J. Peyran, and Wayne Johnson. "Rotor Design for Whirl Flutter: An Examination of options for imporvingTiltrotorAeroelastic Stability Margins." (1999): 1-16. Print. • 3:Sadraey, Mohammad. "Wing Design." Aircraft Design: A Systems Engineering Approach. (2012): 167-275. Web. 5 Feb. 2013. <http://faculty.dwc.edu/sadraey/Chapter 5. Wing Design.pdf>. • 4: Doenhoff, Albert. Theory of Wing Sections. Dover. New York: Dover Publications, INC, 1959. 635-636. Print.

  21. Cost Analysis with MatLab • Using the MatLab function lsqnonlin, which solves non-linear least-squares data fitting problems using the form: • Taking the data inputs in the form of an array where DOC/DMC, Weight, Power were each a column the function solved until the sum of the squares changed less than the tolerance value of 1E10-6.

  22. Predicted Cost Equations are using the form: 0.4*(Helicopter) + 0.6*(Turboprop) Where Helicopter and Turboprop denote the appropriate equation with the Wingman-22 Weight and Power values. For the first mission the time spent in a turboprop configuration is 54% of the time, and 75% for the second mission. Third mission involves 10km of descent, landing, take-off, and climb; I wasn’t sure how to break that up in for a length of time.

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