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Wingman-22: Airfoil selection

Wingman-22: Airfoil selection. Arnab Roy Chengzhi Qi. Wing Design Process. High Wing. Geometry. Increases the dihedral effect. It makes the aircraft laterally more stable . (fuselage will also make contribution) Eases and facilitates to maintenance.

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Wingman-22: Airfoil selection

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  1. Wingman-22:Airfoil selection Arnab Roy Chengzhi Qi

  2. Wing Design Process

  3. High Wing • Geometry. • Increases the dihedral effect. It makes the aircraft laterally more stable. (fuselage will also make contribution) • Eases and facilitates to maintenance. • Rolling landing/Rolling take-off: Rotor blade and ground interactions

  4. Clvs alpha • Clmax: Required stall speed mainly governs the Clmax ( Clmaxgives Cd, but Clmaxgives better flight envelope) • αs: stall angle ( : 12° - 16° flight safety ) • α0: Zero lift angle of attack ( {more negative value}: Leaves the capacity for more lift at 0 AOA) • Cl0: Cl at zero angle of attack ( : Implies we can create more lift at 0 AOA) • Clα: Affects the transition ( : Less power used in the rotor) • Cli : Ideal lift coefficient (Clcruise should be close to this to have minimum drag) • Stall Behavior: An airfoil with a gentle drop in lift after the stall is more desired

  5. Clvsalpha (Continued) Req & Assumption: • Cl max around 1.3 • zero lift angle of attack (negative, with flag should around - 5-10 degree) • stall angle > 12 degree better around 15 • zero angle of attack, no requirement, but as good as high it goes.

  6. Cm1/4 Vs. α & Cmac Vs. α • The slope of Cm Vs. alpha at ¼ chord relates to the stability of the airplane (a reasonable negative slope is required) • Size of the tail, elevators are governed by Cm value. More negative Cm results in larger tail = Higher drag, heavier aircraft, higher costs. Req & Assumption: • Cm vs alpha slope is negative • Cm at AC is around -.02 to -.05

  7. Cd vsCl • Cd minimum as low as possible, reduce fuel required • At minimum slope: (Cd/Cl)min = (Cl/Cd)max • During 240 knots (Cruise): Cl should be Cl (ideal) • During 180 knots (loiter): Cl should be Cl(design) Req& Assumption: • Cdmin about .003 to .006

  8. Thickness • Lift curve slope :Cla=1.8*pi*(1+0.8tmax/c) • Strength to support torque by rotors • Storing fuels • Enough space for rotation motion of the rotor • Reduce flutter Req & Assumption: • t/cmaxis about 15% to 20%

  9. Airfoil Selection Criteria

  10. Comparison of airfoils

  11. Airfoils Choices: • NACA 23015 • Sm 701 • NACA 64(4) 421 • NACA 65(3) 218

  12. Airfoil Design Objectives(in progress)

  13. Evaluation of the performance (In Progress)

  14. Sm701

  15. NACA 64(4) 421

  16. NACA 65(3) 218

  17. NACA 23015 (In Progress)

  18. Preliminary Wing Analysis:(In Progress)

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