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Aerodynamics PDR 2. Team 2: Balsa to the Wall. Ashley Brawner Neelam Datta Xing Huang Jesse Jones. Matt Negilski Mike Palumbo Chris Selby Tara Trafton. Overview. Design Point Airfoil Selection Component Drag Buildup Drag Polar AR trade study (C L ) max Approximation
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Aerodynamics PDR 2 Team 2: Balsa to the Wall Ashley Brawner Neelam Datta Xing Huang Jesse Jones Matt Negilski Mike Palumbo Chris Selby Tara Trafton
Overview • Design Point • Airfoil Selection • Component Drag Buildup • Drag Polar • AR trade study • (CL)max Approximation • (Cl)max method • (CL)max Raymer method • Flap analysis
The Design Point • Planform area based on approximated (CL)max and weight estimate • Dihedral angle of 0° taken from Roskam • Design speed decreased from 150 ft/sec • Designed to high speed mission
Airfoil Selection: Main Wing • Wing Section • NACA 1408 • Gives approximate 2D Cl needed for dash • Relatively thin for minimizing drag • Thick enough for structural strength
Airfoil Selection: Tail • Tail Sections • Horizontal Stabilizer • Symmetric with low Cd over a wider range of a.o.a. compared to other similar airfoils • Symmetric Jones airfoil (≈8% t/c) • Vertical Stabilizer • NACA 0006
Drag Build-up Method (Raymer) • Cfc = Component skin friction coefficient • FFc = Component form factor • Qc = Component interference effects • Swet,c = Component wetted area • Sref = Wing planform
Inputs: Drag Build-up Method results
(Cl)max Approximation • Compare XFOIL with Abbott & Doenhoff wind tunnel data • Conclusion • αClmax ≈ 0.8αClmax(XFOIL)
Flap analysis • Use (CL)max approximation from Raymer • Ads • Use XFOIL to find (Cl)max with flaps • Observation - • Flapped (Cl)max follows linear trend • Determine maximum achievable (CL)max • Find flap configuration that acheives optimal (CL)max
Flap analysis: (continued) • Use linear fit lines to find a Δ(Cl)max and then find Δ(CL)max with the following equation from Raymer: • ads • The ratio blank is based on the intial sizing of the wing area and tail span and is assumed to remain constant
Flap Geometry: • flap hinge location (x/c) = 0.8 • maximum flap deflection = 35° • constant (cf/c) flap • (CL)max (w/ flaps) = 1.06 • (Cl)max (w/o flaps) = 0.85