Aerodynamics PDR 2 Team 2 Balsa to the
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 1
Overview n n n Design Point Airfoil Selection Component Drag Buildup Drag Polar AR trade study (CL)max Approximation ¡ ¡ ¡ (Cl)max method (CL)max Raymer method Flap analysis 2
The Design Point n Weight 5. 5 [lbs] Dihedral Angle 0° Speed 110 [ft/sec] Horizontal Tail Span n 1. 5 [ft] n n 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 3
Airfoil Selection: Main Wing Section ¡ NACA 1408 n n n Gives approximate 2 D Cl needed for dash Relatively thin for minimizing drag Thick enough for structural strength 4
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Airfoil Selection: Tail n Tail Sections ¡ Horizontal Stabilizer n n ¡ 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 n NACA 0006 6
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Drag Build-up Method (Raymer) n n n Cfc = Component skin friction coefficient FFc = Component form factor Qc = Component interference effects Swet, c = Component wetted area Sref = Wing planform 8
Component Coefficient of friction 9
Drag Build-up Method results Inputs: 10
Drag Polar 11
AR Trade study 12
AR Trade study 13
(Cl)max Approximation n Compare XFOIL with Abbott & Doenhoff wind tunnel data n Conclusion ¡ αClmax ≈ 0. 8αClmax(XFOIL) 14
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Flap analysis n Use (CL)max approximation from Raymer ¡ n n Use XFOIL to find (Cl)max with flaps Observation ¡ n n Ads Flapped (Cl)max follows linear trend Determine maximum achievable (CL)max Find flap configuration that acheives optimal (CL)max 19
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Flap analysis: (continued) n Use linear fit lines to find a Δ(Cl)max and then find Δ(CL)max with the following equation from Raymer: ¡ n ads The ratio blank is based on the intial sizing of the wing area and tail span and is assumed to remain constant 22
Flap Geometry: n n n 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 23
Summary Table (CL)max (w/ flaps) (CL)max (w/o flaps) CD 0 AR b croot ctip troot ttip Flap location (x/c) Maximum flap deflection 1. 06 0. 84 0. 0253 6 5 [ft] 16. 24 [in] 7. 35 [in] 1. 3 [in] 0. 6 [in] 0. 8 35° 24
Questions? 25
- Slides: 25