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Induced Drag Aerodynamics Introduction Read: ANA 61-68 Overview Differences Between Airfoils and Wings Wing Terminology Review Wing Vortices (Development of Lift by a Wing) and induced drag Effect of wing planform on induced drag. Differences Between Airfoils and Wings Airfoils Infinite wings – no wing tips – no wing tip vortices. 2D flow Air flows in a straight line from leading edge to trailing edge. No spanwise flow. No consideration of overall wing shape. Wings Finite wings with wing tips and wing tip vortices. 3D flow Includes spanwise flow components. Wing Vortices (Development of Lift by a Wing) and Induced Drag Wingtip vortices - ANA Figure 1.29 s1. Rectangular wing producing lift. Induced Downwash Vortices produce induced downwash Addition to downwash necessary to produce lift Produces a net downward component to relative wind Tilts Lift Vector The lift vector reward tilting produces a component of lift PARALLEL to relative wind –this is induced drag Induced Downwash = Induced Drag Wing Planforms wrt Vortices Qualitative approach only, no calculations. Wing planform affects wing tip vortex intensity, spanwise lift distribution, and induced drag. *An elliptical wing provides the least induced drag for a given aspect ratio. Each sq foot of area along span produces exactly the same lift pressure.