# lift/drag ratio

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lift/drag ratio
The ratio of the coefficient of lift to the coefficient of drag of an airfoil at various angles of attack. It is a measure of the airfoil’s efficiency. The angle of attack that gives the best lift-by-drag ratio is the most efficient angle of attack. In normal airfoils, this generally corresponds to 4°. Lift/drag = CL 1/2ρV2 S/CD 1/2ρV2 S = CD .

Aviation dictionary. 2014.

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