Equivalent angle-of-attack method for estimating nonlinear aerodynamics of missile fins

A method has been developed for estimating the nonlinear aerodynamic characteristics of missile wing and control surfaces. The method is based on the assumption that if a fin on a body has the same normal force coefficient as a wing alone composed of two of the same fins joined together at their root chords, then the other force and moment coefficients of the fin and the wing alone are the same, including the nonlinearities. The method can be used for deflected fins at arbitrary bank angles and at high angles of attack. In this paper a full derivation of the method is given, its accuracy is demonstrated, and its use in extending missile data bases is shown.