Roll Damping for Projectiles Including Wraparound, Offset, and Arbitrary Number of Fins

An algebraic correlation for the roll-damping and roll-producing moments for finned projectiles and missiles has been extended and verified to accept bodies with an arbitrary number of fins—not only cruciform fins, but curved wraparound fins with fin cant, and fins with offset angles. The extended correlation is applicable at subsonic, transonic, and supersonic speeds. A direct method to compute the fin roll-producing moment from the fin normal force is provided to circumvent the existing lengthy and cumbersome semiempirical methods. Seven different missile and projectile configurations with widely varying fin shapes and sizes were tested, and their measured data are tabulated. The present correlation is very simple, and can be used to refine initial configuration selection and thus reduce the number of costly full-flowfield computations. The correlation is limited to missiles with only one set of fins and to small angles of attack.