Influence of Moving Internal Parts on Angular Motion of Spinning Projectiles

Projectiles containing movable internal components, when compared with rigid but otherwise equivalent projectiles, have been observed to have different damping rates, range losses, and rapid spin-downs. Two types of internal parts motion are considered: 1) linear motion of the centers of mass of the components relative to the external shell center of mass, and 2) angular motion of the components' spin axes with respect to the external shell spin axis. Motions at the projectile's pitching and yawing frequencies are considered, and such motions are shown to explain the observed flight behavior. £