Abstract: The aerodynamic asymmetry can produce a periodic forced interference to the angular motion of projectile when it rotates. Under certain conditions, this can form a rotating motion of the projectile longitudinal axis relative to the velocity vector in which the angle between the long itudinal axis and the velocity vector is fixed. This kind of rotating motion can be used to realize the stable scanning of terminal sensitive ammunition. On the premise of considering the forces and moments, including asymmetric aerodynamic force and moment, the motion differential equation of projectile is established, and the angle-of-attack equation in complex number form is derived. On the basis of angle-of-attack equation, the conditions under which projectile can form stable spin resonance movement are discussed. The simulating calculation of a certain aerodynamic asymmetric projectile is performed. The result shows that aerodynamic asymmetric projectile can form spin resonance movement under certain conditions, which provides theoretical support to the pneumatic design for terminal sensitive ammunition.

Key words: ordnance science and technology, aerodynamic asymmetry, asymmetric projectile, spin resonance, large angle-of-attack, terminal sensitive ammunition