Abstract: A coordinate system for mechanics analysis is established based on the structural features of the asymmetric-fin terminal sensitive ammunition. The force and moment models are analyzed with consideration of pneumatic eccentric angle and large angle of attack asymmetries, and the 6D differential equation set of motion is deduced. The simulation calculation is performed according to the structure of a certain asymmetric terminal sensitive projectile. The calculated result shows that the pneumatic eccentric angle which is in the same plane as the wingspan direction can induce stable spiral scanning motion, and the scanning angle must be in the same plane as the pneumatic eccentric angle. The result also shows that the scanning rolling speed decreases but the scanning angle increases linearly as the pneumatic eccentric angle increases.

Key words: ordnance science and technology, terminal sensitive ammunition, asymmetric fin, pneumatic eccentric angle, stable scanning, large angle of attack, aerodynamic asymmetry