Spin Characteristics of the 60-mm High Explosive M49A4 Projectile With ModifiedM2 Fin Assembles

摘要

The 6O-mm M49A4 mortar projectile experienced large range standard deviations,short round, and excessive duds during lot acceptance tests conducted during 1992. Previous wind tunnel testing and trajectory analysis identified resonance instability as a possible cause of the poor test results. The current wind tunnel test was performed to study the spin characteristics of the M49A4 projectile with both standard and modified M2 fin assemblies. Tests performed using standard fin assemblies show the projectile develops spin rates close to the natural pitching frequency, supporting the resonance instability theory. Wind tunnel tests performed with modified fin assemblies indicate it is possible to produce enough roll torque to rapidly spin the projectile through the maintain a spin rate above the projectile's natural pitching frequency. Test firings conducted with the modified fin assemblies resulted in improved performance.