Transverse Motion of 8 Inch Projectile, XM673, in the XM201, M2A2 Gun Tube, Mk-16 and MCLG Gun

Abstract

Abstract : The dynamic behavior of a projectile during acceleration in the gun tube requires a quantitative description, since, if balloting becomes excessive, undesirable conditions such as damage to fuzing, shell body engraving, inaccuracy of fire due to yaw, and yaw velocity at the muzzle may result. The approach taken in this report utilizes the equations of motion derived in an earlier report titled, 'Transverse Motion of an Accelerating Shell' to describe the balloting motion of the 8-inch XM673 projectile fired in the MK-16, MCLG gun, XM201 and M2A2 gun tubes. Most previous solutions which have appeared in published works to date discuss the problem in a simple way, or consider separately the main factors that effect projectile motion. Effects of friction forces at the bourrelet and the driving band, changes of the eccentricity and the location of the center of gravity, and the wall thickness of the shell were considered in this formulation. The analysis shows that the contact of the bourrelet on the gun tube is intermittent when the C. G. eccentricity is zero or very small and the contact is continuous when the eccentricity is large and that this parameter is the one that most affects the performance of the projectile and the associated fuze. The analytical results are presented in graphic form.