Temperature-Controlled Bending of a Gun Tube

摘要

For some ammunition types, the projectile impact location appears to be gun tubedependent, even though the aim point, barrel mount, and ammunition lot may be the same. It is thought that such barrel dependency is due to manufactured differences in the straightness of each tube. To test this hypothesis, we have devised a means to reversibly control the centerline curvature of a gun tube. This preliminary report describes how a series of heating pads, adhered to the external surface of the barrel, can be used to change the bore centerline curvature. Several centerline alterations are demonstrated on a 120-mm M256 tank cannon. The theoretical prediction for each of several heat-pad-induced centerline changes compares favorably with borescope measurements of the muzzle angle change and dial-indicator measurements of the outer-wall barrel displacement. Future gun firings of this temperature-controlled barrel will be used to examine the correlation between shot impact location and centerline curvature.