EMPIRICAL MEASUREMENTS OF CANNON LAUNCH PRESSURE ON A FINNED 155mm ARTILLERY PROJECTILE

摘要

For years, ballisticians have been studying the phenomena associated with cannon launched projectiles. In particular is the study of the pressures about the base during cannon launch through to muzzle exit. Pressure on the base is thought to be uniform and therefore hydrostatic, even though the there are undulations in the magnitude of the pressure from the burning propellent. This paper studies various phenomena of the launching of a 155mm artillery projectile that has a finned base and a slip band obturator. Specifically, pressure gradients in and around the finned base are characterized during the interior ballistic flight and muzzle exit. In addition, the projectile accelerations in all three axes are also characterized. The finned base was instrumented with nine ballistic pressure gages. The figure below depicts the base with one gage on the aft face, four gages on the boat tail and four gages inside the fin slots. This base was adapted to a modified M864, 155mm artillery shell. Data is recorded in real time as one can see the transmitter and antenna are within the M864 shell. The objective is characterize localized base pressurization on an artillery cannon launched projectile. Data indicates localized fluctuations in pressure that are not uniform over the base region. Further studying the data may provide insight into other projectile dynamics such as fin deployment, set forward accelerations at muzzle exit, and obturator performance.