Verification of Ground Test Data by Instrumented Flight Test of an Artillery Shell

Abstract : Service tests of a new low-drag projectile showed unexpected behavior at intermediate temperatures and low gun elevations where no problems were expected. An extensive test program was initiated to investigate the causes of this behavior. This program included wind tunnel and spark range tests at a wide range of Mach numbers and angles of attack. Given the shell's pitch damping, static, and highly nonlinear Magnus moment coefficients, it was possible to predict its behavior mathematically if the initial pitching rate of the projectile was permitted to vary within the observed limits. Instrumented flight tests verified some of the ground test results although there still remains some unexplained discrepancies in the details of flight behavior. This investigation proved the necessity of a thorough aerodynamic test program if details of a shell's behavior are to be mathematically simulated.