INFLUENCE OF MASS UNBALANCE ON A SMALL-CALIBER PROJECTILE TRAJECTORY

The purpose of this article is to use an uncoupled method based on Rigid Body Dynamics (RBD) and Computational Fluid Dynamics (CFD), to determine the aerodynamic coefficients of geometrically symmetric small-caliber projectiles but with a fixed mass asymmetry to complement previous findings in large caliber. In addition to having to take into account the evolution as a function of the yaw angle and the Mach number for the calculation of the coefficients, a common 6-DoF model is adapted to also take into account the unbalance position in flight without any modification of the twelve differential equations of motion. It appears very clearly that the effects related to the presence of the unbalance are much more important at the exit of the tube, than in air, since the orientation problems are quickly compensated by the gyroscopic effect whereas the direction of the trajectory is definitely deviated.