Aerodynamic characteristics of high performance rounds at Mach 1.8 to 4

This paper presents a wind tunnel investigation of the aerodynamic performance of two high performance supersonic rounds: a standard 155 mm M549 projectile and a new optimum round that was redesigned from the standard round. The experiments were performed over a wide range of Mach numbers ( M = 1.8 , 2, 2.5, 3, 3.5, and 4) providing new data for the consideration that these rounds can be flown beyond the maximum nominal flight speed of Mach 2.5. The angle of attack was varied during the test over a range of angles (−5° to +5°) in order to determine the pitching moment derivative. The results show that the redesigned body provides significantly lower drag and pitching moment derivative, which are both desirable to enhance the range of the round and its stability. In comparison of the experimental data with the simulation predictions, good agreement was observed for the drag, the normal force derivative and the pitching moment derivative. It was also found that increasing the Reynolds number only significantly affects the skin friction drag.