Karpov B.G. The effect of various boattail shapes on base pressure and other aerodynamic characteristics of a 7-caliber long body of revolution at M = 1.70

Aberdeen Proving Ground, Maryland: Ballistic Research Laboratories, 1965. — 48 p.Models, 7 calibers long, with a variety of conical, ogival (convex) and concave boattails were free-fligbt tested at M = 1.70, for drag and other aerodynamic characteristics. The total drag decreases monotonically for boattails longer than 0.5 calibers. For shorter boattails, the drag is higher than that of the square based body. For boattail lengths between 0.5 and 1.5 calibers, conical boattails have lower drag than either the ogival or concave configurations.
The base pressure decreases with boattail length but increases with the boattail angle at the base. Among other aerodynamic characteristics, the boattailing appears to cause the most significant change in the Magnus torque coefficient. For certain boattails, this change may be sufficiently large to make the configuration dynamically unstable.