Tests of the 5" HVAR Projectile with Fin and Ring Tails

Abstract

This report covers tests of a 2-inch diameter model of the 5" HVAR Projectile, conducted at the Hydrodynamics Laboratory of the California Institute of Technology. This work was authorized by a letter dated January 31, 1944 from Dr. E. H. Colpitts, Chief of Section 6.1, Office of Scientific Research and Development. The purpose of the tests was to determine the performance of the projectile with the standard 4-fin tail, and to investigate possible changes in the proportion of the fins in order to better the performance or make a more compact design. This report also includes an extensive investigation of the performance of various fin and ring tails applied to this projectile, as well as to similar projectiles of different lengths. It is hoped that the data contained herein may be of use in the design of a variety of bullet-shaped projectiles having either ring or fin tails. The Water Tunnel tests apply only to the projectile moving at subsonic speeds, i.e., during the acceleration period. The attached appendix gives definitions of the terms used throughout the text, as well as other pertinent data.