The Effect of Sabot Grooves on Lift Force for Kinetic Energy Projectiles.

Report No. ARL-TR-1776
Authors: Mikhail, Ameer G.
Date/Pages: February 1999; 52 pages
Abstract: The effect of grooves on the normal force of an anti-armor long rod kinetic energy (KE) projectile was analyzed and numerically quantified. The effect was studied for body alone and body with fins in which clear and distinct effects were experimentally observed for each. Wind tunnel data sets were analyzed, and algebraic, semi-empirical correlations were constructed using the main physical parameters of the projectile body and fins, as well as the flow parameters. The correlations provide a simple method of estimating the increase or decrease in the vehicle's total normal force attributable to grooves and can be implemented in fast aerodynamics design codes. One separate set of data was dedicated for independent validation, and the correlation predicted the effect reasonably well, both in magnitude and sign. The present correlation is the only one known in the literature for predicting the lift loss (or gain) attributable to grooves. In addition, a better understanding of the contributions of grooves to both body alone and fins in the presence of a body is presented. The correlation is constructed for the Mach number range of 2.0 < M < 5.5 and for small angles of attack (less than 60), which cover the flight envelope of tactical KE anti-armor projectiles. The established correlations provide direct incremental lift coefficient corrections over smooth body values for useful direct design use.
Distribution: Approved for public release
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Last Update / Reviewed: February 1, 1999