Depth Prediction for Earth-Penetrating Projectiles

An empirical equation is developed for the prediction of total penetration distance of a projectile in many natural earth targets. Development of this equation was based on approximately 160 full-scale penetration tests into a variety of targets, including rock, gypsite, permafrost, ice, desert alluvium, silt, sand and saturated clay. The parameters considered in the development (other than target materials) were (1) projectile weights from 222 to 5,750 lb, (2) projectile diameters from 3.1 to 18 in., (3) impact velocities from 78 to 1,077 fps, and (4) 11 projectile nose shapes. The equation fits 91% of the data within 20% and fits 98.5% of the data within 25%. The necessary tables of nose-performance coefficients and soil constants are presented for practical engineering usage.