Sabot Designs for Launching Penetrators and Projectiles

Abstract

Sabot is the French word for a wooden shoe. It is a successful word choice in the present case because some important features of a functioning projectile sabot are included in the word: The wooden shoe must be light and strong, must conform to the foot, and should be easily removable. These and other requirements play an important role in the design of sabots for impact and free-flight tests. The design and fabrication of sabots is a small but important part of the complex operation of impact and free-flight ranges, because a satisfactory sabot is necessary if success of an experiment is to be guaranteed. What is a sabot? It is a technical device conforming on its outer surface to the launch tube wall and on its inner surface to the projectile. It carries the projectile through the launch tube under the action of the driver gas. In a weapon system it is designed to deliver a specific projectile to a target with an acceptable dispersion and velocity. With a sabot it is possible to launch most regular and irregular shapes and subcaliber projectiles over a wide range of velocities. The functions of sabots are diverse: • The sabot positions and supports the projectile during launch. • It seals, or obturates, the driver gases within the launch tube. Imperfect sealing permits blow-by of the driver gas, resulting in asymmetric loading of the sabot-projectile assembly and disturbance of the sabot as it is separated from the projectile. • It should minimize undesired lateral or yawing motions produced by bore and/or projectile asymmetries, variations in bore friction, and asymmetries in pressure loading. Imperfect machining of the sabot results in a tight or loose fit in the launch tube, with the consequences of either excessive friction or blow-by of driver gases. Imperfect honing of the launch tube and cleaning after firing can also cause variation in bore friction. Undesired lateral effects can be caused by disturbances of the propellant burning rate in powder guns or by shock waves in light gas guns.