Accession Number : ADA321400

Title :   Plastic Fins for Kinetic Energy (KE) Penetrators.

Descriptive Note : Final rept. 1987-1996,

Corporate Author : ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD

Personal Author(s) : Bundy, Mark L.

PDF Url : ADA321400

Report Date : DEC 1996

Pagination or Media Count : 49

Abstract : Most conventional sub-caliber long rod penetrators maintain flight stability by using near-full-caliber hardcoated aluminum fins that extend from the base end of the projectile. Prior to launch, these fins are buried within the propellant bed of the ammunition cartridge case. During launch, the fins are subjected to high propellant gas temperature and pressure, as well as propellant grain impacts. This thermally abrasive in-bore environment can remove pieces of the fin's hardcoat, thus exposing the aluminum substrate to temperatures far beyond its melting point. Thermal erosion of the fin degrades projectile stability and accuracy. Thus, the U.S. Army is exploring more effective thermal coatings and/or substitute fin materials to replace hardcoated aluminum. The use of plastics is one alternative. This report will document some of the successes and failures of plastic fin assemblies on kinetic energy (KE) penetrators. For example, it was found that fins made from some plastics incur less in-bore thermal damage than hardcoated aluminum. On the other hand, it appears that plastic fins, at least relatively thin plastic fins, are susceptible to mechanical failure out of bore if they traverse the reverse muzzle gas flow at all but small yaw angles. Nonetheless, there appears to be design latitude for a plastic fin assembly that would be lighter in weight and more erosion resistant than the current hardcoated aluminum fin.

Descriptors :   *KINETIC ENERGY PROJECTILES, *FINS, THERMAL PROPERTIES, ANGLES, TEMPERATURE, STABILITY, YAW, ENVIRONMENTS, IMPACT, DAMAGE, HIGH TEMPERATURE, PROJECTILES, ACCURACY, SUBSTRATES, GASES, PROPELLANTS, COATINGS, EROSION, PENETRATION, FLIGHT, ALUMINUM, THINNESS, SUBSTITUTES, ASSEMBLY, HEAT, PLASTICS, MELTING POINT, GAS FLOW, GUN MUZZLES, INTERIOR BALLISTICS, PROPELLANT GRAINS, LATITUDE, ABRASIVES, SECONDARY FLOW, AMMUNITION CASES, CARTRIDGE CASES.

Subject Categories : Ammunition and Explosives

Distribution Statement : APPROVED FOR PUBLIC RELEASE