Plastic Guidance Fins for Long Rod Projectiles .

Defence Science Journal

Mark L. Bundy¹ 

[1] US Army Research Laboratory, Aberdeen Proving Ground

关键词: Solid propellant;    Projectiles;    Target penetration;    Aerodynamic drag;    Kinetic energy (KE) penetrators;   

DOI  :  

学科分类：社会科学、人文和艺术（综合）

来源: Defence Scientific Information & Documentation Centre

【 摘 要 】

Projectile tail fins on long rod kineticenergy (KE) penetrators serve the same purpose as fletchings (feathers)on an arrow, namely, they help align the projectile axis with itsvelocity vector. This reduces the projectile's yaw and hence reduces itsaerodynamic drag. In addition, a low yaw angle at target impact helpsto maximise the projectile's target penetration. It is typical forprojectiles to exit the gun muzzle and enter free flight at somendn-zero yaw angle. Aerodynamic forces acting on yawed tail fins create astabilising torque about the projectile's centre of gravity (CG). Thistorque can be increased by making the fin material lighter. Mostconventional long rod penetrators fired from high performance guns havetail fins made from aluminium. However, aluminium can undergocatastrophic oxidation (rapid burning) in-bore. Coating aluminium withAl/sub 2/O/sub 3/ {hardcoat) prevents ignition of the substrate,provided solid propellant grain impacts do not chip the brittle hardcoatoff the surface. Plastic is lighter than aluminium and less exothermicwhen oxidized. Therefore, other factors aside, it is conceivable thatplastic fins could increase projectile stability while incurring lessthermal erosion than aluminium. However, thermal loads are not the onlyconcern when considering plastic as an alternative tail fin material.The mechanical strength of plastic is also a critical factor. This paperdiscusses some of the successes and failures of plastic fins, at leastrelatively thin fins, for use as KE stabilisers.

【 授权许可】

Unknown