Discarding armature and barrel optimization for a cannon caliber electromagnetic launcher system

Abstract

This publication details the optimization and baseline design of the discarding metal armature and electromagnetic railgun developed for the U.S. Army Armament Research Development and Engineering Center and U.S. Marine Corps sponsored Cannon Caliber Electromagnetic Launcher program.The primary goals of this program have been to defeat specified targets at 1,500 and 3,000 m range utilizing an electromagnetic launcher system weighing less than 5,000 Ib.An optimization algorithm was developed to integrate the armor-penetrating sub-projectile with a discarding armaturdsabot forming an integrated launch package. This algorithm coupled integrated launch package electromagnetic and structural design requirements to launcher design parameters including rail resistance per unit length and inductance per unit length as a function of launcher rail geometric2 and structural configurations. Pulsed power supply size and mass requirements were subsequently estimated from launcher performance predictions.This study shows that minimizing breech energy required by the launcher will minimize total system mass. A two-turn augmented, rectangular bore barrel, firing a mid-drive discarding armature that launches its subprojectile at 1,850 d s resulted in minimum system mass. The series augmented electromagnetic launcher will be powered by a 4-pole, air-core, compulsator that stores the total launch energy inertially in its composite rotor. This compulsator driven electromagnetic test bed will be capable of accelerating 15 each, 185 g integrated launch packages in three salvos of five shots, with a shot rate of 300 rounds per minute and two seconds between salvos.

An optimized double ramp integrated launch package design for railguns

“…The armature/sabot model adopted for use builds from the previous work of Zielinski [6] and Price [1]. Fig.…”

“…The fin and mid section of the design are borrowed and enhanced forms of the largely successful CCEMG design [1] (enhancements are discussed below). The fin rake angle is set to 25º as a compromise to fin rail-to-rail stiffness and location of the mass center of the package with respect to the stabilizer (bore rider).…”

“…The model for this design was assembled and executed in FORTRAN and results were compared to many earlier designs [1][2][3][4][5][6][7][8][9][10][11]. For the purpose of validation, an ambiguous 2,300 m/s launch package was designed and validated using a dynamic 3D mechanical finite element analysis.…”

“…Early front end compulsator and switching designs had little or no coupling with the launcher and ILP. The most successful approach to designing these systems, however, seems to be that which starts with as much information as possible with the ILP including sub projectile performance on the target [1,2]. Generally, little is known about performance at the target using an innovative penetrator so it has been widely acceptable to use the total ILP muzzle kinetic energy to begin the design process.…”

Application of electromagnetic guns to future naval platforms

“…Launchers have evolved from very heavy, low bore pressure devices [1][2] to lightweight composite reinforced structures capable of operating at bore pressures near that used in conventional powder guns [3][4] [5]. Projectiles have evolved from small plastic cubes accelerated by plasma armatures [6] [7] to fully capable launch packages with integral solid armature and sabot structures supporting relevant payload projectiles [8][9] [10]. Compact power supplies using rotating machines to both store energy and generate the required current pulses for the gun are also being developed [11][12] to replace the large capacitor or iron-based rotating machine laboratory systems now in use.…”