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.

Flywheel energy storage systems employing high speed composite flywheels and advanced electric motor/generators are being evaluated by the Department of Defense (DoD), NASA [1], and firms [2,3] to replace electrochemical battery banks in satellites and manned space applications. Flywheel energy storage systems can provide extended operating life and significant reduction in weight and volume compared to conventional electrochemical systems. In addition, flywheels can provide momentum or reaction wheel functions for attitude control. This paper describes the design, fabrication, and spin testing of two 10 MJ composite flywheel energy storage rotors. To achieve the demonstrated energy density of greater than 310 kJ/kg in a volume of less than 0.05 m 3 , the rotors utilize flexible composite arbors to connect a composite rim to a metallic shaft, resulting in compact, lightweight, high energy density structures.The paper also describes the finite element stress and rotordynamics analyses, along with a description of the fabrication and assembly techniques used in the construction of the rotor. A description of the experimental setup and a discussion of spin testing of the rotors up to 45,000 rpm (965 m/s tip speed) are also presented. Accurate measurements of rotor centrifugal growth made with laser triangulation sensors confirmed predicted strains of greater than 1.2% in the composite rim.Due to the weight penalty associated with flywheel designs requiring containment structures, there is a strong need to develop flywheel systems which operate safely in space, preferably without dedicated containment structures. A future paper will describe results of a 28,600 rpm composite rotor burst test performed in a containment structure as a step towards understanding composite rotor failure modes.

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