Experimental validation of a capacitor discharge induction launcher model

Abstract

This paper describes the early stages of the experimental validation of a mathematical model of a capacitor discharge co-axial induction launching system. The model forms part of a family of computer programs produced to aid the design of launchers, so that either the maximum possible armature velocity on exit from the launcher or a specific performance requirement such as a controlled armature acceleration is achieved. The programs range in complexity from relatively simple models, used for initial capability studies, to detailed representations used in the design and development of launcher structures and their control systems. The model described is one of the more complex under development, being based on filamentary representations of both the stator and armature conducting regions. The single-stage experimental launcher described in the paper has been constructed purely for model validation purposes. To this end its geometry is constrained to a straightforward co-axial form, with the armature being a simple 80 gm aluminium ring of 100 mm diameter. The launcher operates vertically, accelerating the armature in free flight in order to avoid difficulties caused by barrel friction. Current and position data are obtained using digital sampling techniques, with post-processing allowing a direct comparison to be made with simulated results. >