A Same-Scale Comparison of Electromagnetic Launchers

A same-scale comparison of conventional railguns, augmented railguns, and helical launchers is presented and discussed. While the ideal launcher is always 100% efficient, practical launchers have an efficiency which is a function of the projectile velocity and a new parameter called the characteristic velocity. The characteristic velocity is the velocity needed for 50% maximum efficiency. The motivation for a same-scale comparison is an accounting for the velocity-dependent efficiency effect. The same scale concept states that launcher comparisons should be done on an equal bore diameter, launcher length, projectile mass, and velocity basis. Other parameters developed by the authors and included in the analysis, are the launcher constant and the mode constant that account for the launcher geometry and the mode of operation, respectively. The analysis uses experimental data collected by the authors with conventional railgun, augmented railgun, and helical gun launchers