Progress on developing the "magnetic obturator," a novel railgun armature

The "magnetic obturator" is an armature concept developed by IAP Research in the late 1980s. Advantages of the magnetic obturator include lower mass than conventional "C-type" railgun armatures (approaching the theoretical minimum mass), compatibility with mid-drive sabots, and the potential for nontransitioning operation. The Institute for Advanced Technology (IAT) at The University of Texas at Austin began testing magnetic obturators in 1997. Our tests showed that magnetic obturators can operate very well, but not yet as reliably as C-type armatures. This paper discusses experiments conducted to understand and resolve several recurrent problems that include difficulties associated with start-up, high contact pressures leading to local yielding of copper rails, and susceptibility to develop intermittent arcing contact before transition. This paper reports our progress in addressing these three areas and presents recommendations for further research.