Diagnostics and hardware techniques for measuring in-bore pressures from transitioning metal armatures

For new tactical gun systems to have the potential be integrated into future lightweight combat vehicles, mass optimization is a key design feature. In an electromagnetic launcher during normal solid metal armature operation, the magnetic field pressure forces the conducting rails outward, applying an asymmetric load to the bore containment. This loading can be accounted for in the containment design. When a solid armature transitions, a gas pressure is developed, causing additional force to be applied to the insulator and the containment in the insulator direction. This force generates requirements for additional strength in the insulator and bore containment and creates an additional mass penalty. Quantification of transitioning armature pressure allows for optimization of the launcher design. In this paper, we describe the technique used in measuring these in-bore pressures. Detailed are the test setup, hardware, instrumentation, and data acquisition equipment used for the experiments. Additionally, initial testing results of measured pressure are presented here along with some comparisons to theoretical average pressures across the bore area.