Flexible Sliding Contact Between Armature and Rails for the Practical Launcher Model

Hypervelocity sliding contact between armature and rails remains a key technology for electromagnetic railgun performance. A U-shaped aluminum armature and two copper alloy rails are widely adopted for those simple railguns nowadays. The advantages of U-shaped aluminum armature and the defects of the corresponding sliding contact were analyzed systematically for simple railgun performance in this paper. Meanwhile, a practical launcher model with complex structure was proposed in 2012. The complex railgun has an opportunity to provide a flexible sliding contact between armature and rails. The flexible sliding contact concept was proposed, and the advantages of flexible sliding contact were analyzed and summarized, which could weaken or eliminate such sliding contact problems for simple railgun as wear and abrasion, transition, discharge and ablation, gouging, velocity skin effect, and grooving. In other words, the flexible sliding contact between armature and rails for practical launcher has much superiority over the rigid and electromagnetic-controlled sliding contact for simple railgun. After the prototypical launcher and relevant armature were fabricated, the flexible sliding contact test and the primary launch experiment were performed. The actual contact interfaces between each armature unit and the relevant rail were lengthened and moved forward from the ends when the contact force was strengthened. The proper contact interface with a length of about 50-60 mm was located in the middle part when the minimum pushing force by a hydraulic machine was recorded about 5.6 kN. A tentative launching experiment with low power was carried out, in which the peak current got 94.67 kA and the corresponding electromagnetic driving force rose to about 32.36 kN.