Design and Development of an Electromagnetic Catapult for Life-Saving Projectile

In this article, a kind of electromagnetic coil catapult for life-saving projectile (LSP) is designed and developed for water rescue. We adopted the single-stage coil launcher scheme to save costs and improve reliability. Two launch modes, armature-load integrated launch (ALIL) and armature-load separated launch (ALSL), are compared by simulation. In the ALIL mode, LSP and armature are integrated together. The LSP will be decelerated due to the armature drag effect after being launched to the maximum speed. In the ALSL mode, the armature will separate from the LSP after reaching the maximum speed due to the electromagnetic drag force. The LSP will fly out of the catapult at peak speed due to inertia, which will improve the muzzle speed of the LSP compared with the ALIL. Further analysis shows that in the ALSL mode, reducing the initial power supply voltage, reducing the armature-load mass ratio, and increasing the number of coil turns are beneficial to the armature recovery. The armature recovery method can make the armature reusable. A set of electromagnetic catapult devices for LSP is developed. Finally, armature launch and LSP launch tests are carried out. It is proven that the simulation and test results are consistent. Under the full voltage state, the catapult can make the LSP obtain a muzzle speed of 52 m/s, and the throw distance exceeds 180 m. The armature can be recovered and reused. Experiments verify the feasibility of the electromagnetic catapult for LSP, which has good application value.