Comparison of Salvo Performance Between Stacked and Paralleled Double-Projectile Railguns

Multiprojectile railguns are novel electromagnetic launchers because of their ability to launch synchronously many projectiles per shot. Salvo performance, which means that all projectiles can leave the muzzle at the same time and hit the target simultaneously, is very important to increase lethality. However, several armature factors caused the asymmetric conditions to reduce the performance, such as different initial position, friction, and mass. To acquire a better salvo performance, we proposed and compared two types of double-projectile railgun structures, in which rail pairs are stacked and paralleled, respectively. With different armature positions, a 3-D harmonic eddy current field analysis is conducted to calculate the self- and mutual-inductance gradients. The results show that the values of the mutual-inductance gradient of the two pairs of rails (M´₁₂, M´₂₁) are different (M´₁₂ ≠ M´₂₁). The circuit simulation was conducted to verify the influence of different initial position, friction, and mass in the launching process. It is found that the armature falling behind always gets larger propulsive force than the front one for stacked railguns, but the situation is opposite for paralleled railguns. Finally, two small-size prototypes are designed and manufactured to compare their salvo performance. The results indicate that the salvo performance of the stacked railgun is better than that of the paralleled railgun. Therefore, this configuration should be considered in the design of a multiprojectile railgun.