First design study of an electrical catapult for unmanned air vehicles in the several hundred kilogram range

The principle of electromagnetic launch remains a permanent subject of military research because of its outstanding advantages. For instance, the acceleration profile is completely under control. The railgun is the first choice to accelerate low masses from some grams to several kilograms up to velocities greater than 1000 m/s. On the contrary, accelerating heavy masses such as combat aircraft leads to quite different solutions, namely to the use of linear induction machines. We have studied the launch of an unmanned air vehicle (UAV) weighing several hundred kilograms up to an initial velocity of 50 m/s with a linear synchronous motor (LSM) capable of replacing chemical boosters or mechanical launchers. This paper presents a basic concept study of a catapult for launching a UAV by means of an LSM. A numerical code has been developed to give the main characteristics (thrust, input power, efficiency, current, mass) of the launch system.