Design and simulation of an electromagnetic aircraft launch system

Electric actuators are increasingly supplanting or replacing mechanical actuators (steam or hydraulic) in ship systems. This trend started in commercial shipping, especially cruise ships, and there is now a move to adopt the benefits in military systems. This paper describes the design and analysis of a very large actuator for a military ship system an Electro-Magnetic Aircraft Launching System, or EMALS, which will accelerate aircraft to flight speeds in very short distances. The aim is to replace the steam catapult currently used on aircraft carriers with a linear electric motor. The entire system should fit within the confines of the existing steam catapult. The advantages of such a system are increased operational availability, lower airframe stress due to programmable acceleration profiles, and reduced maintenance (and hence reduced manning). The goal of the study described here is to investigate the many feasible solutions and to use simulations to compare their performance. This paper reports on the initial stages of the work, which uses the Virtual Test Bed (VTB) as the simulation and virtual prototyping environment. This yields substantial side benefits because the EMALS research program represents a meaningful test case for the VTB itself. Models of the different parts of the systems are being built up from the specifications and the characteristics required by the US Navy, and will be refined with increasing detail as the project is developed.