EMALS

Electromagnetic Aircraft Launch System (EMALS) is a complete launch system designed to replace the existing steam catapult currently being used on aircraft carriers. The USS Gerald R. Ford, the first ship of the CVN-21 Future Aircraft Carrier Class, will use electromagnetic launch systems.

EMALS provides:

  • Reduced Manning Workload
  • Reduced Thermal Signature
  • Increased Launch Availability
  • Reduced Topside Weight
  • Reduced Installed Volume
  • Launch capability for unmanned aerial vehicles

The EMALS system is a multimegawatt electric power system involving generators, energy storage, power conversion, a 100,000 hp electric motor, and an advanced technology closed loop control system with diagnostic health monitoring. In addition to building the power conversion and motor equipment, GA provides the power system integration and logistics support for this state-of-the-art power electronic system. During the current SDD phase, GA will design, build, and operate a fully integrated EMALS system at the SDD test site in Lakehurst, N.J.


EMALS linear motors under construction at GA’s plant in Tupelo, Miss.

EMALS SDD test site at the Naval Air Engineering Center in Lakehurst, N.J.
EMALS dead-load testing

The EMALS consists of six major subsystems:

 

 

 

Prime Power Interface
This system provides the interconnect with the ship's electrical distribution system and delivers power to drive the energy storage generators.

Launch Motor
Developed in a linear induction motor configuration, the launch motor is a compact, modular, integrated flight-deck structure that converts electrical current into the electromagnetic forces to accelerate the aircraft along the launch stroke. The motor design will tolerate the range of conditions experienced in the flight-deck environment and operating scenarios. A simple moving shuttle will interface with the aircraft in the same manner as the existing catapults. After the aircraft launches, the electric current in the motor will reverse to brake the shuttle to a complete halt without the use of a water brake.

Power Conversion Electronics
The power conversion electronics derive power from the energy stored and convert this power to a traveling wave of energy of the appropriate voltage and current to drive the shuttle along the launch stroke. Based on solid-state technology GA uses in its line of commercial power equipment, the power electronics are packaged as compact modules in cabinets that are located below deck.

Launch Control
The EMALS uses a state-of-the-art system to control the current into the launch motor in real time. More precise endspeeds are achievable over a wider range of aircraft types and weights over those of steam catapults. The smoother acceleration may extend the lifetime of the aircraft. High reliability and a system architecture with inherent redundancy is achieved by use of commercial off-the-shelf components where possible. Modularity is emphasized to ease installation and maintenance — important factors in life cycle planning.

Energy Storage
The required energy for a launch is drawn from the energy storage devices during each two- to three-second launch. The energy storage devices are recharged from ship’s power between launches. In March 2008, the program celebrated a milestone with the successful completion of factory acceptance testing of the motor generator component of the EMALS energy storage subsystem (ESS). Four additional ESS systems will be built to support development testing at the NAES Lakehurst, N.J., culminating in aircraft launches at the test site.

Energy Distribution System
This system delivers the energy from the power conversion system to the launch motor and comprises cables, disconnects, and terminations.