How EMALS and Steam Catapults Differ on Aircraft Carriers
Aircraft carriers use catapults to accelerate heavily loaded aircraft to takeoff speed within the length of a flight deck. The two systems at the center of the Navy’s current debate are the traditional steam catapult and the newer Electromagnetic Aircraft Launch System, or EMALS.
How steam catapults work
Steam catapults use high-pressure steam to drive a piston beneath the flight deck. The piston is connected to a shuttle that grips an aircraft’s launch bar and pulls the plane forward. Valves and control systems regulate the force so the catapult can launch different aircraft safely.
The U.S. Navy used steam catapults for more than half a century, and the technology remains deployed on Nimitz-class carriers. NAVAIR describes steam as a mature launching technology, but it requires extensive piping, machinery, water, maintenance, and crew support. (navair.navy.mil)
How EMALS works
EMALS replaces the steam piston with a linear motor. Energy is stored in rotating machinery, converted into electrical power, and released through a moving electromagnetic field that accelerates the launch shuttle along the deck.
According to Naval Air Systems Command, EMALS offers more precise control over launch speed, smoother acceleration, lower weight and volume, and the ability to handle a wider range of aircraft. That range matters as carriers add lighter unmanned aircraft alongside large manned fighters. (navair.navy.mil)
The system was designed for the Ford-class carrier, beginning with USS Gerald R. Ford. The Navy has conducted shipboard testing and operational launches using EMALS, including thousands of launches during Ford’s first full-length deployment, according to reporting based on Pentagon testing data. (navy.mil)
What a return to steam would involve
A recent presidential memorandum directs the Defense Department and Navy to develop plans to replace EMALS and related electromagnetic weapons elevators with steam and hydraulic systems on a future Ford-class carrier, beginning with CVN-81, USS Doris Miller. That is different from immediately removing EMALS from every carrier already in service. The exact schedule, cost, and final engineering design remain subject to the required review.
The change would be substantial because Ford-class ships were designed around electrical systems and do not simply contain unused steam-catapult infrastructure. General Atomics, EMALS’s developer, has warned that changing the design after production has begun would create cost, schedule, and integration risks. (apnews.com)
The central engineering trade-off is therefore not simply “old versus new.” Steam offers familiarity and a long operating history, while EMALS is intended to reduce manpower and expand the launch envelope. A decision to switch systems would affect carrier construction, aircraft compatibility, maintenance training, shipyard schedules, and the Navy’s future use of unmanned aviation.