Electromagnetic catapult

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Diagram of the launch system

An electromagnetic catapult, also known as the electromagnetic aircraft launch system (EMALS) when specifically referring to the system used by the United States Navy, is a type of aircraft catapult that uses a linear induction motor system, rather than the single-acting pneumatic cylinder (piston) system in conventional steam catapults. The system is used on aircraft carriers to launch fixed-wing carrier-based aircraft, employing the principles of electromagnetism and Lorentz force to accelerate and assist their takeoff from the shorter flight deck runways. Currently, only the United States and China have successfully developed electromagnetic catapults, which are installed on the Gerald R. Ford-class aircraft carriers (currently only the lead ship CVN-78 being operational), the Type 003 aircraft carrier Fujian and the upcoming Type 076 amphibious assault ship Sichuan (51).

Electromagnetic catapults have several advantages over their older, superheated steam-based counterparts. Electromagnetic operation recharges via electric energy and thus much faster than the pressurization process of steam systems, and does not suffer power loss with distance (where volume expansion within the steam catapult cylinder proportionally reduces pressure), temperature changes (which directly affects pressure according to ideal gas law) and leakages (which matters in pressure vessels but is irrelevant in electromagnet systems). The electromagnetic acceleration is also more uniform (unlike steam acceleration, whose accelerative force is always highest at the very initial phase, thus creating a distinct "jolt"), therefore reducing the stress upon the airframe considerably, resulting in increased safety and endurance as well as lower maintenance costs for the aircraft. Electromagnetic catapults are configurable and can assigned varying power outputs to different sections, thus allowing them to tailor optimal acceleration to individual aircraft according to different payload weights and takeoff behaviours. Electromagnetic systems are more compact and also weigh less, have fewer linkage components and thus are expected to cost less and require less maintenance, and also require no fresh water boiling for their operation, thus reducing the need for energy-intensive desalination and sophisticated piping systems used in steam catapults, which take up significantly more space below the flight deck.

History

Developed in the 1950s, steam catapults have a proven history of reliability due to it being a mature technology. Carriers equipped with four steam catapults have been able to use at least one of them at 99.5% of the time.<ref>Schank, John. Modernizing the U.S. Aircraft Carrier Fleet, p. 80.</ref> These have, however, several drawbacks. One group of Navy engineers wrote: "The foremost deficiency is that the catapult operates without feedback control. With no feedback, there often occurs large transients in tow forces that can damage or reduce the life of the airframe."<ref>Doyle, Michael, Douglas Samuel, Thomas Conway, and Robert Klimowski. "Electromagnetic Aircraft Launch System – EMALS". Naval Air Engineering Station Lakehurst. 1 March. p. 1.</ref> The steam system is massive, inefficient (4–6%),<ref>Doyle, Michael, "Electromagnetic Aircraft Launch System – EMALS". p. 1.</ref> and hard to control. These control problems allow Template:Sclass steam-powered catapults to launch heavy aircraft, but not aircraft as light as many unmanned aerial vehicles.

General Atomics Electromagnetic Systems (GA-EMS) developed the first operational modern electromagnetic catapult,<ref>Template:Cite web</ref> named Electromagnetic Aircraft Launch System (EMALS), for the United States Navy. The system was installed on USS Gerald R. Ford aircraft carrier, replacing traditional steam catapults. This innovation eliminates the traditional requirement to generate and store steam, freeing up considerable area below deck. With the EMALS, Gerald R. Ford can accomplish 25% more aircraft launches per day than the Nimitz class and requires 25% fewer crew members.<ref>Template:Cite web</ref> The EMALS uses a linear induction motor (LIM), which uses alternating current (AC) to generate magnetic fields that propel a carriage along a track to launch the aircraft.<ref name="new_emals">Template:Cite web</ref><ref name=howitworks>Template:Cite news</ref> A system somewhat similar to EMALS, Westinghouse's electropult, was developed in 1946 but not deployed.<ref>Template:Cite web</ref>

China developed an electromagnetic catapult system in the 2000s for aircraft carriers, but with a different technical approach. Chinese adopted a medium-voltage, direct current (DC) power transmission system,<ref>Template:Cite web</ref> instead of the alternating current catapult system that United States developed.<ref name="new_emals" /><ref>Template:Cite web</ref> The system first installed on the Chinese aircraft carrier Fujian. The ship is the first aircraft carrier in the world to successfully launch a fifth-generation fighter using the electromagnetic catapult system.<ref>Template:Cite news</ref>

The concept of a ground carriage is intended for civilian use and takes the idea of an electromagnetic aircraft launch system one step further, with the entire landing gear remaining on the runway for both takeoff and landing.<ref>Template:Cite journal</ref>

Operational systems

China

Rear Admiral Yin Zhuo of the Chinese Navy said in 2013 that China's Type 003 next aircraft carrier would also have an electromagnetic aircraft launch system.<ref>Template:Cite web</ref> Multiple prototypes were spotted by the media in 2012, and aircraft capable of electromagnetic launching were undergoing testing at a Chinese Navy research facility.<ref>Template:Cite web</ref>

According to a report in July 2017, construction of Type 003 was rescheduled in order to choose between a steam or electromagnetic catapult, and the latest competition results showed electromagnetic launchers would be used on Type 003.<ref>Template:Cite web</ref><ref name="ainonline_1">Template:Cite web</ref>

China's electromagnetic catapult was installed on its third aircraft carrier Fujian in 2021, becoming the only carrier besides the U.S. Navy's Gerald R. Ford-class to deploy this technology.<ref>Template:Cite web</ref><ref>Template:Cite web</ref> The electromagnetic catapult is also installed on the upcoming Type 076 amphibious assault ship, enabling the ship to launch unmanned combat aerial vehicles (UCAV) and possibly manned carrier-based aircraft.<ref name="csis_2408">Template:Cite web</ref>

Fujian began sea trials in May 2024.<ref>Template:Cite web</ref> By May 2025, she had completed eight sea trials, including takeoff and landing tests with J-15T heavy multirole fighters, J-35 stealth fighters and KJ-600 AEW&C aircraft.<ref>Template:Cite web</ref> In August 2025, Chinese media released a video teasing the launch of the Shenyang J-15T variant on the Fujian with electromagnetic catapults. Though no complete sequence of the take-off and recovery was shown,<ref name="bloomberg_250922" /> analysts believed the carrier and its air wing were reaching an important milestone.<ref>Template:Cite web</ref>

On 22 September 2025, the Chinese state broadcaster released multiple videos and photos — suspected to be from a sea trial earlier in the year — showing the complete catapult launch and arrestor recovery (CATOBAR) sequence for J-15T, J-35 and KJ-600 aircraft on the Fujian.<ref name="bloomberg_250922">Template:Cite web</ref> PLA Navy also announced that Fujian had achieved "initial full-deck operational capability", laying the foundation for the subsequent integration with the carrier aviation wing and the carrier battle group.<ref>Template:Cite web</ref> The EMALS of Fujian is powered by a Medium-Voltage Direct Current (MVDC) integrated power system—the first of its kind in the world, which is more reliable compared to the AC-based EMLAS of the Gerald R. Ford-class.<ref name="China’s J-35 Electromagnetic Launch: Not a Catch-Up to the US, But an Overtake">Template:Cite web</ref>

The planned Type 004 aircraft carrier, a suspected nuclear-powered supercarrier<ref name=national-interest-may-17>Template:Cite web</ref><ref name="foxtrotalpha">Template:Cite web</ref> currently in construction at the Dalian Shipyard since 2024,<ref>Template:Cite web</ref> will almost certainly be also equipped with electromagnetic catapults due to the success of the system on Fujian.<ref name="ArmyRecognition2025">Template:Citeweb</ref>

United States

General Atomics EMALS was designed for and into the Template:Sclass.<ref>Template:Cite web</ref> A proposal to retrofit it into Template:Sclass carriers was rejected. John Schank said: "The biggest problems facing the Nimitz class are the limited electrical power generation capability and the upgrade-driven increase in ship weight and erosion of the center-of-gravity margin needed to maintain ship stability."<ref>Schank, John. Modernizing the U.S. Aircraft Carrier Fleet: Accelerating CVN 21 Production Versus Mid-Life Refueling. Santa Monica: Rand Corporation, 2005. p. 76.</ref>

On 28 July 2017, Lt. Cmdr. Jamie "Coach" Struck of Air Test and Evaluation Squadron 23 (VX-23) performed the first EMALS catapult launch from USS Gerald R. Ford (CVN-78) in an F/A-18F Super Hornet.<ref>Template:Cite web</ref>

By April 2021, 8,000 launch/recovery cycles had been performed with the EMALS and the AAG arrestor system aboard USS Gerald R. Ford. The USN also stated that the great majority of these cycles had occurred in the prior 18 months and that 351 pilots had completed training on the EMALS/AAG.<ref>Template:Cite web</ref>

The Ford was certified for flight deck operations using the EMALS in 2022.<ref>Template:Cite web</ref><ref>Template:Cite web</ref>

Systems under development

India

In 2013, the Indian Navy reportedly sought to equip the aircraft carrier with electromagnetic catapult, which could enable the launching of larger aircraft as well as unmanned combat aerial vehicles.<ref name="shukla1">Template:Cite news</ref><ref name="navaltechinses">Template:Cite web</ref>

As per August 2024 media report, Research & Development Establishment (Engineers) has developed a scaled-down technology demonstrator, known as Electro-Magnetic Launch System (EMLS) capable of launching payloads up to Template:Convert (equivalent to an unmanned aerial vehicle) over a short span of Template:Convert. The demonstrator is being further developed into a full-scale EMLS for application on future aircraft carriers.<ref>Template:Cite web</ref> Industry partners were reportedly being sought to develop the full-scale system to launch platforms weighing up to 40 tons can be handled by the system. Two crucial technologies including Pulse Power (which controls the electromagnetic catapult's power requirements and ensures precise and dependable launches) and Linear Electric Machine (which produces the electromagnetic force required to launch aircraft) were successfully developed.<ref>Template:Cite web</ref><ref>Template:Cite tweet</ref><ref>Template:Cite tweet</ref>

Russia

Russia's United Shipbuilding Corporation (USC) is developing new launch systems for warplanes based on aircraft carriers, USC President Alexei Rakhmanov told TASS on 4 July 2018.<ref>Template:Cite news</ref>

Ships with electromagnetic catapult

United States

China

France

Russia

India

See also

References

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