Electromagnetic catapult

Last updated

EMALS.JPG

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 Laplace 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).

Contents

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 maturity technology. Carriers equipped with four steam catapults have been able to use at least one of them at 99.5% of the time. [1] 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." [2] The steam system is massive, inefficient (4–6%), [3] and hard to control. These control problems allow Nimitz-class aircraft carrier 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, [4] 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. [5] 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. [6] [7] A system somewhat similar to EMALS, Westinghouse's electropult, was developed in 1946 but not deployed. [8]

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, [9] instead of the alternating current catapult system that United States developed. [6] [10]

Systems under development

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. [11]

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. [12] Multiple prototypes were spotted by the media in 2012, and aircraft capable of electromagnetic launching were undergoing testing at a Chinese Navy research facility. [13]

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. [14] [15]

China's electromagnetic catapult was installed on its third aircraft carrier Fujian in 2021, becoming the only carrier besides the U.S. Navy Gerald R. Ford-class to deploy this technology. [16] [17] The electromagnetic catapult was also installed on China's Type 076 amphibious assault ship, enabling the class to launch helicopters, unmanned combat aerial vehicles (UCAV), or optionally manned aircraft. [18]

Fujian began sea trials in May 2024. [19] By May 2025, she had completed eight such trials, including test with J-35 fighters and KJ-600. [20] 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, [21] analysts believed the carrier and its air wing were reaching an important milestone. [22]

On 22 September 2025, the Chinese state broadcaster released multiple videos and photos showing the complete catapult launch and recovery (CATOBAR) sequence for Shenyang J-15, along with Shenyang J-35 and Xi'an KJ-600 aircraft on the Fujian, via the ship's electromagnetic catapults. [21] PLA Navy also announced that J-15T, J-35 and KJ-600 were certified for CATOBAR operations, and Fujian had achieved "initial full-deck operational capability", laying the foundation for the subsequent integration with the carrier aviation wing and the carrier strike group. [23]

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. [24]

United States

General Atomics EMALS was designed for and into the Gerald R. Ford-class aircraft carrier. [25] A proposal to retrofit it into Nimitz-class 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." [26]

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. [27] Though, it was initially planned to be imported from foreign firms for INS Vishal, reports as of 2024 suggests, it is being developed indigenously by Bharat Electronics with assistance from private sector companies. The system concept has been demonstrated to senior Indian Navy officials and Minister of Defence. The Navy plans to gain clearance for construction of ground-based full scale model to initiate development. [28]

In August 2024, Research & Development Establishment (Engineers) has developed a scaled-down prototype capable of launching payloads up to 400 kg over a short span of 16 to 18 meters. Two technologies successfully developed for the electromagnetic catapult were 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. [29] [30] [31] [32]

Ships with electromagnetic catapult

United States

China

France

Russia

India

See also

References

  1. ↑ Schank, John. Modernizing the U.S. Aircraft Carrier Fleet, p. 80.
  2. ↑ Doyle, Michael, Douglas Samuel, Thomas Conway, and Robert Klimowski. "Electromagnetic Aircraft Launch System – EMALS". Naval Air Engineering Station Lakehurst. 1 March. p. 1.
  3. ↑ Doyle, Michael, "Electromagnetic Aircraft Launch System – EMALS". p. 1.
  4. ↑ PEO Carriers Public Affairs (15 May 2015). "Navy Announces Successful Test of Electromagnetic Catapult on CVN 78". US Navy.
  5. ↑ "New Ford-class aircraft carrier: 25 percent more flights per day". The Christian Science Monitor . 9 November 2013. Archived from the original on 9 November 2013.
  6. 1 2 "EMALS: Learning to Launch". New England Wire. 4 May 2020.
  7. ↑ Schweber, Bill (11 April 2002). "How It Works". EDN Magazine. Retrieved 7 November 2014.
  8. ↑ Excell, Jon (30 October 2013). "October 1946 – Westinghouse unveils the Electropult". The Engineer. Archived from the original on 7 September 2015. Retrieved 30 June 2017.
  9. ↑ Gady, Franz-Stefan (6 November 2017). "China's New Aircraft Carrier to Use Advanced Jet Launch System". The Diplomat.
  10. ↑ Yeo, Mike (9 November 2017). "China claims breakthrough in electromagnetic launch system for aircraft carrier". Defense News.
  11. ↑ Rohacs, Daniel; Voskuijl, Mark; Rohacs, Jozsef; Schoustra, Rommert-Jan (2013). "Preliminary evaluation of the environmental impact related to aircraft take-off and landings supported with ground based (MAGLEV) power" . Journal of Aerospace Operations. 2 (3–4): 161–180. doi:10.3233/AOP-140040.
  12. ↑ "Chinese aircraft carrier should narrow the gap with its U.S. counterpart". english.peopledaily.com.cn. People's Daily. 18 October 2013. Retrieved 18 October 2013.
  13. ↑ "简氏:中国试飞改进型歼-15 或用于测试电磁弹射器_《参考消息》官方网站". Cankaoxiaoxi.com (in Chinese). Archived from the original on 2 December 2016. Retrieved 30 June 2017.
  14. ↑ "China's Third Aircraft Carrier will be First to use Steam Catapults to Launch Aircraft". yibada. 12 February 2017.
  15. ↑ "China Explores Electromagnetic Carrier Launch System". AIN online. 6 July 2017.
  16. ↑ Sutton, H. I. (15 April 2021). "China's New Aircraft Carrier Is In Same League as US Navy's Ford Class". Naval News. Retrieved 17 June 2022.
  17. ↑ 布藍 (3 August 2020). "【國產航母】003型航母進入最後組裝進程 高清航拍照曝光". 香港01 (in Chinese (Hong Kong)). Retrieved 17 June 2022.
  18. ↑ P. Funaiole, Matthew; Hart, Brian; Powers-Riggs, Aidan; S. Bermudez Jr., Joseph (1 August 2024). "China's Massive Next-Generation Amphibious Assault Ship Takes Shape". Center for Strategic and International Studies.
  19. ↑ Zhao, Ziwen (8 May 2024). "Smooth sailing for China's Fujian aircraft carrier as it finishes first sea trial". South China Morning Post.
  20. ↑ "China's advanced Fujian carrier conducts 'intensive' eighth sea trial". South China Morning Post. 25 May 2025. Retrieved 29 May 2025.
  21. 1 2 Xiao, Josh (22 September 2025). "China Showcases Electromagnetic Carrier Catapult For First Time". Bloomberg News.
  22. ↑ Trevithick, Joseph (1 August 2025). "China Teases First Catapult Launches From Its New Carrier Fujian". The War Zone.
  23. ↑ Zhao, Lei (22 September 2025). "CNS Fujian achieves milestone with electromagnetic launch of advanced Naval aircraft". China Daily.
  24. ↑ "Russia developing new launch catapults for aircraft carriers". TASS. 4 July 2018. Retrieved 14 July 2018.
  25. ↑ "Carrier Launch System Passes Initial Tests". Archived from the original on 28 September 2012. Retrieved 11 September 2018.
  26. ↑ Schank, John. Modernizing the U.S. Aircraft Carrier Fleet: Accelerating CVN 21 Production Versus Mid-Life Refueling. Santa Monica: Rand Corporation, 2005. p. 76.
  27. ↑ "Indian Navy seeks EMALS system for second Vikrant-class aircraft carrier". Naval Technology. 30 May 2013. Archived from the original on 12 August 2013. Retrieved 17 May 2015.
  28. ↑ "India Seeks Indigenous Electromagnetic Aircraft Launch System for Upcoming IAC-III Carrier". India Defence. 7 March 2024. Retrieved 27 April 2024.
  29. ↑ "DRDO Nears EMALS Breakthrough for Mach 6 Aircraft Launches, Seeks Industry Partner for Further Development". Defence.in. 12 September 2024. Retrieved 13 September 2024.
  30. ↑ Singh, Aarav (24 August 2024). "India's EMALS Breakthrough: DRDO and HAL Push the Boundaries of Naval Aviation Technology". PUNE.NEWS. Retrieved 14 September 2024.
  31. ↑ Prasad, Manish (23 August 2024). "Electromagnetic Launch System". X (formerly Twitter). Retrieved 14 September 2024.
  32. ↑ Navy, Indian (21 February 2024). "Maritime Technical Exposition 2024" . Retrieved 15 September 2024.
  33. 1 2 Zhao, Suisheng (2024). "Is Beijing's Long Game on Taiwan about to End? Peaceful Unification, Brinksmanship, and Military Takeover". In Zhao, Suisheng (ed.). The Taiwan Question in Xi Jinping's Era: Beijing's Evolving Taiwan Policy and Taiwan's Internal and External Dynamics. London and New York: Routledge. p. 18. doi:10.4324/9781003521709. ISBN   9781032861661.
  34. ↑ "视频丨满载排水量4万余吨！海军四川舰来了 舷号"51" - 新华网客户端". app.xinhuanet.com. Retrieved 27 December 2024.
This page is based on this Wikipedia article
Text is available under the CC BY-SA 4.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.