Electromagnetic catapult

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For the system under development by the United States, see Electromagnetic Aircraft Launch System.

An illustration of the EMALS

An electromagnetic catapult, also called EMALS ("electromagnetic aircraft launch system") after the specific US system, is a type of aircraft launching system. Currently, only the United States and China have successfully developed it, and it is installed on the Gerald R. Ford-class aircraft carriers and the Chinese aircraft carrier Fujian. The system launches carrier-based aircraft by means of a catapult employing a linear induction motor rather than the conventional steam piston.

Electromagnetic catapults have several advantages over their steam-based counterparts. Because the rate of aircraft acceleration is more uniform (and is configurable), stress on the airframe is reduced considerably, resulting in increased safety and endurance and lower maintenance costs for the aircraft. Electromagnetic systems also weigh less, are expected to cost less and require less maintenance, and can launch both heavier and lighter aircraft than steam catapults. They also take up less space below the flight deck and require no fresh water for their operation, thus reducing the need for energy-intensive desalination.

History[edit]

Developed in the 1950s, steam catapults have proven exceptionally reliable. 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[edit]

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[edit]

Rear Admiral Yin Zhuo of the Chinese Navy has said that China's next aircraft carrier will also have an electromagnetic aircraft launch system.[12] Multiple prototypes have been spotted by the media in 2012, and aircraft capable of electromagnetic launching are undergoing testing at a Chinese Navy research facility.[13]

According to a report in July 2017, the construction of the Type 003 aircraft carrier has been rescheduled in order to choose between a steam or electromagnetic catapult and the latest competition results shows that the electromagnetic launchers will be used in the Type 003 aircraft carrier.[14][15]

China's military chief claims a breakthrough in electromagnetic launch systems for aircraft carriers has been made, and will utilize such a system in the third aircraft carrier that China will build after Type 002. The launch system is powered by fossil fuel via generators and capacitors.[16][17][18] The design on the Type 003 carrier is being led by Rear Admiral Ma Weiming.

China's electromagnetic catapult has been installed on its third aircraft carrier, the aircraft carrier Fujian.[19][20]

Russia[edit]

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.[21]

United States[edit]

General Atomics EMALS was designed for and into the Gerald R. Ford-class aircraft carrier.[22] 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."[23]

Ships with electromagnetic catapult[edit]

United States[edit]

Gerald R. Ford-class aircraft carrier (in service)

China[edit]

Chinese aircraft carrier Fujian (outfitting)

Type 076 landing helicopter dock (planned)[24]

Type 004 aircraft carrier (planned)

France[edit]

Future French aircraft carrier (planned)

Russia[edit]

Project 23000E (proposed)

See also[edit]

References[edit]

  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. ^ a b "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. ^ "Breakthrough to power most advanced jet launch system on China's second home-grown aircraft carrier". SCMP. 1 November 2017.
  17. ^ "China's New Aircraft Carrier to Use Advanced Jet Launch System". The Diplomat. 1 November 2017.
  18. ^ "China claims to have developed conventionally powered electromagnetic catapult". Jane's 360. 2 November 2017. Archived from the original on 11 November 2017. Retrieved 16 November 2017.
  19. ^ 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.
  20. ^ 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.
  21. ^ "Russia developing new launch catapults for aircraft carriers". TASS. 4 July 2018. Retrieved 14 July 2018.
  22. ^ "Carrier Launch System Passes Initial Tests". Archived from the original on 28 September 2012. Retrieved 11 September 2018.
  23. ^ Schank, John. Modernizing the U.S. Aircraft Carrier Fleet: Accelerating CVN 21 Production Versus Mid-Life Refueling. Santa Monica: Rand Corporation, 2005. p. 76.
  24. ^ Joe, Rick. "Whispers of 076, China's Drone Carrying Assault Carrier". thediplomat.com. Retrieved 17 June 2022.

External links[edit]

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