View source for Aircraft catapult

{{short description|Device used to launch aircraft from ships}}
[[File:USS Saratoga (CVA-60), F-14 on catapult.jpg|thumb|[[Grumman F-14 Tomcat|F-14 Tomcat]] preparing to connect to a steam catapult on {{USS|Saratoga|CV-60|6}}.]]
An '''aircraft catapult''' is a device used to help [[fixed-wing aircraft]] reach [[V speeds#Regulatory V-speeds|liftoff speed]] (V<sub>LOF</sub>) faster during [[takeoff]], typically when trying to take off from a very short [[runway]], as otherwise the [[aircraft engine]]s alone cannot [[accelerate]] to sufficient [[airspeed]] quickly enough for the [[wing]]s to generate the [[lift (force)|lift]] needed to sustain [[flight]]. Launching via catapults enables aircraft that typically are only capable of [[CTOL|conventional takeoff]]s, especially heavier aircraft with significant [[payload]]s, to perform [[short takeoff and landing|short takeoff]]s from the roll distances of [[light aircraft]]. Catapults are usually used on the [[deck (ship)|deck]] of a [[ship]] — such as the [[flight deck]] of an [[aircraft carrier]] —  as a form of [[assisted takeoff]] for [[navalised aircraft]], but can also be installed on land-based runways, although this is rare.

The catapult system used on aircraft carriers consists of a straight track or slot built into the flight deck, on top of which is a [[sliding (motion)|sliding]] piece called a ''shuttle'', which protrudes above the deck and is hooked onto the [[landing gear|nose gear]] of the aircraft; or in some cases a [[wire rope]] called a ''[[#Bridle catchers|catapult bridle]]'' is attached between the aircraft and the catapult shuttle. When launching, the shuttle is driven forward by [[force]] mechanisms within the track system, "hurling out" the aircraft and imparting an additional [[propulsion]] on top of the aircraft's own engine [[thrust]] to help it accelerate. Other forms of catapult have been used historically, such as mounting a launching cart holding a [[seaplane]] on a long girder-built structure mounted on the deck of a [[warship]] or [[merchant ship]], but most catapult systems share a similar sliding track concept.

Historically it was most common for [[seaplane]]s (which have [[float (nautical)|pontoon]]s instead of [[landing gear]]s and thus cannot utilize runways) to be catapulted from ships onto nearby water for takeoff, allowing them to conduct [[aerial reconnaissance]] missions and be [[crane (machine)|crane]]-hoisted back on board during retrieval, although by the late [[First World War]] their roles are largely supplanted by the more versatile [[biplane]]s that can take off and land on carrier decks unassisted. During the [[Second World War]] before the advent of [[escort carrier]]s, [[monoplane]] [[fighter aircraft]] (notably the [[Hawker Hurricane]]) would sometimes be catapulted from "[[CAM ship|catapult-equipped merchant]]" (CAM) vessels for one-way [[sortie]]s to repel enemy aircraft harassing [[shipping lane]]s, forcing the returning pilot to either divert to a land-based [[airstrip]], jump out by [[parachute]], or [[water landing|ditch]] in the water near the [[convoy]] and wait for rescue. By the time [[fleet carrier]]s became the norm in WW2, catapult launches have become largely unnecessary and [[carrier-based aircraft|carrier-based]] [[fighter-bomber]]s would routinely perform self-powered takeoffs and landings off and onto carrier decks, especially during the [[Pacific War]] between the [[United States]] and the [[Empire of Japan]]. However, escalating [[arms race]]s during the [[Cold War]] accelerated the adoption of the heavier [[jet aircraft]] for naval operations, thus motivating the development of new catapult systems, especially after the popularization of [[angled flight deck]]s further limited the practical distance available as takeoff runways. Nowadays, jet aircraft can launch from aircraft carriers via either catapults or [[ski-jump (aviation)|ski-jump deck]], and perform [[optical landing system|optics-assisted]] [[landing]] onto the same ship with help from decelerative [[arresting gear]]s.

Different means have been used to propel the catapult, such as [[weight]] and [[derrick]], [[gunpowder]], [[flywheel]], [[compressed air]], [[hydraulic]], [[steam power]], and [[solid-propellant rocket|solid fuel rocket]] boosters. Since the second half of the [[20th century]], [[steam catapult]]s have been the mainstay form of aircraft carrier catapults, especially on the [[nuclear marine propulsion|nuclear-powered]] {{sclass|Nimitz|aircraft carrier|0}} [[supercarrier]]s, and is the core component of the [[catapult-assisted takeoff but arrested recovery]] (CATOBAR) system. Into the [[21st century]], [[General Atomics]] has developed an [[AC motor|alternating current]] [[linear motor]]-based [[electromagnetic catapult]] system called the [[Electromagnetic Aircraft Launch System]] (EMALS), which is installed on the [[United States Navy]]'s new {{sclass|Gerald R. Ford|aircraft carrier|2}}s. A [[DC motor|direct current]]-based electromagnetic catapult has also been developed by the [[People's Republic of China]] for the [[People's Liberation Army Navy]]'s [[Type 003 aircraft carrier]] {{ship|Chinese aircraft carrier|Fujian||2}}, as well as the upcoming [[Type 076 amphibious assault ship]] {{ship|Chinese landing helicopter dock|Sichuan||2}} (currently [[fitting out]]) and [[Type 004 aircraft carrier]]s (in-construction).

==History==

===First recorded flight using a catapult===
[[Image:Langley1903.jpg|thumb|[[Samuel Langley]]'s catapult, houseboat and unsuccessful man-carrying [[Langley Aerodrome|Aerodrome]] (1903)|left]]

[[Aviation pioneers|Aviation pioneer]] and [[Smithsonian Institution|Smithsonian]] Secretary [[Samuel Langley]] used a spring-operated catapult to launch his successful flying models and his failed [[Langley Aerodrome|Aerodrome]] of 1903.{{sfn|McFarland|1997||p=[https://archive.org/details/concisehistoryof0000mcfa/page/2 2]}} Likewise the [[Wright Brothers]] beginning in 1904 used a weight and derrick styled catapult to assist their early aircraft with a takeoff in a limited distance.{{sfn|Chant|Campbell|2013|p=289}}

On 31 July 1912, [[Theodore Gordon Ellyson]] became the first person to be launched from a U.S. Navy catapult system. The Navy had been perfecting a compressed-air catapult system and mounted it on the Santee Dock in [[Annapolis, Maryland]]. The first attempt nearly killed Lieutenant Ellyson when the plane left the ramp with its nose pointing upward and it caught a crosswind, pushing the plane into the water. Ellyson was able to escape from the wreckage unhurt. On 12 November 1912, Lt. Ellyson made history as the Navy's first successful catapult launch, from a stationary coal barge. On 5 November 1915, Lieutenant Commander [[Henry C. Mustin (1874–1923)|Henry C. Mustin]] made the first catapult launch from a ship underway.{{sfn|Skerrett|1916}}

===Application timeline===

{|class="wikitable sortable"  style="font-size: 88%;"
|- 
!Feature !! First seen !! First demonstrated on !! First commissioned carrier !! Entry into service !! Notes
|-
|Naval catapult || 1915 || {{USS|North Carolina|ACR-12|6}} || USS ''Langley'' – compressed air<br />  {{USS|Lexington|CV-2|6}} – fly wheel<br />{{HMS|Courageous|50|6}} – hydraulic|| 1922<br />1927<br />1934 || Lt. Cmdr. Henry Mustin made the first successful launch on November 5, 1915,
|-
|Steam catapult || 1950 || {{HMS|Perseus|R51|6}} || {{USS|Hancock|CVA-19|6}} || 1954 || added to ''Hancock'' during her 1953 [[SCB-27]]C refit.
|-
|[[Electromagnetic catapult]] || 2010 || [[Lakehurst Maxfield Field]] || {{USS|Gerald R. Ford}} ||  2017 || [[General Atomics]] [[Electromagnetic Aircraft Launch System|EMALS]]
|-
|}

===Interwar and World War II===
[[Image:HMS Bermuda aircraft.jpg|thumb|A [[Supermarine Walrus]] being launched from the catapult of {{HMS|Bermuda|52|6}} (1943)]]
The US Navy experimented with other power sources and models, including catapults that utilized gunpowder and flywheel variations. On 14 December 1924, a Martin MO-1 observation plane flown by Lt. L. C. Hayden was launched from {{USS|Langley|CV-1|6}} using a catapult powered by gunpowder. Following this launch, this method was used aboard both [[cruiser]]s and [[battleship]]s.<ref name=":0">{{Cite web|title = Launch and Recovery: From Flywheels to Magnets|url = http://navalaviationnews.navylive.dodlive.mil/2013/08/05/launch-and-recovery-from-flywheels-to-magnets/|website = navalaviationnews.navylive.dodlive.mil|access-date = 2015-11-24|url-status = live|archive-url = https://web.archive.org/web/20151125044442/http://navalaviationnews.navylive.dodlive.mil/2013/08/05/launch-and-recovery-from-flywheels-to-magnets/|archive-date = 2015-11-25}} {{PD-notice}}</ref>

By 1929, the German ocean liners [[SS Bremen (1928)|''SS Bremen'']] and [[SS Europa (1928)|''Europa'']] had been fitted with compressed-air catapults designed by the [[Heinkel]] aviation firm of Rostock,<ref>{{cite web |url=http://histaviation.com/heinkel_catapult_on_the_bremen.html |title=The Heinkel Catapult on the S.S. BREMEN |author=<!--Not stated--> |date=August 3, 1929 |website=histaviation.com |access-date=July 13, 2017 |quote=THE HEINKEL K2 catapult installed upon the North German Lloyd liner "Bremen," which figured prominently in the establishment of the recent trans-Atlantic mail record, is the result of two years of experimentation and development by Dr. Ernst Heinkel, its designer.}}</ref> with further work with catapult air mail [[Dornier Do J#South Atlantic air mail|across the South Atlantic Ocean]], being undertaken during the first half of the 1930s, with [[Dornier Do J|Dornier ''Wal'']] twin-engined flying boats.

Up to and during [[World War II]], most catapults on aircraft carriers were hydraulic. United States Navy catapults on surface warships, however, were operated with explosive charges similar to those used for {{convert|5|inch|mm|order=flip|adj=on|sp=us|abbr=off}} guns. Some carriers were completed before and during World War II with catapults on the hangar deck that fired [[List of ship directions|athwartships]], but they were unpopular because of their short run, low clearance of the hangar decks, inability to add the ship's forward speed to the aircraft's airspeed for takeoff, and lower clearance from the water (conditions which afforded [[Aviator|pilot]]s far less margin for error in the first moments of flight). They were mostly used for experimental purposes, and their use was entirely discontinued during the latter half of the war.<ref name=":0" />[[File:Hawker Hurricane launched from CAM ship c1941.jpg|thumb|Test launch of a Hurricane using the rocket-catapult of a CAM ship, [[Greenock]], Scotland, 31 May 1941|left]]

Many naval vessels apart from aircraft carriers carried float planes, seaplanes or amphibians for reconnaissance and spotting. They were catapult-launched and landed on the sea alongside for recovery by crane. Additionally, the concept of [[submarine aircraft carrier]]s was developed by multiple nations during the interwar period, and through until WW2 and beyond, wherein a submarine would launch a small number of floatplanes for offensive operations or artillery spotting, to be recovered by the submarine once the aircraft has landed. The first launch off a [[Royal Navy]] battlecruiser was from {{HMAS|Australia|1911|6}} on 8 March 1918. Subsequently, many Royal Navy ships carried a catapult and from one to four aircraft; battleships or battlecruisers like {{HMS|Prince of Wales|53|6}} carried four aircraft and {{HMS|Rodney|29|6}} carried two, while smaller warships like the cruiser {{HMNZS|Leander}} carried one. The aircraft carried were the [[Fairey Seafox]] or [[Supermarine Walrus]]. Some like {{HMS|Nelson|28|6}} did not use a catapult, and the aircraft was lowered onto the sea for takeoff. Some had their aircraft and catapult removed during World War II e.g. {{HMS|Duke of York|17|6}}, or before ({{HMS|Ramillies|07|6}}).
[[File:Phyrexian - Marina militare 012.jpg|thumb|An [[IMAM Ro.43]] floatplane catapulted by a [[Regia Marina|RM]] cruiser in the early 1940s]]
During World War II a number of ships were fitted with rocket-driven catapults, first the [[fighter catapult ship]]s of the Royal Navy, then [[armed merchantmen]] known as [[CAM ship]]s from "catapult armed merchantmen". These were used for convoy escort duties to drive off enemy reconnaissance bombers. CAM ships carried a [[Hawker Hurricane variants#Sea Hurricanes|Hawker Sea Hurricane 1A]],{{efn-lr|The Mk 1A Sea Hurricane was a simple conversion of battle-weary Hurricanes, in the expectation that they would be lost after one flight. There was no strengthening of the undercarriage for landing, merely the attachment points for the catapult launch.}} dubbed a "Hurricat" or "Catafighter", and the pilot bailed out unless he could fly to land.<ref>{{Cite web|title = HMS Ariguani aircraft carrier profile. Aircraft Carrier Database of the Fleet Air Arm Archive 1939-1945|url = http://www.fleetairarmarchive.net/Ships/ariguani.html|website = www.fleetairarmarchive.net|access-date = 2016-02-15|url-status = usurped|archive-url = https://web.archive.org/web/20160303211025/http://www.fleetairarmarchive.net/Ships/ariguani.html|archive-date = 2016-03-03}}</ref>

While imprisoned in [[Colditz Castle]] during the war, British prisoners of war planned an escape attempt using a falling [[bathtub]] full of heavy rocks and stones as the motive power for a catapult to be used for launching the [[Colditz Cock]] glider from the roof of the castle.

Ground-launched [[V-1 flying bomb|V-1s]] were typically propelled up an inclined launch ramp by an apparatus known as a ''Dampferzeuger'' ("steam generator").{{sfn|Werrell|1985}}<ref>{{cite web|url=https://www.youtube.com/watch?v=Bl580XVFWqw|title=Фау 1 самолёт снаряд, 2 часть|last=Testator|date=2 May 2011|access-date=24 April 2018|via=YouTube|url-status=live|archive-url=https://web.archive.org/web/20160411114300/https://www.youtube.com/watch?v=Bl580XVFWqw|archive-date=11 April 2016}}</ref>

===Steam catapult===
[[Image:French aircraft carrier Charles de Gaulle - catapult maintenance 2008.jpg|thumb|Elements of the catapult of {{ship|French aircraft carrier|Charles de Gaulle||2}}, disassembled during her refit in 2008]]
[[File:US Navy 090504-N-7780S-277 PACIFIC OCEAN (May 4, 2009) Aviation Boatswain's Mate (Equipment) 1st Class Brandon Benedict, from Tulsa, Okla., performs final checks on an aircraft catapult prior to flight operations aboard the Nim.jpg|thumb|upright|Final checks on an aircraft catapult prior to flight operations aboard {{USS|John C. Stennis}}]]

Following World War II, the Royal Navy was developing a new catapult system for their fleet of carriers. Commander  [[C. C. Mitchell]], [[Royal Naval Volunteer Reserve|RNVR]], recommended a steam-based system  using a slotted cylinder as an effective and efficient means to launch the next generation of naval aircraft. One motive was that the British ships were smaller than their American counterparts and so they had shorter catapult runs, making hydraulic catapults ineffective for launching the new heavier [[Jet aircraft|jet]] [[fighter aircraft|fighters]]. Trials on {{HMS|Perseus|R51|6}}, flown by pilots such as [[Eric Brown (pilot)|Eric "Winkle" Brown]], from 1950 showed its effectiveness. NATO navies introduced steam catapults based on the British design in the mid-1950s; the U.S. Navy was also motivated by the need to launch heavy nuclear-armed jet bombers such as the [[Douglas A-3 Skywarrior]] and by [[USS Bennington (CV-20)#1954 catapult explosion and fire|fatalities caused by flammable hydraulic fluid]].  [[Gunpowder|Powder]]-driven catapults were also contemplated, and would have been powerful enough, but would also have introduced far greater stresses on the airframes and might have been unsuitable for long use.<ref name=":0" />{{sfn|Friedman|2016}}{{sfn|Edwards|2011}}

At launch, a release bar holds the aircraft in place as steam pressure builds up, then breaks (or "releases"; older models used a pin that sheared), freeing the piston to pull the aircraft along the deck at high speed. Within about two to four seconds, aircraft velocity by the action of the catapult plus apparent wind speed (ship's speed plus or minus "natural" wind) is sufficient to allow an aircraft to fly away, even after losing one engine.{{sfn|Friedman|1983}}

Nations that have retained large aircraft carriers, i.e., the United States Navy and the [[French Navy]], are still using a [[CATOBAR]] (Catapult Assisted Take Off But Arrested Recovery) configuration. U.S. Navy tactical aircraft use catapults to launch with a heavier warload than would otherwise be possible.  Larger planes, such as the [[E-2 Hawkeye]] and [[S-3 Viking]], require a catapult shot, since their thrust-to-weight ratio is too low for a conventional rolling takeoff on a carrier deck.<ref name=":0" />

====Steam catapults types====
Types previously or still operated by the British, U.S. and French navies include:{{sfn|Friedman|1983}}{{sfn|Power|1996|p=72}}<ref>{{Cite web|title = Chapter 4 STEAM CATAPULTS|url = http://navyaviation.tpub.com/14001/css/14001_139.htm|website = navyaviation.tpub.com|access-date = 2015-11-24|url-status = live|archive-url = https://web.archive.org/web/20151125084413/http://navyaviation.tpub.com/14001/css/14001_139.htm|archive-date = 2015-11-25}}</ref><ref>{{cite web |url=http://www.hnsa.org/wp-content/uploads/2014/08/cv41.pdf |title=Archived copy |access-date=2016-05-13 |url-status=live |archive-url=https://web.archive.org/web/20160603181928/http://www.hnsa.org/wp-content/uploads/2014/08/cv41.pdf |archive-date=2016-06-03 }}</ref><ref>{{cite web |url=http://www.hnsa.org/wp-content/uploads/2014/08/cv60.pdf |title=Archived copy |access-date=2016-05-13 |url-status=live |archive-url=https://web.archive.org/web/20160603185909/http://www.hnsa.org/wp-content/uploads/2014/08/cv60.pdf |archive-date=2016-06-03 }}</ref><ref>{{cite web|url=http://www.mnvdet.com/CV-Cats&SkiRamps.html|title=CV-Cats&SkiRamps|website=www.mnvdet.com|access-date=24 April 2018|url-status=live|archive-url=https://web.archive.org/web/20170827083434/http://www.mnvdet.com/CV-Cats%26SkiRamps.html|archive-date=27 August 2017}}</ref><ref>{{cite book |title=Aviation boatswain's mate E3 & 2 |year=1983 |page=152 |publisher=Naval Education and Training Program Development Center |hdl=2027/uiug.30112101044656?urlappend=%3Bseq=154 |hdl-access=free}}</ref><ref>{{cite book |title=TFX Contract Investigation Hearings Before the Permanent Subcommittee on Investigations of the Committee on Government Operations |location=Washington DC |page=19 |publisher=US Government Printing Office |hdl = 2027/uc1.a0000159228?urlappend=%3Bseq=19 |hdl-access=free}}</ref>

{| class="wikitable" 
|-
!  style="text-align: left;" | Type
! Overall length{{break}}ft (m) !! Stroke{{break}}ft (m) 
! width=170px | Capacity{{break}} lb (tonnes)  !! Carriers 
|-
!BS 4
|
|{{Convert|151|ft|m|abbr=values}}{{sfn|Denison|1957}}
|
|[[HMS Ark Royal (R09)|HMS ''Ark Royal'']] (2 catapults)
|-
! style="text-align: left;" | C-11 and C-11-1
| {{convert|225|ft|m|abbr=values}}
| {{convert|211|ft|m|abbr=values}}
| {{convert|39,000|lb|t|abbr=values}} at 136 knots; {{break}}{{convert|70,000|lb|t|abbr=values}} at 108 knots
| [[SCB-27C]] {{sclass|Essex|aircraft carrier|0}} conversions, {{USS|Coral Sea|CV-43|6}}, bow installations on {{USS|Midway|CV-41|6}} and {{USS|Franklin D. Roosevelt|CV-42|6}}, waist installations on {{USS|Forrestal}} and {{USS|Saratoga|CV-60|6}}
|-
! style="text-align: left;" | C-11-2
| {{convert|162|ft|m|abbr=values}}
| {{convert|150|ft|m|abbr=values}}
| 
| Waist catapults on USS ''Midway'' and USS ''Franklin D. Roosevelt''
|-
! style="text-align: left;" | C-7
| {{convert|276|ft|m|abbr=values}}
| {{convert|253|ft|m|abbr=values}}
| {{convert|40,000|lb|t|abbr=values}} at 148.5 knots; {{break}}{{convert|70,000|lb|t|abbr=values}} at 116 knots
| {{USS|Ranger|CV-61|6}}, {{USS|Independence|CV-62|6}}, bow installations on USS ''Forrestal'' and USS ''Saratoga''
|-
! style="text-align: left;" | C-13

| {{convert|265|ft|m|abbr=values}}
| {{convert|250|ft|m|abbr=values}}
| {{convert|78,000|lb|t|abbr=values}} at 139 knots
| {{sclass|Kitty Hawk|aircraft carrier|4}}, USS ''Midway'' after SCB-101.66 modernization, {{USS|Enterprise|CVN-65|6}}
|-
! style="text-align: left;" | C-13-1

| {{convert|325|ft|m|abbr=values}}
| {{convert|310|ft|m|abbr=values}}
| {{convert|80,000|lb|t|abbr=values}} at 140 knots
| One installation on {{USS|America|CV-66|6}} and {{USS|John F. Kennedy|CV-67|6}}, all on {{USS|Nimitz}}, {{USS|Dwight D. Eisenhower}}, {{USS|Carl Vinson}}, and {{USS|Theodore Roosevelt|CVN-71|6}}
|-
! style="text-align: left;" | C-13-2

| {{convert|325|ft|m|abbr=values}}
| {{convert|306|ft|m|abbr=values}}
| 
| {{USS|Abraham Lincoln|CVN-72|6}}, {{USS|George Washington|CVN-73|6}}, {{USS|John C. Stennis}}, {{USS|Harry S. Truman}}
|-
! style="text-align: left;" | C-13-3

| {{convert|261|ft|m|abbr=values}}
| {{convert|246|ft|m|abbr=values}}
| {{convert|60,000|lb|t|abbr=values}} at 140 knots 
| {{ship|French aircraft carrier|Charles de Gaulle}} 
|}

====Bridle catchers====
[[File:Bow view of USS Saratoga (CV-60) in the 1980s.jpg|thumb|USS ''Saratoga'' underway. The bridle catchers are the extensions at the end of the forward catapults]]

The protruding angled ramps (Van Velm Bridle Arresters or horns) at the catapult ends on some aircraft carriers were used to catch the bridles (connectors between the catapult shuttle and aircraft fuselage) for reuse. There were small ropes that would attach the bridle to the shuttle, which continued down the angled horn to pull the bridle down and away from the aircraft to keep it from damaging the underbelly. The bridle would then be caught by nets aside the horn. Bridles have not been used on U.S. aircraft since the end of the [[Cold War]], and all U.S. Navy carriers commissioned since then have not had the ramps. The last U.S. carrier commissioned with a bridle catcher was USS ''Carl Vinson''; starting with USS ''Theodore Roosevelt'' the ramps were omitted. During [[Refueling and Overhaul|Refueling and Complex Overhaul]] refits in the late 1990s–early 2000s, the bridle catchers were removed from the first three {{sclass|Nimitz|aircraft carrier|2}}s. USS ''Enterprise'' was the last U.S. Navy operational carrier with the ramps still attached before her inactivation in 2012.{{Citation needed|date = February 2016}}

Like her American counterparts, the French aircraft carrier ''Charles De Gaulle'' is not equipped with bridle catchers because the modern aircraft operated on board use the same launch systems as in US Navy.<ref>{{cite web|url=http://www.acam.asso.fr/histo/histo_messier5.php|title=¤ A C A M ¤ Connexion|website=www.acam.asso.fr|access-date=24 April 2018|url-status=live|archive-url=https://web.archive.org/web/20170808080037/http://www.acam.asso.fr/histo/histo_messier5.php|archive-date=8 August 2017}}</ref> Because of this mutual interoperability, American aircraft are also capable of being catapulted from and landing on ''Charles De Gaulle'', and conversely, French naval aircraft can use the US Navy carriers' catapults. At the time when the [[Dassault-Breguet Super Étendard|Super Étendard]] was operated on board of the ''Charles de Gaulle'', its bridles were used only once, as they were never recovered by bridle catchers.

The carriers {{ship|French aircraft carrier|Clemenceau|R98|2}} and {{ship|French aircraft carrier|Foch|R99|2}} were also equipped with bridle catchers, not for the Super Étendards but only to catch and recover the [[Vought F-8 Crusader#Exports|Vought F-8 Crusader]]'s bridles.{{clarify|date=October 2016}}

=== Electromagnetic catapult ===
{{main|Electromagnetic catapult}}
[[File:EMALS.JPG|left|thumb|A computer-generated model of the linear induction motor used in the EMALS.]]
The size and manpower requirements of steam catapults place limits on their capabilities. A newer approach is the  electromagnetic catapult, such as [[Electromagnetic Aircraft Launch System]] (EMALS) developed by General Atomics. Electromagnetic catapults place less stress on the aircraft and offer more control during the launch by allowing gradual and continual acceleration.  Electromagnetic catapults are also expected to require significantly less maintenance through the use of solid state components.<ref>{{cite web|url=http://www.airspacemag.com/military-aviation/electromagnetic-catapults.html|title=History, Travel, Arts, Science, People, Places - Air & Space Magazine|work=airspacemag.com}}</ref>

[[Linear induction motor]]s have been experimented with before, such as Westinghouse's Electropult system in 1945.{{sfn|Laithwaite|1975}} However, at the beginning of the 21st century, navies again started experimenting with catapults powered by linear induction motors and [[electromagnet]]s. Electromagnetic catapult would be more energy efficient on [[Nuclear marine propulsion|nuclear-powered]] aircraft carriers and would alleviate some of the dangers posed by using pressurized steam. On [[gas turbine|gas-turbine]] powered ships, an electromagnetic catapult would eliminate the need for a separate steam boiler for generating catapult steam. The U.S. Navy's {{sclass|Gerald R. Ford|aircraft carrier|2}}s and PLA Navy's [[Type 003]] aircraft carrier included electromagnetic catapults in their design.<ref>{{cite web|url=http://www.naval-technology.com/projects/cvn-21/|title=Gerald R Ford Class (CVN 78/79) – US Navy CVN 21 Future Carrier Programme - Naval Technology|work=naval-technology.com|url-status=live|archive-url=https://web.archive.org/web/20131220095616/http://www.naval-technology.com/projects/cvn-21|archive-date=2013-12-20}}</ref>{{sfn|Gady|2017}}

=== Combustion catapult ===
An alternative approach to solving the problem posed by steam catapults was to power the shuttle with a small rocket integrated into the catapult shuttle using jet fuel and compressed air. Presenting many of the same potential benefits as the electromagnetic catapult, a combustion catapult system known as the C-14 Internal Combustion Catapult Powerplant was developed by [[Reaction Motors]] starting in 1954. A full-scale mockup of the system was installed at [[Naval Air Station Lakehurst]], and proved capable of generating {{cvt|70,000,000|ftlbf|abbr=on}} of energy compared to {{cvt|66,000,000|ftlbf|abbr=on}} of the existing C-13, but the system was never fielded. Originally intended for use on [[USS Enterprise (CVN-65)|USS ''Enterprise'' (CVN-65)]], the ship was redesigned to use conventional C-13 catapults at the behest of [[Admiral Rickover]] shortly after launch in 1961 to reduce engineering risk and total cost.<ref name="NAN1958">{{Cite news |date=April 1958 |title=BIG V, LITTLE g |work=Naval Aviation News |pages=10-11}}</ref><ref name="NAN1960">{{Cite news |date=April 1960 |title='CATS' MAKE NEWS AT LAKEHURST |work=Naval Aviation News |pages=22}}</ref>{{sfn|McKay|2013}}

==Civilian use==
From 1929, the German [[Norddeutscher Lloyd]]-liners {{SS|Bremen|1928|6}} and {{SS|Europa|1930|2}} were fitted with compressed air-driven catapults designed by the ''[[Heinkel Flugzeugwerke]]'' to launch mail-planes.<ref>{{cite web |url=http://histaviation.com/heinkel_catapult_on_the_bremen.html |title=The Heinkel Catapult on the S.S. BREMEN |author=<!--Not stated--> |date=August 3, 1929 |website=histaviation.com |access-date=July 13, 2017 |quote=THE HEINKEL K2 catapult installed upon the North German Lloyd liner "Bremen," which figured prominently in the establishment of the recent trans-Atlantic mail record, is the result of two years of experimentation and development by Dr. Ernst Heinkel, its designer. |url-status=live |archive-url=https://web.archive.org/web/20170913231729/http://histaviation.com/heinkel_catapult_on_the_bremen.html |archive-date=September 13, 2017 }}</ref> These ships served the route between Germany and the United States. The aircraft, carrying mail–bags, would be launched as a [[mail tender]] while the ship was still many hundreds of miles from its destination, thus speeding mail delivery by about a day. Initially, [[Heinkel He 12]] aircraft were used before they were replaced by [[Junkers Ju 46]], which were in turn replaced by the [[Vought O2U Corsair|Vought V-85G]].{{sfn|Cook|2002}}

German airline [[Deutsche Luft Hansa|Lufthansa]] subsequently used dedicated catapult ships {{SS|Westfalen|1905|6}}, {{MS|Schwabenland|1925|6}}, ''Ostmark'' and ''Friesenland'' to launch larger [[Dornier Do J]] ''Wal'' (whale), [[Dornier Do 18]] and [[Dornier Do 26]] [[flying boats]] on the South Atlantic airmail service from Stuttgart, Germany to Natal, Brazil.{{sfn|Leonhardt|1933|p=13-15}} On route proving flights in 1933, and a scheduled service beginning in February 1934, ''Wals'' flew the trans-ocean stage of the route, between [[Banjul|Bathurst]], [[the Gambia]] in West Africa and [[Fernando de Noronha]], an island group off South America. At first, there was a refueling stop in mid-ocean. The flying boat would land on the open sea, be winched aboard by a crane, refueled, and then launched by catapult back into the air. However, landing on the big ocean swells tended to damage the hull of the flying boats. From September 1934, ''Lufthansa'' had a support ship at each end of the trans-ocean stage, providing radio navigation signals and catapult launchings after carrying aircraft out to sea overnight. From April 1935 the ''Wals'' were launched directly offshore, and flew the entire distance across the ocean. This was possible as the flying boats could carry more fuel when they did not have to take off from the water under their own power, and cut the time it took for mail to get from Germany to Brazil from four days down to three.

From 1936 to 1938, tests including the [[Blohm & Voss Ha 139]] flying boat were conducted on the North Atlantic route to New York. ''Schwabenland'' was also used in an [[German Antarctic Expedition (1938–1939)|Antarctic expedition in 1938/39]] with the main purpose of finding an area for a German whaling station, in which catapult-launched ''Wals'' surveyed a territory subsequently name after the ship, [[New Swabia|"Neu-Schwabenland"]]. All of ''Lufthansa''{{'s}} catapult ships were taken over by the [[Luftwaffe]] in 1939 and used as [[seaplane tender]]s in World War II along with three catapult ships built for the military.

After World War II, [[Supermarine Walrus]] amphibian aircraft were also briefly operated by a British [[whaling]] company, United Whalers. Operating in the Antarctic, they were launched from the [[factory ship]] FF ''Balaena'', which had been equipped with an ex-navy aircraft catapult.{{sfn|London|2003|p=213}}

==Alternatives to catapults==
The [[People's Liberation Army Navy|Chinese]], [[Russian Navy|Russian]], [[Indian Navy|Indian]] and currently the [[Royal Navy]] have operated conventional aircraft from aircraft carriers without catapults, via the "[[short take-off but arrested recovery]]" (STOBAR) system. STOBAR carriers use an upward-curved [[ramp]] called a [[aircraft ski-jump|ski-jump]] to assist aircraft takeoff with a positive initial [[rate of climb]], which gives the aircraft's [[aircraft engine|engine]]s more time to accelerate it to the miminum [[airspeed]] needed. Carrier-based aircraft such as the [[Shenyang J-15|J-15]], [[Mikoyan MiG-29K|Mig-29K]] and [[Sukhoi Su-33|Su-33]] can [[conventional take-off and landing|take off conventionally]] from a ski-jump relying only on their own engines for accelerative propulsion, but they typically can only do so with a reduced weight, meaning that they have to make sacrifices on [[payload]] such as [[aviation fuel|fuel]] and [[armament]]s. As a result, STOBAR systems are less optimal than CATOBAR systems, but they allow navies who do not have the capabiliity to acquire catapult carriers to still launch fixed-wing aircraft at sea.

Other navies with aircraft carriers typically operate [[STOVL|short take-off and vertical landing]] (STOVL) aircraft, such as the B variant of the [[Lockheed Martin F-35 Lightning II]], the [[BAE Sea Harrier]] and the [[AV-8B Harrier II]]. These aircraft have [[thrust vectoring]] and can take off vertically with a light load, or use a ski-jump to assist a conventional takeoff with a heavy load. STOVL carriers are less expensive and generally a lot smaller in size than CATOBAR or STOBAR carriers.<ref>{{Cite web|url =http://www.thinkdefence.co.uk/2012/06/why-i-joined-the-dark-side/|title =Why I Joined the Dark Side|work =Think Defence|date =28 June 2012|archive-url =https://web.archive.org/web/20150520071541/http://www.thinkdefence.co.uk/2012/06/why-i-joined-the-dark-side/|archive-date =2015-05-20}}</ref> The British [[Queen Elizabeth-class aircraft carrier|''Queen Elizabeth''-class aircraft carrier]]s were built to use STOVL aircraft due to the expected high cost of an [[electromagnetic catapult]]; because their propulsion is electrically powered from diesel and gas turbine generators they do not have the means to generate steam for a conventional catapult.

==See also==
* [[Ground carriage]]
* [[Jet blast deflector]]
* {{slink|List of auxiliaries of the United States Navy#Seaplane catapult, light (AVC)}}
* {{slink|List of yard and district craft of the United States Navy#Catapult barges (YVC)}}
* [[Modern US Navy carrier operations]]
* [[Naval aviation]]
* {{Annotated link|Arresting gear}}

==Citations==
=== Footnotes ===
{{Notelist-lr}}
=== References ===
{{Reflist}}

=== Sources ===
* {{Cite book |last1= Chant |first1=Stephen J. |last2= Campbell |first2=Douglas E. |title=Patent Log: Innovative Patents that Advanced the United States Navy |year=2013 |publisher=Syneca Research Group, Inc. |isbn=978-1-105-62562-6 }}
* {{cite web |last=Cook |first= John |title=Shot from Ships: Air Mail Service on Bremen and Europa |date=March 2002 |publisher=Air Classics | url=http://celticowboy.com/Mail%20Service%20From%20German%20Passengerships%20Bremen%20And%20Europa.htm | access-date=February 27, 2013 |url-status=live |archive-url=https://web.archive.org/web/20140201192038/http://celticowboy.com/Mail%20Service%20From%20German%20Passengerships%20Bremen%20And%20Europa.htm |archive-date=February 1, 2014 }}
* {{Cite journal |last=Denison |first=K. B. |title=A steam catapult installation |date=April 1957 |journal=Journal of Naval Engineering |volume=10 |number=2 |url=https://libcom.navalmarinearchive.com/research/docs/catapult_ark_royal.html |access-date=2023-05-15 |via=Naval Marine Archive – The Canadian Collection}}
* {{cite journal |last=Edwards |first=Christopher |title=Fire Down Below! |journal=Naval History |date=January 2011 |volume=25 |issue=1 |publisher=U.S. Naval Institute |url=https://www.usni.org/magazines/naval-history-magazine/2011/january/fire-down-below }}
* {{Cite book |last=Friedman |first=Norman |author-link= Norman Friedman |title=U.S. Aircraft Carriers: An Illustrated Design History |year=1983 |publisher=U.S. Naval Institute |isbn=978-0-87021-739-5}}
* {{cite journal |last=Friedman |first=Norman |title=Armaments & Innovations - The Steam-Powered 'Cat' |journal=Naval History |date=December 2016 |volume=30 |issue=6 |publisher=U.S. Naval Institute |url=https://www.usni.org/magazines/naval-history-magazine/2016/december/armaments-innovations-steam-powered-cat }}
* {{cite web |last=Gady |first=Franz-Stefan |title=China's New Aircraft Carrier to Use Advanced Jet Launch System |website=The Diplomat |date=6 November 2017 |url=https://thediplomat.com/2017/11/chinas-new-aircraft-carrier-to-use-advanced-jet-launch-system/ }}
* {{cite journal |last= Laithwaite |first=Eric R. |title=Linear Electric Machines- A Personal View |date=February 1975 |journal=Proceedings of the IEEE |volume=63 |issue=2 }}
* {{cite journal |last=Leonhardt |first=Rene |title=First Transatlantic Airline Links Two Continents |date=1 February 1933 |journal=Popular Science |volume=122 |issue=2 |publisher=Bonnier Corporation |url=https://books.google.com/books?id=pigDAAAAMBAJ&q=Popular+Science+1931+plane&pg=PA13  |access-date=24 April 2018 |via=Google Books }}
* {{cite book |last=London |first=Peter |title=British Flying Boats |date=2003 |publisher=Sutton Publishers Ltd. |location=Stoud, UK |isbn=0-7509-2695-3 }}
* {{Cite book |last=McFarland |first=Stephen L. |title=A Concise History of the U.S. Air Force |year=1997 |publisher = Ft. Belvoir: Defense Technical Information Center |url=https://archive.org/details/concisehistoryof0000mcfa/page/2 |url-access=registration |isbn=0-16-049208-4}}
* {{Cite book |last=McKay |first=Dave |title=USS Enterprise CVA(N)-65 to CVN-65: The World's First Nuclear-Powered Aircraft Carrier |year=2013 |publisher=Wilsonscott Publishing |location=Christchurch, New Zealand |language=en |trans-title=25 |isbn=9781877427503 }}
* {{Cite book |last=Power |first=Hugh Irvin |title=Carrier Lexington |year=1996 |publisher=Texas A&M University Press |location=College Station, TX |isbn=978-0-89096-681-5 }}
* {{Cite newspaper |last=Skerrett |first=Robert G. |title = Our Navy Has the Best Seaplane Catapult; New Invention of Captain Washington I. Chambers Makes It Possible to Launch Aircraft from a Warship's Deck at Sea |date=April 2, 1916 |publisher=New York Times |url = https://timesmachine.nytimes.com/timesmachine/1916/04/02/101572853.pdf |website = query.nytimes.com |access-date=2015-11-24 }}
* {{citation |last=Werrell |first=Kenneth P. |title=The Evolution of the Cruise Missile |year=1985  |publisher=Air University Press |location=Maxwell Air Force Base, Alabama }}

==Further reading==
{{Commons category}}
* {{cite book |last=Miller |first=Jerry |title=Nuclear Weapons and Aircraft Carriers: How the Bomb Saved Naval Aviation |date=2001 |publisher=Smithsonian Institution Scholarly Press |isbn=978-1560989448 }}

{{Types of take-off and landing}}

{{DEFAULTSORT:Aircraft Catapult}}
[[Category:Naval aviation technology|Catapult]]
[[Category:Aircraft carriers| Catapult]]