page_title: Aircraft catapult
section_title: Interwar and World War II
hierarchical_section_title: Aircraft catapult / History / Interwar and World War II
caption_attribution_description: A Royal Air Force Hawker Hurricane Mk IA is launched from a CAM (Catapult Armed Merchant) Ship at Greenock, Scotland (UK). The first RAF trial CAM launch was from SS Empire Rainbow at Greenock on the River Clyde on 31 May 1941, the Hurricane landed at Abbotsinch.
context_page_description: An aircraft catapult is a external device used to allow aircraft to takeoff from a very limited amount of space, such as the deck of a vessel, but also installed land-based runways in rare cases. It is now most commonly used on aircraft carriers, as a form of assisted take off. In the form used on aircraft carriers the catapult consists of a track, or slot, built into the flight deck, below which is a large piston or shuttle that is attached through the track to the nose gear of the aircraft, or in some cases a wire rope, called a catapult bridle, is attached to the aircraft and the catapult shuttle. Other forms 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 vessel, but most catapults share a similar sliding track concept. Different means have been used to propel the catapult, such as weight and derrick, gunpowder, flywheel, air pressure, hydraulic, and steam power, and solid fuel rocket boosters. The U.S. Navy is developing the use of Electromagnetic Aircraft Launch Systems with the construction of the Gerald R. Ford-class aircraft carriers.
context_section_description: 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 using a catapult powered by gunpowder. Following this launch, this method was used aboard both cruisers and battleships.
  By 1929, the German ocean liners SS Bremen and Europa had been fitted with compressed-air catapults designed by the Heinkel aviation firm of Rostock, with further work with catapult air mail across the South Atlantic ocean, being undertaken during the first half of the 1930s, with 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 5" guns. Some carriers were completed before and during World War II with catapults on the hangar deck that fired 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 pilots 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.
  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 carriers 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 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 carried four aircraft and HMS Rodney 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 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, or before (HMS Ramillies).
  During World War II a number of ships were fitted with rocket-driven catapults, first the fighter catapult ships of the Royal Navy, then armed merchantmen known as CAM ships from "catapult armed merchantmen." These were used for convoy escort duties to drive off enemy reconnaissance bombers. CAM ships carried a Hawker Sea Hurricane 1A, dubbed a "Hurricat" or "Catafighter", and the pilot bailed out unless he could fly to land.
  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-1s were typically propelled up an inclined launch ramp by an apparatus known as a Dampferzeuger ("steam generator").
caption: Test launch of a Hurricane using the rocket-catapult of a CAM ship, Greenock, Scotland, 31 May 1941
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