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| America's first "rocket-assisted" take-off, an ERCO Ercoupe fitted with a GALCIT booster, in 1941, performed at March Field, California. |
JATO is an acronym for jet-fuel assisted take off. It is a system for helping overloaded aircraft into the air by providing additional thrust in the form of small rockets.
The term is used interchangeably with the (more specific) term RATO, for Rocket-Assisted Take Off (or, in RAF parlance, RATOG for Rocket-Assisted Take Off Gear).
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Early experiments using rockets to boost gliders into the air were conducted in Germany in the 1920s (Lippisch Ente), and later both the Royal Air Force and the Luftwaffe introduced such systems in World War II.[1] The British system used fairly large solid fuel rockets to shoot planes (typically the Hawker Hurricane) off a small ramp fitted to the fronts of merchant ships, known in service as Catapult armed merchantmen (or CAM Ships), in order to provide some cover against German reconnaissance planes. After firing, the rocket was released from the back of the plane to fall into the water and sink. The task done, the pilot would fly to friendly territory if possible or parachute from the plane, hopefully to be picked up by one of the escort vessels. Over two years the system was only employed nine times to attack German aircraft with 8 kills recorded for the loss of a single pilot.
The Luftwaffe also used the technique in order to help their small bombers, and the enormous Gigant, Messerschmitt Me 321 glider, conceived in 1940 for the invasion of Britain, and used to supply the Russian front which also had air tow assistance from up to three bombers, into the air with loads that would have made the takeoff run too long otherwise. This became especially important late in the war when the lengths of usable runways were severely curtailed due to the results of Allied bombing. Their system typically used Walter HWK 500 Starthilfe ("start-help") rocket engines driven by chemical decomposition of "T-Stoff", essentially almost pure hydrogen peroxide. A parachute pack at the front of the motor was used to slow its fall after being released from the plane, so the system could be re-used. First experiments were held in 1937 on an Heinkel He 111, piloted by test-pilot Erich Warsitz at Neuhardenberg, a large field about 70 kilometres east of Berlin, listed as a reserve airfield in the event of war.[2] Other German experiments with JATO were aimed at assisting the launch of interceptor aircraft such as the Messerschmitt Me 262C, as the Heimatschützer special versions, usually fitted with either a version of the Walter HWK 109-509 liquid fuelled rocket engine from the Me 163 Komet program either in the extreme rear of the fuselage or semi-"podded" beneath it just behind the wing's trailing edge, to assist its Junkers Jumo 004 turbojets, or a pair of specially rocket-boosted BMW 003R combination jet-rocket powerplants in place of the Jumo 004s, so that the Me 262C Heimatschützer interceptors could reach enemy bomber formations sooner. Two prototypes of the Heimatschützer versions of the Me 262 were built and test flown, of the three designs proposed.
In early 1939, the United States National Academy of Sciences provided $1,000 to Theodore von Kármán and the Rocket Research Group at the Guggenheim Aeronautical Laboratory to research rocket-assisted take-off of aircraft. This JATO research was the first rocket research to receive financial assistance from the U.S. government.[3][4]
After World War II JATO became particularly common owing to the low slow-speed thrust of then-current jet engines or for assisting heavy aircraft; the prop-engined Avro Shackelton used Armstrong Siddeley Viper turbojets for takeoff. As the take-off thrust of jet engines has grown, JATO has fallen from favor. It is still used, however, when heavily-laden aircraft need to take off from short runways or when operating in "high and hot" conditions.[5]
Two similar zero-length launch experimental programs were carried out by the US Air Force and by the Soviet VVS at around the same time in the late 1950s. The US Air Force used a modified Republic F-84, designated EF-84G, which used the MGM-1 Matador cruise missile's solid fuel booster. The Soviet VVS used a modified MiG-19 fighter, designated SM-30, launched from a special launcher, and using a nearly identical solid fueled rocket booster design to that of the EF-84G. The F-100 and F-104 were also used for zero-length launch experiments.[6]
Operation Credible Sport was a United States military operation plan in late 1980 to rescue hostages held by Iran using C-130 cargo planes modified with rocket engines to enable a very short take off and landing. The plan was canceled after an accident during the test landing when JATO units designed to cushion the landing fired too soon, causing the aircraft to crash-land.
The JATO Rocket Car is an urban legend that relates the story of a car equipped with JATO units that is later found smashed into a mountainside. This story is often given as an example of a Darwin Award; however it appears to be apocryphal, with no basis in fact.[7] The legend has been examined twice on the Discovery Channel show MythBusters. For the first attempt, in a 2003 pilot episode, the crew replicated the scene and the thrust of the JATO with some commercially-available amateur rocket motors. The car did go very fast, outrunning the chase helicopter, but nowhere near the 300 mph (500 km/h) reported in the original story, and failed to become airborne. The myth was revisited in 2007, using a different configuration of rockets in an attempt to make the car fly; however, it exploded before reaching the end of its launch ramp.
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