Assisted Take Off - JATO and RATO

JATO and RATO

JATO stands for 'Jet-assisted take off' (and the similar RATO for 'Rocket-assisted take off'). In the JATO and RATO systems, additional engines are mounted on the airframe which are used only during take off. After that the engines are usually jettisoned, or else they just add to the parasitic weight and drag of the aircraft. However some aircraft such as the Avro Shackleton MR.3 Phase 2, had permanently attached JATO engines. The four J-47 turbojet engines on the B-36 were not considered JATO systems; they were an integral part of the aircraft's powerplants, and were used during takeoff, climb, and cruise at altitude.

During WW2 the German Arado 234 and the Messerschmitt 323 "Gigant" used rocket units beneath the wings for assisted take off. Such systems were popular during the 1950s, when heavy bombers started to require two or more miles of runways to take off fully laden. This was exacerbated by the relatively low power available from jet engines at the time — for example the B-52 Stratofortress required 8 turbojet engines to yield the required performance, and still needed RATO for very heavy payloads ( a proposed update of the B-52 replaces these with half the number of much more powerful engines). In a Cold War context, RATO and JATO bottles were seen as a way for fighter aircraft to utilize the undamaged sections of runways of airfields which had been attacked.