Harrier Jump Jet two systems are fully interlinked but air is not supplied to the reaction control valves during conventional wingborne flight. Harrier Jump Jet The Harrier, informally referred to as the Harrier Jump Jet, is a family of jet-powered attack aircraft capable of vertical/short takeoff and landing operations (V/STOL). Named after a bird of prey, it was originally developed by British manufacturer Hawker Siddeley in the 1960s. The Harrier emerged as the only truly successful V/STOL design of the many attempted during that era, despite being a subsonic aircraft, unlike most of its competitors. It was conceived to operate from improvised bases,
Hawker Siddeley Harrier the P.1154 was cancelled, as the Royal Navy had already begun procurement of the McDonnell Douglas Phantom II and the RAF placed a greater importance on the BAC TSR-2's ongoing development. Work continued on elements of the project, such as a supersonic PCB-equipped Pegasus engine, with the intention of developing a future Harrier variant for the decades following cancellation. Following the collapse of the P.1154's development the RAF began considering a simple upgrade of the existing subsonic Kestrel and issued Requirement ASR 384 for a V/STOL ground attack jet. Hawker Siddeley received an order for six pre-production aircraft in 1965,