PPRuNe Forums - Harrier Engine Origins

Shamelessly lifted from John Farleys lecture ..

The vectored thrust story

The vectored thrust story started in the mid 1950s when a Frenchman, Michel Wibault, proposed a single seat fighter that he called the Gyroptere.Wibault proposed to vector the thrust of four separate centrifugal blowers driven by a single 8000 HP Bristol Orion engine (fig 5). He chose the Bristol engine because it was then the most powerful turbo-shaft engine in prospect. He was unable to interest the French authorities with this idea, but in 1956 he left a brochure with the US officer running the Paris office of the Mutual Weapons Development Programme Colonel Chapman USAF.
http://www.harrier.org.uk/history/im..._vectoring.jpg
Fig 5 Origins of thrust vectoring

Chapman was working on the Orpheus engine with Bristol Aero-Engines' Technical Director Stanley Hooker, so he naturally turned to Hooker for advice on Wibault's brochure. At Chapman's request, Hooker directed a study on Wibault's idea that led to an all new Bristol engine, the Pegasus, having four rotating nozzles. By 1959 the Pegasus 1 was running on a Bristol test-bed and Hawkers were making the P1127 airframe.

and this from Wikipedia..

Background
Although unconnected, the Rolls-Royce Thrust Measuring Rig provided VTOL knowledge in 1953/4 and the Short SC.1 flew in 1958.
Michel Wibault, of France, had the idea much earlier to use vectored thrust for vertical take-off aircraft. This thrust came from four fans driven by a jet engine. Gordon Lewis planned an engine with two thrust vectors, driven by the compressor, with forward thrust from a conventional rear exhaust in his initial BE.52 design.
The Bristol Engine Company began work on the BE.53 Pegasus in 1957. The engine was designed in tandem with the prototype of the Hawker Siddeley Harrier, the Hawker P.1127, which first flew in 1960. The next stage of development was the flown in the Kestrel, of which nine were built. It was developed from the Bristol Siddeley Orpheus, overseen by Stanley Hooker. The low pressure stages came from the Bristol Olympus engine.
The engine was designed in isolation for a year, then it was helped greatly by understanding what type of aircraft it was designed for. The team received a supportive letter from Sydney Camm in May 1957. The aircraft designer, Ralph Hooper, suggested having the four thrust vectors, with hot gases from the rear two. Two thrust vectors did not provide enough lift. The 1957 Defence White Paper, which focussed on missiles, and not aircraft, also was not good news.