page_title: Ralph Hooper
section_title: Harrier
hierarchical_section_title: Ralph Hooper / Career / Harrier
caption_attribution_description: English: Plan-view silhouettes of the Hawker P.1127, Kestrel FGA.1, and Harrier GR.3
context_page_description: Ralph Spenser Hooper OBE FREng FRAeS is an English aeronautical engineer, recognised mostly for his work on the Hawker Siddeley Harrier, specifically in relation to the marriage between the Pegasus engine and the layout of the aircraft, allowing it to safely hover with margins of stability.
context_section_description: Working from 1957 with the designer of the Bristol Siddeley Pegasus engine, Gordon Lewis, they came to an arrangement of engine and aircraft design, resulting in the initial designs of the Hawker Siddeley P.1127. The Pegasus design was initially designated as the BE.53, when the final four-nozzle layout was not arrived at. The Bristol Siddeley Orpheus had been the starting point for the engine, with the Orpheus 3 first used, then an Orpheus 6. The Harrier project, unlike most modern British military aircraft, had not been developed in response to a Government requirement but was Hawker's own unsupported project, and from 1959 was the only aircraft that Hawker was working on. It was also produced at a time when many concurrent aircraft projects, from Government requirements, would be drastically cancelled. The Pegasus engine development was financially supported by a department of NATO.
  The first design had an engine that only vectored the thrust from the engine's fan (cool air) - this was only 50% of the engine's total thrust. Vectoring from the high-temperature engine exhaust was not originally contemplated, or thought possible. However he realised that the hot exhaust gases could be bifurcated, as demonstrated on the earlier Hawker Sea Hawk, to provide enough thrust for vertical take off, the fundamental layout of the Harrier.
  By March 1958 he had finally arrived at (what would become) the design of the Harrier, with its distinctive anhedral wing design and undercarriage with wing-tip outriggers. The undercarriage design was much disliked by Sir Sydney Camm. Detailed design of the wing began in August 1958. In March 1959, the Government issued the General Operational Requirement (GOR) 345 for a vertical take off aircraft, in response its knowledge of the design work of the P.1127. This was followed in May 1959 by the Government specification ER 204D.
  In early 1960, work at NASA's Ames Research Center had demonstrated that transition from vertical to conventional flight would be possible. On 22 June 1960, the project finally received a contract and finance from the Ministry of Aviation.  XP831 first flew (tethered) on 21 October 1960 (now at the Royal Air Force Museum London) with a Pegasus 2 engine at Hawker's Dunsfold Aerodrome flown by Bill Bedford. Untethered flight first took place on 19 November 1960. The first conventional flight took place on 13 March 1961 from RAE Bedford, and it was there on 12 September 1961 that the first full transition from vertical to conventional flight took place, surprisingly with little incident. The first crash took place (XP636) on 14 December 1961 with the pilot successfully ejecting. Anhedral tailplanes were introduced in 1962.
  In 1964, the prototypes were improved with a more swept wing and a more powerful Pegasus 5 engine, and in November 1964 it was designated as the Hawker Siddeley Kestrel, and was trialled by pilots from the RAF, the German Luftwaffe and the US Air Force at RAF West Raynham until November 1965. It was funded by these other two air forces as well. Hawker had become Hawker Siddeley in 1963.
  The Kestrel was only meant to be a development aircraft for the later P.1154, but was what became the Harrier. The RAF was not pleased about this change of events. The Kestrel was developed under Air Staff Requirement 384. The resulting aircraft had a Pegasus 6 engine, with a new design of air intakes, and redesigned wings to improve longitudinal stability. In December 1966, 60 aircraft were ordered by the Government, and by 1967 had been christened as the Harrier.
caption: Evolution of the Harrier's wing
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