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The Armstrong Siddeley Sapphire was a British turbojet engine produced by Armstrong Siddeley in the 1950s. It was the ultimate development of work that had started as the Metrovick F.2 in 1940, evolving into an advanced axial flow design with an annular combustion chamber that developed over . It powered early versions of the Hawker Hunter and Handley Page Victor, and every Gloster Javelin. Production was also started under licence in the United States by Wright Aeronautical as the J65, powering a number of US designs. ==Design and development== Design evolution of the Sapphire started at Metropolitan-Vickers (Metrovick) in 1943 as an offshoot of the F.2 project. With the F.2 reaching flight quality at about , the Metrovick engineers turned to producing larger designs, both an enlarged F.2 known as the ''Beryl'', as well as the much larger F.9 ''Sapphire''. (The names were chosen after a decision to use gemstones for future engine names). The Beryl was soon running and eventually developed 4,000 lbf (18 kN) thrust, but the only project to select it, the Saunders-Roe SR.A/1, was cancelled. By this point the F.9 MVSa.1 was developing about 7,500 lbf (33 kN), somewhat more than its competitor from Rolls-Royce, the Avon. A number of companies expressed interest in the F.9, and it was considered as either the main or backup powerplant for most British designs of the late '40s and early '50s. At about the same time, Metrovick exited the jet engine industry,〔Depending on the sources, Metrovick either left the engine business on their own to concentrate on steam turbines, or were forced from the market by the Ministry of Supply in order to reduce the number of companies they had to deal with.〕〔Gunston 1989, p.102. Note: "...the firm had decided in 1947, under Ministry pressure, to get out of aviation"〕 and their design team was quickly acquired by Armstrong Siddeley, who already had a turbine development of their own, the ASX, but they were primarily focused on turboprops and the Metrovick team was a welcome addition. Work on the F.9 continued, now renamed the ASSa.5, and was delivered at ratings. This early engine was used only on the English Electric P.1.A, prototype for the famed Lightning. The fit was not entirely a happy one, and the afterburning ASSa.5R did little to address this, delivering an improved "wet", but doing so in an unreliable fashion that demanded a short period of "no use" while the problems were addressed.〔(English Electric Lightning )〕 Future versions of the Lightning were powered by the Avon instead. The engine was soon passing tests at ever-increasing thrust settings. The ASSa.6 reached , and was used on the Gloster Javelin FAW Mk.1, Hawker Hunter F.Mk.2 and F.Mk.5, and the prototype Sud Ouest SO 4050 Vautour. The dramatically more powerful ASSa.7 at was the first British engine to be rated above , powering the Gloster Javelin FAW Mk.7, Handley Page Victor B.Mk.1 and a prototype Swiss fighter-bomber, the FFA P-16. Afterburners of limited performance (also known as "re-heat") were also added to the ASSa.7, producing the wet ASSa.7LR, used on some Gloster Javelin FAW Mk.8's. An improved model produced above , appearing on other FAW Mk.8's and all FAW Mk.9's.〔(Armstrong Siddeley Sapphire )〕 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Armstrong Siddeley Sapphire」の詳細全文を読む スポンサード リンク
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