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The Metropolitan-Vickers F.2 was an early turbojet engine and the first British design to be based on an axial-flow compressor. It was an extremely advanced design,〔 using a nine-stage axial compressor, annular combustor, and a two-stage turbine. It first powered a Gloster Meteor in November 1943, outperforming similar models from Power Jets. In spite of this excellent start, it was considered unreliable and never saw use during the war. In the post-war era a number of engines had much higher performance, and interest in the F.2 waned. The potential of the engine and the investment did not go to waste, however, the design was passed from Metropolitan-Vickers to Armstrong Siddeley when Metrovick left the gas turbine business. Armstrong Siddeley produced a larger version as the successful Sapphire. ==Development== Alan Arnold Griffith published a seminal paper in 1926, ''An Aerodynamic Theory of Turbine Design'', that for the first time clearly demonstrated that a gas turbine could be used as a practical, and even desirable, aircraft powerplant. The paper started by demonstrating that existing axial compressor designs were "flying stalled" due to their use of flat blades, and that dramatic improvements could be made by using aerofoil designs instead, improvements that made a gas turbine practical. It went on to outline a complete compressor and turbine design, using the extra exhaust power to drive a second turbine that would power a propeller. In today's terminology the design was a turboprop. In order to prove the design, Griffith and several other engineers at the Royal Aircraft Establishment built a testbed example of the compressor in 1928 known as ''Anne'', the machinery being built for them by Fraser and Chalmers. After Anne's successful testing they planned to follow this up with a complete engine known as ''Betty'', or B.10. In 1929 Frank Whittle's thesis on pure jet engines was published, and sent to Griffith for comment. After pointing out an error in Whittle's mathematics, he went on to deride the entire concept, saying that the centrifugal compressor Whittle used would be impractical for aircraft use due to its large frontal area, and that the use of the jet exhaust directly for power would be extremely inefficient. Whittle was distraught, but was convinced that he should patent the idea anyway. Five years later a group of investors persuaded him to start work on what would be the first working British jet engine. Griffith continued development of his own concepts, eventually developing an advanced compressor design using two contra-rotating stages that improved efficiency. His partner, Hayne Constant, started discussions in 1937 with Manchester-based Metrovick, a maker of steam turbines, to produce the new machinery. Incidentally, Metrovick had recently merged with British Thomson-Houston, another turbine builder who were supporting Whittle's efforts. By 1939 this work had developed several improved versions of the Betty compressor design, which were incorporated into the new ''Freda''. In April 1939, Whittle gave a startling demonstration of his experimental engine, the WU, running it for 20 minutes at high power. This led to a rash of contracts to build a production quality design suitable for aircraft use. Metrovick's lead of design, David Smith, decided to end development of the turboprop concepts and focus on pure-jets instead. Development had just started when Whittle started building his W.1 design, planning to install one for flight in the Gloster E.28/39 the next year. 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「Metropolitan-Vickers F.2」の詳細全文を読む スポンサード リンク
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