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The Vickers Vanguard was a British short/medium-range turboprop airliner introduced in 1959 by Vickers-Armstrongs, a development of their successful Viscount design with considerably more internal room. The Vanguard was introduced just before the first of the large jet-powered airliners, and was largely ignored by the market. Only 44 were built, ordered by Trans-Canada Air Lines (TCA) and British European Airways (BEA). After only about 10 years service TCA experimentally converted one of theirs to a freighter configuration, calling it the Cargoliner. This was considered successful, and in the early 1970s most were converted to freighters, those from BEA becoming the Merchantman. These freighters remained in service for many years, with the last one (G-APEP) only retiring in 1996. ==Design and development== The aircraft was designed to a BEA requirement for a 100-seat aircraft to replace their Viscounts. The original Type 870 design was then modified when TCA expressed their interest in the design as well, and Vickers returned the updated Type 950 that filled both requirements. The main difference between the Viscount and Vanguard was the construction of the fuselage. The Vanguard started with the original Viscount fuselage, but cut it off about halfway up from the bottom, replacing the top section with a larger-diameter fuselage to give it a ''double bubble'' cross-section (similar to the Boeing Stratocruiser). The result of the larger upper portion was a roomier interior, with increased cargo capacity below the floor.〔Swanborough 1962, p. 99.〕 With this larger, and heavier, fuselage came the need for a new engine to lift it. Rolls-Royce delivered their new Tyne design with a nominal (compared to the Viscount's Dart of about ). This allowed for a much higher service ceiling and cruising speed. The Vanguard was one of the fastest turboprops ever and was faster than the present day Saab 2000 or de Havilland Canada Dash 8. A (hyped ) pilot report describes maintaining 10,000 ft altitude with three engines feathered and the port outer at maximum cruise power; weight at start of that flight was about 112,000 lb. This is notably better performance than a Lockheed C-130, an aeroplane of similar weight and power that could not (in its introductory version of 1957) maintain a constant altitude on a single engine. Nevertheless, the Vanguard was certainly overpowered.〔''Aviation Week'' 14 September 1959, p. 59.〕 The first Type 950 prototype ''G-AOYW'' flew on 20 January 1959〔Wright ''Air International'' April 1997, p. 242.〕 The flight, a transfer to Wisley 3 miles away, had been planned for December but the engines were returned to Rolls-Royce for minor work. Proper flight testing was then carried out from Wisley.〔("Vanguard Maiden Flight." ) ''Flight,'' 30 January 1959, p. 150.〕 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「Vickers Vanguard」の詳細全文を読む スポンサード リンク
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