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The Howard 500 was an American executive transport aircraft produced by Howard Aero Inc during the early 1960s. ==Design and development== During the 1950s and '60s, ''Howard Aero Inc'' had been remanufacturing military surplus Lockheed Lodestars and Lockheed Venturas for the executive market. While the Howard 500 bore a strong resemblance to these aircraft, it was a substantially new design, and all 500s had completely new fuselages. The only major components taken directly from its Lockheed forebears were the outer wing panels (from surplus Venturas) and undercarriage (from Harpoons). Howard purchased wing and fuselage jigs from Lockheed to use as patterns for jigs for the new aircraft. The fuselage differed from the Ventura's in being designed from the outset for pressurisation, and the wings were designed wet. The pressurisation system maintained a differential of which was greater than any other prop or turboprop executive aircraft on the market at the time and maintained a sea level cabin pressure at up to .〔Marson, 2001, p. 26〕 The engine chosen was a new, higher-power and lighter-weight version of the Pratt & Whitney R-2800 that had been developed for the Douglas DC-6. Propeller hubs were taken from F4U Corsairs, four-blade propellers and spinners from DC-7s. The Howard 500 could accommodate 10 to 14 passengers with a large window for each. Increased fuel tankage over the PV-2 Ventura gave a maximum range with full reserves of . Maximum cruising speed was at . This exceptional performance for a piston engined executive aircraft unfortunately came just as the competing turbo prop designs were coming to the market, and this restricted sales of the type. The prototype flew in September 1959,〔 and certification was achieved on February 20, 1963.〔 By this time, however, the executive market was already dominated by turboprop aircraft, and although its performance was comparable to (or even better than) these new machines, and its price substantially lower, the Howard 500 could not effectively penetrate the market. 22 Howard 500s were produced initially, with a further eight being converted from earlier PV-2s to virtually the same standard.〔Marson, 2001, p. 27〕 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「Howard 500」の詳細全文を読む スポンサード リンク
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