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The Short Empire was a medium range four engined monoplane passenger and mail carrying flying boat, of the 1930s and 1940s, that flew between Britain and the British colonies in Africa, Asia and Australia as well as providing service between Bermuda and New York City. It was manufactured by Short Brothers and was developed in parallel with the Short Sunderland patrol bomber of World War II and the piggy-back Short Mayo Composite. ==Design and development== The origins of the Empire boats lay in an Air Ministry requirement for passenger and mail carriers that could provide air mail service to the colonies of the British Empire in Africa and Australia. The Empire was officially known as the C-class by Imperial Airways and each aircraft operated by them was given a name beginning with C. The first aircraft, G-ADHL ''Canopus'', was completed in June 1936 and launched on 3 July. A total of 42 Empires were built, all at Short's Rochester factory. Imperial Airways (and its successor BOAC), Qantas and TEAL operated the Short Empire in commercial service, while the Royal Air Force, Royal Australian Air Force, Royal New Zealand Air Force and briefly the Royal Canadian Air Force used them on military operations during the Second World War, particularly for anti-submarine patrol and transport duties. The first series of the Short Empires, the S.23, could carry 5 crew, 17 passengers, and 4,480 lb (2,035 kg) of cargo at a maximum speed of 174 knots (320 km/h) and were powered by four Bristol Pegasus radials. The Short Empire was designed to operate along the Imperial Airways routes to South Africa and Australia, where no leg was much over . After the design was finalized and production was started it was realized, with some pressure from the United States, that it would be desirable to offer a similar service across the Atlantic. The range of the S.23 was less than that of the equivalent US Sikorsky "Clipper" flying boats and as such they could not provide a true trans-Atlantic service. Two boats (''Caledonia'' and ''Cambria'') were lightened and given long range tanks and experimented with in-flight refuelling so they could make the trip but that meant they could carry fewer passengers and less cargo. In an attempt to manage the Atlantic crossing, a piggy-back approach was tried. Using the S.21 design (based on the S.23) as the carrier, with a smaller four-engined floatplane, the Short S.20, mounted on its back. Only a single example was built of the S.21 carrier aircraft, the ''Maia'', and of the S.20 ''Mercury''. Together they were known as the Short Mayo Composite.〔(Robert Mayo – Short Aircraft Engineer's Concept )〕 A successful mid-air launch of Mercury was made in 1938, and it was to set a number of long distance records however a launch aircraft was required for both sides of the Atlantic and the Mercury was limited to carrying mail, and no further development of this concept occurred in the UK. The S.30 series were fitted with the more efficient, but lower power Bristol Perseus sleeve valve engines and had a strengthened airframe allowing the take off weight to be increased to , giving a range of . ''Cabot'', ''Caribou'', ''Clyde'' and ''Connemara'' were fitted with in-flight refuelling equipment and extra fuel tanks so they could be used for a regular trans-atlantic airmail service. The idea was for the aircraft to take off at lower weights and once airborne take on extra fuel to an all up weight of giving a range of over . The extra fuel did reduce the payload to against the of the standard craft. The refuelling was by three converted Handley Page Harrow bombers, one operating out of Ireland and two out of Newfoundland. The S.33 was a further follow-on to the S.30 with the same Pegasus engine as fitted to the S.23 Initially, they were designed for a 40,500 lb gross weight but by 1939 aircraft were strengthened for .〔"The Greatest Short" ''Flight'' 20 July 1939. page ''e''〕 Wartime experience in operating at overload resulted in the realization that the Empires could take off at considerably higher weights than the conservative maxima provided by Shorts and, although the last Empire crossings to America were made in 1940 (by ''Clare'' and ''Clyde''), many more flights were made on the long, demanding and vital over-water Lisbon-Bathurst flights. A completely new flying boat, the S.26 "G class" was produced for year-round use on the North Atlantic route (although it was used instead between the UK and West Africa. Of similar appearance to the C-class boats but about 15% larger in all dimensions with the more powerful Hercules engines and an improved hull design, they had a wing span of and a length of . 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「Short Empire」の詳細全文を読む スポンサード リンク
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