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The Short S.7 Mussel was a single-engined two-seat monoplane built by Short Brothers to test the performance of their duralumin monocoque floats. Two were built. ==Development== Having demonstrated the watertightness and corrosion resistance of duralumin monocoque flying boat hulls with the Short Cockle, Shorts became leaders in the design of metal floats for seaplanes. The floats for both the Supermarine S.4 and Gloster III Schneider Cup seaplanes were built by Shorts. They had built their own hydrodynamic testing canal at their Rochester base to explore the performance of floats on the water and decided to build a small aircraft to test them in flight.〔 This was the Short S.7 Mussel; the name was a natural complement to the Cockle but also a nod to "Mussel Manor", the clubhouse on Shorts' first airfield at Sheppey. It was a two-seat, single-engined low-winged monoplane, mounted originally on twin floats.〔 Like the slightly earlier Short Cockle, Satellite and Springbok, it had a duralumin monocoque fuselage of oval cross section.〔〔(''Flight'' 11 March 1926 pp. 141-5 )〕 There were a pair of tandem open cockpits over the wing fitted with dual controls. Contemporary commentators〔 regarded the mounting of the upright four cylinder ADC Cirrus I engine as particularly neatly done, in a U-shaped extension of the monocoque which initially left the top of the engine exposed. This engine was changed for an Cirrus II in January 1928.〔 The fuel tank was immediately behind the fire wall, high enough to gravity feed the carburettor.〔 There was a direct reading fuel gauge above the tank, just in front of the forward cockpit, enclosed a in variety of fairings over the Mussel's lifetime. The constant chord wings were gimbal mounted to the lower fuselage,〔 with pairs of streamlined compression struts from about 30% span to the upper fuselage just ahead of each cockpit. The wing spars were duralumin structures, though the first of the two Mussels had spruce ribs. The wing section was the untried, thick RAF 33. The wings and empennage were fabric covered; the fin and unbalanced rudder had a shape not unlike the de Haviiland vertical tail and the horizontal tail was externally braced from below.〔 The all-important floats were similar to those Shorts had made for the Gloster III, single stepped, small heeled and long enough that the Mussel sat in flight position on the water, not on a tail float like their many earlier seaplanes.〔 This first set of floats was mounted with two pairs of struts to the lower fuselage fore and aft, with a pair of cross bracing struts between the floats. The Mussel also had a built in tail skid in anticipation of a landplane configuration.〔 The performance of the Mussel on its first flight, piloted by John Lankester Parker on 6 April 1926 was disappointing, but the problem was traced to wing-root interference and solved with fabric root fillets.〔〔(''Flight'' 26 August 1926 pp. 538-9, where the fillets can be clearly seen )〕 Thereafter it seems to have been a pleasant machine to fly and one that met its original objectives. The first Mussel was lost when Eustace Short flew clipped a mast in August 1928; Short was unhurt but the Mussel was damaged beyond economic repair.〔 Its replacement, the Mussel II〔 first flew on 17 May 1929. It was similar to the first machine, but had metal ribbed wings of NACA M.12 section; a flat sided fuselage near the wing roots to avoid the need for filleting and water rudders on the floats. It was powered by a Cirrus III engine until August 1930, when it was replaced with a de Havilland Gipsy II.〔 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 Mussel」の詳細全文を読む スポンサード リンク
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