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The Short R.24/31 (or Short S.18 and nicknamed the ''Knuckleduster'') was a British twin-engined, high-wing cantilever gull winged monoplane flying-boat designed and built by Short to Air Ministry specification R.24/31 for a "General Purpose Open Sea Patrol Flying Boat". The contract also specified the use of the experimental Rolls-Royce Goshawk engine.〔 The Saunders-Roe London and the Supermarine Stranraer competed successfully for this contract. Although it never saw military service, the Knuckleduster provided useful information on the steam-cooling of engines and the handling of monoplane flying-boats; much experimental data gathered contributed to the design of the successful Empire and Short Sunderland aircraft.〔Barnes and James 1989, p. 284.〕 ==Design and development== The British Air Ministry issued its Specification R.24/31 for a "General Purpose Open Sea Patrol Flying Boat" in 1931 and ordered one prototype from each of Saunders-Roe, Supermarine and Shorts. Whereas the other two companies opted for traditional biplane designs, Shorts decided to produce a more modern, all-metal monoplane aircraft〔 with the experimental steam-cooled, cast block Rolls-Royce Goshawk engine, itself a development of the smaller Kestrel engine. The Knuckleduster's straight-sided hull was of all-metal (Alclad) box-section construction, from the bow as far as the pointed main step at the rear of the planing bottom; aft of the main step the fuselage was of monocoque construction. The central section of the hull was boxed and braced by diagonal frames to bear the loads from the wing-root attachments.〔Barnes and James 1989, p. 281.〕 The wing sections inboard of the engines were attached at a 30° dihedral angle, thus providing sufficient clearance for the airscrews from water-spray during takeoff. The wings were designed for high torsional stiffness, each comprising a box-spar with four tapered stainless steel tubular booms. Fuel tanks were mounted within the wings; sprung and braced wingtip floats were fitted. The wing surfaces were of fabric. The experimental 720 hp Rolls-Royce Goshawk steam-cooled engine was specified for the "Knuckleduster," which led to many problems due to the engine's unreliability. The engines, with conspicuous condensers protruding vertically from the nacelles, were mounted at the "knuckle" between the dihedral inner and the horizontal outer wing sections. The tail unit comprised a horizontal plane braced by struts with two vertical fins and rudders, also supported by diagonal bracing to the fuselage. As a result of early test results, fin area was increased; a major redesign of the tail unit was requested by John Parker and implemented at considerable cost. In addition to the enclosed cockpit in which the pilot and the navigator sat side by side, there was a gunner's cockpit in the bow, stations for the engineer and radio operator and a navigator station with a chart-table, sighting ports and two folding bunks. A third folding bunk and two fixed bunks were mounted in the crew's living quarters, which also included a galley and, further aft, stowage space for drogues and a lavatory. Further armament was provided by a midships gun mounting and a rear gunner's cockpit in the tail; bombs could be mounted in underwing bomb racks and there was also provision for a torpedo to be transported (but not launched). All guns mountings carried a single Lewis Gun. 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 Knuckleduster」の詳細全文を読む スポンサード リンク
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