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The Blackburn B-25 Roc was a British Second World War-era Fleet Air Arm fighter aircraft designed by Blackburn Aircraft Ltd. It took its name from the mythical bird of the tales of the Arabian Nights, the Roc. Derived from the Blackburn Skua and developed in parallel, the Roc differed in its adoption of a turret for its armament. Operationally, the Roc came to be viewed as inferior to existing aircraft, such as the Skua and the type only had a brief front line service. ==Design and development== On 31 December 1935, the British Air Ministry issued Specification O.30/35 for a carrier-based turret-armed fighter.〔Brew 2002, p. 26.〕 Blackburn proposed a derivative of the Blackburn Skua dive bomber, of which two prototypes had been ordered for the Fleet Air Arm earlier that year, while Boulton Paul proposed the P.85, a redesigned version of its land-based Defiant P.82 turret fighter, with either a Hercules radial or Merlin in-line engine.〔〔Jackson 1968, p. 399.〕〔Buttler, Tony ''British Secret Projects: Fighters and Bombers'' p55〕 Although the "Sea Defiant" was expected to be faster, the Roc was chosen.〔 Like the Skua, the B-25 Roc was a two-seat low-wing cantilever monoplane of all-metal construction, fitted with a retractable tailwheel undercarriage, while its wings folded for storage aboard aircraft carriers. It was powered by a Bristol Perseus radial engine driving a three-bladed propeller, and used the same Boulton Paul power operated gun turret as the Defiant, with four .303 in (7.7 mm) Browning machine guns. It retained the wing mounted dive brakes of the Skua, with bomb racks under each wing for two 250 lb (110 kg) bombs and eight practice bombs to be carried.〔Mason 1992, p. 271.〕〔Jackson 1968, pp. 411–412.〕 On 28 April 1937, the Air Ministry placed an order for 136 Rocs. As Blackburn already had full order books for the Skua and the Botha torpedo bomber for the RAF, it was decided to sub-contract detailed design and production to Boulton Paul at Wolverhampton, which delayed deliveries of the Defiant.〔Jackson 1968, p. 412.〕〔Buttler, Tony ''British Secret Projects: Fighters and Bombers'' p. 54〕 The first flight by a Roc was on 23 December 1938; handling was acceptable and better than that of the Skua but its performance was poor, with a maximum speed of only .〔Thetford 1978, p. 60.〕〔Lumsden and Heffernen ''Aeroplane Monthly'' March 1990, p. 149.〕 It had already been realised by some that this performance was inadequate, with the Fifth Sea Lord (the Chief of Naval Air Services) Alexander Ramsay suggesting in October 1938 that the Roc be abandoned. Production was allowed to continue, as cancellation would cause too much disruption for Boulton Paul, with work beginning to adapt the aircraft for target towing.〔Brew 2002, pp. 38–39.〕 As well as its primary role as a carrier-based fighter, the Roc was also required to be capable of operating as a floatplane, with a conversion kit being designed for a set of floats from a Blackburn Shark to be fitted. The first example to be converted proved to be unstable and, in December 1939, crashed when being tested at Helensburgh (where the Marine Aircraft Experimental Establishment had moved to at the start of the war.) While the addition of an enlarged ventral fin solved the stability problems, the effect of the floats on the aircraft's performance was too great to be ignored, with maximum speed falling to only ; plans to form a fighter squadron equipped with Roc floatplanes were abandoned.〔Brew 2002, pp. 50–51.〕 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「Blackburn Roc」の詳細全文を読む スポンサード リンク
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