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The Dornier Do 17, sometimes referred to as the ''Fliegender Bleistift'' ("flying pencil"), was a World War II German light bomber produced by Claudius Dornier's company, Dornier Flugzeugwerke. It was designed as a ''Schnellbomber'' ("fast bomber"), a light bomber which, in theory, would be so fast that it could outrun defending fighter aircraft. The Dornier was designed with two engines mounted on a "shoulder wing" structure and possessed a twin tail fin configuration. The type was popular among its crews due to its handling, especially at low altitude, which made the Do 17 harder to hit than other German bombers. Designed in the early 1930s, it was one of the three main ''Luftwaffe'' bomber types used in the first three years of the war. The Do 17 made its combat debut in 1937 during the Spanish Civil War, operating in the Condor Legion in various roles. Along with the Heinkel He 111 it was the main bomber type of the German air arm in 1939–1940. The Dornier was used throughout the early war, and saw action in significant numbers in every major campaign theatre as a front line aircraft until the end of 1941, when its effectiveness and usage was curtailed as its bomb load and range were limited. Production of the Dornier ended in mid-1940, in favour of the newer and more powerful Junkers Ju 88. The successor of the Do 17 was the much more powerful Dornier Do 217, which started to appear in strength in 1942. Even so, the Do 17 continued service in the Luftwaffe in various roles until the end of the war, as a glider tug, research and trainer aircraft. A considerable number of surviving examples were sent to other Axis nations as well as countries like Finland. Few Dornier Do 17s survived the war and the last was scrapped in Finland in 1952. On 3 September 2010, the Royal Air Force Museum London announced the discovery of a Henschel-built Dornier Do 17Z buried in the Goodwin Sands off the coast of Kent, England. On 10 June 2013, the salvage team successfully raised the airframe from the seabed. ==Development== In 1932, the Ordnance Department (''Heereswaffenamt'') issued a specification for the construction of a "freight aircraft for German State Railways", and a "high speed mail plane for Lufthansa".〔Dressel and Griehl 1994, p. 25.〕 The factory at Friedrichshafen began work on the design on 1 August 1932.〔 When the Nazis took power in 1933, Hermann Göring became National Commissar for aviation with former Deutsche Luft Hansa employee Erhard Milch as his deputy, soon forming the Ministry of Aviation. The Ministry of Aviation designated the new aircraft Do 17, and on 17 March 1933, just three months after taking office, Milch gave the go ahead for the building of prototypes. At the end of 1933, the Ministry of Aviation issued an order for a "high speed aircraft with double tail," and for a "freight aircraft with special equipment," in other words, a bomber. The original design (the Do 17 V1) configuration in 1932 had sported a single vertical stabilizer, and Dornier continued developing that model. The Do 17 was first demonstrated in mock-up form in April 1933. The "special equipment" was to be fitted later, to disguise its offensive role.〔Griehl 2005, p. 2.〕 In April 1934, the Dornier works at Manzell began project "definition." During this month, the defensive armament was designed and the bomb release mechanism details ironed out. Production of these prototypes began on 20 May 1934 and, on 23 November 1934, the Do 17 V1, with a single fin and powered by two BMW VI 7.3 motors, took off on its first flight. Testing was delayed by a series of accidents, with V1 being damaged in landing accidents in February and April 1935. The twin-tailed V2 (powered by low-compression BMW VI 6.3 engines) first flew on 18 May 1935 and was evaluated together with the V1 by the Ministry of Aviation at Rechlin in June. During the tests, the single fin proved to be only marginally stable, resulting in the V1 being modified with a twin tail. The aircraft was destroyed in a crash after an engine failure on 21 December 1935.〔Green and Swanborough 1986, pp. 42–43.〕 The V3, also fitted with a twin tail, was originally planned to be powered by Hispano-Suiza 12Ybrs engines, but as these were unavailable, it was fitted with BMW VI 7.3 engines like the V1 and flew on 19 September 1935.〔Green and Swanborough 1986, p. 43.〕 The V1 prototype remained the only built machine with the single stabilizer.〔 It is claimed that, unlike the Heinkel He 111 series, whose military use was planned from the start, the Do 17 V1 was contracted as a fast six-passenger mail plane to compete with the smaller Heinkel He 70 monoplane〔Nowarra 1990, pp. 4–5.〕 It has been suggested that it was rejected by Luft Hansa, as the cramped cabin was too uncomfortable for passenger use and the operating costs were too high for a mail plane.〔Nowarra 1990, p. 4.〕 According to the story, the three prototypes remained unused in the Dornier factory in Lowental for almost six months, until Flight Captain Untucht of Luft Hansa came across them. After receiving permission to fly one of the machines, he proceeded to put it through an almost stunt flying routine. After landing, he said that "the machine is as nimble as a fighter, give it more lateral stability and we'll have a high speed bomber!" Untucht's comments prompted Dornier to redesign the tail unit and revived interest in the type.〔Nowarra 1990, p. 5.〕 Dornier was then ordered to produce the V4 prototype. Some sources state this differed from the V3 in that the passenger portholes were removed and the single fin was replaced with two smaller ones.〔Goss 2005, p. 7.〕〔Munson 1983, p. 296.〕 Photographic evidence demonstrates the V3 had twin stabilizers from the start of its construction.〔Griehl 2005, p. 12.〕 The tests of the "twin-tailed" V4, V6 and V7 prototypes were positive and more prototypes like the V8 emerged as the forerunner of the long-range reconnaissance version, while the V9 was tested as a high-speed airliner.〔Dressel and Griehl 1994, p. 26.〕 The V9 machine was still flying in 1944.〔 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「Dornier Do 17」の詳細全文を読む スポンサード リンク
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