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The Airco DH.6 was a British military trainer biplane used by the Royal Flying Corps during the First World War. Known by various nicknames, including the "Skyhook", the trainer became a widely used light civil aircraft in the postwar era.〔Boughton 1963, p. 10.〕 ==Design and development== The DH.6 was specifically designed as a military trainer, at a time when it was usual for obsolete service types to be used in this role.〔Baker 1990, p. 24〕 Geoffrey de Havilland seems to have had two design criteria in mind.〔Jackson 1962, p. 53.〕 The first was that it should be cheap and easy to build, and above all, simple to repair after the mishaps common in ab initio training. The top and bottom wings were "brutally" square cut, and were interchangeable. (Hence the roundels in unconventional positions on many wartime photographs of the type.) They were heavily cambered, and braced with cables rather than streamlined wires. On the original version of the type there was no stagger. Even the rudder, on the prototype of the usual curved de Havilland outline, was on production machines cut square. The fuselage structure was a straight box with no attempt at refinement of outline – instructor and pupil sat in tandem on basketwork seats in a single cockpit that was Spartan even by the standards of the time.〔 The standard engine was the ubiquitous and readily available 90 hp (67 kW) RAF 1a. Because of its use in the B.E.2〔Cheeseman 1962, p. 48.〕 the engine had the advantage of being very familiar indeed to RFC mechanics. It was stuck onto the front of the DH.6 in the most straightforward way possible, without any type of cowling, and the usual crudely upswept exhaust pipes of this type of engine were fitted. Eventually even stocks of the RAF 1a ran short, and various other engines were fitted to DH.6s, including the 90 hp (67 kW) Curtiss OX-5 and the 80 hp (60 kW) Renault. This was an era when instructors in the RFC referred to their pupils as "Huns" (the term used for enemy airmen) and casualties at training schools were high.〔Lee 1968〕 The second design criterion was that the new trainer should be "safe" to fly, both for a new pupil and his instructor. One way to obtain this safety was a "decouple" on the dual controls so that the instructor could take control at any time without having to wrestle with a panicking pupil.〔 Another route to the desired safety was through the new trainer's flying characteristics. De Havilland's work at the Royal Aircraft Factory, where much basic research had been carried out into the nature of stability and control in aircraft, left him well qualified to design a "safe" aircraft.〔 In the event, the DH.6 had very gentle flying characteristics; it was probably the most "forgiving" aircraft of its time, allowing itself to be flown "crab wise" in improperly banked turns, and being almost impossible to stall or spin, in fact it was able to maintain sustained flight at speeds as low as .〔Jackson 1987, p. 86.〕 In fact, the DH.6 has been frequently described as "too safe" to make a good trainer;〔Cheeseman 1962, p. 60.〕 this referred to its gentle reaction to inexpert piloting rather than to excessive stability however, as it was designed with a degree of inherent ''in''stability about all three axes.〔 With the "Skyhook's" low power, strong but rather heavy construction and lack of streamlining, its maximum speed was naturally very low, even by the standards of the time. 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「Airco DH.6」の詳細全文を読む スポンサード リンク
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