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Control line (also called U-Control ) is a simple and light way of controlling a flying model aircraft. The aircraft is connected to the operator by a pair of lines, attached to a handle, that work the elevator of the model. This allows the model to be controlled in the pitch axis. It is constrained to fly on the surface of a hemisphere by the control lines. There is also a control system that uses only a single solid wire that is twisted around its own axis, that spins a spiral inside the airplane to move the elevator. While it can be used with some success on any type of model, it is best for speed models where the reduced aerodynamic drag of the single line is a significant advantage. The control provided is not as precise as the two-line control system. The control lines are usually either stranded stainless steel cable or solid metal wires of anywhere from to . Sewing thread or fishing line may be used instead of wires to control very small models, but its air resistance is greater. A third line is sometimes used to control the engine throttle, and more lines may be added to control other functions. Electrical signals sent over the wires are sometimes used in scale models to control functions such as retracting undercarriage and flaps. Almost all control-line models are powered with conventional model aircraft engines of various types. But it is possible to fly control-line models that do not use on-board propulsion, in a mode called "whip-powered", where the pilot "leading" the model with his arm and wind supply the necessary energy to keep the airplane aloft, in a fashion similar to kite-flying. ==History== Models on lines and flying in circles predate manned flight.〔http://members.aol.com/kmyersefo/page19.htm〕 Early versions merely constrained the model to fly in a circle but offered no control. This is known as Round-the-pole flying. The origins of control-line flight are obscure but the first person to use a recognizably modern system is generally considered to be Oba St. Clair, in June 1936, near Gresham, Oregon.〔http://obastclair.com/〕 Oba’s system used a rather large apparatus similar to a television antenna, onto which many lines were attached. This system is very different from those currently in use on modern control line models. But the name most associated with the promotion of control line, and the inventor of the formerly patented system known as "U-Control" (which was a trademark, and is the system in use on virtually every two line control line model today.) was Nevilles E. " Jim" Walker.〔http://www.americanjuniorclassics.com/〕 His "American Junior" company was by far the biggest producer of models, and held numerous patents on the two-line system until overturned during a patent infridgement suit, by Walker, against Leroy M Cox, based on "prior art" from St. Clair in the 1955 trial.〔Thornburg, Dave: ''Do you Speak Model Airplane'', page 142-157. Pony X Press, 1992.〕 One of the most coveted prizes in control-line aerobatics competition sanctioned by the AMA, awarded to the winner of a flyoff between the US Junior, Senior, and Open age class Champions, was originally provided by and is named for Walker. This is one of the oldest perpetual trophies in modeling that is still awarded. 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「Control line」の詳細全文を読む スポンサード リンク
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