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An autogyro (from Greek α’υτός + γύρος, ''self-turning''), also known as gyroplane, gyrocopter, or rotaplane, is a type of rotorcraft which uses an unpowered rotor in autorotation to develop lift, and an engine-powered propeller, similar to that of a fixed-wing aircraft, to provide thrust. While similar to a helicopter rotor in appearance, the autogyro's rotor must have air flowing through the rotor disc to generate rotation. Invented by the Spanish engineer Juan de la Cierva to create an aircraft that could fly safely at slow speeds, the autogyro was first flown on 9 January 1923, at Cuatro Vientos Airfield in Madrid.〔(Vector Flight )〕 De la Cierva's aircraft resembled the fixed-wing aircraft of the day, with a front-mounted engine and propeller in a tractor configuration to pull the aircraft through the air. Under license from Cierva in the 1920s and 1930s, the Pitcairn & Kellett companies made further innovations.〔(Pitcairn-Cierva PCA-1A, Smithsonian National Air and Space Museum )〕 Late-model autogyros patterned after Etienne Dormoy's Buhl A-1 Autogyro and Igor Bensen's designs feature a rear-mounted engine and propeller in a pusher configuration. The term ''Autogiro'' was a trademark of the Cierva Autogiro Company, and the term ''Gyrocopter'' was used by E. Burke Wilford who developed the Reiseler Kreiser feathering rotor equipped gyroplane in the first half of the twentieth century. The latter term was later adopted as a trademark by Bensen Aircraft. ==Principle of operation== An autogyro is characterized by a free-spinning rotor that turns because of passage of air through the rotor from below.〔Bensen, Igor. "(How they fly - Bensen explains all )" (Archive ) ''Gyrocopters UK''. Accessed: 10 April 2014. Quote: "air.. (is) deflected downward"〕〔Charnov, Bruce H. (Cierva, Pitcairn and the Legacy of Rotary-Wing Flight ) ''Hofstra University''. Accessed: 22 November 2011.〕 The vertical (downward) component of the total aerodynamic reaction of the rotor gives lift for the vehicle, and sustains the autogyro in the air. A separate propeller provides forward thrust, and can be placed in a tractor configuration with the engine and propeller at the front of the fuselage (e.g., Cierva), or pusher configuration with the engine and propeller at the rear of the fuselage (e.g., Bensen). Whereas a helicopter works by forcing the rotor blades through the air, drawing air from above, the autogyro rotor blade generates lift in the same way as a glider's wing by changing the angle of the air〔 as the air moves upwards and backwards relative to the rotor blade.〔http://www.phenix.aero/PHE-1210.html Gyrocopter vs. Helicopter〕 The free-spinning blades turn by autorotation; the rotor blades are angled so that they not only give lift,〔"Autorotation", ''Dictionary.com Unabridged (v 1.1)''. Random House, Inc. 17 April 2007 http://dictionary.reference.com/browse/Autorotation〕 but the angle of the blades causes the lift to accelerate the blades' rotation rate, until the rotor turns at a stable speed with the drag and thrust forces in balance. Because the craft must be moving forward (with respect to the surrounding air) in order to force air through the overhead rotor, autogyros are generally not capable of vertical takeoff or landing (unless in a strong headwind). A few types have shown short takeoff or landing. Pitch control of the autogyro is by tilting the rotor fore and aft; roll control is by tilting the rotor laterally (side to side). Three designs to affect the tilt of the rotor are a tilting hub (Cierva), swashplate (Air & Space 18A), or servo-flaps. A rudder provides yaw control. On pusher configuration autogyros, the rudder is typically placed in the propeller slipstream to maximize yaw control at low airspeed (but not always, as seen in the McCulloch J-2, with twin rudders placed outboard of the propeller arc). 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「autogyro」の詳細全文を読む スポンサード リンク
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