An autogryo, also known as gyroplane, gyrocopter or rotaplane, is a type of rotorcraft which uses a non-powered 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 up 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. 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. Later model autogyro designs feature a rear-mounted engine and propeller in a pusher configuration.
An autogyro is characterized by a free-spinning rotor that turns because of passage of air through the rotor from below.
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.The free-spinning blades turn by autorotation; the rotor blades are angled so that they not only give lift, 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.
– Source credit: Wikipedia –