Invented by Spanish engineer Juan de la Cierva to create an aircraft that could safely fly at slow speeds, the gyrocopter (also known as an autogyro) was first flown on 9 January 1923 at Cuatro Vientos Airfield in Madrid, Spain. In essence it is a micro-helicopter, but a gryocopter has a free-spinning rotor that turns because of passage of air upward through it. The vertical component of the turning rotor gives lift. A separate propeller provides forward thrust, which can be placed in a pull configuration with the engine and propeller at the front of the fuselage, or pusher configuration with the engine and propeller at the rear of the fuselage. Whereas a helicopter works by forcing the rotor blades through the air and pushing air downwards, the gyrocopter rotor blade generates lift in the same way as a glider's wing by changing the angle of the air as it moves upwards and backwards relative to the rotor blade. 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.
As a bit of trivia, Raleigh in North Carolina was named after Walter Raleigh, a 16th-17th century English explorer (among other things) who popularised tobacco in Britain.
|a Bensen company postcard taken near its Raleigh factory|