The autogiro is a curious mechanical invention. To most inexpert eyes they look like helicopters, but the main difference is that the rotor, which supports the aircraft, does not take the torque of an engine; therefore, it is not necessary to introduce the anti-torque tail rotor that all helicopters must have.

The "Avro-Cierva C30A", shown in the pictures, is exhibited in excellent conditions at the Museo Aeronautico in Buenos Aires, Argentina. It is one of the few currently existing autogiro in the world and was produced by the English company Avro. The designer of this aircraft was the Spanish Juan de la Cierva, who patented his invention, and in the 1920's sold licenses to the United Kingdom, USA, France and Japan.

One particular feature of this aircraft that should be highlighted is its mechanism for a fast take-off. There is a clutch that connects the engine traction to the rotor, which gains speed fast, thus enabling the aircraft to take off. Once in the air, the Autogiro is propelled forward by its 7-cylinder engine and the rotor revolves due to the aerodynamic effect. Obviously, once the aircraft has already taken off, the pilot must disconnect the traction in order to avoid the torque and the consequent instability produced by it.