Conceiving the Idea of Non-engine Rotor System Plane
A gyroplane flies by using a rotor wing similar to a helicopter and a propeller typical of a light airplane, providing certain characteristics of both aircraft types. Unlike a helicopter, a gyroplane’s rotor system is not driven by the engine, which only powers the propeller for forward thrust. Air forced through the rotor blades by the forward movement of the aircraft causes the rotor to turn in autorotation and thereby provide lift. Since the gyroplane in flight is always in autorotation, it is inherently safer, simpler and quieter than a helicopter.
Autorotative flight was conceived in 1919 by the Spanish aviator and airplane designer, Juan de la Cierva, as a means of achieving slow flight without the risk of stalling the aircraft. Cierva flew his first autogiro (gyroplane) in the early twenties and continued to develop increasingly sophisticated gyroplanes over the following fifteen years. Under license from Cierva in the 1920’s and 1930’s, the Pitcairn & Kellett companies made further innovations leading to gyroplanes capable of vertical takeoff and landing.
The gyroplane concept demonstrated itself as a proven technology in the 1930’s and 1940’s when the U.S. Post Office used these aircraft for nearly ten years for mail delivery from the roofs of post offices. In the run up to WWII, however, the helicopter with its ability to hover appeared to the government and military to be the next logical step in the evolution of rotorcraft. With the economy in depression, investment was directed to the helicopter and further development of the gyroplane was curtailed.
The complexity of the helicopter both to design and to operate meant that its promise was not fully realized until the Vietnam War, when the versatility of vertical flight proved very valuable. For widespread civilian use, however, the helicopter is difficult to fly and has become too expensive, providing an opportunity for the much less complex and much more manageable gyroplane to reemerge.