Rotorcraft, refers to the use of unpowered rotor blades to provide lift, heavier than air "flying machine". By the propulsion device to provide thrust forward, the propulsion device has a propeller and jet two. Forward when the airflow blowing rotor and generate lift, it can not take off vertically or hover, often in the takeoff also give the rotor an initial power, so that the rotor's lift increases. With the help of the rotor can do a near-vertical landing. The rotor makes the structure complex and speed increase is limited. Rotorcraft were made in 1923, but because of the high rotor drag, the flight speed was below 300km/h, thus not much development, but the development of helicopters was promoted. Only a small number of rotorcraft were used for research and sports activities
Rotorcraft and helicopters are virtually identical: they both have a large-diameter rotor overhead and rely on the rotation of the rotor to generate lift in flight. But excluding these superficial consistency, rotorcraft and helicopters are two completely different types of aircraft.
