Radio controlled (RC) helicopters, although often grouped with RC airplanes, are unique because of the differences in construction, aerodynamics and flight training. Several designs of RC helicopters exist, some with limited maneuverability (and thus easier to learn to fly), and those with more maneuverability (and thus harder to learn to fly).
Flight controls allow pilots to control the collective and throttle (usually at the same time), the cyclic controls (pitch and roll), and the tail rotor (yaw). Controlling these in unison makes the helicopter perform all the maneuvers and stunts an aeroplane can do, and more besides.
An advanced form of RC helicopter flying is called 3D. During 3D flying, helicopters perform advanced aerobatics in a free flowing freestyle form. There are a number of 3D competitions around the world, two of the best known are 3D Masters in the UK and the eXtreme Flight Championship (XFC) in the USA.