RC quadrocopter, is the latest development in radio controlled vertical lift platforms that are able to take off vertically, hover, and fly in all directions. As the name suggests, there are 4 propellers arranged in a cross type configuration. RC Quadrocopter is also called quad rotor RC helicopter or multi-rotor.
There is no single large collective pitch rotor or tail rotor which is used on a conventional RC helicopter. These propellers are fixed pitch, two will spin clockwise and the other two will spin counter clockwise. By precisely and accurately spinning these four propellers at different speeds, all the common directional movements of a standard helicopter are attainable - Hover, forward/backward movement, left/right movement, and yaw (turn rate) movement.