The tail rotor of a helicopter is mounted on the tail of a single-rotor helicopter, perpendicular to the main rotor. It is primarily used in order to counteract the yaw motion and the torque that a rapidly turning disk naturally produces.

In some more recent helicopter designs, the tail rotor has been mounted tangential to the furthest back point of the top rotor. That is to say that it looks much like an old propeller plane, only at the back of the helicopter instead of the front of a wing. In these new designs the rotor spins in a direction opposite to the top rotor (i.e. counter-clockwise if the rotor spins clockwise and vise-versa). This in effect, cancels the spin and has the added benefit of producing forward thrust.

Most, if not all, dual-rotary helicopters do not use tail rotors, instead, the design of the two main rotors is such that they spin in the opposite directions of each other, thus each cancels out the torque and yaw produced by the other.

Helicopters

Heckrotor-Konfiguration | Rotor anti-couple | Staartrotor | Fenestron