Definition
A small rotor mounted vertically on the tail boom of a single-main-rotor helicopter that produces sideways thrust to counteract the torque reaction caused by the spinning main rotor. The pilot controls its thrust with the foot pedals to keep the helicopter pointed in the desired direction.
Plain English
The little rotor on the tail of a helicopter. It pushes sideways to stop the body of the helicopter from spinning the opposite way to the big rotor on top, and it also lets the pilot point the nose left or right.
Context Anchor
Encountered in helicopter controls, tail rotor discussions, hover practice, and emergency procedures involving loss of tail rotor effectiveness.
Derivation
Anti- (Greek, 'against') plus torque (from Latin torquere, 'to twist'). The name describes its job directly: it works against the twisting force the main rotor tries to impose on the helicopter's body.
Why Pilots Care
Maintains directional control and prevents the fuselage from rotating uncontrollably in single-main-rotor helicopters.
Analogy
It is like using a small side push to stop a shopping cart from twisting as you move it. The push is not the main force lifting or moving the cart, but it keeps the direction controlled.
Intuition Check
Do not think of the antitorque rotor as a small propeller for forward speed. Its main job is to oppose the helicopter’s twisting tendency and control where the nose points.
Example Sentence 1
When the pilot added power on takeoff, she pressed the left pedal to increase antitorque rotor thrust and keep the nose straight.
Example Sentence 2
A failed antitorque rotor leaves a helicopter unable to resist the main rotor's twisting force, causing rapid rotation.