Definition
Helicopters that use one main rotor to provide lift and thrust, paired with a smaller tail rotor that counteracts the torque produced by the main rotor and provides directional (yaw) control.
Plain English
A helicopter with one big spinning rotor on top and a small rotor on the tail. The big rotor lifts and moves the aircraft; the tail rotor stops the body from spinning the opposite way and lets the pilot point the nose left or right.
Context Anchor
Seen in helicopter instrument flying when discussing how power changes affect heading control in straight-and-level flight.
Derivation
Rotor comes from the idea of something that rotates, or turns. In this term, single-rotor points to the helicopter having one main rotating wing system doing the lifting work.
Why Pilots Care
Correct power application in single-rotor helicopters requires active compensation for torque effects to maintain coordinated flight and altitude.
Intuition Check
Single-rotor does not mean the helicopter has only one spinning part. It means it has one main lifting rotor, with another system used to control the twisting effect.
Example Sentence 1
In single-rotor helicopters, the pilot uses the anti-torque pedals to keep the nose straight as power is increased.
Example Sentence 2
During instrument flight, torque compensation in single-rotor helicopters is managed through coordinated pedal and throttle inputs.