Definition
A long, narrow airfoil that rotates about a central hub on a helicopter or other rotary-wing aircraft to generate lift and, through cyclic and collective control, the forces needed to climb, descend, hover, and move in any direction.
Plain English
One of the spinning 'wings' on a helicopter. As it spins through the air it produces lift, which is what holds the aircraft up and lets the pilot control where it goes.
Context Anchor
Seen in discussions of helicopter aerodynamics, airfoil shape, rotor systems, and preflight inspection.
Derivation
Rotor' comes from the Latin 'rotare,' meaning 'to turn,' and is short for 'rotator' — something that rotates. So a rotor blade is simply a blade that turns, in contrast to the fixed wing of an airplane.
Why Pilots Care
Rotor blade condition and shape directly determine lift, stability, and safe control in every phase of helicopter flight.
Analogy
Think of a fixed wing sliced into long, narrow strips and mounted to a hub so it can spin. Each strip is a rotor blade, and instead of the whole aircraft moving forward to make air flow over the wing, the blades spin to create that airflow themselves.
Intuition Check
Do not think of a rotor blade as just a fan blade. In aviation, it is a lifting surface that must be shaped and angled correctly to support and control the aircraft.
Example Sentence 1
A helicopter's rotor blades produce lift the same way an airplane's wings do, except the blades move through the air by rotating rather than by the aircraft flying forward.
Example Sentence 2
In forward flight the advancing rotor blade produces more lift than the retreating blade.