Definition
A lifting surface (a wing) that produces lift by rotating around a vertical or near-vertical mast rather than by moving forward through the air with the aircraft. The rotating blades function as wings, generating lift as they slice through the air, allowing the aircraft to take off vertically, hover, and fly without forward motion. Helicopters, gyroplanes, and tiltrotors are classified as rotary-wing aircraft.
Plain English
A wing that spins to make lift, instead of staying still while the whole aircraft moves forward. This is what lets a helicopter rise straight up and hover.
Context Anchor
Seen when comparing helicopters and similar aircraft with fixed-wing airplanes in aircraft categories, training, maintenance, and operating rules.
Derivation
Rotary' comes from the Latin rotare, 'to turn or revolve.' Combined with 'wing,' it describes a wing that turns. The term was coined to distinguish these aircraft from fixed-wing airplanes, where the wings are bolted in place and don't move relative to the fuselage.
Why Pilots Care
The distinction affects pilot certification categories, training requirements, and operational procedures unique to rotorcraft.
Intuition Check
Do not read “rotary wing” as a normal airplane wing that has been bent into a circle. In aviation, it means spinning blade surfaces that act like wings and create lift as they rotate.
Example Sentence 1
Because the helicopter is a rotary-wing aircraft, it can land on a hospital rooftop where no runway exists.
Example Sentence 2
Preflight checks on rotary wing aircraft include inspection of the main rotor head and swashplate.