Definition
A rotary-wing aircraft that uses a freely rotating, unpowered overhead rotor to generate lift, while forward thrust is provided by a separate engine-driven propeller. The rotor is not driven in flight; it spins on its own as air flows up through the rotor disc — a process called autorotation. Because the rotor is not powered, an autogiro cannot hover or take off vertically like a helicopter, but it can fly very slowly and land in a short distance.
Plain English
An aircraft with a propeller in front for forward motion and a free-spinning rotor on top for lift. The rotor turns by itself as the aircraft moves through the air.
Context Anchor
Seen in older aviation books, rotorcraft discussions, and references to early gyroplanes.
Derivation
From Greek 'autos' (self) and 'gyros' (turning or circle) — literally 'self-turning.' The name was coined in the 1920s by Spanish engineer Juan de la Cierva, who invented the aircraft. The name describes exactly how it works: the rotor turns itself, without engine power.
Why Pilots Care
Autogiros fly under different rules and handling characteristics than airplanes or helicopters. Knowing the category matters for certification, identification, and understanding why one cannot hover despite having a rotor.
Grounding Statement
Picture a small aircraft moving forward with a propeller while the overhead rotor spins in the airflow and provides lift.
Intuition Check
“Auto” does not mean the aircraft flies automatically. Here it points to the rotor turning on its own in flight because of airflow.
Example Sentence 1
The autogiro lifted off after a short ground roll, its overhead rotor already spinning up to flight speed.
Example Sentence 2
Early Autogiros demonstrated the principle of autorotation that later influenced helicopter design.