Leonardo da Vinci’s rotating aerial machine is commonly called the aerial screw.
Leonardo drew the design around 1489, describing a large helical rotor made from a reed, linen, and wire framework. The drawing shows people turning the mechanism, reflecting Leonardo’s interest in translating rotary motion into lift. The concept resembles a modern helicopter rotor in broad principle, although it could not have flown as designed.
The aerial screw lacked a lightweight engine and the aerodynamic efficiency required for powered flight. Its large spiral surface would also have been difficult to rotate fast enough with human muscle power. For these reasons, it is best described as a helicopter precursor or conceptual study rather than a functioning helicopter.
The design is sometimes incorrectly called Leonardo’s helicopter. “Aerial screw” is the established name associated with the drawing and emphasizes its helical shape rather than claiming that it was a working aircraft.