Leonardo da Vinci called his rotating flight concept the aerial screw. The drawing shows a large helical surface wrapped around a central mast, with a frame and people turning a mechanism beneath it.
Leonardo recorded the design around 1489. His idea was that the screw might penetrate or “screw” into the air if rotated rapidly enough. In modern terms, it resembles a very early conceptual helicopter rotor, although the proposed human power and materials could not have generated enough lift for practical flight.
The aerial screw is different from Leonardo’s ornithopter designs. An ornithopter relies on flapping wings, while the aerial screw depends on rotation. It is also not evidence that Leonardo built a helicopter; the sketch is a theoretical study rather than a tested aircraft.
Later historians and engineers have often cited the design as an ancestor of vertical-flight ideas. Modern helicopters use aerodynamic rotor blades, engines, controls, and lightweight structures that were unavailable to Leonardo.