Leonardo da Vinci’s helical flying machine was called the aerial screw. He sketched it around 1489 in the Codex Atlanticus, imagining a large spiral surface that would rise by pushing against the air.
The design had a central mast, a rotating framework, and a linen-covered helical surface. Leonardo compared its action to a screw moving through a solid material, but the machine was never built or tested during his lifetime.
The aerial screw is often described as an early conceptual ancestor of the helicopter, although it lacked an engine and a practical method for producing sustained rotation. It is also commonly confused with Leonardo’s ornithopter, which used flapping wings rather than a spiral rotor.
Modern helicopter rotors rely on aerodynamic lift from rotating blades, not a continuous screw-shaped sail. Leonardo’s sketch is therefore most important as an example of Renaissance mechanical imagination rather than as a directly workable aircraft.