Leonardo da Vinci’s aerial screw used a screw-shaped rotor intended to lift a passenger vertically. Leonardo drew the design in 1489, making it one of his best-known studies of powered flight.
The machine had a large helical surface wound around a central mast. Leonardo reasoned that, if the screw were rotated rapidly, its linen-covered frame would bite into the air in a manner analogous to a screw moving through a solid material. The design is therefore commonly described as a precursor to the helicopter.
However, the drawing does not show a practical power source capable of turning the rotor fast enough. The proposed human crew would not have produced sufficient energy for sustained lift, and the structure would have been extremely heavy. Modern versions are generally experimental reconstructions or museum models rather than working aircraft.
The aerial screw should also be distinguished from Leonardo’s ornithopter studies, which sought lift through flapping wings. The two designs represent different mechanical approaches to flight.