Leonardo da Vinci drew an aerial screw around 1489, using a helical sail as a concept for vertical flight.
The design has a large spiral-shaped surface mounted around a central mast. Leonardo proposed that the spiral could “screw” into the air if rotated rapidly, creating lift. The idea is often described as a distant precursor of the helicopter, although it was not a helicopter in the modern engineering sense.
Leonardo’s aerial screw was probably inspired partly by the Chinese flying top, a toy known in Europe through descriptions and examples. His drawing shows a machine requiring several people to turn mechanisms and provide power.
The machine was never built and flown by Leonardo. Modern helicopters generate lift with powered rotor blades, while the aerial screw relies on a continuous helical surface. Its historical importance lies in identifying vertical flight as a separate engineering problem from ordinary forward flight.