Leonardo da Vinci sketched an aerial screw around 1489, using a helical linen-covered rotor.
His drawing shows a large spiral surface wrapped around a central mast. Leonardo proposed that the rotating structure could “screw” itself upward through the air, an idea that is often compared with the principle of a helicopter rotor. The concept was inspired partly by the flight of the screw-shaped seed pods of some maple trees.
The aerial screw was not a working helicopter. Leonardo did not have an engine light and powerful enough to turn such a large rotor, and the proposed mechanism would not have supplied practical lift as drawn. The design nevertheless anticipated the idea of vertical flight through rotating blades.
The machine is sometimes called a helicopter in popular descriptions, but “aerial screw” is the historical name associated with Leonardo’s sketch. Modern helicopters use powered rotors with carefully shaped blades, a much more developed aerodynamic system.