Leonardo da Vinci’s aerial screw was a flying-machine concept based on the rotating motion of a screw.
Leonardo drew the aerial screw in the Codex Atlanticus, generally dated to about 1489. The design shows a large helical surface wrapped around a central mast, with a platform and framework beneath it. He suggested that if the screw-like surface were spun rapidly, it might rise through the air.
The idea resembles the basic visual principle of a modern helicopter rotor, but the mechanism would not have provided enough lift with the materials and power sources available in the fifteenth century. Leonardo’s drawing therefore represents a theoretical machine, not a documented working aircraft.
The aerial screw is frequently described as a helicopter ancestor, though that comparison should be made carefully. A helicopter uses powered rotors and aerodynamic blades rather than a linen-covered helical screw. Leonardo’s importance here is his attempt to study vertical flight through geometry, materials, and mechanical rotation.