Leonardo da Vinci designed an aerial screw as a concept for lifting a machine vertically through the air.
Drawn around 1489, the design shows a large helical surface wrapped around a central mast. Leonardo reasoned that if the screw rotated rapidly enough, its shape might “screw” upward through the air. The surviving drawing resembles a distant ancestor of the helicopter, although it lacks a practical engine and modern rotor system.
The aerial screw was not a helicopter in the modern engineering sense. Leonardo proposed human-powered rotation, but the people and mechanisms available in his era could not provide enough continuous power for flight. The design was therefore an important imaginative step, not a tested aircraft.
The name can cause confusion because “screw” refers to the spiral lifting surface, not an ordinary fastener. Later vertical-flight machines used rotating blades with very different aerodynamic principles and power sources.