Leonardo da Vinci’s aerial screw was a conical spiral machine intended to lift itself into the air.
Leonardo drew the design around 1489 in a manuscript now known as the Codex Atlanticus. The machine featured a large helical sail or screw, supported by a circular frame. His notes suggested that rotating the screw could force air downward and raise the structure.
The aerial screw is often described as a helicopter ancestor, but it was not a working helicopter. The sketch does not provide a practical engine or a complete method for generating enough power, and the proposed materials would have made the machine heavy.
The important idea was aerodynamic rather than mechanical perfection. Leonardo recognized that a rotating spiral surface could interact with air in a lifting motion. Modern helicopters use powered rotor blades, not a single large fabric-covered screw.