Leonardo da Vinci’s aerial screw was a flying-machine concept that used a large rotating spiral to rise through the air.
Leonardo drew the design around 1489 in a manuscript now associated with the Codex Atlanticus. The machine had a helical surface wrapped around a central mast, resembling a giant screw or modern helicopter rotor. His notes suggested that if the screw-shaped sail rotated rapidly, it might “screw” upward through the atmosphere.
The aerial screw is frequently described as an early helicopter idea, but that comparison needs care. Leonardo did not build a working prototype, and the drawing does not provide a complete power system capable of turning the enormous rotor fast enough. The concept also lacked the modern helicopter’s separate controls for lift, direction, and stability.
Its historical importance lies in the recognition that rotating blades could generate upward force. Modern helicopters use powered rotors with aerodynamic blades, not a solid spiral sail. Leonardo’s sketch is therefore a visionary predecessor, not a functioning helicopter.