Leonardo da Vinci’s aerial screw was a rotating-air machine drawn in 1489 and often regarded as an early helicopter concept.
The design shows a large helical sail mounted around a central shaft. Leonardo reasoned that if the screw were rotated rapidly, its surface might bite into the air and lift the structure upward. The drawing was an imaginative study rather than a practical aircraft, because the proposed human-powered mechanism could not generate enough lift.
The machine is frequently confused with the modern helicopter. A helicopter uses powered rotors and aerodynamic blades, while Leonardo’s concept relies on a continuous spiral surface. It therefore belongs more accurately to the history of vertical-flight ideas.
Leonardo’s aerial screw helped illustrate how he applied observations of birds, air resistance, and motion to engineering. Centuries later, powered aircraft made vertical flight practical using principles that differed substantially from his sketch.