What did Leonardo da Vinci call his screw-shaped aerial-lift concept?

Leonardo da Vinci called his screw-shaped aerial-lift concept an aerial screw.

Drawn around 1489, the aerial screw has a helical surface wrapped around a central mast. Leonardo reasoned that if the screw rotated rapidly enough, its surface might push against the air and lift the machine. The concept is often described as an early ancestor of the helicopter, although it was not a helicopter in the modern engineering sense.

The design was probably too heavy and lacked a suitable power source. Leonardo’s drawing does not provide a complete engine or practical control system, and the materials available in Renaissance Italy could not easily have produced a lightweight working rotorcraft.

Its historical importance lies in the idea of vertical lift. Centuries later, powered helicopters used rotating blades rather than a continuous screw-shaped sail, but the aerial screw remains one of Leonardo’s best-known aviation concepts.