What was Leonardo da Vinci’s aerial screw intended to achieve?

Leonardo da Vinci’s aerial screw was intended to achieve vertical flight.

Drawn around 1489, the design shows a large helical rotor made from reed, linen, and wire. Leonardo reasoned that if the screw rotated quickly enough, its helical surface could push against the air and lift the structure upward. The sketch is often described as an early helicopter concept, although it was never built or tested by Leonardo.

The design would not have worked as drawn with Renaissance materials and human muscle power. Its importance is conceptual: it treats air as a medium that a rotating surface can push against, anticipating later rotorcraft. It is not the same invention as Leonardo’s self-moving vehicle, parachute, or ornithopter; those designs addressed ground movement, descent, and flapping flight respectively.