What was Leonardo da Vinci’s rotating-wing flying machine commonly called?

Leonardo da Vinci’s rotating-wing flying machine was commonly called the aerial screw.

Drawn in 1489, the aerial screw consisted of a large helical rotor made from reeds, linen, and wire, supported by a circular frame. Leonardo reasoned that the screw might “screw” itself upward through the air if turned quickly enough.

The sketch is frequently described as a helicopter ancestor, but it was not a practical helicopter. The design lacked a modern engine, and the proposed materials and human-powered mechanism would not have provided enough thrust for controlled flight.

The aerial screw should also be distinguished from Leonardo’s ornithopter. The ornithopter depended on flapping wings, while the aerial screw depended on a rotating helical surface. Its historical importance lies mainly in showing Leonardo’s attempt to explain vertical flight mechanically.