What was Leonardo da Vinci’s proposed rotating airborne machine commonly called?

Leonardo da Vinci’s proposed rotating airborne machine is commonly called the aerial screw.

Leonardo drew the aerial screw around 1489, describing a large helical structure supported by a reed-and-canvas frame. His idea was that the screw would rotate and push against the air, producing upward motion. The concept resembles the basic principle of a modern helicopter rotor, although the proposed machine could not have lifted itself with the materials and power available at the time.

The aerial screw is often described as a helicopter ancestor, not as an actual helicopter. It had no engine, and Leonardo did not build a working full-scale version. Its importance lies in recognizing that rotary motion could provide vertical lift.

The design is frequently mixed up with Leonardo’s ornithopter. An ornithopter uses flapping wings; an aerial screw uses a rotating helical surface. That difference makes the aerial screw a distinct invention concept.