Leonardo da Vinci’s aerial invention that used a helical sail to rise into the air was the aerial screw.
Leonardo drew the concept in a manuscript usually dated to about 1489. The machine has a large spiral-shaped linen surface stretched over a reed framework. His notes suggest that, if the screw rotated rapidly enough, the helical surface could push against the air and lift the machine.
The aerial screw is frequently linked with the later helicopter because both use rotating lifting surfaces. However, Leonardo’s design was not a helicopter in the modern engineering sense. It had no practical engine, and the proposed mechanism would not have produced enough power for sustained flight with the materials and technology available in Renaissance Europe.
The design nevertheless shows Leonardo thinking about vertical flight rather than relying only on wings or gliding. Modern helicopters use powered rotors with carefully shaped blades, while the aerial screw’s continuous spiral surface was a very different aerodynamic idea.