Leonardo da Vinci’s helical flying-machine design was called the aerial screw.
Leonardo recorded the concept in a manuscript usually dated to about 1489–1490. The drawing shows a large helical surface made from reeds, linen, and wire, intended to rotate and push against the air like a screw moving through water. He suggested that the frame could be held together by reeds and that the linen might be coated to make it more airtight.
The aerial screw is often described as an ancestor of the modern helicopter, but it was not a working helicopter. Leonardo did not have a practical engine or a sufficiently light structure, and the design offered no proven method for controlling flight. Its importance lies in recognizing that rotary motion might produce vertical lift.
It is also commonly confused with Leonardo’s ornithopter, which used flapping wings. The aerial screw instead relied on a rotating helical surface.