Leonardo da Vinci’s aerial screw is often called an early helicopter concept because it used a rotating helical rotor.
Leonardo sketched the device around 1489–1490 in his notebooks. Its large spiral surface was intended to push against the air and lift the machine, much as a screw advances through a solid material. The drawing shows a broad linen-covered frame supported by reeds, with people turning a central mechanism.
The aerial screw was not a working helicopter. Renaissance materials, human power, and the design’s weight would not have produced enough lift for sustained flight. It is therefore best understood as a speculative flying-machine study, not the first helicopter. The concept is still important because it anticipated the basic idea of vertical lift by a rotating rotor.
Leonardo’s other flight studies included flapping-wing machines, or ornithopters. Those designs copied bird movement, while the aerial screw used rotary motion—a distinction that makes it especially relevant to later helicopter history.