Leonardo da Vinci sketched an aerial screw, a conical spiral machine intended to rise through the air by spinning.
The drawing appears in Leonardo’s famous Codex Atlanticus and is usually dated to around 1489. It shows a large helical structure supported by a framework, with a mechanism at its center. Leonardo reasoned that the spiral surface could press against the air and produce upward motion if rotated rapidly.
The aerial screw is often described as an early ancestor of the helicopter, but it was not a functioning helicopter. Leonardo did not have a sufficiently light engine or a demonstrated method for producing the necessary rotation. The design therefore belongs to the history of flight concepts rather than successful aviation.
It is sometimes confused with Leonardo’s ornithopter. The ornithopter depends on flapping wings; the aerial screw depends on a rotating spiral surface. That distinction makes “aerial screw” the precise answer.