Leonardo da Vinci’s aerial screw was a proposed flying machine with a large rotating helical structure intended to lift it into the air.
Leonardo sketched the aerial screw in the 1480s, probably around 1489. The design used a linen-covered helical surface stretched around a frame. He reasoned that, if the screw rotated rapidly, it might “screw” upward through the air in a way comparable to a screw moving through wood.
The concept is often described as an early ancestor of the helicopter, but it was not a helicopter in the modern engineering sense. It lacked an engine, a practical rotor system, and a demonstrated method for producing enough lift. Human operators could not realistically provide the required power with the proposed mechanism.
The aerial screw remains important as an example of Leonardo’s mechanical imagination. It shows him applying ideas from screws, mills, and fluid motion to the problem of flight, even though the machine was never shown to fly.