Leonardo da Vinci designed an aerial screw to create lift with a rotating helical blade.
His famous sketch shows a large spiral surface wrapped around a central mast. Leonardo suggested that if the spiral were spun rapidly, it could screw into the air and rise. The concept is widely discussed as an ancestor of the helicopter, although it was not a helicopter in the modern engineering sense.
The design was probably too heavy and lacked an efficient power source for practical flight. Leonardo did not build a successful working aerial screw, and the sketch does not provide all the details needed for a modern aircraft. Its importance lies in recognizing that rotary motion might produce vertical lift.
The aerial screw differs from Leonardo’s wing-based flying-machine studies. Those designs attempted to imitate flapping or gliding flight, whereas the aerial screw used a rotating helical surface.