Leonardo da Vinci sketched an aerial screw as a possible way to lift a machine into the air.
The drawing, made around 1489, shows a large helical structure supported by a framework. Leonardo proposed that rapid rotation would make the screw press against the air and rise, an idea resembling the action of a modern helicopter rotor. The concept is often called the helicopter screw or aerial screw.
Leonardo did not build a powered prototype. The materials, available power sources, and aerodynamic understanding of the period were insufficient to make the design practical. The drawing also does not show the modern rotor, engine, tail control, or stable flight system required by helicopters.
The aerial screw should not be confused with Leonardo’s parachute or bird-inspired ornithopter sketches. The parachute is intended to slow descent, while the aerial screw seeks lift through rotation. Its historical importance lies in recognizing that a helical rotating surface might interact with air in a useful way.