Leonardo da Vinci sketched an aerial screw as a precursor to the helicopter.
The aerial screw appears in a drawing dated about 1489. Leonardo imagined a large helical rotor made from reed, linen, and wire, with a platform and people turning mechanisms below it. He reasoned that the screw might “screw” itself upward through the air, in a way comparable to a screw moving through a solid material.
The design is often called Leonardo’s helicopter, but that label can create confusion. It had no modern engine, and its proposed human-powered mechanism could not generate enough lift to raise the structure. It was a theoretical aeronautical experiment rather than a practical aircraft.
The drawing remains historically important because it identifies rotating lift as a possible route to flight. Modern helicopters use powered rotors and aerodynamic blades, not a linen-covered spiral surface. Leonardo’s aerial screw therefore resembles the helicopter in concept, not in engineering detail.