Leonardo da Vinci called his rotating air machine the aerial screw.
Leonardo sketched the aerial screw around 1489. The design showed a large helical surface made from reeds, linen, and wire, with a central mast and a platform for people to turn. He proposed that the rotating helix could “screw” upward through the air, an idea that resembles the lift-producing action of a helicopter rotor.
The machine was never built and tested by Leonardo. The proposed human-powered mechanism could not have produced enough lift with the materials and power available at the time. The sketch is therefore best understood as an early theoretical study of vertical flight, not a functioning helicopter.
Modern helicopters use rotating blades shaped as airfoils and powered by engines. Leonardo’s aerial screw did not use that aerodynamic principle in its modern form, but it demonstrated an important attempt to reason about flight through rotation rather than flapping wings.