Leonardo da Vinci’s rotating flight machine powered by a helical sail is called the aerial screw.
Leonardo drew the design in the Codex Atlanticus around 1489. It showed a large spiral surface made from linen, with a reed framework and a central mast. He proposed that people could turn the mechanism and force the spiral surface upward through the air, much like a screw advances through wood.
The aerial screw is frequently described as an early helicopter concept, but that comparison needs care. Leonardo’s machine had no powered engine, rotor blades, or practical method for producing sustained lift. Its rotating helical surface would also have faced major aerodynamic problems. The drawing is therefore best understood as a visionary flight study rather than a working aircraft.
Its importance lies in the attempt to apply mechanical rotation to vertical flight. Modern helicopters use rotating airfoils and engines, not a solid linen screw.