Leonardo da Vinci designed an aerial screw as a flying-machine concept with a rotating helical screw above its frame.
Leonardo drew the design around 1489–1490 in a manuscript now associated with the Codex Atlanticus. The machine’s large, linen-covered screw was intended to turn and push against the air, somewhat like a modern helicopter rotor in broad concept. The drawing shows a framework supporting the screw and a central mast.
The aerial screw was not a powered aircraft. Leonardo had no lightweight engine capable of providing the sustained power needed for flight, and the proposal was never built and tested successfully. It is therefore best described as an early helicopter-like concept, not the first helicopter. Its rotating screw also differs from the separate ornithopter idea, which imitates flapping bird wings.
The design is historically important because it shows Leonardo reasoning about lift, propulsion, materials, and mechanical power together. Modern helicopters use powered rotors and aerodynamic control systems rather than a single fabric-covered helical screw.