Leonardo da Vinci’s aerial screw is often called the ancestor of the modern helicopter.
Leonardo drew the design around 1489–1490 in the Codex Atlanticus. It shows a large helical sail made from linen stretched over a reed framework, with a platform and rotating mechanism beneath it. Leonardo reasoned that the spiral surface could “screw” upward through the air if turned rapidly.
The aerial screw was a conceptual machine rather than a successfully tested aircraft. Its proposed materials and human-powered mechanism could not provide enough lift to raise the full structure. Modern helicopters instead use powered rotors whose blades generate lift through aerodynamic motion. The aerial screw is therefore best understood as an early study of vertical flight, not a functioning helicopter or a direct working prototype. Leonardo’s sketch remains important because it demonstrates his attempt to apply mechanical principles to flight long before powered aviation existed.