Leonardo da Vinci sketched an aerial screw, a spiral-powered flying-machine concept often described as an early helicopter idea.
The drawing appears in the Codex Atlanticus and shows a large helical structure made from reeds, linen, and wire. Leonardo proposed that the spiral surface could screw upward through the air if rotated rapidly. The concept was not powered by an engine and was never tested successfully in his lifetime.
The aerial screw resembles a modern helicopter rotor in its broad goal of producing vertical lift, but its mechanism and scale were very different. Modern helicopters use powered rotors with carefully shaped blades, while Leonardo’s design depended on a continuous spiral surface.
Calling it a helicopter can therefore be misleading. The helicopter was developed centuries later through advances in engines, aerodynamics, and materials. Leonardo’s sketch is best understood as a striking early study of rotary flight rather than a functioning helicopter.