Leonardo da Vinci’s aerial screw used a large helical blade to imitate a helicopter.
Leonardo drew the aerial screw in the Codex Atlanticus around 1489. His design showed a spiral structure made from reeds, linen, and wire, with a platform and a crew intended to turn the mechanism. Leonardo reasoned that the helical surface would “screw” upward through the air if rotated rapidly enough.
The idea resembles a helicopter rotor, but the original design could not have lifted itself with the materials and human power available in Renaissance Italy. It was a conceptual study of aerial motion rather than a demonstrated aircraft. Modern experiments have built models, but these do not prove that Leonardo’s exact machine was practical.
The aerial screw is also called Leonardo’s helicopter in popular accounts. That label is convenient, but “aerial screw” is the more precise historical name for the drawing.