Leonardo da Vinci’s aerial screw was a spiral device intended to rise from the ground.
Leonardo sketched the aerial screw in the 1480s, probably around 1489. The drawing shows a large helical sail wrapped around a central mast, with a platform and supporting framework beneath it. He reasoned that turning the spiral rapidly could make it “screw” upward through the air.
The aerial screw was not a working helicopter. Leonardo lacked a sufficiently light engine and a practical method for producing the necessary rotational power. Modern helicopters instead use powered rotors, whose blades generate lift as they rotate through the air.
The sketch is nevertheless an important milestone in the history of vertical flight. It is frequently described as a helicopter precursor, but it should not be confused with a completed aircraft. Leonardo’s other flight studies included flapping-wing machines and gliding devices, each based on different ideas about how humans might fly.