Leonardo da Vinci's giant propeller-like flying-machine concept was called the aerial screw.
Leonardo sketched the aerial screw in a manuscript usually dated to about 1489. The design showed a helical, linen-covered surface wrapped around a central mast, with a large circular frame supporting it.
His idea was that the rotating screw would push against the air and lift the machine, an approach that resembles the principle behind a modern helicopter rotor. However, the sketch did not provide a practical engine or a workable method for producing the required power.
It is often called a helicopter in popular summaries, but “aerial screw” is the more historically precise name for Leonardo's concept. The drawing was a study of aerial propulsion, not a functioning helicopter.