Leonardo da Vinci's early helicopter concept was called the aerial screw.
Leonardo drew the device in a manuscript dated about 1489. It featured a large helical rotor made from reeds, linen, and wire, with a wooden platform and several people turning bars to rotate the mechanism. Leonardo reasoned that the screw could rise by “screwing” into the air.
The aerial screw was not a functioning helicopter. Its proposed human power source could not generate enough energy to lift the heavy structure, and the design lacked the controls and lightweight materials used by later helicopters.
Nevertheless, the sketch is historically important because it presents a vertical-lift aircraft using a rotating spiral surface. Modern helicopters use powered rotors rather than Leonardo's continuous helical sail.