Leonardo da Vinci's 1489 spiral machine proposed for vertical flight is commonly called the aerial screw.
The aerial screw is drawn as a large helical structure supported by a framework. Leonardo reasoned that if the screw-shaped surface rotated rapidly enough, it might push against the air and rise. The concept resembles the principle behind a modern helicopter rotor, although it was not a practical helicopter and no working full-scale version was built by Leonardo.
The drawing appears in the manuscript generally known as the Codex Atlanticus. Its date is often given as about 1489, placing it among Leonardo's earliest recorded ideas about mechanical flight.
The design is sometimes described as a “helicopter” in popular accounts, but that label can be misleading. Modern helicopters use powered rotors, aerodynamic blades, and controlled flight systems; Leonardo's aerial screw was a theoretical precursor. It remains one of his best-known engineering sketches because it anticipates vertical-lift thinking centuries before powered aviation.