Leonardo da Vinci’s 1489 aerial screw was an early helicopter concept.
The sketch shows a large helical rotor made from reed, linen, and wire, mounted on a platform. Leonardo reasoned that the screw could rise if its surface were driven rapidly enough through the air. The idea was inspired partly by the action of an Archimedean screw, which moves through water or raises it.
The aerial screw was not a working helicopter. No engine in Leonardo’s time could provide enough power for a human-sized rotor, and the machine lacked a practical method for controlling flight. Modern helicopters also depend on carefully shaped rotor blades and powered rotors.
The design is still historically significant because it identified vertical lift as a possible route to flight. It should not be confused with Leonardo’s ornithopter studies, which attempted to imitate the flapping motion of birds rather than use a rotating screw.