Leonardo da Vinci’s 1489 aerial-screw design is commonly described as a precursor to the helicopter. The drawing shows a large helical rotor intended to compress air and lift a platform from the ground.
Leonardo probably understood that the machine would need substantial power, but the design was not built or tested in his lifetime. Its importance is conceptual: it explores vertical flight with a rotating screw rather than wings or a fixed lifting surface.
The aerial screw is often called a helicopter prototype, but it was not a functioning helicopter. Modern helicopters use powered rotors, aerodynamic blades, engines, and controls that Leonardo’s sketch did not provide.
The drawing is associated with Leonardo’s manuscripts from the late 15th century. It remains one of his best-known studies of flight, alongside his parachute and ornithopter designs.