Leonardo da Vinci’s 1489 rotating-air screw was called the aerial screw.
Leonardo drew the aerial screw as a large helical rotor made from reeds, linen, and wire. His notes suggest that the rotating screw would push against the air and lift the machine, an idea that resembles the principle behind a helicopter rotor.
The design was never built as a practical flying machine. Its proposed size, weight, materials, and human-powered mechanism made flight unrealistic. Nevertheless, the sketch is historically important because it shows Leonardo reasoning about vertical lift rather than relying only on bird-like flapping wings.
The aerial screw is often called a helicopter precursor, not the first helicopter itself. Modern helicopters use powered rotors, aerodynamic blades, and control systems that were unavailable in Renaissance Italy.