Leonardo da Vinci sketched an aerial screw around 1489 as a spiral flying machine centuries before practical helicopters.
The drawing shows a large helical structure supported by a framework. Leonardo proposed that rotating the screw could make it rise by forcing air downward, an idea related in broad principle to the lift produced by helicopter rotors.
The design could not work as drawn because its materials and human power source would not provide enough thrust. It also lacked the control systems, lightweight engines, and rotor arrangements needed for stable flight. Calling it a helicopter is therefore a useful comparison, not its historical name.
The aerial screw is one of Leonardo’s best-known engineering sketches. It demonstrates his interest in translating observations of air and water into mechanical motion, even when contemporary technology could not build the machine.