Leonardo da Vinci’s “aerial screw” is commonly regarded as an early helicopter concept.
The drawing, made around 1489, shows a large helical rotor-like structure intended to rise by turning through the air. Leonardo compared the action to a screw moving through a solid material. The design was probably meant to be powered by people operating internal mechanisms, although the sketch does not provide a fully workable propulsion system.
The aerial screw was not a helicopter in the modern technical sense. It lacked an engine, practical controls, and a demonstrated means of generating enough lift. Its importance lies in recognizing that a rotating surface could produce upward force, an idea later developed with powered rotors.
The design is often called a helicopter in popular summaries, but “aerial screw” is Leonardo’s historical name. The first practical helicopters appeared centuries later, after lightweight engines and improved rotor engineering became available.