Leonardo da Vinci designed an aerial screw with a large rotating screw intended to lift an aircraft into the air.
The drawing, usually dated to around 1489, shows a helical surface wrapped around a frame. Leonardo reasoned that rotating the screw could push against the air and raise the machine, an idea often compared with the principle of a modern helicopter rotor. The proposed craft would have required several people to turn the mechanism.
The aerial screw was not a successful helicopter and was never demonstrated as a powered aircraft by Leonardo. Its materials, weight, and human-powered mechanism would not have supplied enough lift. The design is important because it shows Leonardo thinking about vertical flight and aerodynamic force centuries before practical helicopters appeared.
It is sometimes called a helicopter in popular accounts, but that name can suggest a closer technical resemblance than the design deserves. “Aerial screw” is the historical name associated with Leonardo’s sketch. It is also distinct from his flapping-wing studies, which pursued a different method of flight.