Leonardo da Vinci sketched an aerial screw as a possible ancestor of the helicopter.
The aerial screw appears in one of Leonardo’s notebooks from around 1489. His drawing shows a large helical surface surrounding a central mast. Leonardo reasoned that if the screw could be rotated rapidly enough, its structure might push against the air and lift the machine upward.
The idea resembles a modern helicopter rotor in its use of rotating lift, but it was not a helicopter in the modern engineering sense. Leonardo’s design lacked a practical engine, a suitable lightweight frame, and a proven method for controlling the machine. The proposed silk-covered screw would also have been too heavy and inefficient for human-powered flight.
The aerial screw is often called a helicopter precursor, not the first helicopter. Modern helicopters use powered rotors with carefully shaped airfoils and control systems, while Leonardo’s concept was primarily a theoretical study of vertical flight.