Leonardo da Vinci sketched an aerial screw as a possible vertical-lift aircraft.
Leonardo drew the aerial screw in a manuscript generally dated to about 1489. The design shows a large helical surface wrapped around a vertical frame. His notes suggested that if the screw-shaped surface were spun rapidly, it might press against the air and rise, an idea that resembles the operating principle of a helicopter rotor.
The proposal was a thought experiment rather than a tested aircraft. Renaissance materials and human-powered mechanisms could not provide the power-to-weight ratio needed to lift the structure. The design also lacked the control systems, lightweight engines, and aerodynamic understanding required for practical flight.
The aerial screw is frequently described as a helicopter ancestor, but it was not a helicopter in the modern engineering sense. Modern helicopters use rotating blades that generate lift through airfoils, while Leonardo’s drawing proposed a continuous helical surface. The concept remains important because it shows his attempt to reason mechanically about vertical flight.