Leonardo da Vinci drew an aerial screw, a rotating-wing aircraft concept often regarded as an early helicopter precursor.
The design appears in a manuscript page dated to around 1489. It shows a large helical surface made from reed, linen, and wire, with a platform beneath it for people to operate. Leonardo reasoned that the spiral surface could screw itself upward through the air if turned rapidly enough.
The concept resembles a modern helicopter because it uses a rotating lifting surface, but it could not have taken off with Renaissance materials and human power. It lacked an engine capable of producing enough continuous power and did not include the control systems needed for stable flight.
The aerial screw should therefore be treated as a conceptual ancestor, not a working helicopter. Modern helicopters use powered rotors, aerodynamic blades, and careful control of pitch and balance. Leonardo’s sketch is significant because it identified rotation as a possible way to generate vertical lift.