Leonardo da Vinci’s spiral-rotor flying-machine design is called the aerial screw.
Leonardo described the device in a drawing generally dated to around 1489. It shows a large helical surface wrapped around a central mast, with a frame and platform below. His notes suggest that rotating the spiral could make it rise through the air, an idea often compared with the modern helicopter rotor.
The aerial screw was not a working helicopter. Renaissance materials and human muscle power could not provide enough lift, and Leonardo did not build a successful full-scale version. Its importance lies in the principle it anticipated: a rotating airfoil can generate upward force.
The design is often confused with Leonardo’s ornithopter, which used flapping wings. The aerial screw instead relied on a rotating spiral surface, making it one of his most recognizable studies of vertical flight.