Leonardo da Vinci sketched an aerial screw as a concept for vertical flight.
The aerial screw appears in one of Leonardo’s notebooks from around 1489. Its design has a helical surface wrapped around a central mast, resembling a large screw or spiral. Leonardo reasoned that if the spiral moved rapidly enough, it might “screw” itself upward through the air.
The idea is often described as an early ancestor of the helicopter, but it was not a practical helicopter design. Leonardo did not provide a workable engine, and the materials and power available in Renaissance Italy could not have driven such a large device effectively. The sketch is therefore best understood as a theoretical study.
The aerial screw also differs from Leonardo’s ornithopter. An ornithopter uses flapping wings, whereas the aerial screw relies on rotating blades or a helical surface. Modern helicopters use powered rotors with carefully shaped airfoils, making them far more efficient than Leonardo’s proposal.