Leonardo da Vinci’s helical flying-machine design was called the aerial screw.
Leonardo drew the aerial screw in the Codex Atlanticus around 1489. The design showed a large helical linen surface wrapped around a central reed-and-wood frame. He proposed that turning the screw would make it “bore” upward through the air, much as a screw moves through a material.
The aerial screw is often described as an ancestor of the modern helicopter, but it was never built and tested by Leonardo. Its proposed mechanism also lacked a practical power source strong enough to lift the structure and passengers. The resemblance to a helicopter concerns the principle of vertical lift, not a fully workable engine or rotor system.
Leonardo’s notes on flight also included parachutes, gliders and flapping-wing machines. These designs show his interest in studying air resistance and lift centuries before powered aviation became possible.