Leonardo da Vinci’s rotating aerial machine with a linen-covered helical screw is called the aerial screw.
Leonardo drew the machine in a manuscript dated to about 1489. Its large spiral surface was intended to press against the air and lift the structure when rotated. The concept resembles a modern helicopter rotor in broad outline, but it would not have had a practical power source or a lightweight enough frame.
The drawing is often described as an early helicopter concept, although “aerial screw” is the more historically precise name for Leonardo’s design. The machine depended on people turning a central mechanism, and the available materials would not have produced enough lift for sustained flight.
Leonardo’s notes show that he was studying air as a fluid and comparing its behavior with water. His flight investigations also included wings, gliding devices, and parachute-like structures. None of these designs is known to have flown successfully in his lifetime.