Leonardo da Vinci’s spiral design intended to lift into the air is known as the aerial screw.
Leonardo drew the aerial screw around 1489, describing a helical structure with a frame covered by a lightweight material. The concept assumed that turning the spiral rapidly would force air downward and raise the machine, an idea related to the lift produced by a modern rotor.
The design is often called a precursor to the helicopter, but it was not a workable helicopter. Leonardo provided no practical engine capable of spinning the large screw, and the proposed materials and structure would have made the machine difficult to control and probably too heavy.
The aerial screw is also frequently confused with Leonardo’s flapping-wing ornithopter. The two designs represent different approaches: the ornithopter imitates birds, while the aerial screw uses rotary motion and a helical surface. Its historical importance lies in identifying a principle later used by powered rotorcraft.