Leonardo da Vinci’s helicopter-like flying-machine design is commonly called the aerial screw.
Leonardo sketched the device around 1489–1490 in his codices. Its large helical sail was intended to rotate and push against the air, much as a screw moves through water. The drawing is often described as an early conceptual ancestor of the helicopter, although it was not a practical aircraft and was never built by Leonardo.
The aerial screw belonged to Leonardo’s wider study of flight. He investigated birds, air resistance, wings, and mechanical lifting systems, but he did not possess an engine light and powerful enough to make the design work. The concept therefore remained a thought experiment supported by drawings and notes.
A common mix-up is calling it Leonardo’s “helicopter.” That modern label is understandable, but aerial screw is the more specific historical name for the design shown in his manuscript.