Aerial screw

The screw is made of a spiral-shaped linen canvas arranged around a vertical mast, inserted onto a circular platform. By running on the platform and pushing the horizontal bars connected to a central mast, a number of men can operate this screw.

This project is part of the study of the physical and chemical characteristics of air: Leonardo reached the conclusion that air can be compressed and that it has its own material thickness. He therefore retained that a screw-shaped device, if rapidly rotated, could rise in flight by screwing itself into the thickness of the air, in exactly the same manner a common screw can screw into another material.