AIR SCREW

«I believe that if this mechanism is well built with starched linen cloth, and if it is spun rapidly, the screw will engage its gear when in the air and it will rise up on high». In studying the air screw, Leonardo anticipates by centuries the formulation of the tractive power of the helix. The screw has a 5 metre diameter and is made of reed, linen cloth and wire. The shaft is spun by four men who stand on the central platform and push the bars in front of them with their hands