Aerial Screw Between 1480 and 1490 Leonardo drew his famous Aerial Screw, which represents the first idea of propeller (the same principle used by modern helicopters). By a rotary mechanism a screw with starched canvas and a radius of 4,80 m should be turned so fast that it would mount aloft. As a kit the screw is a little smaller but fully versatile and designed by the original drawing and by the historical model of the Museo Nazionale della Scienza e della Tecnologia Leonardo da Vinci in Milano.