The Leodrone: aerodynamics of Leonardo Da Vinci's Aerial Screw

Exhibited in “The analogue notebook: A forgotten exercise?” Cassinelli, Alvaro (Artist). Leonardo da Vinci, Art & Science Then & Now. Curated by I. Frank and A. Rocca, Assoc. Curators: J. Shaw and N.Patrzynski, Indra and Harry Banga Gallery, City University of Hong Kong. 20 September – 15 December 2019.

Incredible as it may be, and despite the widespread recognition of Leonardo Da Vinci as the “father” of aerodynamics, nobody seems to have studied the aerodynamic efficiency of one of his more iconic designs: the aerial screw. I modelled the aerial screw, and simulated Leonardo Da Vinci contraption using modern computational fluid dynamics (CFD, SimScale). The screws were then slightly modified to compensate for excentricity and diminish the weight, and 3d printed (SLA) before being attached to a small Tello drone.

As expected, the thrust is dramatically lower (at least 50 times less) than that of a modern propellers; nevertheless, it was possible to lift a small “Tello” drone for some seconds, but the design did not resist the excentric vibrations of the 3d printed propellers. It should be possible to make it flight though by using lighter propellers (paper?) and or slightly modified aerial screws. Speed of rotation is also critical: Leonardo’s screw seems to be conceived as… a screw, screwing in a substance with a much less density than, say, wood. The lifting principle is different in many ways (air is less dense and also create vortices and flows). Trying with a higher speed did not work; I investigated several designs and the more I tried, the more the design ressembled a double (or triple) blade helicopter propeller, and the more it looked like an archimedes screw. I stopped there, trying to stay close to the original Leonardo helicopter.

In any case, the resulting (pataphysical) experiment is a small tribute to the genius of the man. This updated, toy version of Leonardo Da Vinci helicopter was demonstrated – crashing and finally hung to the ceiling – at an exhibition showcasing real Leonardo Da Vinci works (Ambrosiana collection) at City Univesity of Hong Kong.