Studies for the design of a perpetual wheel with articulated arms

In folios 147v and 148r Leonardo analyses a traditional perpetual wheel with articulated arms and integrated with a mechanical system that should anticipate the opening of the arms. These two sheets, dated to the mid-1490s, are packed with his trains of thought on this topic, plus later additions, which conclude with the demonstration of the impossibility of their working. Interesting is, however, the note on the margin of folio 147v: not yet convinced of the impossibility of this wheel, Leonardo reasons on the forces involved in the rotation, as he is trying to measure the contribution of the percussion produced in the opening of the arms that has to be added to the power of their weight. He affirms that, if each arm does not succeed in turning the sixth part of the wheel, the system cannot work. Interesting, too, is the study of the arms that, alternately, are equipped with a curved extension which, at the time of activation of one arm, anticipates the opening of the next. Leonardo also makes a geometric analysis of the moments of the individual arms to try and determine the constant overbalance that would induce the wheel to move: he makes reference to the propositions of his theoretical treatise on the powers of nature to argue that this wheel cannot work.