"I determine that standing upright is more useful than going face downward, because the instrument can never turn upside down, and besides, habituation from long use will require such. And the rising and lowering motion will come from the rising and lowering of the two legs, and this is of great power, and the hands will remain free. And if you had to go face downward, the joints where the legs meet the thights would endure great effort in holding themselves up"
The model represents a study of a flying
machine with beating wings actuated by
muscular force. It is constituted of a vertical
cage structure on which two wing structures
are mounted, connected in turn to a double
system of pulleys actuated by two foot brackets.
In this study, one of the last dedicated by
Leonardo to “instrumental”, or mechanical, flight, the beating of the wings is caused by the pilot, who would have donned the cage structure,
slipping his feet into the two foot brackets and thus actuating the pulleys. Leonardo now
considers the vertical position to be more
secure for the pilot, abandoning the idea of the
prone position described in previous studies.
The model is based on the drawing:
