The genius Da Vinci drew inspiration for his work from his direct observation of the flight of a bird. Da Vinci described its dimensions, the materials with which it is to be built, and its shape and how it works; the whole notebook revolves precisely around the construction and use of the machine.
Da Vinci also imparted some “flying lessons” on how the pilot should operate the machine. The piloting must have been complex. He would use his hands and feet to activate ropes and could rotate, move and open and close the wings with his own movements.
Da Vinci’s design is not drawn in its entirety. We must therefore reconstruct the indispensable parts. These include: the canvas to cover the wings, some articulations and pulleys, and the tail, which Da Vinci knew was indispensable for controlling the machine.