The flying wing

Leonardo observed and studied the flight of birds very meticulously. Numerous drawings bear witness to his research into wings as part of his work to perfect a "flying machine".
This "Ornithopter Wing" as he called it, is accompanied by the following advice: "If you want to experiment with the wing, build one 20 braccia (around 12 metres) high and wide with reed branches and paper, and attach it to a base weighing 200 pounds. Then lower the lever rapidly. If the base takes off before the wing collapses, the experiment has been successful".