While da Vinci is known for designing a simple helicopter, he also made a sketch for a flotation device, better known today as a parachute. He stated "if a man has a tent made of linen of which the apertures [openings] have all been stopped up, and it be twelve braccia [about 23 feet] across and twelve in depth, he will be able to throw himself down from any great height without suffering any injury." The design consisted of sealed linen cloth around the sides of a pyramid with a square base. It differed from modern parachute designs, as these are typically rounded and include a harness. The notebook in which this sketch was included was dated 1483. Like many of his designs, it was likely never tested during his lifetime.

Source and Image Source:
Leonardo Da Vinci's Life. (n.d.). Retrieved May 11, 2019, from http://www.davincilife.com/davincis-parachute.html