The first flight of the Vought V-173 "Flying Pancake"

The Vought V-173 "Flying Pancake" was a unique disc-shaped plane that came out during WW2, with its first flight in 1942. It was designed by one of the greatest aviation engineers -  Charles H. Zimmerman. It was built of wood and canvas and featured a conventional, fully symmetrical aerofoil section. It reached a maximum speed of 138 mph. It was retired in 1947, and now you can see it in the Frontiers of Flight Museum in Dallas, TX.