Ling-Temco-Vought
Vought V-173 Pancake

The Vought V-173 "Flying Pancake" was an American experimental test aircraft built as part of the Vought XF5U program during World War II. Both the V-173 and the XF5U featured an unorthodox "all-wing" design consisting of a flat, somewhat disk-shaped body (like a pancake flying, hence the nickname) serving as the lifting surface. Two piston engines buried in the body drove propellers located on the leading edge, at the wingtips

The original prototype, designated the V-173 (Flying Pancake), was built of wood and canvas and featured a conventional, fully symmetrical aerofoil section (NACA 0015). Designed as a "proof-of-concept" prototype, the initial configuration V-173 was built as a lightweight test model powered by two 80 hp (60 kW) Continental A-80 engines turning F4U Corsair propellers. These were replaced by a pair of specially modified 16 ft 6 in three-bladed units. A tall, fixed main undercarriage combined with a small tailwheel gave the aircraft a 22° "nose-high" angle.

The disc wing design featured a low aspect ratio that overcame the built-in disadvantages of induced drag created at the wingtips with the large propellers actively canceling the drag-causing tip vortices. The propellers were arranged to rotate in the opposite direction to the tip vortices, allowing the aircraft to fly with a much smaller wing area. The small wing provided high maneuverability with greater structural strength. The empennage consisted of two vertical fins with rudders, all-moving stabilizers with anti-servo tabs, and two large elevator/trim surfaces on either side of centerline on the trailing edge of the wing planform.