Almost certainly the most unusual aircraft designed by the company, the Chance Vought XF5U-1 was intended to produce a fighter aircraft which, in a fully-developed form, would have a speed range from 32 to 740km/h. It had a wing of almost circular planform, which also comprised the primary structure of the aircraft. Control surfaces were confined to the rear of the wing, consisting of twin fins and rudders, with a swept tailplane on each side. These latter surfaces each had an elevator which could be used collectively for control in pitch or differentially for roll control. Landing gear was of retractable tailwheel type. Power was provided by two Pratt & Whitney radial engines buried in the wing, one on each side for the fuselage and driving, via right-angle gearboxes, specially developed propellers, one at the forward extremity of each wing. Clutches and shafting were provided to ensure that, in emergency, both propellers could be driven by one engine.

To flight-test the concept a low-powered full-scale version was built as the V-173. Of wood and fabric construction, low-powered engines and fixed landing gear, this flew for the first time on 23 November 1942. Although the prototype XF5U-1 was completed and prepared for testing at Muroc Dry Lake (since renamed Edwards AFB), this aircraft was never flown.