11/30/2019. Remarks by Johan Visschedijk: "Although it was an unsuccessful competitor against the Boeing XP-936 P-26 for the US Army's interim monoplane pursuit of 1933-1936, the single-seat Model 66 Swift was still a significant design in that it brought Curtiss further into the new design era and revealed important new design problems associated with it. Encouraged by the Army, Curtiss undertook the development of a new pursuit as a company-funded project for which the Army provided the power plant and military equipment and assigned the experimental project number XP-934 for test under a bailment contract.

The all-metal Swift drew heavily on the design features of the A-8 Shrike, including a pilot's enclosed cockpit, wing flaps, and full-span leading edge slats that opened automatically at 15 mph (22.6 kmh) above stall speed. Four 0.30 in (7.62 mm) caliber machine guns were carried, two in troughs in the nose and two in external packages on each side of the cockpit.

XP-934 with radial engine (Jack Fisher Collection)

The aircraft was designed for the 600 hp Conqueror engine but the Army, correctly believing that this liquid-cooled model was nearing the end of its usefulness for pursuit types, insisted on a change to the 700 hp F-series Wright Cyclone air-cooled radial.

The single Swift left the factory in July 1932 but its performance was disappointing. Within a month, the Cyclone was replaced with a G1V-1570F Conqueror. While the speed increased, other performance characteristics were handicapped by serious overweight. The Army bought the aircraft in February 1933, assigning the designation XP-31 and Army serial number 33-178. The civil-type engine was replaced with an equivalent military V-1570-53. Soon redesignated ZXP-31 (Z for Obsolete), it accumulated a total of 287 flying hours by July 1936 when it was retired to an USAAC mechanics' school.