Curtiss XP-31 Swift


The Curtiss XP-31 Swift was a 1930s American experimental monoplane fighter built by Curtiss for the United States Army Air Corps.
The XP-31 featured the first enclosed cockpit on a U.S. pursuit aircraft and was also the last pursuit aircraft to have fixed landing gear and externally braced wings. Despite its innovations, the XP-31 did not offer any advantages compared to its rival the Boeing P-26 Peashooter and was not ordered into series production.

Design and development

Curtiss offered the XP-31 in a 1932 competition with the P-26. It was a low-wing monoplane with fixed landing gear, first flown in July. It was the AAC's first single-seat closed-cockpit fighter, and the last with fixed gear and wing struts. Despite its small size, it was badly overweight, and carried 125 gallons of fuel. Although Curtiss considered the design significant in that it introduced various new technologies, compared to its contemporaries the XP-31 was already outmoded, and, more importantly, testing showed that it fell below performance expectations.

Testing and evaluation

Powered by a 700 hp R-1750 Cyclone radial, its performance was dismal, despite retractable leading edge slots and large trailing-edge flaps, so a 600 hp Curtiss V-1570 Conqueror was substituted. In this form, the Curtiss XP-31 Swift was delivered on 1 March 1933, having already lost to the P-26. The sole example was scrapped in 1935.

Operators