Despite some scepticism concerning the practicability of the monoplane configuration for the shipboard fighter, the US Navy's BuAer issued a second requirement for such a warplane on 24 January 1933, the first having been issued seven weeks earlier and for which the Boeing Model 273 was designed and built (as the XF7B-1). To meet the later but essentially similar requirement, a contract was let to Northrop for a prototype assigned the designation XFT-1.
A single-seat all-metal cantilever monoplane with split flaps, spatted main undercarriage members and an enclosed cockpit, the XFT-1 was designed by a team led by Ed Heinemann. Powered by a Wright R-1510-26 14-cylinder radial rated at 600hp at sea level and 625hp at 1830m, and carrying two 7.62mm cowl guns, the XFT-1 first flew on 16 January 1934.
The US Navy was critical of its manoeuvrability, its tendency to spin out of certain manoeuvres, its low speed characteristics and its landing speed. During the course of initial tests, an XR-1510-8 engine affording 650hp at 2590m was substituted for the -26, and, in April 1936, the XFT-1 was returned to the manufacturer for more extensive modification. A Pratt & Whitney R-1535-72 Twin Wasp Jnr 14-cylinder radial rated at 700hp for take-off and 650hp at 2285m was installed, this having a long-chord cowling; the vertical tail surfaces were enlarged, and the mainwheel spats were revised.
Redesignated XFT-2, the fighter was now 118kg heavier in empty condition, speed and climb performance were marginally improved, but manoeuvrability and low speed characteristics were worse. It was pronounced unairworthy by the US Navy and crashed on 21 July 1936 while being returned to its manufacturer.
Max take-off weight: 1704 kg / 3757 lb
Empty weight: 1120 kg / 2469 lb
Wingspan: 9.75 m / 31 ft 12 in
Length: 6.43 m / 21 ft 1 in
Height: 2.87 m / 9 ft 5 in
Wing area: 16.44 sq.m / 176.96 sq ft
Max. speed: 378 km/h / 235 mph
Range: 1570 km / 976 miles