Curtiss XP-23 / YP-23
Ordered in July 1931, the Curtiss XP-23 was the last biplane in the pursuit series, altered on the production line from the final airframe of the 45 ordered as Y1P-22 but redesignated P-6E. With fabric-covered metal wings of standard P-6 planform and a new metal-skinned fuselage and initially powered by a 447kW Curtiss GIV-1570C Conqueror with a turbo-charger and three-blade propeller, the YP-23 was delivered 16 April 1932. Evaluated by operational fighter pilots at Wright Field with turbo-charger removed, two-blade propeller retrofitted, and its designation changed to YP-23, the YP-23 seems to have performed very well, subject only to the limitations of the biplane configuration. Some reports that the XP-23 was excessively heavy, with maximum take-off weight as high as 1950kg appear to be based on an erroneous interpretation of Curtiss documents from the period. The XP-23 was denied a production contract, competing not with other biplanes but with the monoplane Boeing P-26 'Peashooter'.
Ultimately, the YP-23 was deleted from Army inventory and turned back to Curtiss, where its wings were retained for use on the prototype US Navy XF11C-1 shipboard fighter.
Engine: Curtiss V-1570-23 Conqueror, 447kW
Wingspan: 9.60 m / 31 ft 6 in
Length: 7.26 m / 23 ft 10 in
Height: 2.90 m / 9 ft 6 in
Wing area: 23.23 sq.m / 250.05 sq ft
Take-off weight: 1542 kg / 3400 lb
Empty weight: 1315 kg / 2899 lb
Top speed: 354 km/h / 220 mph at 4570 m / 15 000 ft
Initial climb, 1,370 ft/min (6,96 m/sec)
Ceiling: 7925 m / 26000 ft
Range: 700 km / 435 miles
Armament: 1 x 12.7mm + 1 x 7.62mm fixed machine-guns, 227kg of bombs