01/31/2010. The last fighter biplane to be developed by Curtiss for the USAAC, the XP-23 was considered to be the ultimate refinement in this category. Ordered in July 1931, the XP-23 introduced fabric-covered metal wings of standard P-6 planform mated to an all-metal monocoque fuselage of very clean aerodynamic form, new metal tail surfaces, a new nose, and new landing gear. It was produced from the last P-6E and was powered by a turbo-supercharged geared GIV-1570C Conqueror engine.
Delivered to the USAAC on 16 April 1932, the XP-23 offered too insignificant an advance in performance over the P-6E to warrant further development. The XP-23 was redesignated YP-23 when it switched from 'Experimental' to 'Service Test' status, the troublesome turbo-supercharger was removed, and a two-blade propeller replaced the original three-blade model, and the aircraft was returned to the USAAC in April 1932. After additional testing the aircraft was then returned to Curtiss and its wings used for the XF11C-1.