The XP-8 (Model 66) actually preceded the XP-7, being delivered in July 1927, having been launched as a private venture late in the previous year. Powered by a 600hp Packard 2A-1500 water-cooled engine, the XP-8 utilised an airframe essentially similar to that of the US Navy XF2B-1, but performance failed to meet the requirements of the 1925 USAAC specification which it had been designed to meet, and the aircraft was finally scrapped in June 1929. Armament comprised one 7.62mm and one 12.7mm machine gun.