 {| |} the curtiss-wright xp-55 ascender (company designation cw-24) was a 1940s united states prototype fighter aircraft built by curtiss-wright. along with the vultee xp-54 and northrop xp-56, it resulted from united states army air corps proposal r-40c issued on 27 november 1939 for aircraft with improved performance, armament and pilot visibility over existing fighters; it specifically allowed for unconventional aircraft designs. a highly unusual design for its time, it had a canard configuration, a rear mounted engine, swept wings and two vertical tails. because of its pusher design, it was sarcastically referred to as the "ass-ender".jenkins 2008. p. 8 like the xp-54, the ascender was initially designed for the pratt & whitney x-1800 engine and had to be redesigned when that engine project was cancelled. it would also be the first curtiss fighter aircraft to use tricycle landing gear. ==design and development== thumb|right|curtiss cw-24b at langley wind tunnel on 22 june 1940, the curtiss-wright company received an army contract for preliminary engineering data and a powered wind tunnel model. the designation p-55 was reserved for the project. the usaac was not completely satisfied with the results of these tests, and curtiss-wright took it upon itself to build a flying full-scale model which it designated cw-24b. the flying testbed was powered by a  menasco c68-5 inline engine. it had a fabric-covered, welded steel tube fuselage with a wooden wing. the undercarriage was non-retractable. on 10 july 1942, the united states army air forces issued a contract for three prototypes under the designation xp-55. serial numbers were 42-78845 through 42-78847. during this time, the pratt & whitney x-1800 h-block sleeve valve engine was experiencing serious developmental delays, and was eventually cancelled. curtiss decided to switch to the  allison v-1710 (f16) liquid-cooled inline engine because of its proven reliability. armament was to be two [[hispano-suiza hs.404#us production|{{
Canard_aircraft Cancelled_military_aircraft_projects_of_the_United_States Curtiss_aircraft Single-engined_pusher_aircraft United_States_fighter_aircraft_1940a1949