Curtiss - Wright XP - 55 Ascender 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 XP - 54 and 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 " . 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 . 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 cannon s and two machine gun s . During the mock - up phase , it was decided to switch to the more powerful V - 1710 - 95 . The 20 mm cannons were also replaced by 0 . 50 in machine guns . A special feature of the XP - 55 was a propeller jettison lever located inside the cockpit to prevent the pilot from hitting the propeller during bailout . Operational history . The first XP - 55 ( 42 - 78845 ) was completed on 13 July 1943 and had the same aerodynamic configuration as the final prototype CW - 24B . The aircraft made its first test flight on 19 July 1943 from the Army ' s Scott Field near the Curtiss - Wright plant in St Louis , Missouri . The pilot was J . Harvey Gray , Curtiss ' test pilot . Initial testing revealed that the takeoff run was excessively long . To solve this problem , the nose elevator size was increased and the aileron up trim was interconnected with the flaps so that it operated when the flaps were lowered . On 15 November 1943 , test pilot Harvey Gray , flying the first XP - 55 ( S / N 42 - 78845 ) , was testing the aircraft ' s stall performance at altitude when the XP - 55 suddenly flipped over on its back and fell in an uncontrolled , inverted descent . The pilot was unable to right the airplane , and it fell out of control for before Gray was able to parachute to safety . The aircraft was destroyed . The second XP - 55 ( S / N 42 - 78846 ) was similar to the first but with a slightly larger nose elevator , modified elevator tab systems , and a change from balance tabs to spring tabs on the ailerons . It flew for the first time on 9 January 1944 . All flight tests were restricted so that the stall zone was avoided . The third XP - 55 ( S / N 42 - 78847 ) flew for the first time on 25 April 1944 . It was fitted with four machine guns , and incorporated some of the ideas learned from the loss of the first XP - 55 . It was found that the aircraft ' s stall characteristics could be greatly improved by the addition of four - foot wingtip extensions , and by increasing the limits of the nose elevator travel . Between 16 September and 2 October 1944 , the second XP - 55 ( 42 - 78846 ) , which had been modified to the same standards as the third aircraft , underwent official USAAF flight trials . The performance of the XP - 55 was not very impressive and was often inferior to that of more conventional fighter aircraft already in service . In addition , by 1944 jet - powered fighter aircraft were already well along in development and there was no further development of the XP - 55 . The third prototype XP - 55 ( s / n 42 - 78847 ) was lost on 27 May 1945 during the closing day of the Seventh War Bond Air Show at Wright Field in Dayton , Ohio .