An unusual design for its time, it had a canard configuration with a rear-mounted engine, and two vertical tails at end of swept wings.

[1] Like the XP-54, the Ascender was designed for the 1,800 hp Pratt & Whitney X-1800 24-Cylinder H-engine, but was redesigned after that engine project was canceled.

In June 1940, the Curtiss-Wright company received an Army contract for preliminary engineering data and a powered wind tunnel model.

[5] On 10 July 1942, the United States Army Air Forces issued a contract for three prototypes under the designation XP-55.

During this time, the Pratt & Whitney X-1800 H-block sleeve valve engine was delayed, and was eventually canceled.

[7] Curtiss decided to switch to the 1,000 hp (750 kW) Allison V-1710[4] (F16) liquid-cooled inline engine because of its proven reliability.

The aircraft made its first flight on 19 July 1943[3][8] from the Army's Scott Field near the Curtiss-Wright plant in St Louis, Missouri.

The engine failed "making recovery impossible"[2] and it fell out of control for 16,000 ft (4,900 m) before Gray was able to parachute to safety.

[4][7] All flight tests were restricted so the stall-zone was avoided; included no stalling below 20,000 ft.[5][7][9] The third XP-55 (serial 42-78847) flew for the first time on 25 April 1944.

[7][10] After a low pass in formation with a Lockheed P-38 Lightning and a North American P-51 Mustang[7] on each wing, its pilot, William C. Glasgow, attempted a slow roll,[7] but lost altitude and crashed, sending flaming debris into occupied civilian ground vehicles on a highway near the airfield.

Data from Green and Swanborough 1977[16] [17] Air and Space Museum [18]General characteristics Performance Armament