The Short-Lived Saga of XP-55: Unveiling the World’s Most Unique Aircraft

Unlike more traditional aircraft of the time, the XP-55 defied conventional wisdom by incorporating a 1,275 hp Allison V-12 engine behind the pilot.

The sole remaining Curtiss XP-55, on display at the Air Zoo in Kalamazoo, Michigan.

In the world of aircraft design, the late 1930s and early 1940s were defined by rapidly expanding technologies and open-mindedness. Aeronautical engineers and operators were reimagining the rules and opening new possibilities in aviation. Trailblazing gear had recently surfaced, and retractable landing gear was gaining popularity. All-metal aircraft construction quickly gained traction as well, replacing fabric-covered frameworks.

As aircraft designs advanced, engineers pushed the limits further. In late 1939, when the Army requested a new fighter that performed better than any existing fighter at a lower price, Curtiss engineers embraced innovation. They responded to the Army’s proposal with a swept-wing design, powered by a 1,275 hp Allison V-12 engine, similar to those used in P-38s, P-40s, and P-51s. Unlike these more conventional aircraft, however, the XP-55 pushed it beyond the pilot and emerged as an aft-mounted pusher propeller.

Curtiss reasoned that the XP-55 would provide many benefits over conventional designs. They claimed the unusual configuration would achieve superior or better speeds, maneuverability, and superior out-of-the-box forward visibility. They also touted the design as advantageous for the pilot, including the superior ground handling characteristics affected by the trickier gear and engine placement that occasionally sparked concerns.

Once the XP-55’s safety-related flight tests started in July 1943, it became apparent that the conventional design issues that the CW-24B had resolved would persist. In addition to insufficient pitch authority on takeoff, the first prototype struggled with in-flight stability – so much so that when a test pilot entered a stall, the aircraft flipped over and entered an unrecoverable, inverted descent. The pilot managed to bail out, but the project was terminated.

Curtiss proceeded to build and fly the second and third prototypes with the second one exhibiting improved flight stability but falling short of performance expectations, and the third undergoing only ground testing. Despite significant modifications to address issues such as poor stall recovery and insufficient engine cooling, the XP-55’s propeller remained a significant challenge, especially when compared to contemporary designs, which were shifting towards rear-propeller-driven fighter aircraft. The XP-55 program was eventually discontinued.

In 1945, the third XP-55 was selected to fly in an airshow held in Dayton, Ohio. Tragically, while performing a roll in front of the crowd, the aircraft dove into the ground, killing the pilot and leaving the wreckage as the sole reminder of the valiant experiment at the National Museum of the United States Air Force in Dayton.