An Interesting Bit Of Aviation History

As the US Army Air Corps forwarded a tender to several US aviation companies in 1939 about the need for a powerful, oustanding and fast interceptor, which should have flight characteristics, far above these ones of all known fighter types at that time, also the company Curtiss Wright answered with a truly interesting design. The project CW-24. A aircraft, which not only looked far ahead of it`s time, it also looked as it came directly from the future. Curtiss decided to set one focus on a perfect visibilty for the pilot, without the engine and propeller installed in the nose section, as it was pretty common and standard at that time. Instead, the company decided to move the whole engine section to the rear of the aircraft. So it was driven from behind, a concept which was at that time absolutely new. 

It was a radical new design conception, which also interested the USAAC, which gave in 1940 it`s official "ok" for the manufacturering of a first wooden mock up for wind channel testings. The results of these tests were not very positive and the USAAC doubted, if such an aircraft would be really so effective as Curtiss promised, not to talk about if it was even able to take off. To prove that, Curtiss decided to manufacturer a first prototype in original size on their own costs. This first kind of prototype was completely operational and even equipped with a first six cylinder Menasco C-68 engine. Curtiss decision was not a bad one, as this first "real" aircraft, still designated as CW-24, proved during the following evaluations that some of the problems which appeared during the wind channel testings disappeared with the operational aircraft. 

This new row of evaluations led to a new interest from USAAF side, which gave in 1942 it`s "go" for the production of three prototypes, now designated as XP-55. Like many other aircraft companies at that time, also Curtiss suffered under problems with the availability of modern and powerful engines. They planned with the Pratt & Whitney X-1800 H Bloc, but in 1942 it was still under development and at the end never finished and later cancelled. So Curtiss decided for the less powerful Allison V-1710-95 engine, which equipped the first three prototypes. The propeller of these prototypes were modified and the pilot was able to remove the blades shortly before he would eject from the aircraft to avoid any injuries. To achieve that, Curtiss included some small explosive cartridges which would jettisoned the blades. A at that time also very new feature. 

The first prototype took off for it`s maiden flight in July 1943, now named by Curtiss engineers the XP-55 "Ascender" and flown by test pilot Harvey Gray. The first flight ended with mixed results. The take off run was far too long, so Curtiss modified parts of the flight mechanics of the prototype, which should improve the take off distance in a major way. Several more test flights followed with results which were not bad, but also not outstanding. During one of these test flights in November 1943, Harvey Gray was forced to eject from the aircraft as he lost control of it and was not able to get it back, as it went into a uncontrollable spin groundwards. He had much luck, as the small explosive cartridges among the propeller blades not detonated, but he was still able to jump out of the cockpit without any further injuries. This incident led to further modifications like an enlarged wingspan and the addition of canard deflection angles among the nose section of the aircraft, also visible on the photos. Further test flights proved that such changed were necessary and improved the flight characteristics in a major way. 

The second prototype joined the testings in early 1944 and the third mid of 1944. The third XP-55 prototype already included all improvements and modifications, made from the experiences of the preceded test flights. It´s wing span was for example much larger, compared to the other two prototypes. This third aircraft was also used for the first weapon testings with the XP-55 in late 1944. It should be armed with two 20mm and two Cal. 50 machine guns. But at the time of these testings, the USAAF already lost interest on the project, which led to a official cancellation in December 1944. 

This decision was a major disaster for Curtiss, but what they didn`t knew at that time, it got even worse. The third prototype participated in May 1945 on a USAAF airshow at Wright Field, Ohio, where it conducted several flights, including formation flights with other types like the P-51 or P-38. During one of these formation flights, Captain William C. Glasgow, a highly experienced US fighter pilot, lost control of the aircraft during a barrel roll and crashed on the ground. Glasgow was directly killed, but also three civilians on the ground, as the XP-55 crashed into a parked car. It was the official disastrous end of the XP-55 story. 

A story which is nowadays just a sidenote of US aviation history, but a pretty interesting one. Curtiss design was in 1939/1940 far ahead of it`s time and I think exactly that was their problem. The whole design, new flight mechanics and systems were a completely new area. A area, which included many difficulties and also many aspects of the project, which were just not to handle. Designs like the XP-55, with a engine located in the rear of the aircraft, were not the future. Why? Because it led to dozens of complicated problems with the flight characteristics of the aircraft. The XP-55 is a perfect proof for that. The Germans developed a similar design, but they decided to not remove the regular frontal engine, but to add a additional one in the rear. The Dornier Do-335 "Arrow". Curtiss design was probably needed to prove that it was not very effective or needed much longer time and costs for development. 

But one of the most important reasons why the USAAF lost interest on the project was the incoming jet age. As the XP-55 conducted it`s first evaluations and tests, it was already a fact that jets were the future and piston engined aircraft the past. 

Luckily one aircraft was preserved. The second prototype, which was owned for decades by the National Air and Space Museum in Washington D.C and later forwarded to the Kalamazoo Aviation History Museum in Michigan, where it was restored during the early 2000s. From 2007 on it is on public display at the museum until today.