at Freeman Field
Serial numbers were 42-78845/78847 

A Curtiss XP-55 Ascender. Usually the US government is careful about how they name their aircraft. They normally turn down comical names. This aircraft's designation is an example of one slipping by the reviewers. The aircraft's official designation, ascender, sounds suitable if pronounced using these three syllables (a-scend-er). You can tell the suggester's true intention if you pronounce it using these syllables (asc-end-er).

The performance of the 4 XP-55 prototype aircraft built (S/N 42-39347, 42-78845-7) was roughly the same as conventional fighters of the time and never entered production.

PERFORMANCE
Maximum speed: 390 mph. at 19,300 ft.
Service ceiling: 34,600 ft.

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  S/N 42-78846
  Only surviving plane

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This aircraft information is from the USAF Museum Archives.
There isn't an actual aircraft in the Museum collection.

OLD PHOTO, ORIGINAL, CURTISS XP-55. 19 JULY, 1943 

Old, original 8 x 10 glossy black and white photograph of an experimental fighter plane from the early 1940s, the Curtiss XP-55, on its first flight with pilot J. Harvey Gray at the controls. This was the first XP-55 built and this plane, 278845, has a fascinating history, as is detailed below. On the back of the print is an abbreviated history of the plane and various official US government credits, including, "RELEASED FOR PUBLICATION, AC/AS, Intelligence Photographic Division, Official Photo U.S.A.D.". The Curtiss XP-55 Ascender was another response to Circular Proposal R-40C, which was issued on November 27, 1939. It called for a fighter that would be much more effective than any extant--with a top speed, rate of climb, maneuverability, armament, and pilot visibility, all of which would be far superior to those of any existing fighter. In addition, the fighter was required to have a low initial cost and had to be easy and inexpensive to maintain. The Army specifically mentioned in R-40C that they would consider aircraft with unconventional configurations. No less than 50 responses came in. Many of them were quickly ruled out, but by the end of 1940, four designs were considered sufficiently worthy of further study. These were designs submitted by Bell, by Curtiss, by Northrop, and by Vultee. The Curtiss entry, designated CW-24 by the company, was perhaps the most unconventional of the four finalists. It was to be one of the last projects supervised by Donovan Berlin before he left the Curtiss company to go over to Fisher to work on the P-75. The CW-24 was a swept-wing pusher aircraft with canard (tail-first) elevators. The low-mounted sweptback wings were equipped with ailerons and flaps on the trailing edge as well as directional fins and rudders mounted near the wing tips both above and below the airfoil. The elevators were located near the front of the nose in a horizontal surface. A completely-retractable tricycle undercarriage was to be used, the first time such an undercarriage was to be employed in a Curtiss fighter. Curtiss proposed to use the new and untried Pratt & Whitney X-1800-A3G (H-2600) liquid-cooled engine, mounted behind the pilot's cockpit and driving a pusher propeller. Project maximum speed was no less than 507 mph! On June 22, 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. Since the USAAC was not completely satisfied with the results of the wind tunnel tests, Curtiss-Wright took it upon itself to build a flying full-scale model. Designated CW-24B by the company, the flying test bed was powered by a 275 hp Menasco C68-5 engine. It had a fabric-covered, welded steel tube fuselage and a wooden wing. The undercarriage was fixed. After completion, the CW-24B was shipped out to the Army flight test center at Muroc Dry Lake (later Edwards AFB) in California. It made its first flight there on December 2, 1941. Although the maximum speed was only 180 mph because of the low engine power, the CW-24B proved out the basic feasibility of the concept. However, early flights indicated that there was a certain amount of directional instability.

The original auxiliary wingtip fins were increased in area and moved four feet farther outboard on the wings, which enhanced the directional stability. The wingtips were made longer, and further improvements were obtained by adding vertical fins to both the top and the bottom of the engine cowling. 169 flights with the CW-24B were made at Muroc between December 1941 and May 1942. After that, the airplane (having been assigned the USAAC serial number 42-39347) was transferred to Langley Field, Virginia, for further testing by NACA. During the flight testing of the CW-24B, work on the CW-24 fighter project continued. On July 10, 1942, a USAAF contract was issued for three prototypes under the designation XP-55. Serial numbers were 42-78845/78847. Since the Pratt & Whitney X-1800 engine was experiencing serious program delays (it eventually was cancelled outright before attaining production status) Curtiss decided to switch to the Allison V-1710 (F16) liquid-cooled inline engine for the sake of reliability and availability. Armament was to be two 20-mm cannon and two 0.50-inch machine guns. During the mockup phase, it was decided to switch to the 1275 hp Allison V-1710-95 engine, and the 20-mm cannon were replaced by 0.50-inch machine guns.

The first XP-55 (42-78845) was completed on July 13, 1943. It had essentially the same aerodynamic configuration as did the final CW-24B. It made its first test flight on July 19, 1943 from the Army's Scott Field near the Curtiss-Wright St Louis plant. The pilot was J. Harvey Gray, Curtiss's test pilot. Initial flight testing revealed that the takeoff run was excessively long. In order to solve this problem, the nose elevator was increased in area and the aileron up trim was interconnected with the flaps so that it operated when the flaps were lowered. On November 15, 1943, test pilot Harvey Gray was flying the first XP-55 (42-78845) through a series of stall tests when the aircraft suddenly flipped over on its back and fell into an uncontrolled, inverted descent. Recovery proved impossible, and the plane fell out of control for 16,000 feet before Gray was able to parachute to safety. The aircraft was destroyed in the ensuing crash.

 At the time of the crash, the second XP-55 (42-78846) was too far advanced in construction for its configuration to be conveniently modified to incorporate any changes resulting from an analysis of the cause of the loss. The second XP-55 was essentially similar to the first one, apart from a slightly larger nose elevator, a modified elevator tab system, and a change from balance tabs to spring tabs on the ailerons. It flew for the first time on January 9, 1944, but all flight tests were restricted so that the stall zone was carefully avoided until the third XP-55 had been satisfactorily tested.

The third XP-55 (42-78847) flew for the first time on April 25, 1944. It was fitted with the designed complement of four machine guns. It incorporated some of the ideas learned from the investigation into the cause of the loss of the first XP-55. It was found that stall characteristics could be improved by adding four-foot wingtip extensions of greater area and by increasing the limits of nose elevator travel. However, the first flight revealed that the increased elevator limits resulted in the pilot being able to hold such a high elevator angle during takeoff that the elevator could actually stall. After modifications, stall tests were performed satisfactorily, although the complete lack of any warning prior to the stall and the excessive loss of altitude necessary to return to level flight after the stall were undesirable characteristics. An artificial stall warning device was introduced to try and correct some of these problems, and between September 16 and October 2, 1944, the second XP-55 (42-78846), which had been modified to the same standards as that of the third aircraft, underwent official USAAF trials. The trials indicated that the XP-55 had satisfactory handling characteristics during level and climbing flight, but at low speeds and during landings there was a tendency on the part of the pilot to over control on the elevators because of a lack of any useful "feel". Stall warning was still insufficient, and stall recovery still involved an excessive loss of altitude. Engine cooling was also a problem. The performance of the XP-55 was not very impressive and was in fact inferior to that of the more conventional fighters already in service. In addition, by 1944, jet-powered fighter aircraft were clearly the wave of the future. Consequently, no production was undertaken, and further development was abandoned. The name Ascender had originated as a joke on the part of a Curtiss engineer. The name stuck, and eventually became official. The third prototype (42-78847) survived the testing program, but was destroyed in a crash during an airshow at Wright Field, Ohio on May 27, 1945, killing the pilot.

The sole surviving XP-55 (42-78846) was flow to Warner Robins Field in Georgia in May of 1945. It was later taken to Freeman Field to await transfer to the National Air Museum at the Smithsonian Institution in Washington.

For a long time, its fuselage was on display at the Paul Garber facility in Suitland, Maryland. In December of 2001, the aircraft was sent to the Kalamazoo Aviation History Museum for restoration, which will take two or three years. Specs of the XP-55: One 1275 hp Allison V-1710-95 (F23R) twelve-cylinder liquid-cooled Vee engine. Four 0.50-inch Colt-Browning M2 machine guns with 200 rpg. Maximum speed 390 mph at 19,300 feet, 377.5 mph at 16,900 feet. Normal range was 635 miles at 296 mph. Maximum range was 1440 miles. An altitude of 20,000 feet could be attained in 7.1 minutes. Service ceiling was 34,600 feet. Weights were 6354 pounds empty, 7330 pounds normal loaded, and 7939 pounds maximum. Dimensions were wingspan 44 feet 0 1/2 inches, length 29 feet 7 inches, height 10 feet 0 3/4 inches, wing area 235 square feet.

Czech Models Curtiss XP-55 ‘Ascender’

Kit # 4806                                                  MSRP $29.95
Model, images and text Copyright © 2004 by Matt Swan

Developmental Background
       One of the most unusual Army Air Forces research projects to be revealed to the public by the Air Technical Service Command is the Curtiss XP-55 Ascender, a tail-first, pusher fighter. The XP-55 resulted from Army Air Corps proposal R-40C calling for unconventional aircraft designs. It called for a fighter that would be much more effective than any currently in inventory or under development with a top speed, rate of climb, maneuverability, armament, and pilot visibility, all of which would be far superior to those of any existing fighter. In addition, the fighter was required to have a low initial cost and had to be easy and inexpensive to maintain. The Army specifically mentioned in R-40C that they would consider aircraft with unconventional configurations.
       
Perhaps the most unconventional of the four finalists was the Curtiss entry, designated CW-24 by the company. It was to be one of the last projects supervised by Donovan Berlin before he left Curtiss to work on the P-75 project for Fisher. The CW-24 was a swept-wing pusher aircraft with canard elevators. The low-mounted sweptback wings were equipped with ailerons and flaps on the trailing edge as well as directional fins and rudders mounted near the wing tips both above and below the airfoil. A completely retractable tricycle undercarriage was to be used, the first time such an undercarriage was to be employed in a Curtiss fighter. Curtiss proposed to use the new and untried Pratt & Whitney X-1800-A3G liquid-cooled engine, mounted behind the pilot's cockpit and driving a pusher propeller. The three-bladed propeller could be jettisoned to allow the pilot to safely bail out of the aircraft in the event of an in-flight emergency. Projected maximum speed was no less than 507 mph! On June 22, 1940, the Curtiss-Wright Company received an Army contract for preliminary engineering data and a powered wind tunnel model.

       On July 10, 1942, a USAAF contract was issued for three prototypes under the designation XP-55. The 2000 hp Pratt and Whitney X-1800 engine died on the development table and the prototypes were redesigned for the semi-obsolescent Allison V-1710 used in the P-40. Thus, at best, the XP-55 was condemned to a level of performance allowed by a dated 1275 hp engine. Armament was to be two 20-mm cannons and two 0.50-inch machine guns. During the mockup phase the 20-mm cannon were replaced by 0.50-inch machine guns.
       
The first XP-55 (42-78845) was completed on July 13, 1943. It made its first test flight on July 19, 1943 from the Army's Scott Field near the Curtiss-Wright St Louis plant. The aircraft experienced stability problems and underwent several modifications to increase the canard elevator surface, vertical stabilizer area, and eventually received four-foot wing tip extensions to improve stall characteristics. The first prototype underwent stall testing in December 1942 and on the third attempt the aircraft pitched forward 180 degrees onto its back and fell into the same inverted descent predicted in original Air Corps wind tunnel tests. The engine quit and nothing the pilot did could break the stall. After a perfectly stable fall of 16,000 feet, the pilot, J. Harvey Gray, bailed out safely. The aircraft continued straight down and dug a large smoking hole in the desert floor. After modifications, stall tests were performed satisfactorily, although the complete lack of any warning prior to the stall and the excessive loss of altitude necessary to return to level flight after the stall were undesirable characteristics.

       An artificial stall warning device was introduced to try and correct some of these problems, and between September 16 and October 2, 1944, the second Ascender underwent official USAAF trials. The trials indicated that the XP-55 had satisfactory handling characteristics during level and climbing flight, but at low speeds and during landings there was a tendency on the part of the pilot to over-control on the elevators because of a lack of any useful "feel". Pilot, Russ Schleeh, commented that it was terribly unstable, and that if you took your eyes off the horizon for a moment, even in the landing pattern, the plane would drift wildly off course.

       The performance of the XP-55 was not very impressive and was in fact inferior to that of the more conventional fighters already in service. Performance was mediocre with the Allison V-1710 engine attaining only 377 mph instead of the hoped-for 500 mph. Engine cooling was also a problem. In addition, by 1944, jet-powered fighter aircraft were clearly the wave of the future. Consequently, no production was undertaken, and further development was abandoned. The third prototype survived the testing program, but was destroyed in an accident on May 27, 1945, at Wright Field, Ohio. The pilot came in low over the field during an air show, attempted a barrel roll at low altitude, and crashed. Not only was the aircraft destroyed but the pilot was killed as well as a passing motorist. The sole surviving XP-55 (42-78846) was flow to Warner Robins Field in Georgia in May of 1945. It was later taken to Freeman Field to await transfer to the National Air Museum at the Smithsonian Institution in Washington. Currently the aircraft is in the Kalamazoo Aviation History Museum undergoing a complete restoration.

       The name Ascender had originated as a joke on the part of a Curtiss engineer, a reference to the aircrafts rather odd design which was not appreciated by the congressional oversight committee. The name stuck, and eventually became official. Had the aircraft been fitted with the originally intended 2000 hp engine and had fly-by-wire systems been available at the time, it most likely would have been a successful design. Ultimately, it simply became another aerial oddity.
 

  The Kit
        Czech Models has provided us with another exotic multi-media, limited run kit here. The one aspect about Czech Models that I never was happy with was the annoying box that opens from the end rather than having the lift off top. Hopefully some day they will change their packaging approach. Inside we have a small collection of rather interesting parts. There are two sprues of light gray plastic injection-molded pieces featuring crisply engraved panel lines, no obvious sink marks and little to no excess flash. The mold separation lines were subdued and there were no serious injector pin markings that caught my attention. All together these two trees comprise thirty-seven injection-molded pieces. Also here we have just one vacuformed canopy. This is very disappointing because there is now no room for error. I was determined to build mine with the cockpit open – this canopy hinges like a ‘B’ model P-51 Mustang so very careful cutting with a scalpel was required.
         Next we have a bag full of resin goodies. Cast in light tan resin are the cockpit interior pieces including sidewalls, main landing gear bay inserts, wheels and exhaust pipes. There are eighteen resin pieces but the main cockpit tub on mine is severely warped. The impression I get is that the pieces were pulled too soon from the molds and packed before they had completely set up. The resin pieces do display a very nice level of detail and the pilot’s seat has beautifully done seat belts. The main wheels have a very nicely done tread pattern on them also. For this kit we have a total parts count of fifty-six pieces and three that must be scratch built – these being two cockpit levers and the dorsal aerial. I went just a little further and added some fine fuse wire as canopy door restraints.
        Like all the kits coming out of the Czech republic and surrounding areas, there are no locator pins on any of the pieces. While this requires that the modeler pay particular attention to lining the main pieces up properly in some instances it is a boon. More than once I have found locator pins that are poorly located causing misalignment problems. The pieces do fit together well and everything lines up without a lot of difficulty. The only place where I ran into trouble with fit was installing the landing gear bays. It was necessary to sand the tops of the resin bays until they were nearly transparent and to sand the interior of the top wing. The landing gear doors are cast in one piece and they must be cut apart to build this with the gear down.

Decals and Instructions
        There were only three of these aircraft ever manufactured and two of them met disastrous ends. The decals provided for this kit are for the only surviving example. This was a test-bed aircraft so the markings are basic and include a variety of ‘no step’ placards and basic Hamilton Standard propeller markings. The print registry is precise and the color density is good. The decals behaved well during application, were nice and thin and did not react in any unexpected manner when setting solutions were applied.
        The instructions are comprised of a single large, two-page fold-out. The front page includes a nice black and white photo of the Ascender, a fairly well done historical section, a basic parts diagram and count and some basic instructions on working with resin pieces. The two inside pages consist of seven exploded view construction steps that include some additional construction text. There are no color call-outs here but the last page does include a couple of paragraphs covering all the various colors for the interior and exterior. The last page also covers the decal placement, proper landing gear alignment and wing dihedral.

Conclusions
        This was really a fun kit to build. The only two areas that gave me any trouble were the landing gear bay inserts in the wings and getting the propeller blades at the proper angle and orientation. The rest of the parts fit well and while the lack of a second canopy was a concern, the one provided was thin enough as to not give me a lot of trouble cutting it apart. There were several areas during the construction where I was tempted to succumb to AMS. This would be an excellent kit to open up the engine bay and stick an Aires Allison engine in there or to open the radio compartment door behind the cockpit or even open the access panels for the gun bay. It’s so hard to hold myself back – I just may have to get a second on of these and really let go.

        Compared to some of the other multimedia kits on the market this one is fairly simple. The subject is most definitely unusual and makes a great addition to any World War Two collection. Considering the simplicity of the kit and the ease of assembly I would recommend this as a good introduction kit for the modeler that has mastered basic injection molded kits and would like to break into the exciting world of resin detailed aircraft.