In the history of aircraft construction, very often, in the heat of the design race, trying to bypass competitors and achieve a technical advantage over their developments, aircraft designers have created aircraft of very unusual designs and shapes. At the same time, in some cases, quite viable aircraft were born from unusual projects. In the United States, such models can be safely attributed to fighters: Northrop P-61 Black Widow and North American F-82 Twin Mustang. However, much more often projects of "freak" aircraft either enriched developers with the experience of making not the most successful design decisions, or scared off a potential customer with excessive futurism, never reaching the stage of mass production.
At the same time, the Northrop company, which managed to bring the unusual P-61 Black Widow night fighter to the series, was famous for its non-standard projects in the field of aircraft creation and, apparently, for its love of the word "black" in the name of the projects. There is nothing surprising in the fact that it was the designers of this American company that designed the XP-56 Black Bullet fighter, which never went beyond the experimental stage, but still excites the minds of aviation enthusiasts with its unusual appearance.
For their "bullet", the Northrop designers chose a tailless design, a swept wing, and a small short fuselage. The aircraft also received large air intakes, two coaxial counter-rotating pusher propellers, and a nose landing gear. Externally, the plane made a real sensation - there was nothing familiar in its design for the late 1930s and early 1940s. There should have been no less internal innovations in Black Bullet - suffice it to note the fact that for the first time in aircraft construction, its units and parts were connected using not riveting, but welding. The picture was completed by a very powerful piston engine producing 2,000 hp, as well as armament, according to the project, consisting of two 20-mm aircraft cannons and four large-caliber 12, 7-mm machine guns.
The idea for the XP-56 Black Bullet, a single-seat fighter jet, which today is considered one of the most radical aircraft models created during World War II, was born in the minds of Northrop engineers back in 1939. Originally the aircraft bore the designation Northrop N2B, the project was tied to a 24-cylinder Pratt & Whitney X-1800 engine with 1800 hp. It is worth noting that even before the outbreak of World War II in June 1939, the US army began to receive loans for the development of modern weapons, part of the money was directed to the creation of new models of fighters. General Henry Arnold, who was at that time the commander of the US Air Force, applied to the Ministry of Defense for permission to use funds for the creation of a promising fighter with high flight performance. So the document R40C was born, which regulated the basic requirements for the new aircraft model.
The general's proposal was approved on February 9, 1940, and already on February 20, 7 American aircraft companies were familiarized with the R40C document. On May 15 of the same year, 25 preliminary projects were immediately submitted to the technical commission of the US Air Force, after five days of hard work, the members of the commission chose three winners from the variety presented, who turned out to be: the Vultee company with the V-84 aircraft (in the future XP-54), Curtiss-Wrighte with CW-24B (future XP-55) and Northrop with N-2B (future XP-56). Northrop signed a contract for the development of a new fighter on June 22, 1940. At that time, the Second World War was already raging in Europe with might and main, the act of surrender of France was signed on that day, and exactly one year remained before Germany's attack on the USSR. Work in the United States on the creation of new combat aircraft was accelerated, including based on the emerging situation in the world.
Nobody limited the fantasy of the Northrop designers, so they chose for their promising N2B fighter an unusual tailless aerodynamic configuration with counter-rotating coaxial propellers. In the engine-free nose of the fighter, it was planned to install a real battery of two 20-mm cannons and four 12, 7-mm machine guns. In the shape of the swept wing of this aircraft, the features of the previous development of Northrop engineers - the N-1M model - were guessed. The close relationship of the two projects also gave out drop-down ailerons for directional control and lowered wingtips. The aircraft had a short barrel-shaped fuselage with a protruding cockpit, gargrotto and ventral keel. Externally, the aircraft fuselage really looked like a bullet.
A light magnesium alloy was chosen by the developers as the main structural material for the new fighter. For the first time in aircraft construction, structural parts were to be connected to each other by welding. The fighter's engine was located just behind the cockpit. The N-2B project provided for the installation of an in-line engine with a liquid cooling system Pratt and Whitney X-1800 with a capacity of 1800 hp. Almost the entire volume of the aircraft's fuselage was occupied by the power plant and the cockpit, so it was decided to place the fuel tanks in the wing. In early September 1940, Northrop assembled a 1: 5 scale model of the fighter and began blowing it in a California Institute of Technology wind tunnel.
At this time, the construction of a full-scale mock-up of the future fighter continued, and the rollout of the flight model was to take place in September 1941. At this time, John Northrop was most concerned with the power plant of a promising aircraft. Pratt and Whitney switched to the development of the R-2800, an 18-cylinder engine with 2,000 horsepower. At this point, work on the N-2B project was in jeopardy. As a result of the negotiations, representatives of the Pratt and Whitney company were able to convince the representatives of Northrop to install the R-2800 engine on the new fighter. At the same time, the minders promised to fully undertake the development of a cooling system and a gearbox for driving the propellers.
At the same time, the use of the new engine significantly worsened the initial design characteristics of the aircraft. The flight weight of the N-2B increased by almost a ton. Despite this, the US military approved the version with the Pratt and Whitney R-2800 engine and in the summer of 1941 sent their changes to the concluded contract. Before that, they had time to get acquainted with a large-scale model of the future fighter. The general assessment of the promising aircraft was satisfactory, at the same time it was assigned the XP-56 index and the Black Bullet name. The construction of the first prototype of the experimental aircraft was delayed until early March 1943. The plane left the assembly shop only on the 20th.
The main part of the fighter's cooling system was a huge fan. The air for it came through large oval-shaped air intakes located at the root of the aircraft wing. The exhaust air then escaped from the rear of the fighter fuselage through a slot located in front of the spinner of the propellers. This slit was closed with a crown of adjustable flaps. Behind, there were two three-bladed propellers of opposite rotation, the diameter of the propellers was slightly different (the first - 2.95 m, the second - 2.89 m), the propeller blades were hollow. To ensure the safety of the pilot during an emergency exit from the aircraft, the propellers could be fired off by detonating the installed squibs.
In early April 1943, the XP-56 fighter was transported to Murok. On April 6, test pilot John Meers began his first test runs on the surface of a dried-up lake. The first ground tests showed that when taxiing at high speeds, the aircraft began to throw from side to side. The main culprits of this behavior of the aircraft were the brakes of the main wheels of its landing gear, as a result they had to be updated. Around the same time, problems arose with the power plant and its reliability, which manifested themselves in engine bench tests conducted by Pratt and Whitney. As a result, the first flight was postponed and took place only on September 30, 1943.
Test pilot John Meers' impressions of the first flight of the XP-56 fighter were terrible. The car flew at an altitude of 1.5 meters above the surface of Rogers Lake at a speed of about 270 km / h. At the same time, the pilot had to constantly and with great effort pull the control stick towards himself, and at this time the plane all the time wanted to deviate from the chosen direction of flight. As it turned out, the lowering of the nose of the fighter in flight was associated with the front alignment, and the instability of the experimental machine in the direction was due to the insufficient area of vertical surfaces. In order to remedy the situation, the designers of the Northrop company decided to make changes to the alignment of the aircraft using ballast, and the tail surface of the fighter was increased due to the appearance of another keel on top of the fuselage.
The modified fighter appeared on the runway on October 8, 1943. Before the next flight, the test pilot decided to make several high-speed runs and flights around the airfield. During the third approach at a speed of about 200 km / h, the fighter suddenly turned around, the plane turned over and fell twice. As a result of the accident, the first prototype of the XP-56 Black Bullet was completely destroyed, while by a lucky chance Meers got off with only a few bruises. The investigation showed that the accident was caused by a rupture of the pneumatics of the left landing gear of the fighter.
All the shortcomings discovered during the first tests were tried to be eliminated in the second prototype, which was built at the Hawthorn plant, ranging from problems with the alignment of the aircraft and ending with the replacement of landing gear tires. The completion of the assembly of the second prototype of the fighter, scheduled for November 1943, was postponed to January 1944. Among other things, the aircraft had to change the drive system of the drop-down elevons. The new system included two pipes that were attached to the wingtips. When the pilot wanted to turn the plane in the right direction, he simply shut off the corresponding pipe, after which the air began to flow into a special bellows, which increased in size and in turn moved the elevon opening lever.
The second built prototype of the Black Bullet fighter completed its first flight on March 22, 1944. The plane was lifted into the sky by a new test pilot - Harry Crosby. With great difficulty, he managed to lift the fighter off the ground at a speed of about 250 km / h. To keep the car in the air, the pilot, as before, had to pull the control stick towards himself with all his might with both hands. At the same time, the new course control system was found to be quite controllable, although it was too sensitive. The plane was slowly gaining altitude, the engine power was clearly not enough to accelerate the car with a gross take-off weight of about five tons. 7 minutes after the start of the test flight, the fuel meter failed and Harry Crosby completed the tests.
After 9 days, the plane was ready to make a second flight. The position of the center of gravity of the fighter was changed and the malfunction of the fuel gauge was eliminated. During the second flight, Crosby managed to gain an altitude of 1,500 meters. But when the landing gear was retracted, the fighter suddenly lifted the nose up, after which the flight speed dropped to only 190 km / h. The pilot made the decision to immediately extend the landing gear back, which helped stabilize the aircraft in the air using the trim tabs, and then retracted the landing gear again. Upon reaching a flight speed of 320 km / h, Crosby began to notice strong vibration and noticed a tendency for the plane to fall onto the left wing. Believing that a further increase in speed is dangerous, the pilot took the plane to the airfield.
In May, the XP-56 Black Bullet took to the skies four more times. Each time, the engineers of the Northrop company made minor changes to the design of the machine, but they did not succeed in improving the aerobatic properties of the novelty or achieving a higher flight speed. The company's specialists decided to blow the plane in a full-scale NACA wind tunnel, but at that time it was constantly busy with more important research. While the experimental fighter waited for its turn, Harry Crosby made several more flights, which revealed another unpleasant feature of the model. The plane had an inexplicably high fuel consumption. Ultimately, after the tenth flight, the final decision was made to terminate all further tests of the fighter and the further development process.
According to the American military, the XP-56 was unable to surpass the fighters of its time, for example, the famous P-47 Thunderbolt. As a result, the experienced fighter was left at the Murok base, where it safely stood for two years. The question of the further continuation of the tests of the unusual machine was raised several times, but to no avail. In 1946, the XP-56 Black Bullet fighter was finally excluded from the list of aircraft awaiting flight tests.
History has shown that a large number of innovations that were incorporated into the fighter at the turn of the late 30s and early 40s of the last century only led to a delay in the creation of a flying model. It took 4 years from the start of the design work to the first flight. During this time and time spent on fine-tuning the machine, the military completely lost interest in it. As a result, it all ended with only two prototypes of the "Black Bullet" built. By that time, quite traditional North American P-51 Mustang and Republic P-47 Thunderbolt were already approaching the maximum flight speed of 749 km / h declared for the fighter. Of the two prototypes built, the first crashed during tests in 1943, the second survived to this day and is in the collection of the National Museum of Aeronautics and Astronautics in Washington.
Flight performance of the XP-56 Black Bullet (estimated):
Overall dimensions: length - 8, 38 m, height - 3, 35 m, wingspan - 12, 96 m, wing area - 28, 44 m2.
Empty weight - 3955 kg.
Maximum takeoff weight - 5520 kg.
Power plant - PD Pratt & Whitney R-2800-29 with a capacity of 2000 hp.
The maximum flight speed is 749 km / h (at altitude), 667 km / h (near the ground).
Flight range - 1063 km.
Service ceiling - 10,000 m.
Armament - 2x20-mm cannons and 4x12, 7-mm machine guns.
Crew - 1 person.
