The most massive fighter of the United States
The rapid development of aircraft in the thirties ensured the popularity of the American company "Seversky". It was founded in 1928 year by Alexander Seversky, an engineer and pilot who left Russia. The firm of this Russian emigrant was mainly engaged in the development and production of amphibious aircraft.
By the forties, A. Seversky withdrew from direct management of the company. And in the summer of 1939, she received the new name “Republic Aviation Corporation”, or more simply, “Republic”. Its president was the American Alfred Marchev. A talented engineer and also a Russian emigrant Alexander Kartvelli remained the vice-president and chief designer. He worked for a long time with Alexander Seversky and in his cars he kept many ideas and handwriting of Seversky.
In 1940, the company developed a new fighter P-43 "Lancer", which had a maximum speed of 570 km / h and had a range of up to 1000 km. However, the aircraft no longer met the requirements of the US Air Force. At that time, the American corporations Lockheed, Bell, and Curtiss created the fighters Р-38, Р-39, Р-40, and they had much higher flight and technical characteristics.
However, among the large number of types of aircraft in the US Air Force there was no single-engine long-range, high-altitude, and high-speed heavy escort fighter to protect long-range strategic bombers. In 1940, representatives of the United States Air Force signed a contract with 62 million for the serial production of such an aircraft.
6 May 1941, an experienced prototype fighter, which received the designation XP-47В, rose into the air. The flight performance of the car exceeded all expectations. In horizontal flight, it accelerated to 657 km / h, which was 50-70 km / h higher than all other fighters of the time, with the exception of the Soviet MiG-3, which had a speed of 640 km / h.
The newest Pratt-Whitney XR-2800-21 turbocharger engine was installed on the aircraft (its maximum power reached the 2000 HP) at the maximum mode. No other world fighter then put such a powerful engine. At that time, it was precisely the turbochargers that became the Achilles' heel of all high-speed machines. The solid weight and technical imperfection of these devices, the frequent failures negated all the advantages of such power plants.
Most designers have not been able to solve the problem of reliability of the drive of the turbocharger with heated engine exhaust gases, which quickly burned through its turbine. But Cartvelli found a rather original solution. He mounted the turbocharger not on the engine, as was customary, but in the rear fuselage. He stretched air ducts and a long exhaust pipe through almost the entire fuselage. This, of course, led to a significant weighting of the aircraft design. But the turbocharger, which already had a few cooled exhaust gases, worked without interruption. It was possible to significantly reduce the length of the nose of the fuselage, which made it possible to slightly improve the view from the cockpit for the pilot.
Cartvelli also used the original exhaust system on the fighter. When the engine operates in nominal mode, the exhaust from each cylinder was output to a single manifold and was ejected through two adjustable nozzles located on the sides in the nose of the aircraft. When the pilot needed to increase the power of the power plant, he, in addition to adding fuel, blocked the nozzle flaps. In this case, the heated exhaust gases were redirected to the turbocharger, and then went out into the common nozzle, which was located under the tail fin.
At the same time, another technical problem was solved. When compressed in the turbocharger, the air heated up quite strongly, and it was necessary to cool it before it was fed into the motor. And the pipeline with hot air passed through a conventional air radiator, which was also located in the rear fuselage. The air necessary for the radiator entered through the frontal air intake located under the power unit. Then passed through a long duct. The heated air in the radiator cooled from the turbocharger to the engine cooled out through two flat nozzles placed on the sides of the fuselage in the tail section. A certain amount of heated air from the turbocharger was also directed in the plane of the wings to heat the lubricant of machine guns during high-altitude flights.
Cartvelli tried to improve the aerodynamics of the new aircraft. As an initial, an external form was adopted, similar to that of the Lancer fighter. Well-streamlined nose of the fuselage, despite the fairly large cross-section, turned out to be very perfect aerodynamically. Lantern cockpit differed pointed nose. Behind him, he passed into an elongated thin gargrot.
Cartvelli installed a relatively small footprint on the P-47. And if almost all the fighters of that time had a specific wing load of about 150-200 kg / m2, then for P-47 this value reached 213 kg / m2. By the end of World War II, it had increased even to 260 kg / m2. In order to place the main landing gear in a relatively small wing, the designers had to mount special devices on them, reducing the length of the uprights at the time of harvesting.
However, despite the excellent high-altitude and speed characteristics, as well as good armament, as the P-47 fighter showed insufficient maneuverability. First of all, it was caused by a very large weight of the airframe design and a large volume of fuel tanks. The flight weight of even the prototype machine reached 5,5 t (subsequently increased to 9 t). It became close to the weight of some twin-engined bombers and was practically twice as large as most fighters of the time. The heaviest units, such as the engine, compressor, weapons with ammunition, were located far from the center of gravity, this also had a very negative impact on the maneuverability of the fighter.
In the spring of 1942, the first production vehicles with the designation P-47В for the USAF left the workshops of the Ripablik factory. In November, 1942, they began to arrive in the air force of the British Air Force.
The appearance of "thunderbolts" on the fronts of World War II allowed the Allied bomber aviation gradually move from night to day raids on the most important industrial centers of Nazi Germany.
In the winter of 1942, the company Ripablik received a second order for the supply of fighters P-47. Therefore, the company had to completely stop the production of aircraft of other types.
During the period of testing and operation of the P-47, one very serious drawback emerged. Despite the huge supply of fuel in the 1155 l, the maximum range at 0,9 speed from the maximum was about 730 km. Naturally, such speeds were not required for escorting bombers, and on the most advantageous operating mode of the Thunderbolt power plant flew up to 1500 km. However, in the case of air combat, fuel was consumed too quickly and was not enough to return. This led to the creation of a new modification, which received the designation P-47C. This Thunderbolt could carry an extra outboard tank of up to 750 L under the fuselage, and its flight range immediately increased to 2000 km. To ensure the normal operation of the engine for a long time increased the volume of the oil tank.
In 1942, the launch of the C-1 “Thunderbolts” began. On these machines, water was injected into the working mixture, which entered the engine cylinders. This allowed for a short period in 5 min to increase its power by 300 hp. This mode of operation of the power plant was called emergency. By increasing the power of the power plant, the P-47 C-1 - C-5 aircraft, despite the increase in flight weight to 6776 kg, were able to fly at speeds up to 697 km / h at an altitude of 9000 m.
Due to the placement of the 57-liter water tank, the length of their fuselage increased by 20, see. Production of the P-1943D, the most popular version of the P-47, began in 47. As a rule, they were equipped with a pair of additional underwing holders. They could hang two fuel tanks with a capacity of 568 l. The total fuel supply reached 2574 l. Flight range reached - 3000 km.
The US Air Force increasingly needed such aircraft: squadrons of “flying fortresses” continued to suffer heavy losses from German interceptors. Therefore, in 1943, the US government transferred another state-owned plant in Evansville, Indiana, to Repablik.
Under the code P-47G, “thunderbolts” were also produced by the aircraft company Curtiss-Wright at a factory in the city of Buffalo (New York). In the designation of these machines added the letters CU (the first two letters of the company name). Fighters produced in the factories of the company Ripablik (in the cities of Farmingdale and Evansville), in addition received the designation of the letters RE and RA, respectively.
In 1944, one of the P-47D-10RE fighters with an R-2800-63 engine was tested in the USSR. The design of the fighter was carefully studied in the Bureau of new technology TsAGI. Pilots LII and NII VVS tested the "Thunderbolt" in the air, clarified its flight performance, which, as was usual for American technology, turned out to be slightly lower than those declared by the company.
Overall, the P-47 disappointed our test pilots. Famous pilot engineer LII M.L. Gallay described his impressions of the Thunderbolt in the following way: “Already in the first minutes of the flight I understood that this was not a fighter! Steady, with a spacious and comfortable cabin, comfortable, but not a fighter. P-47 had unsatisfactory maneuverability in the horizontal and especially in the vertical plane. The fighter slowly accelerated, was inert due to the large weight. This plane was great for a simple flight en route without abrupt maneuvers. But for a fighter this is not enough. "
For the Soviet Air Force fighter "Thunderbolt" were not suitable. Intended to accompany the long-range high-altitude bombers, in our country they were out of work. At this time, almost all Soviet fighters were involved exclusively in the performance of tactical combat missions - covering ground troops from the air strikes of German bombers, escorting their front bombers and attack aircraft, and destroying enemy aircraft in the air. In addition, almost all the air operations on the Eastern Front were carried out by the Germans at altitudes below 5000 m. Nevertheless, our Air Force received about 200 Thunderbolt fighters.
Americans used P-47 like that. B-17 bombers went in tight formation and created a dense defensive fire, they themselves reliably defended themselves. The Thunderbolts also acted in fairly large groups and drove the Messerschmitts and Fokkeulfa away from the distant approaches to the bomber and did not allow the enemy to effectively attack. The Thunderbolts won not so many victories - one shot down or damaged enemy aircraft on 45 sorties, although some P-47 pilots did have a combat score of more than a dozen aircraft shot down. The most successful were Francis Gabreski and Robert Johnson (28 had victories), David Schilling (22), Fred Christensen (21), Walter Mahyuren (20), Walter Beskam and Gerald Johnson (on 18).
In 1944, a second front opened in the West. Thunderbolts were used to attack ground targets from low altitudes. And this is not surprising. Indeed, in the US aviation there was no specialized attack aircraft, and the P-39, P-40, P-51 and, of course, P-47 were quite widely involved in its mission.
He was more adapted to this. P-47 had a long range, could reach deep enemy rears. True, the speed of the ground, and especially with the suspended bombs, was lower than that of the main Hitlerite fighters. But other dive bombers and attack aircraft remained far behind. In addition, "Thunderbolt" could carry quite a significant bomb load. Р-47 (series from D-6 to D-11, as well as G-10 and G-15) on the vent holder, instead of an additional tank, they took one 227-kilogram bomb or several bombs of lower weight. A little later, starting with the D-15 series, two more were suspended, according to 454 kg. They were placed on the wing nodes of the suspension. Thus, the total bomb load reached 1135 kg, which was comparable to the combat load of many bombers of that period.
R-47 had powerful machine gun weapons. Of course, this did not allow him to effectively fire on enemy tankslike IL-2 or Ju-87C, on which mounted guns of 23 and 37 mm caliber. However, eight large-caliber machine guns turned out to be quite enough to destroy motor vehicles, steam locomotives and other similar equipment, and to destroy manpower.
On many Thunderbolts, six rocket launchers with bazookas were mounted. Such formidable squadrons Р-47 together with the English attack aircraft “Typhoon” and “Mosquito”, during the landing of the Anglo-American troops in Normandy, practically managed to disrupt the transportation of the Nazi troops and did not allow the Germans to deliver reinforcements in time.
"Thunderbolt" was quite tenacious machine. This was facilitated by the star-shaped air-cooled motor and the lack of fuel tanks in the wing, which, because of their large area, were usually primarily affected. The fuel tanks in the fuselage were protected.
The pilot additionally defended the front with bulletproof glass and steel armor plate, and when attacking from behind - with an armor plate, intermediate radiator and turbocharger, their damage did not lead to the crash of the aircraft. The tunnel of the air radiator, which passed under the fuselage, as well as the exhaust pipe and air ducts, stretched along its sides, covered the pilot, tanks and other vital structural elements and assemblies.
The most interesting and unusual element in the P-47 design was a special steel ski truss located under the fuselage. She protected the fighter from destruction in case of a forced landing with the landing gear retracted. In short, the P-47 turned into a fighter-bomber.
Simultaneously with the production of “Thunderbolt”, the company Ripablik was looking for ways to further improve the aircraft. It was created several experimental machines. In particular, an airtight cabin was installed on one of the P-47В fighters. On the other is a wing with a laminar profile, which has less resistance than a conventional one. These aircraft received the designation XP-47E and XP-47F, respectively.
But the emphasis was on experimental machines with other engines. One of them, the XP-47H, was the most different from all the P-47 variants. An experienced 16-cylinder engine with liquid-cooled Chrysler XI-2220-11 hp 2500 take-off power was installed on this machine.
True, XP-47H for quite a long time brought. His first flight took place only at the end of July 1945. The maximum speed did not exceed 666 km / h.
The experimental machine, which had the designation XP-47J, turned out to be more successful. She was a lightweight fighter with a take-off weight of 5630 kg. Armament was standard - six machine guns. Air-cooled motor R-2800-57 takeoff power 2800 hp In July, the 1944 of the year on this plane reached the maximum speed of 793 km / h, then, in the autumn of the same year, 813 km / h at an altitude of 10500 m.
During flight tests, according to the US Air Force, the XP-47J reached a speed of 816 km / h. Rate of climb was almost 30 m / s. In terms of its altitude and speed characteristics, it surpassed all the piston aircraft of the world known at that time. (It is embarrassing that officially the flight speed was never registered as a world record.)
In 1944, under the leadership of A. Kartvelli, another experienced XP-72 fighter was created. In fact, it was the usual "Thunderbolt", equipped with an R-4360 "Wasp Major" engine with an 3650 horsepower. (which led to a significant change in the shape of the nose of the aircraft). Built two copies of the fighter. On one of them, they installed an ordinary four-bladed screw, on the other - two coaxial three-blades. The maximum speed of the latter reached 788 km / h at an altitude of 6700 m.
Despite the high results achieved, the new cars did not go into the series. The engines were not reliable, the planes required a long tune, and maneuverability became even worse. In addition, the Second World War was already coming to an end, and the board of the company Ripablik decided, without knocking down the pace of production of fighters, to carry out their evolutionary improvement.
Thus, a new large-diameter propeller with blades of a different configuration was installed on the P-47D fighter 22 series. Rate of climb increased by almost 2 m / s.
From the 1944 of the year, starting with the modification of the D-25, the P-47 fighter jets began to be produced with a drop-shaped cockpit lantern, which allowed the pilot to conduct a circular review. At the same time, another 248 l increased the volume of the main intra-fuselage fuel tank. Water tank capacity - from 57 to 114 l.
Not in vain work to create an experimental XP-47J. From the end of 1944, the finished motor R-2800-57 began to be installed on serial "thunderbolts", which received the designation R-47М. In horizontal flight, according to the company, their maximum speed at an altitude of 9150 m reached 756 km / h.
It is interesting to note that the P-47M fighters were designed specifically to fight the German V-1 cruise missiles that the Germans fired at London.
The last version of the Thunderbolt was a long-range high-altitude fighter of super-heavy class P-47N. He had significant differences from the machines of early modifications. As on the P-47M, there was an R-2800-57 engine with an 2800 horsepower hp on it. However, the volume of fuel tanks was much larger. Place additional fuel in the fuselage became impossible, and the wing tanks on the "Thunderbolt" was not provided. Because the designers of the company Ripablik designed a completely new wing. Increased its scope and area. Applied a thinner profile and new ending. But the most important thing is that in the wing they still placed fuel tanks with a volume of 700 l!
In addition, we provided for the suspension of two large additional tanks with a volume of 1136 l under the wing and one 416 l under the fuselage. A total of P-47N could take on board almost 4800 liters of fuel. The normal flight weight of the aircraft of the D and M series was about 6500 kg, and at full load it reached 9080 kg.
The machine could fly to a range of 3780 km and be in the air for almost 10 hours. This, in turn, required the installation of an autopilot on it.
In the shock version, instead of outboard fuel tanks under the wing of the Р-47N, two bombs weighing 454 kg and 10 of 127 caliber mm could be suspended. The maximum speed reached 740 km / h at an altitude of 9150 m. The climb rate, despite the large flight mass 15,25 m / s. However, these aircraft rarely acted on ground targets and were used at the final stage of the war mainly to escort B-29 strategic bombers that raided Japan.
Thunderbolt fighters were mass-produced up to the complete defeat of Japan. Then the plant in Evansville was closed and returned to the government.
In total, during the war, Ripablik built 15 329 fighters Р-47. Of these, P-47B is 171, P-47C is 60602, P-47D is 12600, P-47M is 130 and P-47N-1818. The company has released a number of spare parts, equivalent to about 3000 aircraft. Almost 350 fighter P-47G released the company "Curtis". Thus, the P-47 "Thunderbolt" became the most popular American fighter during the Second World War.
Sources:
Bakursky V. Fighter R-47 Thunderbolt. Historical series. M .: NTK "Aqua Vita", 1991. S. 6-12, 17-21.
Kotelnikov V., Bakursky V., Nikolsky M. R-47 “Thunderbolt” // Aviation and Cosmonautics. 2004. No.10. C.22-29.
Bakursky V. The Long Arm of the “Fortresses” // Wings of the Motherland. 1992. No.6. C.34-37.
Ivanov S. R-47 Thunderbolt. Heavy US fighter // War in the air. No.46. C. 12-19.
Haruk I. Fighters of the Second World War. M .: Yauza Press, 2012. C. 263-266.
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