Thanks to USAAC requirements, YP-43, the first thirteen test aircraft of the future P-47, only remotely resembled his ancestor AP-4.
The YB-43 was powered by a fourteen-cylinder P & W R-1830-35 delivering 1,200 horsepower and driving a three-bladed propeller. The armament consisted of two 12.7 mm machine gun in the nose of the aircraft, and one 7.62 mm machine gun in each wing.
The first of thirteen ordered YB-43s was delivered in September 1940 and the last in April 1941. In the meantime, Republic was working on a new version of the YP-43 with a more powerful engine, this version was marked YP-44 Rocket, and the fighter marked AP -10. The AP-10 was to be a light fighter, powered by a water-cooled Allison V-1710 engine and armed with a pair of 12.7 mm machine guns. Armada sponsored this project and designated it XP-47.
But in the spring of 1940, as the war in Europe gained momentum, the Republic and the USAAC realized that the XP-44 and XP-47 were not able to compete with German fighters. Republic tried to modify the design of the XP-47, creating a version of the XP-47A, but for the USAAC it was not right yet.
Alexander Kartveli, one of the founders of Republic, returned to the drawing board and designed an aircraft that looked like a larger version of the YP-43. The new design was offered by the USAAC in June 1940, and this time the USAAC liked it. USAAC ordered a prototype in September, marked XP-47B. The XP-47A, which had little in common with the new design, was canceled.
The USAAC must have frozen when they first saw the XP-47B with their own eyes. It was a monster, as its creator, Kartveli, said, "a dinosaur, but a dinosaur of good proportions." Empty aircraft weighs 4490 kg, ie 65 percent more than YP-43 .
The new plane was powered by an 18-cylinder engine P & W R-2800 a whole two thousand horsepower with a complex system of pipes leading to the rear of the fuselage to the turbocharger. The armament was 4x 12.7 mm machine guns in each wing, an incredible firepower for the time.
The XP-47B seemed to be the aircraft that the USAAC wanted, and so the XP-44 Rocket project was canceled just like the XP-47A. But the new machine could not go into production yet, so the USAAC ordered 54 P-43s. Due to further delays in the XP-47B program, it was later
ordered another 80 pieces P-43A with slightly modified engine cover. Finally, another 125 aircraft were ordered P-43A-1 urcenych v under the Lend-Lease program for China, armed with 4 12.7 mm machine guns.
Including thirteen YP-43A, a total of 272 P-43 aircraft of all types were produced until March 1942.
But back to the XP-47B. This aircraft first took off on May 6, 1941, piloted by pilot Lowry P. Brabham. Although there were minor problems, the aircraft proved its qualities during the first tests.
The aircraft was basically built around its large engine and turbocharger. The engine was placed in a wide housing, which opened at the front in an elliptical shape. This extension allowed air to be supplied to cool the engine and the left and right oil coolers, as well as to cool the turbo. Exhaust gases were led through a pair of pipes along the entire length of the cockpit to the rear of the fuselage, where they powered the turbo, which was located in the lower part of the fuselage about halfway between the cabin and the tail surfaces. At full power, this pipe was heated to ore. The exhaust gases either escaped or propelled the turbocharger to which they supplied up to 60,000 rpm. This then returned the power back to the engine.
Thanks to this propulsion, the XP-47B had a wide fuselage and wings in a relatively high position.But there was a problem, to use the full power of the engine R-2800 was equipped with a four-bladed electrically operated propeller with a span of 3.17 meters and meant that the aircraft will need a long landing gear, which also represented a large weight and a large space in the wing. Therefore, a chassis with a sliding part of a full 23 centimeters was finally designed.
4 12.7mm machine guns in each wing, graduated to allow the supply of four magazines lying side by side in the outer parts of the wing. Each magazine took up to 170 kg of ammunition.
The main and additional tanks were located under the cockpit and allowed to hold a total capacity of 1155 liters, which was a very large supply at the time, yet proved insufficient.
The cockpit was spacious, as would be expected from such a machine, and the pilot's seat comfortable. This machine offered the pilot complete comfort, including an air-conditioned cabin.
The prototype was an all-metal construction, with the exception of control surfaces covered with a plate, which caused problems, and the prototype was destroyed in an accident in August 1942.
P-47B/P-47C
The XP-47B gave the USAAF (USAAC was renamed the USAAF in June 1941) a cause for optimism and concern. The performance of the aircraft and the firepower were excellent, but the novelty of the aircraft often caused serious difficulties.
The size of this machine was reflected in the demands on the runway. The problems were with the steering, with the machine guns, with the fuel system, with the engine mount. At high altitudes, the devices were often blocked. Plate-coated control surfaces were often torn at high altitudes.
However, the Republic responded to all these problems and came up with a number of improvements.
In the end, the USAAF ordered 171 P-47Bs. The test prototype was delivered in December 1941, the production prototype followed in March 1942 and the first production aircraft then in May 1942. The Republic continued to modify the design and yet it was not the first aircraft, the aircraft gradually underwent changes, non. in all-metal control surfaces or a new GE turbocharger for the engine R-2800-21.
The plane got its name, Thunderbolt. But thanks to its size, reminiscent of a barrel of whiskey, the pilots were nicknamed Jug.
the end of the first part