Thunderbolt: the dictionary defines it as "a flash of lightning accompanied by thunder" and it aptly describes the P-47 during World War II. Thunderbolt pilots flew into battle with the thundering roar of a 2000-horsepower radial engine and the deadly flash of eight .50 caliber machine guns. This combination of a robust, reliable engine and heavy armament made the Thunderbolt successful. U. S. Army Forces (AAF) commanders considered it one of the three premier American fighter aircraft, alongside the North American P-51 Mustang and the Lockheed P-38 Lightning (see NASM collection for both aircraft). In the history of aviation, Americans built more P-47s than any other American fighter airplane.
A design history of the Thunderbolt begins in 1935, when the predecessor to Republic Aviation, the Seversky Aircraft Corporation, won an Army Air Corps fighter design competition with an airplane designated the P-35. Alexander Kartveli, Seversky chief designer, used a distinctive semi-elliptical wing plan-form on the P-35 and all the models that followed including the P-47. Kartveli improved on the P-35 with incrementally more powerful engines equipped with superchargers and these airplanes were designated the XP-41 and the P-43 Lancer. The XP-47A was to have been another modest evolutionary step, but aerial combat reports coming back from Europe in 1940 indicated the need for a breakthrough design.
Republic proposed a fighter never seen before nor hardly imagined. It was to be the largest single-engine fighter airplane built and flown by any nation during World War II and Kartveli armed it with the heaviest armament of any fighter yet built, eight .50 caliber machine guns. The designer also proposed using the Pratt & Whitney R-2800 engine, the largest air-cooled radial available. To make the airplane as fast as possible at high altitude, Kartveli designed a turbo-supercharger system that fit inside the aft fuselage of the big fighter. This was a particularly complex design challenge. Because of the importance of smooth airflow inside several hundred feet of ducting that connected the supercharger, near the tail, with the engine in the nose, the turbo air duct system was designed first, and then the rest of the aircraft was made to fit around it. Ducting filled nearly the entire belly of the XP-47B. After the aircraft became operational and several crashes occurred, post-crash analysis revealed that these ducts formed a safety cushion between the pilot and the ground.
The Army was impressed with the new design and ordered 171 P-47Bs. On May 6, 1941, the XP-47B made its first flight but Republic needed nearly two more years of testing and refining before the Thunderbolt was ready for combat. Upon arrival in England in December 1942, pilots greeted the P-47 with mixed emotions. Many fighter pilots were accustomed to more nimble and lightweight fighters such as the Supermarine Spitfire, Hawker Hurricane. Pilots of the 4th Fighter Group, Eighth Air Force, first took the Thunderbolt into combat. The fighter weighed more than twice as much as the Spitfires many men had flown previously, so someone nicknamed the aircraft 'Juggernaut,' a fitting moniker that was soon shortened simply to the Jug.
Early combat sorties, first flown in April 1943, revealed that the Thunderbolt could out-dive all opposing fighters-a definite advantage in aerial combat. The P-47 could also absorb tremendous battle damage and continue to fly, and the eight .50 caliber machine guns that Kartveli installed gave it the greatest projectile throw-weight of any U. S. fighter that served in World War II, except for the Northrop P-61 Black Widow night fighter. However, initial operational experience revealed problems with the engine, radio, landing gear, range and rate of climb. The first three difficulties were soon sorted out but rate of climb was not dramatically improved until December when new broad-chord "paddle-blade" propellers. Range limitations plagued the P-47 as long as it served in the European Theater. In the Pacific, Republic solved the range problem when the firm introduced the P-47N in April 1945 with a completely redesigned wing that held more fuel. The 'N model could fly more than 3,220 km (2,000 miles) and escort Boeing B-29 Superfortresses (see NASM collection) attacking the Japanese home islands.
During the war, the P-47 underwent many other modifications to improve its combat efficiency. The P-47D model featured water injection to boost engine power, more powerful versions of the R-2800 engine, increased fuel capacity, and a "bubble" canopy for less-restricted visibility from the cockpit. Through Lend-Lease, 247 Jugs went to the British and 103 to the Soviet Union. The Brazilians flew the type in combat in the Italian Theater and in the Pacific, the Mexican 201st Fighter Squadron flies Thunderbolts in the Philippines.
Of the 15,683 P-47s built, about two-thirds reached overseas commands. A total of 5,222 were lost-1,723 in accidents not related to combat. The Jug flew more than half a million missions and dropped more than 132 thousand tons of bombs. Thunderbolts were lost at the exceptionally low rate of 0.7 per cent per mission and Jug pilots achieved an aerial kill ratio of 4.6:1. In the European Theater, P-47 pilots destroyed more than 7,000 enemy aircraft, more than half of them in air-to-air combat. They destroyed the remainder on very dangerous ground attack missions.
In fact, the Thunderbolt was probably the best ground-attack aircraft fielded by the United States. From D-Day, the invasion of Europe launched June 8, 1944, until VE day on May 7, 1945, pilots flying the Thunderbolt destroyed the following enemy equipment:
86,000 railway cars
9,000 locomotives
6,000 armored fighting vehicles
68,000 trucks
The last Jug left the Air National Guard in 1954, but many other countries operated them for some years after that.
The National Air and Space Museum (NASM) Thunderbolt is a P-47D-30-RA, Army Air Forces (AAF) serial number 44-32691. The AAF accepted it on October 27, 1944, and delivered the aircraft to Godman Field, Kentucky. The AAF operated the airplane on the U. S. East Coast primarily as an aerial gunnery trainer. On January 27, 1946, the AAF transferred it from the active inventory to the U. S. Army Air Forces Museum in Dayton, Ohio, and then to the National Air Museum (now NASM) along with other military aircraft. The Smithsonian lent the aircraft to Republic Aviation for restoration and display, and to help the company celebrate the 20th anniversary of the first flight of the P-47. Subsequently, NASM displayed the aircraft at its own Paul Garber Facility in Suitland, Maryland, before lending it to the Museum of Flight at Robins Air Force Base, Georgia.
The P-47 has returned to the museum and is now on display in the National Air and Space Museum, Steven F. Udvar-Hazy Center.
