The Republic P-47 Thunderbolt, commonly called "the Jug," is an excellent example of a successful fighter that evolved through a series of designs by the same team.

The Jug's distinctive configuration can be traced back to the 1933 appearance of the Seversky SEV-3 twin-float amphibian. Its distinctive features were its all-metal construction, its almost circular-cross-section fuselage and its wing planform (straight sweepback on the leading edge and an elliptical trailing edge and wingtips). This trademark wing planform (shared with the Supermarine Spitfire) was retained for all subsequent Seversky and Republic fighters through the P-47 and some of its experimental derivatives.

When he started business, Alexander Seversky, formerly an Imperial Russian Air Force pilot, didn't have a factory. His first airplane was built by EDO of College Point, New York-a famous builder of all-metal seaplane pontoons. Now, with a successful design to sell, Seversky established a factory in Farmingdale, Long Island, New York. The second Seversky airplane, which was similar to the first, was initially tested as a two-seat land-plane fighter with fixed landing gear. It was soon modified (for a U.S. Army fly-off design competition) to a single-seater with an 850hp Pratt & Whitney R-1830 Twin Wasp engine and rearward-retracting gear. Seversky won a production order for 77 P-35s with 950hp R-1830-9 engines, rearward-retracting gear and armament of one .30-caliber and one .50-caliber machine gun. Deliveries began in 1937, and the last production aircraft had a turbo-supercharger fitted in its belly and a new wing (of the same span and area as the XP-41's but with a different center section and inward-retracting landing gear).

By that time, Seversky had been ousted, and the company had been renamed "Republic." The new features of the XP-41 were incorporated into a new model, the P-43, which used the 1,200hp R-1830-35 engine and a standard armament of two .30-caliber and two .50-caliber machine guns. The fuselage lines were refined, and it was nearly 2 feet longer than the P-35/XP-41. There were 272 P-43s and P-43As built. Meanwhile, Republic had been selling export versions of the P-35. Of 120 ordered by Sweden, 60 were drafted by the U.S. after the Arms Embargo went into effect, and they were designated "P-35A." Most were shipped to the Philippines, where they soon fell victim to the Japanese Zero. There was to have been a P-44-essentially the P-43 fitted with the new 1,850hp Pratt & Whitney R-2800 engine-but it was decided that the engine was too big for the existing airframe. A Republic model then being designed (the lightweight XP-47) was canceled, and the designation "XP-47B" was given to an enlarged development of the P-43 that would use a big engine and eight .50-caliber machine guns (the heaviest armament then fitted to a single-seat fighter). The XP-47B, with a 2,000hp XR-2800-21 engine, flew on May 6, 1941, and it was followed by P-47 production models through P-47N (to a total of 15,683 planes).

SHE WAS PORTLY. But she was unbelievably deadly and a surprisingly good dance partner. Those who knew her well loved the Thunderbolt and saw her in a completely different light from those who didn't. The pilots who strapped in behind that big Pratt & Whitney R-2800 and rode it into combat knew the Thunderbolt would take care of them. It could take it as well as it could give it, and more badly damaged Thunderbolts brought their pilots home than any other single engine fighter.

Those who look down their noses at the blunt form of the Jug and smirk are ignoring the facts: most references credit the rotund Jug with having knocked 3,752 enemy aircraft out of the air, many of which were supposedly much more agile. More important, only 0.7 percent of the Jugs that left on a combat mission didn't return.

The most heavily armed fighter in the American arsenal, the Thunderbolt came into its own as a ground-pounder and, because of this, it flew more than twice as many sorties as the Mustang. When its eight .50-caliber Brownings were combined with rockets and bombs, the Jug was a fiercesome ground-attack machine. In the ETO alone, between D-Day and VE day, it is credited with the destruction of 9,000 locomotives and 86,000 rail cars.

Unfortunately, the survival rate of P-47s is among the lowest of any American fighter. In recent years, however, a small handful have been recovered from South America, where they last served as front-line fighters. This P-47D-40 restored by Bill Klaers and Alan Wojciak of Klaers Aviation in Rialto, California, is one of those from far south of the border. Their veritable Thunderbolt "production line" is taking corroded and battered hulks and returning them to the air, where they belong.

(Photo by Budd Davisson)

P-47B. This was the first production model, and 171 were built. Deliveries started late in 1942, and some went into action in Europe on April 8, 1943. In combat, the P-47B-RE had inadequate climbing and maneuverability, but it had plenty of speed and firepower. It also had excellent diving capability, and its heavy structure could absorb terrific punishment. Its wingspan was 40 feet, 9 inches; area, 300 square feet; gross weight, 13,360 pounds; top speed, 429mph at 27,800 feet.

P-47C. The 602 P-47Cs were refined P-47Bs that had their noses lengthened 13 inches and were equipped to carry a 200-gallon drop tank under the fuselage. Although it wasn't quite as fast as the P-47B, its greater range allowed its use on long-range escort missions.

P-47D. This model was the major production version, and 6,315 were built. The initial improvement was a water-injected version of the 2,000hp R-2800-21 engine, which gave it a top speed of 433mph at 30,000 feet. Provision was made for two, 150-gallon drop tanks under the wings or a 250- to 1,000-pound bomb on the same streamlined rack, plus a 500-pound bomb under the fuselage. A new Republic plant was built in Evansville, Indiana, and 2,350 P-47D-RAs were built there.

XP-47E. The last P-47B tested with a pressurized cockpit.

XP-47F. The P-47B tested with a laminar-flow wing.

P-47G. Duplicates of the P-47B built by Curtiss to compensate for the canceled P-60A contract.

XP-47H, J, K and L. Experimental conversions that tested new features and equipment. The XP-47H tested a new, liquid-cooled, 2,300hp, 16-cylinder Chrysler XIV 2220-1 engine; the lightened XP-47J with a 2,100hp R-2800-61 engine was the first piston-engine plane to exceed 500mph; the XP-47K tested the bubble canopy; and the XP-47L had increased internal fuel capacity.

P-47M. The P-47M met the need for a fast, high-altitude fighter. Only 150 were built after three P-47Ds were modified as YP-47M prototypes. The bomb and rocket racks were omitted, and special 2,800hp R-2800-57 engines gave a top speed of 473mph at 32,500 feet. Most of the P-47Ms were in combat in Europe in the closing months of the War.

P-47N. The final production model, P-47, was produced solely for action in the Pacific. Its new wing had a span of 42 feet, 10 inches, an area of 322 square feet and squared-off wingtips. With additional internal fuel (as tested on the XP-47L), two 93-gallon drop tanks under the wings and a 100-gallon drop tank under the fuselage, the P-47N had a total fuel capacity of 1,266 gallons and a range of 2,350 miles, which was enough to permit it to escort B-29s to Japan in the last months of the War. With a 2,800hp R-2800-77 engine, the P-47N had a gross weight of 20,700 pounds and a high speed of 467mph at 32,500 feet.

Republic built 1,667 P-47Ns in Farmingdale and 149 in Evansville. An order for a further 5,934 planes was canceled. The P-47 was retired as a first-line fighter right after the War, but bubble-canopy P-47Ds and P-47Ns stayed in the reserved training squadrons until 1955.
 

There were two notable external changes during P-47D production: a cut-down rear fuselage and a bubble canopy (as tested on the XP-47K) became standard on the P-47D-25 and subsequent marques, and a long, shallow dorsal fin was added to the P-47D-27 and onward. Because of the differences in the two fuselage configurations, the P-47 models prior to D-25 became known as "Razorbacks."

The P-47D proved to be more effective as a fighter/bomber than as an escort fighter, and from P-47D-30 onward, provision was made for the carrying of 10 rockets under the wings in addition to the bombs. Britain took delivery of 240 Razorback P-47Ds as "Thunderbolt I," and 590 P-47D-25s and on as "Thunderbolt II." The gross weight of the P-47D-25 was 19,400 pounds, its high speed was 428mph at 30,000 feet.

XP-47E. The last P-47B tested with a pressurized cockpit.

XP-47F. The P-47B tested with a laminar-flow wing.

P-47G. Duplicates of the P-47B built by Curtiss to compensate for the canceled P-60A contract.

XP-47H, J, K and L. Experimental conversions that tested new features and equipment. The XP-47H tested a new, liquid-cooled, 2,300hp, 16-cylinder Chrysler XIV 2220-1 engine; the lightened XP-47J with a 2,100hp R-2800-61 engine was the first piston-engine plane to exceed 500mph; the XP-47K tested the bubble canopy; and the XP-47L had increased internal fuel capacity.

P-47M. The P-47M met the need for a fast, high-altitude fighter. Only 150 were built after three P-47Ds were modified as YP-47M prototypes. The bomb and rocket racks were omitted, and special 2,800hp R-2800-57 engines gave a top speed of 473mph at 32,500 feet. Most of the P-47Ms were in combat in Europe in the closing months of the War.

P-47N. The final production model, P-47, was produced solely for action in the Pacific. Its new wing had a span of 42 feet, 10 inches, an area of 322 square feet and squared-off wingtips. With additional internal fuel (as tested on the XP-47L), two 93-gallon drop tanks under the wings and a 100-gallon drop tank under the fuselage, the P-47N had a total fuel capacity of 1,266 gallons and a range of 2,350 miles, which was enough to permit it to escort B-29s to Japan in the last months of the War. With a 2,800hp R-2800-77 engine, the P-47N had a gross weight of 20,700 pounds and a high speed of 467mph at 32,500 feet.

Republic built 1,667 P-47Ns in Farmingdale and 149 in Evansville. An order for a further 5,934 planes was canceled. The P-47 was retired as a first-line fighter right after the War, but bubble-canopy P-47Ds and P-47Ns stayed in the reserved training squadrons until 1955.

— Peter M. Bowers