Forging the Thunderbolt

Republic's P-47 Thunderbolt

by Randy Wilson

Copyright © 1994 by the Confederate Air Force and Randy Wilson. All rights reserved.

In 1940, Republic Aviation (formerly Seversky Aircraft) began delivery of 54 P-43 Lancers to the U.S. Army Air Corps. At this time the company had already started development of a more powerful fighter — the P-44 Rocket, which was to be powered by a new Pratt & Whitney R-2180 engine of 1,400 horsepower. However, when the new engine failed, Republic produced another 218 P-43s, with 108 going to the Nationalist Chinese. This production allowed the company to keep the assembly lines open until the next design, the P-47, was ready.

The P-47 Thunderbolt was designed around the most powerful engine, radial or inline, then available — the Pratt & Whitney R-2800 twin-row, air-cooled 18-cylinder radial, which in early versions gave 2,000 hp. The Thunderbolt also had a turbo-supercharger mounted in the rear of the fuselage, which allowed the engine to produce greater power at high altitudes. The resulting design, huge compared to contemporary fighters such as the P-39 and P-40, incorporated lessons from the early air war in Europe, including cockpit armor and self-sealing fuel tanks. The plane quickly became known as the "Jug," as its appearance resembled the milk jug of the day.

The XP-47B first flew on May 6,1941, achieving a top speed of 412 mph and resulting in an immediate order of the P-47B by the USAAF. By November 1942, the three squadrons of the 56th Fighter Group were operational, equipped with P-47Bs. These squadrons joined the Eighth Air Force in England in January 1943. The Thunderbolts flew their first mission on April 8,1943, providing escort for B-17s.

The P-47C was the first model to feature a dropable fuel tank under the belly or wings of the aircraft, thus allowing the Thunderbolt to escort the bombers further into enemy territory. Eight inches were later added to the P-47C's length, forward of the firewall, for better balance and to improve access to engine accessories. About 600 of the C models were produced in 1943.

The next, and best known version of the Thunderbolt was the P-47D, which had 2,300 hp and provision for two 150-gallon drop tanks, allowing even greater long range escort missions. Early versions of the D model continued with the original canopy style and a high, ridged fuselage, often called a "razorback." To increase the pilot's rear view, the P-47D-25 introduced a clear "bubbletop" all-around view canopy, with a cut down rear fuselage. In addition, racks under the wings could hold 10 air-to-ground rockets, which added extra punch as the Thunderbolt was utilized more in the ground attack role in 1944 and 1945.

In some "bubbletop" P-47Ds, the loss of the razorback resulted in severe tail flutter. The P-47D-40 introduced a small dorsal fin in front of the vertical stabilizer which eliminated the problem.

The final Thunderbolt version to see action in World War II was the P-47N, which was designed for long-range operations in the Pacific, such as escorting B-29s. A new wing with four 50 gallon fuel tanks, clipped wingtips and increased span was fitted. With the new wing, the P-47N could carry up to 1,266 gallons of fuel for a range of 2,350 miles. The dorsal fin was also enlarged and truncated differently from that on the D model.

Despite being designed for Pacific operations, the first operational P-47Ns were sent to the 56th Fighter Group in England, but the war in Europe ended before they saw combat

In the Pacific, the 318^th Fighter Group on Saipan first took the P-47N into combat in the spring of 1945. Thunderbolts were sturdy — many returned from missions with large holes in their structure or even cylinders blown off the engine. Over 15,600 P-47s were built, and in 1.3 million hours of combat flying in World War II, less than 0.7 percent were lost, an exceptionally low figure, especially for a fighter-bomber.

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