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 318th 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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