Republic P-47 Thunderbolt

The development of the P-47 began in 1939 with the 1,150-hp Allison V-1710-39 powered XP-47 fitted with two 0.50-in machine-guns. November 1939 saw the United States Army Air Corps contract Republic to build a prototype XP-47 and also a prototype XP-47A. With the outbreak of the Second World War (1939 – 1945) and the war in Europe intensifying during 1940 reports of the air combat taking place showed that the XP-47 and XP-47A would be vulnerable. This was due to their poor armament, lack of self-sealing fuel tanks and lack of heavy armour. As a result both prototypes were cancelled as they were being built.

The design team at Republic, led by Alexander Kartveli, went back to the drawing board and proposed a new aircraft powered by the turbocharged 2,000-hp Pratt & Whitney R-2800 Double Wasp engine. A contract to build a prototype XP-47B, as this new aircraft was known, was issued on the 6th September 1940 by the USAAC. The 6th May 1941 saw the prototype make its maiden flight. The following year on the 8th August 1942 the XP-47B crashed but by this time the first production versions of the 773 which had been ordered were already beginning to enter service.

The production P-47B had a top speed of 429 mph, range of 835 miles and a service ceiling of 42,000 ft. Armament consisted of eight 0.50-in machine-guns. These entered service on the 26th May 1942 when the 63rd Fighter Squadron received the first deliveries. The P-47C was the next Thunderbolt variant and this featured a few modifications over its predecessor. This included the ability for the P-47 to carry external fuel tanks, this gave the aircraft the range to operate over Germany. The P-47C's range, service ceiling and armament were the same as the P-47Bs, however it had a slightly increased top speed of 433 mph.

The P-47D was the next in line, its top speed was the same as its predecessor, it had a range of 800 miles and a service ceiling of 43,000 ft. Armament was eight 0.50-in machine-guns and either 2,500lb bombs or rocket projectiles. Despite increasing their factory at Farmingdale, New York Republic were unable to keep up with demand. This led to a new factory being built at Evansville, Indiana. Curtiss-Wright would also build the P-47 at their factory in Buffalo, New York and P-47s built by Curtiss-Wright were given the designation P-47G. The P-47D entered service during 1943.

Up until now the P-47 had a “razorback” design but during July 1943 one P-47D was tested with the same bubble canopy that was fitted to the Hawker Typhoon under the designation XP-47K. This gave improved rear vision as did the flatter rear fuselage needed to allow the new canopy to be installed. As a result all future production P-47s would feature the new canopy and fuselage design.

The Royal Air Force also used the P-47D in the Far East and these were known as Thunderbolt Mk Is, “Razorback” P-47Ds, and Thunderbolt Mk IIs, bubble canopy P-47Ds. With the addition of three 500lb bombs they were used as fighter-bombers and would go on to equip at least sixteen squadrons.

A number of development P-47s followed but none went past the prototype stage. One of the most notable was the XP-47J powered by the 2,100-hp Pratt & Whitney R-2800-61 engine, this had six 0.50-in machine-guns instead of the usual eight. This would make its first flight on the 26th November 1943, when in level flight it reached a speed of over 500 mph it became the first piston-engined aircraft to do so. In the end an XP-72 project was favoured over the XP-47J.

The P-47M and P-47N were the last two variants to go into production. The P-47M was heavily based on the P-47D and was powered by a 2,800-hp Pratt & Whitney R-2800-57 engine giving the aircraft a top speed of 475 mph, range of 530 miles and a service ceiling of 41,000 ft. Armament was either six or eight 0.50-in machine-guns. This was the fastest P-47 variant and was developed to help combat the new German jet and rocket fighters entering service and the V-1 flying bomb, which was nicknamed the doodlebug.

So the P-47N would be the last of the Thunderbolts built. Powered by the same 2,800-hp Pratt & Whitney R-2800-57 engine as its predecessor the P-47N had a top speed of 467 mph, range of 800 miles and a service ceiling of 40,000 ft. Armament was either six or eight 0.50-in machine-guns and either 2,000lb bombs or rocket projectiles. With the addition of external fuel tanks the P-47N would be able to escort the Boeing B-29 Superfortress squadrons in the Pacific.

The Republic P-47 Thunderbolt would be used by a number of air forces worldwide. These included the Free French, Italian Air Force and Brazilian Air Force. In total 15,677 P-47 Thunderbolts were built and the P-47D and P-47N, later F-47D and F-47N, would eventually be retired by the American Air National Guard in 1955.