I previously posted the story of the later versions of the Republic P-47 Thunderbolt and the North American P-51 Mustang. These two fighters were the most produced and most successful U.S. Army Air Force fighters of World War II and were widely used in all theaters.
A fuller story of the P-47 can be found at Wikipedia:
https://en.wikipedia.org/wiki/Republic_P-47_Thunderbolt
The P-47 was a very large heavyweight fighter with the impressive total of eight .50 machineguns and with a large air induction system using a turbosupercharger for good high-altitude performance. Given its size and the reliability and damage tolerance of its Pratt & Whitney R-2800 radial engine, it also proved useful in the ground attack role. The first P-47s got into the fight in late 1942 when the 56th Fighter Group began flying missions from England. The P-47D was the main production model, built initially in so-called "razorback" form and then later with a bubble canopy for improved visibility. A total of 15,660 P-47s were built from 1941 to 1945, making it the most-produced American fighter of the war. (For the ultimate P-47N version, see my earlier post on advanced P-47s.)
The Wikipedia story of the P-51 Mustang can be found at:
https://en.wikipedia.org/wiki/North_...n_P-51_Mustang
The P-51's origins were rather interesting: The RAF approached North American seeking another source for license production of the Curtiss P-40. North American countered with a proposal for a more modern fighter to be designed and built very quickly and the RAF agreed. The Mustang, though a more advanced design, flew before the P-47 and became operational in early 1942 with the RAF. The U.S. Army Air Force looked at the aircraft with interest and bought limited numbers of early versions.
Then, in mid-1942, the RAF replaced the Mustang's Allison V-1710 V-12 engine with the Rolls-Royce V-1650 V-12 and the Mustang was transformed into a very capable fighter. The U.S. ordered large numbers of P-51B and P-51C versions, which arrived in the UK in mid-1943. The Rolls-powered P-51s had excellent range and extended the protection available to B-17 and B-24 bombers engaged in the daylight bombing campaign against the Axis.
Like the P-47, later P-51s were given a bubble canopy and these became the P-51D produced in very large numbers. (For info on the ultimate P-51H Mustang and the P-82 Twin Mustang, see my earlier posts.)
The production total for the P-47 was about a hundred fighters more than that of the P-51. Note, however, that for much of the war the USAAF had more P-47s as a greater proportion of P-51 production went to the Allies.
After the end of World War II, the P-47 was fairly quickly relegated to second-line duties, while the P-51 continued in front line service. The P-51D played an important role in the Korean War as a ground attack aircraft.
Both types continued to serve into the early 1950s. Today, surviving civilian-owned warbird P-51s far outnumber P-47s, although both types have become extremely valuable.