Although later version of the P-47D Thunderbolt had sufficient range to operate as an escort fighter in Europe, the longer distances of the Pacific war needed an aircraft with even longer range. Republic’s solution was to design a new longer wing, carrying internal fuel tanks.
The new wing was 1ft longer than that used on earlier Thunderbolts. The wing root was expanded by 18 inches, while the wing tip was clipped, taking six inches off the end. A number of small fuel tanks were placed in the wing roots, allowing each wing to carry 100 gallons of fuel. The internal capacity of the Thunderbolt was raised from 370 to 570 gallons. It could also carry large drop tanks, giving the aircraft a potential combat radius of over 1,000 miles when carrying the full 1,170 gallons of fuel.
Work on the prototype XP-47 took place over the summer of 1944. The first YP-47N was completed in September 1944. The first unit to receive the P-47N was the 56th Fighter Group, based in England, but the war in Europe ended before the aircraft became operational. In the spring of 1945 the 318th Fighter Group on Saipan received the type, which then played an important role in the final campaigns against Japan.
The N-1-RE was the first production version of the P-47N. An increasing sophisticated control system automated many features of this aircraft, including some aspects of the water injection. 550 were built.
The second block of P-47Ns featured a variety of modifications. Five zero length rocket launch rails were placed under each wing. The aircraft was given tail warning radar (type AN/APS-13). An auto-pilot unit was fitted to help rest the pilot during long missions, which could include several hours of unopposed flying over the ocean. The type also gained a catapult attachment to allow it to be delivered to newly captured islands by aircraft-carriers. 550 were built.
This designation was used for N-1s retrofitted with rocket stubs.
The N-15-RE appeared in early 1945. This model used a new bomb rack (the S-1, replacing the B-10), a new gun sight (K-14) and arm rests on the pilot seat, again to reduce fatigue on long missions. However, a shortage of autopilot units meant that it was not fitted to the 200 N-20-REs.
Most of the changes made to the N-20-RE involved the fuel system. A backup fuel system was installed, in case the normal system failed or was damaged. It was also possible to carry a mixed load, with a fuel tank on one wing and a bomb on the other. 200 were built.
This was the final version of the Thunderbolt. 167 were produced at Farmingdale before production ended in October 1945. Most changes were minor, including a different style of cockpit floor, strengthened wings designed to resist rocket launches and an improved control system that reduced the complexity of juggling boost, throttle, propeller pitch and mixture controls.
Engine: Pratt & Whitney R-2800-57 “C-series”
Max Speed: 467mph at 32,000ft
Range: 2,200 miles at 25,000ft (with external tanks)
Span: 42ft 6.8in
Length: 36ft 1.75in