12/31/2010. Remarks by Johan Visschedijk: "As part of a program to develop a version of the Thunderbolt specifically for operations in the Pacific Theatre, where the principal requirement was range, the second YP-47M was fitted with a modified, strengthened and slightly enlarged wing, with which it flew in September 1944 as the XP-47N.
The R-2800-57(C) engine and CH-5 turbo-supercharger combination was retained, the new wing embodied internal tankage for the first time, and a strengthened undercarriage was provided to cater for a substantial increase in maximum gross weight which was to result in the P-47N being the heaviest production model of the Thunderbolt. The P-47N standardized on the battery of eight 0.5 in (12.7 mm) machine guns, and the P-47N-5-RE and subsequent production batches had zero-length rocket launchers added, the R-2800-77 engine supplanting the -57 in late production examples.
The P-47N saw extensive service in the Pacific, frequently escorting B-29 Superfortresses and having the ability to fly with the bombers all the way from Saipan to Japan. The final production version of the Thunderbolt, the P-47N was manufactured between December 1944 and December 1945, a total of 1,667 being produced at Farmingdale and a further 149 at Evansville."