The P-47C was the next production version of the Thunderbolt. It began to leave the production lines in September of 1942. It was externally similar to the P-47B, but had a strengthened and revised fin with a metal-covered rudder to eliminate a tail flutter problem which had resulted in several crashes of P-47Bs during high-speed dives. The revised rudder resulting in an increase in overall length of about an inch. A revised oxygen system was fitted, with four oxygen cylinders (one of them in the leading edge of the port wing) in place of the single cylinder of the P-47B. A new radio (SCR-274-N command set and SCR-515-A) was fitted, and the forward-slanted radio antenna mast of the P-47B was replaced by a shorter upright mast.
The first P-47C (41-6066) was completed on September 14, 1942. Even though the P-47C incorporated strengthened tail surfaces, the P-47C still had problems in recovering from high-speed dives. Beyond 500 mph, recovery from power dives was extremely hazardous, with the elevators being unable to respond because of compressibility forces.
The P-47C-1-RE production block differed by having an extra 8-inch section added to the fuselage forward of the firewall giving improved flight characteristics through movement of the center of gravity. The first P-47C (41-6066) was used as a prototype for the fuselage modifications. There were some detail changes to the main undercarriage and brakes. There were also some changes in the tail wheel, and steering was eliminated. There were som changes in the supercharger air ducting. Bob weights were installed in the elevator control system in order to help to overcome the compressibility problems that had made high speed dives in the earlier P-47C extremely dangerous. Latches for linking the engine throttle, propeller, and turbosupercharger were added, which made correlated operation possible by moving a single lever.
On November 13, 1942, Lts. Harold Comstock and Roger Dyar managed to reach indicated airspeeds of 725 mph during high-speed dives in their P-47Cs. This was beyond the speed of sound, which, if accurate, would have made them the first pilots to break the sound barrier. However, it is likely that the airspeed readings were wildly inaccurate, since the terminal velocity of the P-47 is about 600 mph, and that the true speeds reached were probably in the 500 mph range.
The engineers at Wright Field ran an extensive evaluation of the P-47C-1-RE, and found that it had the best rate of aileron roll of any US fighter. However, they found that the view over the nose was restricted, which would make deflection shooting extremely difficult.
The complex ducting that ran along the bottom of the fuselage connecting engine and turbosupercharger had an unintended benefit. It acted as a crushable buffer during belly landings, protecting the pilot's legs and preventing the aircraft from disintegrating upon impact.
The first Thunderbolt to be considered truly combat-ready was the P-47C-2-RE. Perhaps the most important change introduced by this production block was the provision for shackles and a release mechanism for a bomb or a fuel tank on the underside of the belly. When carrying a 200-gallon fuel tank underneath the belly, the range was extended to 1250 miles at an altitude of 10,000 feet and a cruising speed of 231 mph.
The P-47C-5-RE introduced revised radio, instruments, and antenna. Cockpit heating was introduced.
602 P-47Cs were delivered by February 1943, when the improved P-47D replaced it on the production line.
Serials of the P-47C were as follows:
41-6066/6123 Republic P-47C-RE Thunderbolt 41-6124/6177 Republic P-47C-1-RE Thunderbolt 41-6178/6305 Republic P-47C-2-RE Thunderbolt 41-6306/6667 Republic P-47C-5-RE Thunderbolt
Specs of the P-47C-5-RE:
One Pratt & Whitney R-2800-21 supercharged radial air cooled engine rated at 2000 hp. Curtiss Electric C542S propeller, 12 ft 2 in diameter. Maximum speed was 433 mph at 30,000 feet, and 353 mph at 5000 feet. Initial climb rate was 2780 feet per minute. An altitude of 15,000 feet could be attained in 7.2 minutes. Service ceiling was 42,000 feet. Range at maximum cruise power was 640 miles at 335 mph at 10,000 feet. Range with a 166.5 Imp. gall. drop tank was 1250 miles at 10,000 feet at 231 mph. Weights were 9900 pounds empty, 13,500 pounds normal loaded, 14,925 pounds maximum. Wingspan was 40 feet 9 5/16 inches, length was 36 feet 1 3/16 inches, height was 14 feet 3 5/16 inches, and wing area was 300 square feet.