THE 456th FIGHTER INTERCEPTOR SQUADRON

THE PROTECTORS OF  S. A. C.

 

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REPUBLIC P-47 "THUNDERBOLT"

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Affectionately known as the "Jug," the P-47 Thunderbolt was built in larger numbers than any other fighter in American history. Affectionately nicknamed "Jug," the P-47 was one of the most famous AAF fighter planes of WWII. Although originally conceived as a lightweight interceptor, the P-47 developed as a heavyweight fighter and made its first flight on May 6, 1941. The first production model was delivered to the AAF in March 1942, and in April 1943 the Thunderbolt flew its first combat mission--a sweep over Western Europe. Used as both a high-altitude escort fighter and a low-level fighter-bomber, the P-47 quickly gained a reputation for ruggedness. Its sturdy construction and air-cooled radial engine enabled the Thunderbolt to absorb severe battle damage and keep flying. During WW II, the P-47 served in almost every active war theater and in the forces of several Allied nations. By the end of WW II, more than 15,600 Thunderbolts had been built.

Production P-47B, -C, early -D and -G series aircraft were built with metal-framed "greenhouse" type cockpit canopies. Late -D series (dash 25 and later) aircraft--such as the P-47D-40-RA on display--and all -M and -N series production aircraft were given clear "bubble" canopies, which gave the pilot improved rearward vision.

The P-47 was one of America's leading fighter airplanes of WWII. It made its initial flight on May 6, 1941, but the first production article was not delivered to the AAF until March 18, 1942, more than three months after the attack on Pearl Harbor. On April 8, 1943, the P-47 flew its first combat mission, taking off from England for a sweep over western Europe. During the next several months, AAF pilots learned that the Thunderbolt could out-dive any Luftwaffe airplane encountered. An auxiliary fuel tank was suspended under the fuselage beginning in 1943, permitting the P-47 to escort AAF heavy bombers much farther into German territory.

In addition to establishing an impressive record as a high-altitude escort fighter, the P-47 gained recognition as a low-level fighter-bomber because of its ability to absorb battle damage and keep flying. By the end of the war, the Thunderbolt had been used in every active war theater with the exception of Alaska. In addition to serving with the AAF, some were flown in action by the British, Free French, Russians, Mexicans, and Brazilians.

 

AAF Fighter Escort

Early in 1943, the 4th Fighter Group, composed of the three former Eagle Squadrons, converted from the Spitfire to the P-47, a newly-developed AAF fighter with greater range, and on March 10, the P-47 became operational when several made a fighter sweep over Europe. On Apr. 8, two additional P-47 groups became operational. In May, P-47s began flying escort for AAF heavy bombers.

However, P-47s still did not have sufficient range to fly penetration and withdrawal escort all the way to targets deep in Germany. This often led to disastrous results such as on Jun. 13, 1943 when 60 B-17s attacked Kiel in Northwest Germany on the Baltic Sea. As soon as the P-47s turned for home, the AAF bombers were attacked by Luftwaffe interceptors and 22 of the 60 B-17s were shot down.

The aircraft on display was acquired by the Museum in 1981. It is marked as a -D with the 1st Air Commando Group in China in 1944-45.

Type Number Built / Converted Remarks

XP-47
XP-47A
XP-47B
P-47B
P-47C
P-47D-RE
P-47D-RE
P-47D-RA
P-47D-RA
XP-47E
XP-47F
P-47G-CU
XP-47H
XP-47J
XP-47K
XP-47L
YP-47M
P-47M
XP-47N
P-47N-RE
P-47N-RA
 
0
0
1
171
602
3963
2546
2350
3743
1 (cv)
1 (cv)
354
1 (cv)
1
1 (cv)
1 (cv)
3 (cv)
130
1
1667
149

Lt. Interceptor; Canc.
Mod. XP-47;no guns or radios
Imp. P-44 & XP-47 design
1st prod. a/c;8 .50-cal. in wings
Imp. P-47B
Razorback P-47D;Blocks 1-22
Bubble Canopy P-47D; Blocks 25-30
Evansville Ind. Plant; Blks. 2-23
Evansville Bubble Canopy; Blks. 26-40
Mod. -B (171st Built); Press. Cockpit
Mod. P-47B;laminar flow wing
Curtiss Built -D model
Mod. P-47D; 16 cyl. Chrysler eng.
New model; 6 .50-cal.
Mod. P-47D w/ Hawker Typhoon Cnpy.
Mod. P-47D-20
Mod. P-47D; dive brakes
Fighter-bomber version
Imp. -D; new wing
Long-range escort model
5934 canc. after VJ-Day

SPECIFICATIONS
Span: 40 ft. 9 in.
Length: 36 ft. 2 in.
Height: 14 ft. 8 in.
Weight: 17,500 lbs. max.
Armament: Six or eight .50 cal. machine guns and either ten rockets or 2,500 lb. of bombs
Engine: One Pratt & Whitney R-2800-59 of 2,430 hp.
Crew: One
Cost: $85,000

PERFORMANCE
Maximum speed:
433 mph.
Cruising speed: 350 mph.
Range: 1,030 miles
Service Ceiling: 42,000 ft.

PHOTOGRAPHS AND TEXT COURTESY OF THE AIR FORCE MUSEUM

 

 

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"SHE WAS PORTLY. But she was unbelievably deadly and a surprisingly good dance partner. Those who knew her well loved the Thunderbolt and saw her in a completely different light from those who didnít. The pilots who strapped in behind that big Pratt & Whitney R-2800 and rode it into combat knew the Thunderbolt would take care of them. It could take it as well as it could give it, and more badly damaged Thunderbolts brought their pilots home than any other single engine fighter.

"Those who look down their noses at the blunt form of the Jug and smirk are ignoring the facts: most references credit the rotund Jug with having knocked 3,752 enemy aircraft out of the air, many of which were supposedly much more agile. More important, only 0.7 percent of the Jugs that left on a combat mission didnít return.

"The most heavily armed fighter in the American arsenal, the Thunderbolt came into its own as a ground-pounder and, because of this, it flew more than twice as many sorties as the Mustang. When its eight .50-caliber Browning's were combined with rockets and bombs, the Jug was a fierce some ground-attack machine. In the ETO alone, between D-Day and VE day, it is credited with the destruction of 9,000 locomotives and 86,000 rail cars.

"Unfortunately, the survival rate of P-47s is among the lowest of any American fighter. In recent years, however, a small handful have been recovered from South America, where they last served as front-line fighters. This P-47D-40 restored by Bill Klaers and Alan Wojciak of Klaers Aviation in Rialto, California, is one of those from far south of the border. Their veritable Thunderbolt "production line" is taking corroded and battered hulks and returning them to the air, where they belong."


ó
Budd Davisson

 

Republic P-43 & P-44

Darwinism Of The P-47

A Very Brief History Of The P-47

More About The P-47 "Thunderbolt

The Republic P-47M

A Design Analysis of the P-47 Thunderbolt

 

Pratt and Whitney R-2800-21 Engine

 

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 This type of engine was used in the Republic P-47. Rated at 2,000 horsepower for take-off. Many contractors built engines under license during WWII. This engine was built by Ford Motor Co., Dearborn, MI.

PHOTOGRAPHS AND TEXT COURTESY OF THE AIR FORCE MUSEUM

 

 

More About The P&W R-2800 Engine

 

 

 

Republic P-47 Thunderbolt A Brief History

By Joe Baugher

 

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The Thunderbolt was a massive airplane, the biggest and the heaviest single engine, single-placed fighter ever built. The engine, the Pratt & Whitney 18 cylinder twin-row radial, developed 2,000 H.P., was the most powerful engine at the time. However, in turn, it needed a highly efficient duct system for its super-charger. The designer, Alexander Kartveli designed the duct system first, then build the fuselage around it. 
 The heavy fighter was not an instant winner with the pilots that initially took it to combat. The American Ex-Eagle Squadron pilots hated it from the beginning, but the 56th Fighter Group pilots, who initially trained on the P-47, loved it! Low-altitude air-to-air combat remained a problem until a paddle blade was added, but high-altitude combat was a different story. The short range of the P-47 was a distinct handicap until the auxiliary fuel tanks were added. When it came to strafing and dive bombing, the big P-47 excelled. Following D-Day, in France the Thunderbolts performed magnificently in ground support until the end of the war.
 

 

Republic XP-47B Thunderbolt

 

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P47cutaw.jpg (88936 bytes)

The Republic P-47 Thunderbolt originated from the drawing board of Alexander Kartveli of the Seversky Aircraft Corporation (later renamed Republic Aviation). The Thunderbolt is consistently rated as one of the three outstanding USAAF fighters of World War II-- rated right up there along with the North American P-51 Mustang and the Lockheed P-38 Lightning. The P-47 was built in larger numbers than any other American fighter, 15,683 examples rolling off the assembly line before production finally ended.

At one time during the heady days of 1944, there were no less than 31 front-line fighter groups flying Thunderbolts. Thunderbolts fought on all fronts in World War 2, including Alaska. Approximately two-thirds of all Thunderbolts built actually reached operational units overseas. In two and a half years of combat, from March 1943 to August 1945, these Thunderbolts flew over half a million combat missions, destroying over 12,000 enemy aircraft both in the air and on the ground, as against a total of 5222 Thunderbolts lost, only 824 of them in the heat of combat. This corresponded to 54 percent of the Thunderbolts which went overseas being eventually lost either to enemy action or to accidents, which was a fairly typical attrition rate for a wartime fighter. Losses of Thunderbolts on operational missions were 0.7 percent of those dispatched, an exceptionally low figure.

By the end of the war, the Thunderbolt had established an overall ratio of air-to-air combat victories to losses of 4.6 to 1. Thunderbolts dropped 132,482 tons of bombs, fired 59,567 rockets, and expended 135 million belts of machine gun ammunition.

From D-Day to V-E Day in Europe, Thunderbolts destroyed 86,000 railway cars, 9000 locomotives, 6000 armored vehicles and tanks, and 68,000 trucks. By the end of the war, Thunderbolts had destroyed 2752 enemy aircraft in the air and 3315 on the ground.

The P-47 as originally conceived was quite different from the aircraft which was ultimately to emerge from the Republic factories. On August 1, 1939, Kartveli, in response to an official requirement, proposed a lightweight high-altitude interceptor to the USAAC under the company designation of AP-10. It was to be powered by a 1150 hp Allison V-1710-39 liquid-cooled in-line engine. This was a radical change in design philosophy for Kartveli, since he had always preferred radial air-cooled engines for fighters because of their greater simplicity and their ability to absorb a larger amount of battle damage. Gross weight was to be 4900 pounds and estimated maximum speed was 415 mph. Armament was to be a pair of 0.50-in machine guns mounted in the engine housing.

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The USAAC looked over the proposal and was favorably impressed. However, they deemed that additional armament would be required, even if it adversely affected performance. Kartveli increased the size of his AP-10 design somewhat, and added four wing-mounted 0.30-inch machine guns. Gross weight rose to 6570 pounds. In this guise, in November 1939 the USAAC ordered one prototype of the AP-10 design under the designation XP-47. The serial number was 40-3051.

In addition, on January 17, 1940, the USAAC ordered a stripped, unarmed version of the same basic design under the designation XP-47A. It was to be devoid of armament, radio and other tactical equipment so that it could be tested before the fully-equipped XP-47. The serial number of the XP-47A was 40-3052.

In the meantime, combat reports coming in from Europe were changing everyone's ideas about air combat. More firepower, more armament, more armor protection, and self-sealing fuel tanks were likely to be required in future air battles. Both the XP-47 and XP-47A had insufficient engine power to accommodate the additional weight required by these features, and the USAAC came to the conclusion that these designs were likely to fall far short of future air combat requirements. The Army considered the XP-47 to be insufficiently armed, and thought that it had too high a wing loading and was too slow in comparison with the Curtiss XP-46. Anticipating that the Army would ultimately reject his XP-47 design, Kartveli went back to the drawing board.

In order to accommodate the heavy firepower, armor, and self-sealing fuel tanks and still provide a performance capable of meeting enemy aircraft on equal terms, a lot of engine horsepower would be needed. Kartveli decided to produce a design based around a turbo-supercharged Pratt and Whitney R-2800 Twin Wasp eighteen-cylinder air-cooled radial engine, one of the most powerful aircraft engines available at the time. Armament was to be a set of eight 0.50-in machine guns in the wings, following the RAF's trend toward eight-gun fighters and making the Republic proposal among the heaviest-armed fighters yet considered by the USAAC up to that time. Total weight was to be a massive 11,500 pounds, unprecedented for a USAAC single-seat fighter. A maximum speed of 400 mph at 25,000 feet and 340 mph at 5000 feet was envisaged. It was anticipated that an altitude of 15,000 feet could be reached in five minutes.

On June 12, 1940, Kartveli submitted his ideas to the USAAC. The USAAC was sufficiently impressed with the proposal that on September 6, 1940 ordered a prototype under the designation XP-47B. This designation was sort of unusual at the time, namely, using the same P-number for what was in effect a totally new design. All work on the XP-47 and the XP-47A was cancelled, and the serial number of the abortive XP-47 was transferred to the XP-47B.

One week later, on September 13, 1940, 773 production examples of the new fighter were ordered by the USAAC, 171 to be delivered as P-47Bs and 602 as P-47Cs. At the same time, the Army contract placed back in 1939 for 80 P-44 Rockets was cancelled. The contract was replaced with an order for a similar quantity of P-43 Lancers which would keep the Farmingdale production lines occupied pending the introduction of the new fighter.

Kartveli decided to design the XP-47B fuselage around the large turbo-supercharger from the start, rather than to add it onto the aircraft later as sort of an afterthought. In order to preserve a streamlined fuselage with a small cross-section, the large turbo-supercharger was placed in the rear fuselage. It was fed by an air duct located beneath the large R-2800 engine. Engine exhaust gases were directed back to the rear fuselage in separate pipes to the turbine and were expelled through an exhaust under the rear tail. Ducted air was fed to a centrifugal impeller and was returned to the engine under pressure via an intercooler.

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Another problem that had to be solved was that the aircraft required a very large twelve-foot diameter four-bladed propeller in order to take full advantage of the R-2800 engine's high power output. This large propeller in turn required a long and stalky undercarriage in order that the propeller be given adequate ground clearance during takeoff and landing. If a conventional retractable undercarriage were used for the P-47, its suspension would have to have been placed very far outboard on the wings, leaving insufficient space for the eight wing guns and their ammunition. In order to solve this problem, the landing gear telescoped and was nine inches shorter when retracted than when extended. Somewhat surprisingly, this complex telescoping landing gear seems to have caused few problems in the field.

Like the earlier P-35 and P-43 fighters, the P-47 was a cantilever low-wing monoplane, the wing being elliptical in shape with the ailerons on the outer trailing edge and flaps on the inner trailing edge. The semi-monocoque fuselage was all metal, but initially the control surfaces were fabric covered. The tail-wheel was steerable and was fully retractable. All the fuel tanks were inside the fuselage and were self-sealing from the start. The cockpit was protected by armor and was un-pressurized.

The name *Thunderbolt* for the P-47B was originally thought up by C. Hart Miller, Republic's Director of Military Contracts. The company approved his choice, and the name stuck.

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The XP-47B prototype (40-3051) flew for the first time on May 6, 1941, piloted by Lowry L. Brabham. This was only eight months after the order had been placed. The XP-47B was the largest single-engine fighter built up to that time. At a loaded weight of 12,086 pounds, the XP-47B dwarfed all previous fighters, being almost twice as heavy as most of its contemporaries. On the first flight, the pilot was forced to make an unplanned emergency landing because of a leakage of exhaust fumes into the cockpit. Its eighteen-cylinder XR-2800-21 radial engine offered 1960 hp at 25,800 feet, and gave it a maximum speed of 412 mph, 12 mph faster than Kartveli had projected. An altitude of 15,000 feet could be attained in five minutes. Empty and normal gross weights were 9189 pounds and 12,086 pounds respectively. The prototype was destroyed in an accident on August 8, 1942.

 

Republic P-47B Thunderbolt

 

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    P-47B-RA  (S/N 41-5905)     

The first production P-47B (41-5895) was really a specially-built second prototype. It was delivered to the Army on December 21, 1941, and was immediately dispatched to Wright Field for testing. The XP-47B remained with the manufacturer.

The first four P-47Bs from production (41-5896/5899) were delivered in mid-March of 1942, only eight months after the XP-47B prototype had first flown. These planes were used for an extensive test program by various agencies.

Numerous problems soon presented themselves as the test program advanced. 41-5899 crashed on Salisbury golf course on Long Island on March 26, 1942, killing Republic test pilot George Burrrell. Examination of the wreckage showed that part of the tail assembly had broken off in flight. This accident resulted in restrictions being placed on P-47B flying while the cause of the structural failure was under investigation. At altitudes above 30,000 feet, the ailerons tended to snatch and freeze, the cockpit canopy could not be opened, and control forces became excessive. The fabric covering for the elevators was often found to be ruptured after high speed flights, the aerodynamic pressures having caused it to balloon out and burst. These problems caused further P-47 acceptances to be delayed until May of 1942.

The problem of the freezing ailerons and the ruptured elevators was solved by having these control surfaces being fully metal-covered on all subsequent P-47Bs. Some time elapsed before metal-covered elevators and ailerons could be incorporated into production machines, and deliveries went forward with the understanding that appropriate modifications would be completed later. Most earlier P-47Bs were eventually modified to take metal-covered control surfaces, and the earlier restrictions on flight were removed. In addition, the ailerons were revised in shape and were fitted with blunt noses, which largely alleviated the excessive control force problem. Balanced trim tabs were adopted to reduce rudder pedal loads.

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P-47B-RA - (S/N 41-5931)

The stuck cockpit canopy problem was solved by replacing the original hinged canopy by a rearward sliding hood. This change meant that the dorsal radio antenna had to be redesigned and moved further aft to accommodate the rearward-sliding hood. This innovation is believed to have been applied to P-47B serial number 41-5896 onward.

A windshield defroster was introduced with P-47B number 41-5951. Beginning with 41-5974, major changes were made in control surface movement limitations and tailplane incidence. New landing gear tires were introduced from 41-5974 onwards. Modified link ejector chutes were added to the guns on 41-6016 and subsequent aircraft.

The production P-47B was fitted with a production R-2800-21 engine of 2000 hp. The engine drove a 12-foot 2-inch diameter Curtiss Electric C542S-A6 propeller. An increase in the amount of internal equipment raised the empty, normal loaded, and maximum loaded weights to 9346, 12,245, and 13,360 pounds respectively. Consequently, the climb to 15,000 feet now took 6.7 minutes rather than the promised five. However, the increased power of the production-ready engine provided an increase in level speed to 429 mph at 27,000 feet.

At one time, it had been hoped that it would be possible for the RAF to test the Thunderbolt in combat in the Middle East, but production difficulties caused the British Air Ministry to be informed in September 1941 that it was probably not a good idea to do this until all the bugs had been wrung out of the design.

P-47Bs were first issued in mid-1942 to the 56th Fighter Group. This group was chosen to be the first recipient of the P-47B because it was based near New York City and hence located near the Farmingdale plant where Republic engineers could be easily called upon to help in ironing out problems as they arose. The P-47Bs of the 56th Fighter Group were used largely for stateside testing and operational training, and very few ever went overseas.

The 56th Fighter Group found the process of working up to its new mounts rather difficult--13 pilots and 41 aircraft were lost in accidents. By the end of June, the 56th FG had damaged or wrecked half of its aircraft. Many of the crashes were the result of pilot inexperience, but a significant number were caused by loss of control during high-speed dives. After a rudder was ripped from a P-47B in flight, an order was issued on August 1, 1942, restricting the speeds to 300 mph or lest, forbidding violent maneuvers, and stipulating that fuel be carried in the rear tank.

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P-47B-RA

Later, the 80th Fighter Group was moved to Farmingdale with the intention that it too would begin training on P-47s.

The last P-47B was delivered in September 1942. Serial numbers of the 170 P-47Bs constructed were 41-5895/6065. A total of 171 were built.

The last example of the P-47B series (41-6065) was converted during manufacture in September 1942 as the XP-47E with a pressurized cockpit and a hinged canopy. However, increased emphasis on low-level operations over Europe lead to the cancellation of plans to introduce this pressurized Thunderbolt into production.

XP-47F was the designation given to another P-47B airframe (serial number 41-5938) which was used to test a new larger-area wing with a laminar-flow aerofoil. It flew for the first time on September 17, 1942. No production was undertaken.

The P-47B was strictly used for test and training, and was never sent into combat. The designation of the P-47B was changed to RP-47B in 1944, where the R stood for *Restricted*, which meant that it was not to be used for combat.


 

Republic P-47C Thunderbolt

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.

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P-47C-5-RE - S/N 41-6601

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 some 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 turbo-supercharger 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.

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P-47C-2RE  S/N 41-6182

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 turbo-supercharger 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.


 

Republic P-47D Thunderbolt

The P-47D was the first version of the Thunderbolt to undergo really large-scale production. The first USAAF order for the P-47D took place on October 14, 1941, when 850 examples were ordered. However, it was to be followed by many, many more.

In its initial form, the P-47D differed very little from the P-47C-5-RE which preceded it on the Farmingdale production lines. The P-47D had some changes in the turbo supercharger exhaust system which incorporated an adjustable duct and redesigned vents for the engine accessory section. Additional cowl flaps were fitted to prove engine cooling airflow. More extensive armor protection was provided for the pilot. Generally, however, early P-47Ds can be distinguished from Cs only by their serial numbers.

Demand for the Thunderbolt was so great that Republic built a new factory at Evansville, Indiana to augment production of the P-47D. 1050 P-47Ds were ordered from Evansville on January 31, 1942, and the first Evansville-built P-47D (serial number 42-22250) rolled off the assembly line in September of 1942. Evansville-built P-47Ds were distinguished from Farmingdale-built P-47Ds by the use of the RA manufacturer letter code rather than RE. They could be distinguished from Farmingdale-built P-47Ds only by their serial numbers.

Following cancellation of the Army contract for the P-60A in January 1942, the Curtiss-Wright company was given a contract to begin construction of the D-version of the Thunderbolt under license at its Buffalo plant. The Curtiss-Wright built version was designated P-47G. The first delivery of a P-47G took place in December of 1942. The first 20 P-47Gs produced by Curtiss (P-47G-CU) were similar to the concurrent P-47C, but the remainder were similar to Republic-built P-47Ds. Curtiss produced a total of 354 P-47G-1-CU through P-47G-15-CU Thunderbolts by March of 1944, these planes being identical to Republic-built P-47Ds. They could be distinguished from Republic-built Thunderbolts only by their serial numbers. Since P-47Gs tended to lag behind Republic-built models as regards the latest refinements, most of the Curtiss-built Thunderbolts were used for training roles in the US, and very few went overseas. Curtiss production ended in March of 1944

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P-47D-25

P-47D-30-RE  S/N 44-90021

P-47D-40-RE   S/N 44-90386

P-47D 4 SHIP FORMATION Y36 is P-47D-21-RA S/N 43-25372

All early Thunderbolts used the R-2800-21 engine. Water injection capability was added to this engine beginning with the D-4-RA and D-5-RE production blocks. Provision was made for the mounting of 15-gallon tank carrying a water-alcohol mixture to the bulkhead just aft of the engine. A line from this tank was plumbed directly into the fuel intake. When injected into the combustion chamber, the water checked a dangerous rise in cylinder head temperature while manifold pressure was boosted. For brief instants, a 15-percent increase in engine power could be obtained, giving a maximum war emergency power of 2300 hp. In the D-5-RE, D-6-RE, and D-10-RE (D-4-RA, production blocks, the pilot manually controlled the water flow of the injector, but the injection procedure was automatically- controlled on the D-11-RE (D-11-RA) and subsequent blocks. This happened when the throttle was pushed forward into its last half-inch of travel.

When installed at the factory, the water-injected engines were designated R-2800-63. The R-2800-63 engine began to appear on the Farmingdale and Evansville production lines with blocks D-10-RE and D-11-RA respectively. Kits were also made available for the retro- fitting of water injection capability to earlier P-47Cs and Ds. Since they were already built to accommodate water-injection, the D-4, -5, and -6 could be quickly modified, but the D-1, -2, and -3 and the earlier C-2 and C-5 each required about 200 hours of work for each addition of water-injection capability.

Shackles for a belly tank or a 500-pound bomb were added to P-47D-5-RE (D-11-RA) and later blocks.

Under wing pylons were introduced on the D-15-RE and D-15-RA production blocks. These enabled a drop tank or a bomb to be carried underneath each wing in addition to the stores carried on the belly shackles. Fuel changes had to be made to incorporate plumbing for the under wing tanks. Bomb selection increased to two 1000-pound or 3 500-pound bombs, with maximum bomb-load being 2500 pounds. Alternatively, a 108-gallon drop tank could be carried underneath each wing, adding 150 miles to the P-47's range. Earlier P-47C and D models could be modified in the field to accommodate under wing racks, but the amount of work required many man-hours of effort by maintenance personnel. The under wing pylons had a detrimental affect on performance, and their air resistance cut 45 mph off the maximum speed. However, a redesigned, more streamlined pylon cut the loss to about 15 mph.

Two Curtiss-built P-47Gs were converted as tandem, two-seat trainers. One of the fuselage fuel tanks was removed and a second cockpit was fitted in its place. Known as the TP-47G, these aircraft retained the eight-gun armament of the single-seat version.

Toward the end of 1943, Eighth Air Force Thunderbolts began returning from escort missions over the Continent "on the deck", seeking out enemy ground targets of opportunity for their unused ammunition as they made their way back to the Channel. Somewhat surprisingly, it was found that the Thunderbolt was rather well-suited for this new role. This led to perhaps the most successful adaptation of the Thunderbolt--as a fighter-bomber.

Click on Picture to enlarge

 The P-47D-6-RE to P-47D-11-RE and P-47G-10-CU to 15-CU production blocks had only ventral shackles, which were stressed to accommodate one 500-lb bomb, but subsequent production blocks were fitted with under wing pylons and stronger wings which permitted them to carry two 1000-lb bombs, three 500-lb bombs or a combination of bombs and drop tanks. Either six or eight machine guns could be carried, and maximum ammunition capacity was 425 rpg. However with the full ordinance load, ammunition capacity was reduced to 267 rpg.

At about this time, a number of Thunderbolts suffered mysterious engine failures during missions over the Continent that could not be ascribed to enemy action. It was eventually discovered that the additional weight of the bombs and drop-tanks added so much weight to the aircraft that the Thunderbolt was able to build up excessively-high speeds during bombing attacks. During the recovery from these high-speed dives, g-forces got so high that a surge or vapor lock was produced in the fuel lines which the fuel pump was unable to overcome.

Production batches from the P-47D-20-RE onward were fitted with a "universal" wing which could carry a variety of drop tanks or bombs. These batches also introduced the R-2800-59 engine with an improved ignition system. The power was the same as that of the -63, with a war emergency power output of 2300 hp. The length of the tail wheel leg was increased.

Beginning with production blocks D-22-RE and D-23-RA, a larger (13- foot diameter) paddle-bladed propeller (either a Hamilton Standard Hydromatic 24E50-65 or a Curtiss Electric C542S) was fitted to make full use of the additional power provided by water injection. It added 400 feet per minute to the climb rate, but during landings and takeoffs there was only a scant six inches of clearance between blade tips and the ground. Takeoffs and landings must have both been hair-raising.

Blocks D-22-RE and D-23-RA were also provided with a jettisonable cockpit canopy which was activated by the pilot pulling a ring. The hood would then be pushed backward, and the force of the slipstream would then do the rest of the job of pulling the canopy free of the aircraft. A bullet-proof windshield was fitted, and internal fuel capacity was increased.

The 3962 P-47D-1RE to -22-RE Farmingdale-built Thunderbolts, the 1461 P-47D-2-RA to -23-RA Evansville-built Thunderbolts, and the entire lot of 354 P-47G-1-CU through P-47G-15-CU Curtiss-built Thunderbolts all had the original framed sliding canopy that was first used on the P-47B. However, combat experience indicated that the the rear fuselage decking on these Thunderbolts provided a serious blind spot aft which was a real hindrance in air-to-air battles. In an attempt to improve rearward visibility, a few P-47Ds were fitted in the field with the RAF "Malcolm hood", a Spitfire-like bubble canopy made in England which was made famous by its application to the P-51B and C Mustangs flown by both the RAF and USAAF. However, P-47Ds fitted with Malcolm hoods were quite rare, whereas P-51Bs and Cs with Malcolm hoods were quite common.

In the meantime, in search of a more lasting solution the USAAF fitted a standard P-47D-5-RE airframe (serial number 42-8702) with a bubble canopy taken from a Hawker Typhoon. In order to accommodate the bubble canopy, the Republic design team had to cut down the rear fuselage. This conversion was re-designated XP-47K, and was tested in July 1943. This modification was immediately proven to be feasible, and was promptly introduced on both the Farmingdale and Evansville production lines.

Ordinarily, the USAAF would have given such a radical modification as that which produced the bubble-canopy Thunderbolt a completely new variant letter (or perhaps even a new type number). However, the USAAF chose instead to designate it simply by giving it a new production block number in the D-series. Consequently, the first batches to feature this new bubble canopy were Farmingdale's P-47D-25-RE and Evansville's P-47D-26-RA. These batches also had the R-2800-59 or -63 engines, the paddle-bladed propeller, and the "universal" wing first introduced on the "razor-back" P-47D-20-RE. Stronger belly shackles capable of carrying a 91.6 Imp. gall. drop tank were fitted. This tank, together with the 170.6 Imp. gall. main fuselage tank, an 83-gallon auxiliary fuel tank and two 125-gallon under wing tanks, made it possible to carry a total fuel load of 595 Imp. gall, providing a maximum range of 1800 miles at 195 mph at 10,000 feet.

A single P-47D-20-RE (serial number 42-76614) was taken off the production line and modified as XP-47L with a bubble canopy as in the XP-47K and with increased capacity fuel tanks which raised internal fuel capacity from 305 to 370 US gallons. Both of these changes were incorporated in the P-47D-25-RE production batch.

The early "bubble-canopy" Thunderbolts had suffered from some directional instability as a result of the loss of aft keel area. From the P-47D-27-RE production lots onward, a dorsal fin was fitted just ahead of the rudder. This innovation successfully restored the stability.

Under wing zero-length launching stubs for a total of ten five-inch HVAR rockets were fitted to Thunderbolts from production blocks P-47D-30-RA onward.

The high diving speeds of which the Thunderbolt was capable pushed the aircraft into the edge of compressibility, and new blunt-nosed ailerons were fitted to improve controllability at these high speeds. In order to help in dive recovery at these high speeds, an electrically-operated dive recovery flap was fitted on the undersurfaces of each wing.

Farmingdale produced a total of 2547 bubble-canopy P-47Ds and Evansville built 4632. the Japanese.

During the immediate postwar years, numerous surplus ex-USAAF Thunderbolts were supplied to foreign air forces. These included the air forces of Bolivia, Brazil, Chile, China, Colombia, Dominica, Ecuador, Honduras, Iran, Nicaragua, Peru, Turkey, Venezuela, and Yugoslavia. Some of these foreign-operated Thunderbolts remained flying until the late 1960s until they were finally replaced by jet aircraft.

A "razorback" P-47D is on display at the Champlin Fighter Museum at Mesa, Arizona. A Thunderbolt is also on display at the WPAFB museum, but I don't have any record of its serial number.

Specifications of the P-47D-25-RE:

One Pratt and Whitney R-2800-59 Double Wasp eighteen-cylinder air-cooled radial, war emergency power of 2535 hp. Maximum speed was 429 mph at 30,000 feet, 406 mph at 20,000 feet, 375 mph at 10,000 feet, 350 mph at sea level. Initial climb rate was 2780 feet per minute. Climb rate at 30,000 feet was 1575 feet per minute. Service ceiling was 40,000 feet, and range was 950 miles at 10,000 feet. Range with maximum external fuel was 1800 miles at 10,000 feet at 195 mph. Weights were 10,700 pounds empty, 14,600 pounds normal loaded, and 17,500 pounds maximum. Dimensions were wingspan 40 feet 9 3/8 inches, length 36 feet 1 3/4 inches, height 14 feet 7 inches, and wing area 300 square feet.

Serials of Republic-built P-47Ds:

42-7853/7957 	Republic P-47D-1-RE Thunderbolt 
42-7958/8402 	Republic P-47D-2-RE Thunderbolt 
42-8403/8702 	Republic P-47D-5-RE Thunderbolt 
42-22250/22363  Republic P-47D-1-RA Thunderbolt 
42-22364/22563  Republic P-47D-2-RA Thunderbolt 
42-22564/22663  Republic P-47D-3-RA Thunderbolt 
42-22664/22863  Republic P-47D-4-RA Thunderbolt 
42-22864/23113  Republic P-47D-11-RA Thunderbolt 
42-23114/23142  Republic P-47D-16-RA Thunderbolt 
42-23143/23299  Republic P-47D-15-RA Thunderbolt 
42-25274/25322  Republic P-47D-20-RE Thunderbolt 
42-25323/25538  Republic P-47D-21-RE Thunderbolt 
42-25539/26388  Republic P-47D-22-RE Thunderbolt 
42-26389/26773  Republic P-47D-25-RE Thunderbolt 
42-26774/27388  Republic P-47D-27-RE Thunderbolt 
42-27389/28188  Republic P-47D-23-RA Thunderbolt 
42-28189/28438  Republic P-47D-26-RA Thunderbolt 
42-28439/29466  Republic P-47D-27-RA Thunderbolt 
42-74615/74964  Republic P-47D-6-RE Thunderbolt 
42-74965/75214  Republic P-47D-10-RE Thunderbolt 
42-75215/75614  Republic P-47D-11-RE Thunderbolt 
42-75615/75814  Republic P-47D-15-RE Thunderbolt 
42-75865/76118  Republic P-47D-16-RE Thunderbolt 
42-76119/76364  Republic P-47D-15-RE Thunderbolt 
42-76365/76614  Republic P-47D-20-RE Thunderbolt 
43-25254/25440  Republic P-47D-20-RA Thunderbolt 
43-25441/25664  Republic P-47D-21-RA Thunderbolt 
43-25665/25753  Republic P-47D-23-RA Thunderbolt 
44-19558/20307  Republic P-47D-28-RE Thunderbolt 
44-20308/21107  Republic P-47D-30-RE Thunderbolt 
44-32668/33867  Republic P-47D-30-RA Thunderbolt 
44-89684/90283  Republic P-47D-30-RA Thunderbolt 
44-90284/90483  Republic P-47D-40-RA Thunderbolt 
45-49090/49554  Republic P-47D-40-RA Thunderbolt 
Serials of Curtiss-built P-47Gs: 
42-24920/24939 	Curtiss P-47G-CU Thunderbolt 
42-24940/24979  Curtiss P-47G-1-CU Thunderbolt 
42-24980/25039  Curtiss P-47G-5-CU Thunderbolt 
42-25040/25119  Curtiss P-47G-10-CU Thunderbolt 
42-25120/25273  Curtiss P-47G-15-CU Thunderbolt 

 

Republic XP-47E Thunderbolt

 

Click On Picture To Enlarge 

XP-47E - S/N 41-6065

The last example of the P-47B series (41-6065) was converted during manufacture in September 1942 as the XP-47E with a pressurized cockpit and a hinged canopy. However, increased emphasis on low-level operations over Europe lead to the cancellation of plans to introduce this pressurized Thunderbolt into production.


 

Republic XP-47F Thunderbolt

 

XP-47F was the designation given to another P-47B airframe (serial number 41-5938) which was used to test a new larger-area wing with a laminar-flow aerofoil. It flew for the first time on September 17, 1942. No production was undertaken.


 

Curtiss P-47G Thunderbolt

 

Following cancellation of the Army contract for the P-60A in January 1942, the Curtiss-Wright company was given a contract to begin construction of the D-version of the Thunderbolt under license at its Buffalo plant. The Curtiss-Wright built version was designated P-47G.

The first delivery of a P-47G took place in December of 1942. The first 20 P-47Gs produced by Curtiss (P-47G-CU) were similar to the concurrent P-47C, but the remainder were similar to Republic-built P-47Ds. Curtiss produced a total of 354 P-47G-1-CU through P-47G-15-CU Thunderbolts by March of 1944, these planes being identical to Republic-built P-47Ds. They could be distinguished from Republic-built Thunderbolts only by their serial numbers.

Since P-47Gs tended to lag behind Republic-built models as regards the latest refinements, most of the Curtiss-built Thunderbolts were used for training roles in the US, and very few went overseas. Curtiss production of the P-47G ended in March of 1944

Click on Picture to enlarge

P-47G5-CU S/N 42-25032

 

Republic XP-47H Thunderbolt

 

In 1943, two P-47D-15-RE airframes (serials 42-23297/23298) were selected for testing with the new experimental 2300 hp Chrysler XIV-2220-1 sixteen-cylinder inverted Vee liquid-cooled engine. These aircraft were redesignated XP-47H. The liquid-cooled Chrysler engine with its large under-fuselage radiator radically changed the appearance of the Thunderbolt, and increased overall length to 39 feet 2 inches. With the increased power and improved streamlining, a maximum speed of 490 mph was anticipated.

Although the project was begun in August 1943, the two P-47D-15-RE airframes were not actually converted until 1945. Test flights began on July 26, 1945. One of my sources (Green) says that during flight trails, one of the XP-47Hs actually attained a speed of 490 mph in level flight. However, another one (Wagner) says that the Chrysler engine failed to deliver the promised power output, and that the maximum speed attained during tests was only 414 mph at 30,000 feet, poorer performance than the "stock" P-47D. In any case, the Chrysler XIV-2220 engine never achieved production and the advent of jet propulsion killed any further USAAF interest in the development of even faster piston-engined fighters. Consequently, no further work was undertaken on the XP-47H project.

Click on Picture to enlarge

XP-47

 

Republic XP-47J Thunderbolt

 

Click On Picture To Enlarge 

XP-47J - S/N 43-46952

The fastest version of the Thunderbolt was the XP-47J, which was proposed in November 1942 as a lighter-weight version of the Thunderbolt designed to explore the outer limits of the design's basic performance envelope. The XP-47J was fitted with a 2800 hp Pratt and Whitney R-2800-57(C) housed inside a close-fitting cowling and cooled by a fan. The ventral intake for the CH-5 turbo-supercharger was separated from the engine cowling and moved aft. The four-bladed propeller was fitted with a large conical-shaped spinner. The wing structure was lightened and the armament was reduced from eight to six 0.50-inch machine guns. The contract was approved on June 18, 1943.

Click On Picture To Enlarge 

XP-47J

The XP-47J was a completely new airframe and not a conversion of an existing P-47D. The serial number was 43-46952. The XP-47J flew for the first time on November 26, 1943. On August 4, 1944, it attained a speed of 504 mph in level fight, becoming the first propeller-driven fighter to exceed 500 mph. At one time, it was proposed that the J model would be introduced onto the production line, but the advent of the even more advanced XP-72 resulted in plans for the production of the P-47J being abandoned before any more could be completed.

A proposal to adapt the XP-47J to use contra-rotating propellers with an R-2800-61 engine was dropped.

Maximum speed of the XP-47J was 507 mph at 34,300 feet, range was 765 miles at 400 mph, 1070 miles at economical cruising speed. An altitude of 15,000 feet could be reached in 4.5 minutes. Service ceiling was 45,000 feet. Weights were 9663 pounds empty, 12,400 pounds normal loaded, 16,780 pounds maximum. Wingspan was 40 feet 11 inches, length was 33 feet 3 inches, height was 14 feet 2 inches, and wing area was 300 square feet.

 

 

Republic XP-47K Thunderbolt

 

Click On Picture To Enlarge 

XP47K  - S/N 42-8702

As an experiment to improve the rearward visibility, the USAAF fitted a standard P-47D-5-RE airframe (serial number 42-8702) with a bubble canopy taken from a Hawker Typhoon. In order to accommodate the bubble canopy, the Republic design team had to cut down the rear fuselage. This conversion was re-designated XP-47K, and was tested in July 1943. This modification was immediately proven to be feasible, and was promptly introduced on both the Farmingdale and Evansville production lines.

Ordinarily, the USAAF would have given such a radical modification as that which produced the bubble-canopy Thunderbolt a completely new variant letter (or perhaps even a new type number). However, the USAAF chose instead to designate it simply by giving it a new production block number in the D-series. Consequently, the first batches to feature this new bubble canopy were Farmingdale's P-47D-25-RE and Evansville's P-47D-26-RA.

 

 

Republic XP-47L Thunderbolt

 

The designation XP-47L was applied to P-47D 42-76614 modified for production with a bubble canopy as in the XP-47K, but with increased capacity fuel tanks from 305 US gallons to 370 US gallons.

 

 

Republic P-47M Thunderbolt

 

Click On Picture To Enlarge 

YP-47M - S/N 42-27385 Instrumented for flight test (7-28-45)

The P-47M was a special high-speed version of the Thunderbolt specifically evolved to counter the Fieseler Fi 103 (V-1) buzz bomb and the new jet- and rocket-powered fighters that were entering service with the Luftwaffe.

Four P-47D-27-RE airframes (serials 42-27385/27388) were taken off the production line at Farmingdale and fitted with the Pratt & Whitney R-2800-57(C) engine equipped with a larger CH-5 turbo-supercharger. This new engine offered a war emergency power of 2800 hp at 32,500 feet with water injection. Air brakes were fitted underneath the wings to aid in deceleration during dives. These four converted P-47Ds were re-designated YP-47M.

Click On Picture To Enlarge 

P-47M  - S/N 42-21159

This new engine installation was ordered into production in September 1944 for the last 130 P-47D-30-RE aircraft delivered by Farmingdale, the aircraft being subsequently re-designated P-47M-1-RE. The serial numbers of the 130 P-47M-1-RE Thunderbolts built were 44-21108/21237

The first P-47M was delivered in December 1944, and they were rushed to the 56th Fighter Group in Europe. However, engine problems delayed their use until the last few weeks of the war in Europe. Under-wing racks were not fitted, as the P-47M was meant to be operated strictly as a fighter.

Performance of the P-47M-1-RE included a maximum speed of 400 mph at 10,000 feet, 453 mph at at 25,000 feet, and 470 mph at 30,000 feet. Initial climb rate was 3500 feet per minute at 5000 feet and 2650 feet per minute at 20,000 feet. Range (clean) was 560 miles at 10,000 feet. Armament was six or eight 0.50-inch machine guns with 267 or 425 rpg. Weights were 10,432 pounds empty, 13,275 pounds normal loaded, and 15,500 pounds maximum. Dimension were wingspan 40 feet 9 3/8 inches, length 36 feet 4 inches, height 14 feet 7 inches, and wing area 308 square feet.


 

Republic P-47N Thunderbolt

 

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P-47N S/N4488335          2nd  aircraft built

The P-47N version of the Thunderbolt was the last version to be manufactured in quantity. It was a specialized long-range version built specifically for service in the Pacific theatre.

Four P-47D-27-RE airframes (serials 42-27385/27388) had been taken off the production line at Farmingdale and fitted with the Pratt & Whitney R-2800-57(C) engine driving a larger CH-5 turbo-supercharger. This engine could produce a war emergency power of 2800 hp at 32,500 feet with water injection. These aircraft had been re-designated YP-47M and served as the prototypes for the P-47M series.

However, the war in the Pacific required fighter ranges even greater than did operations over Germany. In pursuit of better long-range performance, in mid-1944 the third YP-47M prototype (42-27387) was fitted with a new "wet" wing of slightly larger span and area. The aircraft was re-designated XP-47N. For the first time in the Thunderbolt series fuel was carried in the wings, a 93 US gallon tank being fitted in each wing. When maximum external tankage was carried, this brought the total fuel load of the XP-47N up to an impressive 1266 US gallons. This fuel load make it possible for a range of 2350 miles to be achieved.

The new wing also incorporated larger ailerons and squared-off wingtips. These innovations enhanced the roll-rate of the Thunderbolt and improved the maneuverability. The dorsal fin behind the bubble canopy was somewhat larger than that on the P-47D. However, the increased fuel load increased the gross weight of the aircraft. In order to cope with the increased gross weight, the undercarriage of the XP-47N had to be strengthened, which increased the weight still further. The maximum weight rose to over 20,000 pounds.

Click On Picture To Enlarge 

P-47N-5 - S/N 44-88576, 88589, 88577

The XP-47N flew for the first time on July 22, 1944. Such was the USAAF confidence in the Thunderbolt design that they went ahead and ordered 1900 P-47Ns in June 20, 1944, even before the first XP-47N had flown.

The P-47N was destined to be the last version of the Thunderbolt to be manufactured. The first P-47N-1-RE appeared in September of 1944, and 24 were delivered by year's end. The P-47N-5-RE and subsequent batches had zero-length rocket launchers added. The R-2800-77 engine was installed in late production models such as the P-47N-25-RE.

The P-47N gave excellent service in the Pacific in the last year of the War, particularly in escorting B-29 Superfortress bombers in raids on the Japanese mainland. P-47Ns were able to escort the bombers all the way from Saipan to Japan and on many other long, over water flights.

A total of 1667 P-47Ns was produced by the Farmingdale plant between December 1944 and December 1945, when the Thunderbolt line finally closed down. 149 more P-47Ns were built by the Evansville factory. V-J Day cancellation of 5934 Thunderbolts brought production of the type abruptly to an end.

Performance of the P-47N-5-RE included a maximum speed of 397 mph at 10,000 feet, 448 mph at at 25,000 feet, and 460 mph at 30,000 feet. Initial climb rate was 2770 feet per minute at 5000 feet and 2550 feet per minute at 20,000 feet. Range (clean) was 800 miles at 10,000 feet. Armament included six or eight 0.50-inch machine guns with 500 rpg and two 1000-lb or three 500-lb bombs or ten 5-inch rockets. Weights were 11,000 pounds empty, 16,300 pounds normal loaded, and 20,700 pounds maximum. Dimension were wingspan 42 feet 7 inches, length 36 feet 4 inches, height 14 feet 7 inches, and wing area 322 square feet.

Serials of the P-47N were:

44-87784/88333 	Republic P-47N-1-RE Thunderbolt 
44-88334/88883  Republic P-47N-5-RE Thunderbolt 
44-88884/89083  Republic P-47N-15-RE Thunderbolt 
44-89084/89283  Republic P-47N-20-RE Thunderbolt 
44-89284/89450  Republic P-47N-25-RE Thunderbolt 
45-49975/50123  Republic P-47N-20-RA Thunderbolt 

 

P-47 Thunderbolt in European Theatre with USAAF

 

Click on Picture to enlarge

This account of the P-47 Thunderbolt continues with an account of its service in the European theatre.

At one time in the days before Pearl Harbor, it had been hoped that it would be possible for the RAF to test the Thunderbolt in combat in the Middle East. However, production difficulties caused the British Air Ministry to be informed in September 1941 that it was not a good idea to do this until all the bugs had been wrung out of the design.

Consequently, it was a USAAF outfit that was to be the first to bring the Thunderbolt into service. The 56th Fighter Group based near New York City was the first outfit to receive the P-47B, and began to reequip with the type in June-July 1942. They were entrusted with the task of shaking the bugs out of their new mounts. Since their base was fairly close to the Farmingdale plant, the Group could easily call upon Republic engineers to solve problems as they were encountered. Tests and operational training went slowly, accompanied by the loss of 13 pilots and 41 aircraft in accidents. As more Thunderbolts became available, P-47Bs were subsequently issued to the 348th and 355th Groups.

The first P-47Cs arrived in England as early as December 20, 1942, and equipped the 4th Fighter Group which somewhat reluctantly traded in their Spitfires for the type. P-47Cs also reequipped the 82nd, 83rd, and 84th Squadrons of the 78th Fighter Group. P-47Cs were also supplied to the 56th Fighter Group which left their P-47Bs back home in the States when they transferred to England. Engine and radio problems caused some delays, but the first operational sorties began on March 10, 1943, and consisted of high-altitude escort duties and fighter sweeps. The first encounter with German fighters came on April 15, when the P-47Cs of the 335th Squadron shot down three German fighters for a loss of three of its own.

SPECIFICATIONS

MODEL P-47B P-47C P-47D* P-47D+ P-47N
WING
SPAN
40'9" 40'9" 40'9" 40'9" 42'7"
LENGTH 35' 36'1" 36'1" 36'1" 36'1"
POWER 1 R-2800-21 2000hp 1 R-2800-21 2000hp 1 R-2800-21 2000hp 1 R-2800-59 2300hp 1 R-2800-73 2800hp
ARMAMENT 8 .50 Cal Browning MG 8 .50 Cal Browning MG
2 500 or
2 1000 Lb bombs
8 .50 Cal Browning MG
2 500 or
2 1000 Lb bombs
8 .50 Cal Browning MG
2 1000 Lb bombs or
1 2000 lb + 1 500Lb bombs
8 .50 Cal Browning MG
3 1000 lb Bombs or 10 5" Rockets
EMPTY
WEIGHT
(Lbs)
9,345 9,900 9,900 10,000 11,000
MAXIMUM
WEIGHT
(Lbs)
13,360 14,925 14,925 19,400 20,700
TOP
SPEED
(Mph)
429 433 433 429 467
CRUISING
SPEED
(Mph)
         
MAXIMUM
RANGE
(Miles)
1,700 1,700 1,700# 1,700# 2,200@
CEILING
(Feet)
42,000 42,000 42,000 42,000 43,000
CREW 1 1 1 1 1
*P-47D-RE1 through 20 ("Razorback")
**P-47D-RE25 and later ("Bubbletop)
#480 miles with 500Lb bomb load
@800 miles with 2,000Lb bomb load

The high-altitude performance of the P-47C was far superior to anything the Luftwaffe could put up against it, but at low and medium altitudes the P-47C could not match the maneuverability and climb rates of its opponents. However, the P-47C could out-dive just about anything in the sky, and many a Thunderbolt saved itself from a sticky situation by using its superior diving performance to break off combat at will when it proved necessary to do so. According to Robert S. Johnson of the 56th Fighter Group, the Thunderbolt could out roll any other fighter. The Thunderbolt's eight 0.50-inch machine guns provided sufficient firepower to destroy any enemy plane which had the misfortune to come within its sights. The robust construction of the Thunderbolt enabled it to absorb a considerable amount of battle damage and still stagger home to fight another day.

The P-47Cs of the 56th, 4th and 78th Groups of the 8th Air Force were intended as bomber escorts, but were ineffectual until fitted with auxiliary fuel tanks to lengthen their range at the end of July 1943. These three groups were joined later in 1943 by seven new groups flying P-47Ds-- the 352nd, 353rd, 355th, 356th, 358th, 359th, and 361st Fighter Groups. P-47s flew escort missions until the end of 1943, when they began to be replaced by longer-range P-38 Lightnings and P-51 Mustangs which were better suited for the long-range escort role.

Once the Mustang began to take over the long-range escort role, the Thunderbolt was largely diverted into the ground attack role, where the P-47 was to gain its reputation. After seeing action in North Africa, the Ninth Air Force was transferred to England as part of the build-up for D-Day. The 362nd and 365th Fighter Groups of the Ninth Air Force were the first to receive P-47Ds. They were joined by the 358th Group from the Eighth Air Force. In May 1944, these three groups were joined by many other units flying P-47Ds in providing air cover for the impending landings in France-- the 36th, 50th, 366th, 367th,, 368th, 371st, 373rd, 405th, 406th, 48th, 354th, and 404th Fighter Groups. These units provided much effective ground support for the advancing Allied forces as they penetrated further and further into France. The Thunderbolt, with its heavy machine gun armament and its heavy load of bombs and rockets, was extremely effective in eliminating enemy forces in the face of the Allied advance. Even though the P-51 Mustang had largely replaced the Thunderbolt in the long-range, high-altitude bomber escort role in the ETO by the end of 1944, the P-47D continued to rack up an impressive number of air-to-air kills against the Luftwaffe, while it beat up the Wehrmacht on the ground in its destructive bombing and strafing career.

The Thunderbolt also saw service in Italy. The 325th Group of the 15th Air Force flying P-47Cs saw action at Foggia from December 1943 onward. P-47Ds were flown by the 322 Group for only two months, and 57th, 79th, 37th, 86th, 324th, and 350th Groups of the Twelfth Air Force. One of the less well-known operators of the P-47D Thunderbolt was the 1st Group Aviacao de Caca of the Brazilian Air Force. Brazil had declared war on Germany and Italy on August 22, 1942, and this group was attached to the 350th Group of the Twelfth Air Force. Many pilots became aces while flying the Thunderbolt. Outstanding among these was Lt-Col. Francis S. Gabreski (31 kills, the highest-scoring Thunderbolt pilot), Capt. Robert S. Johnson (28 kills) and Col. Hubert Zemke (20 kills). The highest-scoring USAAF Group in the ETO was the 56th Fighter Group, which destroyed 1006 German aircraft against a loss of 128 Thunderbolts--a ratio of nearly eight to one.


 

P-47 in Service In Pacific Theatre with USAAF

 

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This account of the Republic Thunderbolt continues with an account of its service in the Pacific theatre.

The first P-47Ds to arrive in the Pacific theatre entered service with the 348th Fighter Group of the Fifth Air Force in June of 1943. They were initially operated out of Australia and were used on long-range missions to strike at Japanese targets in New Guinea. The 348th was followed by the 35th Group and at the beginning of 1944 by the 58th Group as well as the 35th Squadron of the 8th Group and the 9th FS of the 49th Group.

Soon after Saipan and Guam were taken, the 318th Group and the 508th group of the Seventh Air Force saw action in June 1944, having been the first to take delivery of the P-47N long-range version. They were followed by the Twentieth Air Force on Okinawa readying for the final assault on Japan--the 413th, 414th, and 507th Fighter Groups equipped with P-47Ns. The long-range P-47N began to reach the Pacific in 1945, and operated as a long-range escort for B-29 Superfortress bombers attacking the Japanese mainland from Saipan.

Several other groups were equipped with the Thunderbolt but saw little or no action, either because they were training units or else were formed after the war had ended--the 6th, 14th, 15th, 18th, 21st, 23rd, 51st, 53rd, 83rd, 84th, 85th, 87th, 326th, 327th, 337th, 338th, 370th, 407th, 408th, 479th, and 507th Fighter Groups.

The war in Europe took precedence over the conflict in the Pacific, and it was not until April of 1944 that the first P-47s reached the China-Burma-India (CBI) theatre. They initially equipped the 33rd, 81st and 80th Fighter Groups as well as the 5th and 6th Fighter Command Squadrons of the Tenth and 14th Air Forces.

P-47D and N Thunderbolts reamined in service with the USAF for several years after the war, serving with SAC, TAC, and ADC squadrons. Eventually they reached Air National Guard squadrons, from which, after being redesignated F-47D and F-47N in 1948, they were finally phased out of service in 1955.

 

P-47 USAAF Squadron Assignments

 

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P47-D-25 of 352 Fighter Squadron / 353 Fighter Group

 

The following USAAF units operated Thunderbolts:

  • Click on Picture to enlarge

    4th Fighter Group
    • 334th, 335th, and 336th Fighter Squadrons
       
  • 8th Fighter Group
    • 36th Fighter Squadron
       
  • 27th Fighter Group
    • 522nd, 523rd, and 524th Fighter Squadrons
       
  • 33rd Fighter Group
    • 58th, 59th, and 60th Fighter Squadrons
       
  • 35th Fighter Group
    • 39th, 40th, and 41st Fighter Squadrons
       
  • 36th Fighter Group
    • 22nd, 23rd, and 58th Fighter Squadrons
       
  • 48th Fighter Group
    • 492nd, 493rd, and 494th Fighter Squadrons
       
    49th Fighter Group

    9th Fighter Squadrons
     

  • 50th Fighter Group
    • 10th, 81st, and 313th Fighter Squadrons
       
  • 56th Fighter Group
    • 61st, 62nd, and 63rd Fighter Squadrons
       
  • 57th Fighter Group
    • 64th, 65th, and 66th Fighter Squadrons
       
  • 58th Fighter Group
    • 69th, 310th, and 311th Fighter Squadrons
       
  • 78th Fighter Group
    • 82nd, 83rd, and 84th Fighter Squadrons
       
  • 79th Fighter Group
    • 85th, 86th, and 87th Fighter Squadrons
       
  • 80th Fighter Group
    • 88th, 89th, and 90th Fighter Squadrons
       
  • 81st Fighter Group
    • 91st, 92nd, and 93rd Fighter Squadrons
       
  • 86th Fighter Group
    • 525th, 526th, and 527nd Fighter Squadrons
       
  • 318th Fighter Group
    • 19th, 73rd, and 333rd Fighter Squadron
       
  • 324th Fighter Group
    • 314th, 315th, and 316th Fighter Squadrons
       
  • 325th Fighter Group
    • 317th, 318th, and 3195h Fighter Squadrons
       
  • 332nd Fighter Group
    • 99th, 100th, 301st, and 302nd Fighter Squadrons
       
  • 348th Fighter Group

    Click on Picture to enlarge

    • 340th, 341st, 460th, and 342nd Fighter Squadrons
       
  • 350th Fighter Group
    • 345th, 346th, and 347th Fighter Squadron
       
  • 352nd Fighter Group
    • 328th, 486th, and 487th Fighter Squadron
       
  • 353rd Fighter Group
    • 350th, 351st, 352nd Fighter Squadrons
       
  • 354th Fighter Group
    • 353rd, 355th, and 356th Fighter Squadron
       
  • 355th Fighter Group
    • 354th, 357th, and 358th Fighter Squadrons

     

  • 356th Fighter Group
    • 359th, 360th, and 361st Fighter Squadrons
       
  • 358th Fighter Group
    • 365th, 366th, and 367th Fighter Squadrons
       
  • 359th Fighter Group
    • 368th, 369th, and 370th Fighter Squadrons
       
  • 361st Fighter Group
    • 374th, 375th, and 376th Fighter Squadrons
       
  • 362nd Fighter Group
    • 377th, 378th, and 379th Fighter Squadrons
       
  • 365th Fighter Group
    • 386th, 387th, and 388th Fighter Squadrons
       
  • 366th Fighter Group
    • 389th, 390th, and 391st Fighter Squadrons
       
  • 367th Fighter Group
    • 392nd, 393rd, and 394th Fighter Squadrons
       
  • 368th Fighter Squadrons
    • 395th, 396th, and 397th Fighter Squadrons
       
  • 371st Fighter Group
    • 404th, 405th, and 406th Fighter Squadrons
       
  • 373rd Fighter Group
    • 410th, 411st, and 412nd Figher Squadrons
       
  • 404th Fighter Group
    • 506th, 507th, and 508th Fighter Squadrons
       
  • 405th Fighter Group
    • 509th, 510th, and 511th Fighter Squadrons
       
  • 406th Fighter Group
    • 512th, 513rd, and 514th Fighter Squadrons
       
  • 413th Fighter Group
    • 1st, 31st, and 34th Fighter Squadrons
       
  • 414th Fighter Group
    • 413rd, 414th, and 415th Fighter Squadrons
       
  • 507th Fighter Group
    • 463rd, 464th, and 465th Fighter  Squadrons

     

 

P-47 With The Air National Guard

The Air National Guard operated P-47s between 1946 and 1955. Originally, the post-war ANG units east of the Mississippi were to operate P-47s and those to the west were to fly P-51s. This plan was generally adhered to, although there were exceptions:

The following ANG units operated Thunderbolts:

  • 101st Fighter Squadron, Massachusetts ANG
     
  • 104th Fighter Squadron, Maryland ANG
     
  • 105th Fighter Squadron, Tennessee ANG
     
  • 118th Fighter Squadron, Connecticut ANG
     
  • 121st Fighter Squadron, District of Columbia ANG
     
  • 128th Fighter Squadron, Georgia ANG
     
  • 131st Fighter Squadron, Massachusetts ANG
     
  • 132nd Fighter Squadron, Massachusetts ANG.
     
  • 133rd Fighter Squadron, New Hampshire ANG
     
  • 134th Fighter Squadron, Vermont ANG
     
  • 136th Fighter Squadron, New York ANG
     
  • 141st Fighter Squadron, New Jersey ANG
     
  • 142nd Fighter Squadron, Delaware ANG
     
  • 143rd Fighter Squadron, Rhode Island ANG
     
  • 146th Fighter Squadron, Pennsylvania ANG
     
  • 149th Fighter Squadron, Virginia ANG
     
  • 153rd Fighter Squadron, Mississippi ANG
     
  • 156th Fighter Squadron, North Carolina ANG
     
  • 157th Fighter Squadron, South Carolina ANG
     
  • 158th Fighter Squadron, Georgia ANG
     
  • 166th Fighter Squadron, Ohio ANG
     
  • 167th Fighter Squadron, West Virginia ANG
     
  • 198th Fighter Squadron, Puerto Rico ANG
     
  • 199th Fighter Squadron, Hawaii ANG

Sources:

  1. American Combat Planes, Ray Wagner, Third Enlarged Edition, Doubleday, 1982.
     
  2. The American Fighter, Enzo Angelucci and Peter Bowers, Orion Books, 1987.
     
  3. War Planes of the Second World War, Fighters, Volume Four, William Green, Doubleday 1964.
     
  4. United States Military Aircraft since 1909, Gordon Swanborough and Peter M. Bowers, Smithsonian, 1989.
     
  5. The Republic P-47D Thunderbolt, Aircraft in Profile, Edward Shacklady, Doubleday, 1969.
     
  6. Famous Fighters of the Second World War, Volume I, William Green, 1967.
     
  7. Thunderbolt!, Robert S. Johnson and Martin Caidin, Ballantine Books, 1958.
     
  8. Thunderbolt: A Documentary History of the Republic P-47, Roger Freeman, Motorbooks, 1992.

 Joe Baugher

 

 

The Plane That Can Do Anything

 

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123745

In the entire history of military aviation, there has never been an airplane that could match the P-47 Thunderbolt for ruggedness and dependability. The pilots who flew it into combat called it "The Unbreakable" and "The plane that can do anything." They were not far from wrong.

P-47's often came back from combat shot full of holes, their wings and control surfaces in tatters. On one occasion a Thunderbolt pilot, Lieutenant Chetwood, hit a steel pole after strafing a train over Occupied France. The collision sliced four feet off one of his wings--yet he was able to fly back safely to his base in England.

The story of the P-47 began in the summer of 1940. At that time Republic was building the P-43 Lancer and had plans to produce a lightweight fighter, designated the P-44 Rocket. In view of combat experience in Europe, however, the Air Corps decided that if the United States became involved in the war something larger and better than the P-44 would be required.

Alexander Kartveli, Republic's chief engineer, quickly prepared a rough sketch of a new fighter. It was a daring concept. He planned to use the new Pratt & Whitney Double Wasp , 2,000 h.p. XR-2800-21 eighteen-cylinder two-row radial engine. It which was largest and most powerful aircraft engine ever developed in the United States. He also envisioned that his plane would have eight .50-caliber machine guns and enough armor plating to protect the pilot from every direction. These features added up to an airplane weighing about 4,000 pounds more than any existing single-engined fighter.

Without such power of the new 2,000 h.p. Pratt & Whitney Double Wasp , Kartveli could see no way of meeting the performance and load carrying demands being made by the U.S.A.A.F. From an engineering standpoint, the requirements presented some enormous problems, but far more problems were presented by the engine. The first of these was the need for an efficient super-charging duct system that would offer the least interrupted airflow. Kartveli therefore adopted the unorthodox method of designing this feature first and then building up the fuselage around it; the large turbo-supercharger was stowed internally in the rear fuselage, with the large intake for the air duct mounted under the engine, together with the oil coolers. Exhaust gases were piped back separately to the turbine and expelled through a waste gate in the bottom of the fuselage, and ducted air was fed to the centrifugal impeller and returned, via an intercooler, to the engine under pressure. Surprisingly, all this ducting of gases under temperature and pressure did not prove very vulnerable in combat, for the fighter was to become renowned for its ability to absorb battle damage and return home.

The new design was approved, and Republic began work on the first test model. The XP-47B was ready in just eight months and was taken up for its first test flight on May 6, 1941. It proved to be an outstanding success, and was able to do everything Kartveli had hoped, plus more. Its speed of 412 miles per hour was even higher than expected.

The conventional three-bladed propeller could not efficiently utilize the power of the new engine and a four-bladed propeller was adopted. Although this propeller was an admirable solution to the power gearing of the engine, there remained the problem of providing sufficient ground clearance for its 12-foot diameter. If a conventional undercarriage were to be employed its suspension would have been too far outboard to permit the wing installation of the guns and ammunition requested by the U.S.A.A.F., and therefore Republic had to design a telescopic landing gear which was nine inches shorter when retracted than when extended. Numerous other problems were to be faced in absorbing the loads and stresses which would be imposed when a battery of eight 0.5-in. guns (a phenomenal heavy armament for that time) was fired simultaneously, and in providing the necessary tankage for the quantities of fuel stipulated to make the machine the first true single-engined strategic fighter. Thus, it was only to be expected that when the first prototype, the XP-47B Thunderbolt, made its first flight, on May 6, 1941, it dwarfed not only its pilots but all previous fighters and, with a loaded weight of 12,086 lb., turned the scales at more than twice the weight of most of its contemporaries.

The prototype Thunderbolt first took to the air on May 6,1941. Production began with the P-47B, which entered United States Army Air Force service in November 1942, first becoming operational with the Eighth Air Force stationed in the UK on April 8,1943. The P-47B's range was not really good enough for escort duties, and its maneuverability was poor, but at least it offered a measure of real protection to the Allied bombers which had previously suffered very heavy losses.

To increase the tempo of flight development of the XP-47B such leading test pilots as Colonel Ira C. Eaker were employed, and at one time it was hoped that the design could benefit from combat testing with the R.A.F. in the Middle East. Production difficulties caused General "Hap" Arnold to notify the British Air Ministry, in September 1941, that it was considered inadvisable to do this until various teething troubles were eradicated, and an optimistic estimate of May 1942 was established as a target date for the Thunderbolt to be combat ready. This was eventually to prove almost a year out. Numerous problems soon presented themselves as the XP-47B test program advanced. At altitudes above 30,000 feet ailerons "snatched and froze", the cockpit canopy could not be opened and control loads became excessive.

773 production versions were ordered. But this was only the beginning. Before the war was over, a total of 15,579 Thunderbolts was built, about two-thirds of which reached operational squadrons overseas.

When, in January 1943, the U.S.A.A.F.'s 56th Fighter Group arrived in the United Kingdom with its massive Republic P-47 Thunderbolts, R.A.F. Spitfire fighter pilots banteringly suggested that their American colleagues would be able to take evasive action when attacked by undoing their harnesses and dodging about the fuselages of their huge mounts. The Thunderbolt was certainly big. In fact it was the largest and heaviest single engined single-seat fighter ever built! But sheer size was not to prove detrimental to the Thunderbolt's subsequent operational career.

The first tasks of the Thunderbolt, which began on April 8, 1943, were high-altitude escort duties and fighter sweeps in which the new aircraft acquitted itself well, despite the inexperience of its pilots. It was soon discovered that the heavy Thunderbolt could out dive any Luftwaffe, or, for that matter, Allied, fighter, providing a decisive method of breaking off combat when necessary, but at low and medium altitudes it could not match the rate of climb or maneuverability of German fighters. One shortcoming, which was even more marked in other Allied fighters, was that of insufficient range to permit deep penetration into Germany, but means were already being sought to add to the P-47B's 307 U.S. gallons of internal fuel. At the time of the Thunderbolt's European debut radial-engined single-seat fighters were a rarity, the only other such fighter operational in Europe being the Fw 190A. To prevent confusion between the two fighters of the opposing sides the engine cowlings of the Thunderbolts were painted white, and white bands were painted around the vertical and horizontal tail surfaces--an appropriate comment on recognition standards appertaining at that time, as it would seem impossible to mistake the sleek and beautifully-contoured German fighter for the portly Thunderbolt.

By mid-1943 improved P-47Cs were becoming available, with external fuel tanks to increase range and a longer fuselage to improve maneuverability. Next came the major production version, the P-47D, and then P-47Gs, and P-47Ms with more powerful engines, giving a maximum speed of 756 km/h (470 mph). They were used for anti V1 Flying Bomb duties.

The final version, the P-47N, was built primarily for use against the Japanese. The fastest model was the XP-47J, which did not go into production. On August 4, 1944, this plane reached a speed of 504 miles per hour. Production plans were shelved in favor of another P-47 development, the Republic XP-72.

P-47's flew more than 546,000 combat sorties between March 1943 and August 1945, destroying 11,874 enemy aircraft, some 9,000 locomotives, and about 6,000 armored vehicles and tanks. Only 0.7 per cent of the fighters of this type dispatched against the enemy were to be lost in combat.

Click on Picture to enlarge

The XP-47J

The P-47M was, essentially, developed collaterally with the XP-47J. The "J" was fitted with a high output version of the P&W R-2800. Specifically, the R-2800-57. This engine made 2,800 hp @ 2,800 rpm at 35,000 feet. This is in War Emergency Power. The aircraft actually attained 507 mph at an altitude of 34,300 feet. 2,800 hp is 133% of rated power. At military power (100%), the XP-47J could sustain 470 mph. 435 mph was attained at 81% of its rated power (1,700 hp). All performance figures were obtained at 34,300 feet. The "J" model was an especially good climbing fighter too. It had a climb rate at sea level of 4,900 fpm. At 20,000 feet, it was still rocketing up at 4,400 fpm, and got there in 4 minutes, 15 seconds. Time to 30,000 feet was only 6 minutes, 45 seconds. Now that's an interceptor! Yet it had a usable range of 1,075 miles. Rather impressive, don't you think? No, this was not a stripped down hotrod. It was fully armed and carried ballast in the wings equal to 267 rds per gun. The aircraft was flown to a height of 46,500 feet and was capable of a bit more.

Click on Picture to enlarge

The XP-47J

Originally designed to defeat the FW-190 series fighters, the XP-47J certainly would have exceeded this requirement. In point of fact, with it's critical Mach of .83, it had the potential to chase down Me-262's by utilizing a shallow dive, taking advantage of itís superior service ceiling. Despite this incredible performance, the XP-47J was really nothing more than a technology demonstrator. Meanwhile, the R-2800 C series was installed in another, more ordinary Thunderbolt P-47C. The purpose was to trade a little performance for simplicity of manufacture. The idea being that a minimum of changes were required to the current aircraft for the C series engine.

Click on Picture to enlarge

The unofficial XP-47M chrome yellow test mule (P-47C)

The aircraft that resulted was designated the XP-47M. Not "officially sanctioned", the XP-47M was an "in-house" development program. The "M" was painted in chromate yellow to distinguish it from the run of the mill C and D models. Likely, this overly bright paint scheme was selected to indicate its test status in order to prevent over-zealous P-47 and F6F pilots from making mock attacks, as was the standard rule of the day over wartime Long Island.

Right out of the starting gate, the XP-47M the horse to beat in terms of speed. The XP-47M proved to be nearly as fast as the XP-47J. 488 mph was obtained on at least one flight. The official maximum speed is 470 mph. However, over-boosting the engine could tweek another 15 to 20 mph out of the big fighter. There is adequate evidence to indicate that some of the more resourceful crew chiefs in the 56th Fighter Group, managed to hotrod the P-47M to the point that some reliable pilots were reporting 500 mph at altitude in level flight. Some may find this next tidbit hard to swallow, however, the test documents still exist.

During durability testing of the C series R-2800 by Republic, it was decided to find out at what manifold pressure and carburetor temperature detonation could be induced. They ran the engine at extreme boost pressures that produced 3,600 hp! But wait, it gets even more amazing. They ran it at 3,600 hp for 250 hours, without any failure! This, with common 100/130 avgas. No special fuels were used. Granted, the engines were completely worn out, but survived without a single component failure. Try that with Rolls Royce Merlin or Allison V-1710.

As the summer of 1944 arrived, so did the first of Germanyís vengeance weapons. The sudden appearance of the V-1 flying bomb caused a serious uproar in Britain. Flying at speeds right around 400 mph., the V-1 was not easy to intercept prior to flying over populated areas where knocking it down could have a worse effect than leaving it alone. Many of the RAFís latest fighters were thrown into intercepting the "Buzz Bombs", preferably over the English Channel. Tempests, Spitfires and even the jet powered (but not very fast) Meteors were put to work intercepting the deadly missiles.

Naturally the British government called upon its allies to aid in this duty. Upon being informed of the XP-47M, three YP-47M development aircraft were ordered. These were built using P-47D-27-RE fighters straight off the production line.

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Number two of three YP-47M development aircraft (P-47D-27-RE).

Having already logged hundreds of flights with the XP-47M, beginning in mid 1943, Republic had a big leg up in terms of development time. This was to be very valuable. The accelerated production of the long ranging P-51D threatened to kill further P-47 production. The AAF was beginning to indicate that since the Mustang could provide for most of their fighter needs, especially in role of escort, the P-47, with itís limited range had but a short future.

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The P-47N

Republic went to work to produce a long range variant of the Thunderbolt. The basis for this new model was the XP-47M. New wings were designed and installed on the fighter, which contained, for the first time, fuel tanks. This new "wet wing", with its "clipped" wing tips, was also fitted to a YP-47M, which was re-designated as the XP-47N. The resulting P-47N was capable of maximum ranges in excess of 2,300 miles and speeds up to 465 mph. However, it was deployed only in the Pacific.

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The P-47M

The production P-47M fighters did not reach operational status until after most of the V-1 launch sites were over-run by Allied ground forces. Deployed to 3 squadrons of the 56th Fighter Group, the new fighter likely did not chase any flying bombs. Inasmuch as most aviation historians claim that the P-47M was designed specifically to intercept the V-1, it will come as a surprise to them to learn that the prototype existed more than a year before the first V-1 was launched at Britain. Moreover, the P-47D, deployed in large numbers, was certainly fast enough to overtake the V-1. It was only coincidence that the XP-47M and the R-2800 C series engines were available when the V-1ís began falling on London.
P-47M performance was as follows:

Max speed: 470-480 mph @ 28,500 ft. Climb, at max. gross weight (including three 75 gallon drop tanks): 4.9 minutes to 15,000 feet at 2,600 rpm (1700 hp). Reportedly, the "M" could reach 20,000 feet in 5.7 minutes at military power (2,100 hp @ 2,800 rpm). 20,000 feet in 4.75 minutes in WEP (2,800 hp @ 2,800 rpm). This is with full internal fuel and ammo. No external stores or drop tanks. In other words, normal load, clean configuration.

 

One Pilot's Initial Reaction To The P-47 Introduction


One day in January 1943 General Hunter, the Commander of the 8th Fighter Command, came to visit us at Debden. He said he had a 'surprise' for us we were soon to re-equip with the very latest American fighter, the P-47 Thunderbolt. As he spoke we heard an unusual engine note outside and one of the new fighters landed and taxied up beside one of our Spitfires. We went outside to look it over. It was huge: the wing tip of the P-47 came higher than the cockpit of the Spitfire. When we strapped into a Spitfire we felt snug and part of the aircraft; the Thunderbolt cockpit, on the other hand, was so large that we felt if we slipped off the Goddamned seat we would break a leg! We were horrified at the thought of going to war in such a machine: we had enough trouble with the Focke Wulfs 190's in our nimble Spitfire Vs; now this lumbering seven-ton monster seemed infinitely worse, a true 'air inferiority fighter'. Initial mock dog-fights between Thunderbolts and Spitfires seemed to confirm these feelings; we lost four Thunderbolt pilots in rapid succession, spinning in from low level while trying to match Spitfires in turns. In the end our headquarters issued an order banning mock dog fighting in Thunderbolts below 8,000 feet.

Gradually, however, we learnt how to fight in the Thunderbolt. At high altitude she was a 'hot ship' and very fast in the dive; the technique was not to 'mix it' with the enemy but to pounce on him from above, make one quick pass and get back up to altitude; if anyone tried to escape from a Thunderbolt by diving, we had him cold. Even more important, at last we had a fighter with the range to penetrate deeply into enemy territory--where the action was. So, reluctantly, we had to give up our beautiful little Spitfires and convert to the new juggernauts. The war was moving on and we had to move with it.

The change to the Thunderbolt might have been necessary militarily, but my heart remained with the Spitfire. Even now, thirty years after I flew them on operations, the mere sound or sight of a Spitfire brings me a deep feeling of nostalgia and many pleasant memories. She was such a gentle little aeroplane, without a trace of viciousness. She was a dream to handle in the air. I feel genuinely sorry for the modern fighter pilot who has never had the chance to get his hands on a Spitfire; he will never know what real flying was like.

 

 

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