The Republic P-47 Thunderbolt

United States of America
United States of America

side view front view under view

The Thunderbolt or Jug was one of the most famous and popular aircraft of the Allied air forces. At the beginning it featured as an air superiority fighter, later it reverted more to the ground attack role.
When the P-47 entered service in 1942, it was the biggest and heaviest single-engined fighter ever to join an airforce, even though it originated as a light-weight design. But let us take a few steps back into the design-history of the P-47.
The origins of the P-47 can be traced to the Seversky Aircraft Corporation created in 1931 by Alexander P.de Seversky, the forefather company of Republic. This organization built some aircraft types before its chief designer, Alexander Kartveli (who was an expatriate Russian like Severski himself), evolved the P-35 fighter that was the production version of the SEV-1XP prototype that was itself the SEV-2XP two-seat prototype revised with single-seat accommodation and retractable landing gear. This type established the type of fighter for which Kartveli became celebrated, for it was a comparatively large cantilever low-wing monoplane of basically all-metal construction with a wing of semi-elliptical planform and a corpulent fuselage carrying a powerful radial piston engine.
In 1938 Seversky ran into financial difficulties and was reorganized. In the first part of the following year, Seversky left the company and in June of the same year the Seversky Aircraft Corporation was renamed as the Republic Aviation Corporation. Kartveli continued as the revised organization’s chief engineer, and during this period was considering how best to evolve a thoroughly modern fighter offering the highest possible performance through development of the Seversky/Republic design philosophy: this emphasized the use of a powerful radial piston engine and a massive airframe of considerable strength. Kartveli’s conclusion was that good performance could only be achieved by the use of the most powerful radial engine currently available in a very clean airframe with, just as importantly, an engine installation of very low drag.
In 1939 this philosophy was put forward when Republic entered 2 prototypes in the US Army Air Corps 1939 fighter competition, the AP-2 (XP-41, revised P-35) and the AP-4 (AP-2 with turbocharger). The USAAC was not particularly enthusiastic about the AP-4, and the competition was won by the Curtiss Model 81 that was ordered into production as the P-40. Even so, the service was sufficiently impressed with the technical advance represented by the AP-4 to order a batch of 13 YP-43 Lancer service test aircraft with the R-1830-35 radial engine rated at 1,200 hp (895 kW) for take-off and using a turbocharger installation revised with its inlet in the engine cowling in stead of the wing root of the left wing. The YP-43s paved the way for a small number of production aircraft, namely 54 examples of the P-43 Lancer with 1 × Pratt & Whitney R-1830-47 radial, rated at 1,200 hp (895 kW) for take-off, and 205 examples of the P-43A Lancer with 1 × Pratt & Whitney R-1830-49 radial, rated at 1,200 hp (895 kW) for take-off.
Not yet satisfied with performance, kartveli looked for a way to further increase performance. It was the use of either a considerably more powerful radial engine in a large airframe, or a Vee engine of more modest power in a smaller and therefore less ‘draggy’ airframe. Although most competitors went for the Vee engines, Kartveli decided to stay with the radial because he was still attracted by the merit of the higher-power radial engine. Republic therefore moved forward with two developments of the P-43 Lancer as the AP-4J with the Pratt & Whitney R-2180-1 Twin Hornet radial, rated at 1,400 hp (1044 kW) for an estimated max level speed of 386 mph (621 km/h), and the AP-4L with 1 × Pratt & Whitney R-2800-7 Double Wasp, rated at 2,000 hp (1491 kW) for a max level speed of 406 mph (653 km/h). This got the attention of the USAAC, and before the end of 1939 placed an order for 80 P-44-1 Rocket fighters based on the less ambitious AP-4J concept, but with the possibility of a P-44-2 Rocket version of the AP-4L still in prospect.
In the meantime Republic also offered a Vee engined desing in August 1939 to the USAAC, designated AP-10. This considerable smaller fighter had a weight of 4,900 lb (2.223 kg), an armament of 2 × 0.50 inch (12,7 mm) Browning machine guns in the forward fuselage with synchronization equipment to fire through the propeller disc, a powerplant of 1 × Allison V-1710-39 Vee, rated at 1,150 hp (857 kW), and a max level speed estimated at 415 mph (668 km/h). The USAAC liked the concept but wanted heavier firepower in the form of the 2 × 0.50 inch (12,7 mm) machine guns supplemented by 4 × 0.30 inch (7,62 mm) Browning machine guns in the wing leading edges. This increased the weight to 6,570 lb (2.983 kg) and reduced the estimated maximum level speed to 400 mph (644 km/h), and in November 1939 the USAAC ordered at Republic a single XP-47 and a single XP-47A prototype with and without the wing-mounted guns respectively.
During the time that the prototypes were being built the first reports from the Air war in Europe were received in America, where the implications of this new information were reason enough to reconsider some design aspects. Offensive as well as defensive characteristics needed to be enhanced: in offensive terms this meant a radical increase in firepower by the addition of more heavy machine guns, and in defensive terms it required the introduction of self-sealing fuel tanks and also the addition of armor protection for the pilot and vital systems. These changes in their turn meant greater weight, and by May 1940 Republic was already trying hard to keep down the weight of the XP-47 prototypes. These problems coincided with the USAAC’s growing uneasiness with the fact that the V-1710 engine had been selected for virtually all of its new generation of fighters, which meant that in case the engine failed in operational conditions the USAAC would face a catastrophe, or maybe the negine wouldnd't be able to be produced in the numbers that were required. Because of these two reasons it was decided to consider the option of a new fighter with a radial-engined powerplant, and the USAAC accordingly asked Republic in June 1940 to revise its AP-4L proposal with a fixed forward-firing armament of 8 × 0.50 inch (12,7 mm) Browning machine guns in the wing leading edges, with a powerplant of 1 × Pratt & Whitney XR-2800 radial and a turbocharger installation that would allow the engine to deliver 2,000 hp (1.491 kW) at 27,800 ft (8.475 m) and, as a bonus made possible by the large size of the airframe, an internal fuel capacity somewhat greater than that of the Vee-engined fighters currently in production. In September 1940 the USAAC decided that the revised AP-4L design offered considerably greater potential than the XP-47 and XP-47A, which were canceled so that Republic could concentrate on the rapid completion of the XP-47B prototype based on the revised AP-4L design.
In the meantime Republic progressed well with the finalization of the P-44-1 type, which had received supplementary orders for 225 and 602 aircraft in July and September 1940. The USAAC then decided that the production version of the XP-47B was likely to offer performance of the level that would probably make the P-44 obsolete instantly and canceled the P-44 just days after the new orders were placed. It was at this stage that the initial 54 P-43 Lancer fighters were ordered as an interim measure that would provide a continuity of work on Republic’s production line, the P-44 order for 80 fighters was transferred to the P-43A, and new orders were placed for 171 and 602 examples of the P-47B and P-47C respectively.
The P-43 and its turbocharged radial-engined powerplant provided Kartveli’s design team with invaluable experience with an installation of this type, and also persuaded it that the nature of the turbocharger installation would ultimately determine the overall capability of the P-47. The crux of the turbocharger installation was that the additional power it provided would have to be significantly greater than its weight and drag penalties. The turbocharger unit for the R-2800 engine was a General Electric product of considerable weight and about the size of a medium-sized refrigerator. Kartveli decided that the need to optimize the turbocharger installation demanded a complete revision of the fuselage to ensure as even a balancing as possible of the engine and turbocharger masses, and also the correct shaping of the ducts supplying air to the turbocharger, compressed air from the turbocharger to the engine, and exhaust gases from the engine to the turbocharger, whose blower was powered by a turbine driven by these gases before they were exhausted. Thus the turbocharger was installed in the rear fuselage, some 22 ft (6.7 m) to the rear of the propeller. Exhaust gases were collected by two exhaust rings, one each for the left- and right-hand groups of cylinders, and then channeled along two ducts, one on each side of the lower fuselage, to power the turbine before being exhausted through a ventral opening just short of the tail. Air for the blower was collected from an inlet in the cowling under the engine, a position in which the ram effect was boosted by the propeller, and then ducted along the bottom of the fuselage toward the turbocharger. Before reaching this, however, the air was divided: some of it was directed into the blower for compression, and some of it was used in the intercooler for temperature-control purposes before being dumped via electrically controlled doors in the sides of the fuselage just forward of the turbocharger proper. Finally the air compressed in the turbocharger and then lowered in temperature by the intercooler and thus made denser was directed along the sides of the fuselage in two ducts to the engine carburetors.
Around this complete powerplant installation (engine, turbocharger, intercooler and associated ducting) Kartveli planned the fuselage as a light alloy unit of semi-monocoque construction. This was built in three primary sections: the upper part of the forward fuselage that included the high-set cockpit (covered by a framed canopy with a side-hinged section and faired into the rear fuselage by a long ‘razorback’) as well as the 171 Imp gal (205 US gal, 776 liters) main fuel tank, the lower part of the forward fuselage that incorporated a 83 Imp gal (100 US gal, 378 liters) auxiliary fuel tank as well as the two major bulkheads that carried the wing loads, and the rear fuselage that carried the turbocharger. The tail unit was of the plain type, and the cantilever mid/low-set wing was of semi-elliptical planform with dihedral, taper in thickness and chord, and the standard trailing-edge combination of outboard Frise-type ailerons and inboard slotted flaps; dive-recovery brakes were fitted under the inner wing panels ahead of the flaps. The airframe was completed by the landing gear, which was of the fully retractable tailwheel type with wide-track main units.
The design of the main landing gear units itself caused some difficulties, for the gear had to be installed inboard of the machine gun armament, which included long outboard channels carrying the belted ammunition. The considerable power of the Double Wasp radial engine required the use of a four-blade Curtiss Electric metal propeller of the constant-speed type with a diameter of 12 ft 0 in (3,66 m), and the need to provide the tips of these blades with adequate ground clearance meant that the main landing gear legs were too long to be retracted into the span left inboard of the machine guns. The Republic design team had therefore to a devise a system that shortened each leg by 9 in (0,23 m) as it retracted.
The XP-47B made its first flight in May 1941 powered with 1 × Pratt & Whitney XR-2800-21 radial, rated at a nominal 2,000 hp (1.491 kW) at 27,800 ft (8.475 m) but in fact delivering less than this because of a number of factors including poor sealing of the turbocharger ducts: for its time the XP-47B was the largest and heaviest fighter planned for the USAAC, which one month later became the US Army Air Forces.

Version list:

Further pictures:

Republic P-47D Thunderbolt on a PSP airfield with belly fuel tank
Republic P-47D Thunderbolt on a PSP airfield with belly fuel tank

Republic P-47D on an airfield
Republic P-47D on an airfield

Republic P-47C during an airshow. Note the Razorback
Republic P-47C during an airshow. Note the Razorback

A section of P-47's in full flight
A section of P-47's in full flight

 

Technical data on the Republic P-47B Thunderbolt
Powerplant 1 × Pratt & Whitney R-2800-21 radial, rated at 2000 hp (1490.98 kW) Role during war
  • Fighter
  • (Ground) Attack Fighter
  • Close Support Attack Fighter
Length 35 ft 0 inch Height 12 ft 8 inch
Empty weight 9346 lb Operational weight 13360 lb max
Wing Span 40 ft 9 inch Wing Aspect ratio 5.535
Wing Area 300 sq ft Service ceiling 42000 ft
Maximum speed 429 mph at 27800 ft Cruising speed 335 mph at optimum altitude
Initial climb rate Climb to 15,000 ft in 6 min 42 sec Range 1100 miles max
Fuel capacity internal unknown Fuel capacity external unknown
Machine guns
  • 8 × 0.50 inch Browning MG53-2 fixed forward-firing in the wing leading edge, 425 rounds each (max, typical 267 each)
Cannons -
Bomb load unknown Torpedoes/rockets unknown
Crew 1 Naval or ground based Ground
First flight (prototype) 6 may 1941 Operational Service Mid 1942 - 1960's
Manufacturer Republic Aviation Corporation Number produced 15.634 total, 172 of all P-47B versions
Metric system
Length 10.67 m Height 3.86 m
Empty weight 4239 kg Operational weight 6060 kg max
Wing Span 12.42 m Wing Aspect ratio 5.535
Wing Area 27.87 m² Service ceiling 12802 m
Maximum speed 690 km/h at 8473 m Cruising speed 539 km/h at optimum altitude
Initial climb rate Climb to 4.527 m in 6 min 42 sec Range 1770 km max
Fuel capacity internal unknown Fuel capacity external unknown
Machine guns
  • 8 × 12,7 mm Browning MG53-2 fixed forward-firing in the wing leading edge, 425 rounds each (max, typical 267 each)
Cannons -
Bomb load unknown Torpedoes/rockets unknown

Technical data on the Republic P-47D-22 Thunderbolt
Powerplant 1 × Pratt & Whitney R-2800-59 radial, rated at 2000 hp (1490.98 kW) Role during war
  • Fighter
  • (Ground) Attack Fighter
  • Close Support Attack Fighter
  • Fighter-bomber
  • Long range (attack) Fighter
Length 36 ft 1 inch Height 14 ft 7 inch
Empty weight 10700 lb Operational weight 13500 lb typical,
16200 lb max
Wing Span 40 ft 9 inch Wing Aspect ratio 5.535
Wing Area 300 sq ft Service ceiling 42000 ft
Maximum speed 435 mph at 30000 ft Cruising speed 350 mph at optimum altitude
Initial climb rate 3,100 ft per min at an altitude of 5,000 ft
Climb to 15,000 ft in 5 min 36 sec
Range 790 miles typical,
1725 miles max
Fuel capacity internal 254 Imp gal (305 US gal) Fuel capacity external Up to 383 Imp gal (460 US gal) in one 92 Imp gal or 62 Imp gal (110 US gal or 75 US gal) and two 125 Imp gal (150 US gal) drop tanks
Machine guns
  • 8 × 0.50 inch Browning MG53-2 fixed forward-firing in the wing leading edge, 425 rounds each (max, typical 267 each)
Cannons -
Bomb load Up to 2,500 lb of disposable stores carried on three underwing hardpoints, one under fuselage rated at 500 lb and two underwing rated at 1,000 lb each.. General disposables load consisted of:
  • 2 × 1,000 lb bombs, or
  • 3 × 500 lb bombs
Torpedoes/rockets
  • Up to 10 × 5 inch HVAR air-to-surface unguided rockets alternatively to bombs
Crew 1 Naval or ground based Ground
First flight (prototype) 6 may 1941 Operational Service Mid 1942 - 1960's
Manufacturer Republic Aviation Corporation Number produced 15.634 total, 12.559 of all P-47D versions
Metric system
Length 11 m Height 4.44 m
Empty weight 4854 kg Operational weight 6124 kg typical,
7348 kg max
Wing Span 12.42 m Wing Aspect ratio 5.535
Wing Area 27.87 m² Service ceiling 12802 m
Maximum speed 700 km/h at 9144 m Cruising speed 563 km/h at optimum altitude
Initial climb rate 945 m per min at an altitude of 1.525 m
Climb to 4.570 m in 5 min 36 sec
Range 1271 km typical,
2776 km max
Fuel capacity internal 1154 liters Fuel capacity external Up to 1.471 liters in one 416 liters or 284 liters and two 567 liters drop tanks
Machine guns
  • 8 × 12,7 mm Browning MG53-2 fixed forward-firing in the wing leading edge, 425 rounds each (max, typical 267 each)
Cannons -
Bomb load Up to 1.134 kg of disposable stores carried on three underwing hardpoints, one under fuselage rated at 227 kg and two underwing rated at 454 kg each.. General disposables load consisted of:
  • 2 × 454 kg bombs, or
  • 3 × 227 kg bombs
Torpedoes/rockets
  • Up to 10 × 127 mm HVAR air-to-surface unguided rockets alternatively to bombs

Technical data on the Republic P-47N Thunderbolt
Powerplant 1 × Pratt & Whitney R-2800-57, 73 or 77 radial, rated at 2800 hp (2087.37 kW) Role during war
  • Fighter
  • (Ground) Attack Fighter
  • Close Support Attack Fighter
  • Fighter-bomber
  • Long range (attack) Fighter
Length 36 ft 1 inch Height 14 ft 8 inch
Empty weight 11000 lb Operational weight 20700 lb max
Wing Span 42 ft 7 inch Wing Aspect ratio 5.63
Wing Area 322 sq ft Service ceiling 43000 ft
Maximum speed 467 mph at 32500 ft Cruising speed 300 mph at optimum altitude
Initial climb rate Climb to 25,000 ft in 14 min 12 sec Range 2350 miles typical
Fuel capacity internal 463 Imp gal (556 US gal) Fuel capacity external Up to 589 Imp gal (710 US gal), 1 × 91 Imp gal (110 US gal) underfuselage and 2 × 249 Imp gal (300 US gal) underwing drop tanks
Machine guns
  • 8 × 0.50 inch Browning MG53-2 fixed forward-firing in the wing leading edge, 425 rounds each (max, typical 267 each)
Cannons -
Bomb load Up to 2,500 lb of disposable stores carried on three underwing hardpoints, one under fuselage rated at 500 lb and two underwing rated at 1,000 lb each.. General disposables load consisted of:
  • 2 × 1,000 lb bombs, or
  • 3 × 500 lb bombs
Torpedoes/rockets
  • Up to 10 × 5 inch HVAR air-to-surface unguided rockets alternatively to bombs
Crew 1 Naval or ground based Ground
First flight (prototype) 6 may 1941 Operational Service Mid 1942 - 1960's
Manufacturer Republic Aviation Corporation Number produced 15.634 total, 1.817 of all P-47N versions
Metric system
Length 11 m Height 4.47 m
Empty weight 4990 kg Operational weight 9390 kg max
Wing Span 12.98 m Wing Aspect ratio 5.63
Wing Area 29.91 m² Service ceiling 13106 m
Maximum speed 752 km/h at 9906 m Cruising speed 483 km/h at optimum altitude
Initial climb rate Climb to 7.620 m in 14 min 12 sec Range 3782 km typical
Fuel capacity internal 2.104 liters Fuel capacity external Up to 2.688 liters, 1 × 416 liters underfuselage and 2 × 1.136 liters underwing drop tanks
Machine guns
  • 8 × 12,7 mm Browning MG53-2 fixed forward-firing in the wing leading edge, 425 rounds each (max, typical 267 each)
Cannons -
Bomb load Up to 1.134 kg of disposable stores carried on three underwing hardpoints, one under fuselage rated at 227 kg and two underwing rated at 454 kg each.. General disposables load consisted of:
  • 2 × 454 kg bombs, or
  • 3 × 227 kg bombs
Torpedoes/rockets
  • Up to 10 × 127 mm HVAR air-to-surface unguided rockets alternatively to bombs

Here is a quick overview of all different versions, without the full technical specifications:

Different versions of the Republic P-47  Thunderbolt
Republic XP-47 Prototypes The P-47 was preceded with several prototypes. The first one, XP-47 was an Allison V-1710 powered aircraft armed with 2 × 0.50 inch (12,7 mm) Browning guns in the nose.
Together with the XP-47, the XP-47A was ordered. It was almost identical to the XP-47, but had additional armament in the form of 4 × 0.30 inch (7,62 mm) Browning guns in the wing leading edges.
Both prototypes were canceled before complete, because of reporst that reached the USAAC upper brass about the War in Europe. In stead of a Vee-engined aircraft the USAAC anted a radial powered aircraft as well, in case the Allison engines would fail to live up to their expectations. This resulted in the first real P-47 prototype, the XP-47B, powered with the Pratt & Whitney XR-2800 radial, and armed with 8 × 0.50 inch (12,7 mm) Browning guns in the wing leading edges.
Number built: 2 uncompleted, 1 completed
Republic P-47B Thunderbolt This was the first operational version of the 'Jug'. The main difference from the prototype was the engine, which in this case was 1 × Pratt & Whitney R-2800-21 radial, a rearward sliding canopy section, metal covered control surfaces as opposed to fabric-covered, and some internal changes.
The P-47B saw no operational service, but was used for training pilots that would eventually fly the Jug overseas.
Number built: 170
Republic P-47C Thunderbolt This version was powered by 1 × Pratt & Whitney R-2800-59 Double Wasp radial, rated at 2,300 hp (1.715 kW) at 27,000 ft (8.230 m) with water injection. This water was drawn from a 25 Imp gal (30 US gal, 114 liters) tank installed ahead of the firewall. The fuselage was lengthened ahead of the engine firewall by 8 inch (0,203 m) to make room for this tank, which increased total length to 36 ft 1.25 inch (11,00 m).
The move forward of the engine shifted the center of gravity, which accounted for an increase in maneuverability of the P-47. Also, now it was possible to add a centerline hardpoint for a drop tank, with a capacity of alternatively 62, 92 or 167 Imp gal (75, 110 or 200 US gal; 284, 416 or 757 liters).
Number built: 602
Republic P-47D Thunderbolt Even before the P-47C entered combat, Republic started deliveries of the P-47D version. In the early production blocks the P-47D was very similar to the P-47C, except for the propeller. The P-47D's propeller had a diameter of 12 ft 2 inch (3,71 m), a redesigned turbo exhaust system with an adjustable duct, redesigned vents, an additional two cooling gills on the rear engine section, one on each side, additional pilot armor protection, and an increase in maximum possible ammunition capacity from 267 rounds per gun to 425 rounds per gun.
Also, since the escort fighter role was gradually taken over by North American P-51 Mustang, the P-47 was slowly rebuilt to a fighter bomber. The first blocks that were prepared as such were the P-47D-6-RE and P-47D-11-RA (RE = the Farmingdale plant, RA = the Evansville plant). These blocks had first a ventral hardpoint fitted, ale to carry a 500 lb (227 kg) bomb in place of the drop tank.
Below is an overview of several production blockas and their respective changes.

P-47D-6-RE Ventral hardpoint made capable of carrying a 500 lb (227 kg) bomb
P-47D-11-RE Ventral hardpoint made capable of carrying a 500 lb (227 kg) bomb
P-47D-15-RE/P-47D-15-RA Additional (underwing) hardpoints to carry either two droptank of 125 Imp gal (150 US gal, 567 liters), or two 1,000 lb or 500 lb (454 kg or 227 kg) bombs. This meant that the max amount of disposables could be 2,500 lb (1.1134), but the lack of additional fuel and higher weight meant that in those cases mostly the ammunition of the guns was reduced to 267 rounds per gun.
P-47D-20-RE Up until this version the main difference of the P-47D from the P-47C was that the propeller had a diameter of 12 ft 2 inch (3,71 m), the turbo exhaust system was redesigned with an adjustable duct, vents were redesigned, there were two additional cooling gills on the rear engine section, one on each side, additional pilot armor protection was added, and the maximum possible ammunition capacity was increased from 267 rounds per gun to 425 rounds per gun.
P-47D-21-RA From this block onward the aircraft were delivered in their natural metal finish, with the exception of a black anti-dazzle ahead of the cockpit, for reduced weight and drag, and thus resulting in a slightly higher performance.
P-47D-22-RE This block introduced a Hamilton Standard metal propeller of 13 ft 0 in (3,96 m) diameter with four wider-chord ‘paddle’ blades.
P-47D-23-RA Same as the P-47D-20-RE, but built by the Evansville plant. This version was fitted also with a Curtiss Electric metal propeller of 13 ft 0 in (3,96 m) diameter with four wider-chord ‘paddle’ blades.
P-47D-25-RE This block introduced an internal fuel capacity increased to 308 Imp gal (370 US gal, 1401 liters) and also the most distinctive change, which was a clear-view ‘bubble’ canopy with a fixed forward section and a rearward-sliding rear section. This allowed the elimination of the previous ‘razorback’ fairing that extended rearward from the canopy, and gave the pilot a full 360° field of vision.
P-47D-26-RE This block introduced a small dorsal fin as a forward extension of the fixed fin. The need for this had arrisen because of the Bubble canopy which had reduced the keel area, resulting in less directional stability.
P-47D-28-RE From this block onward the Farmingdale would deliver their aircraft in a natural metal finish like the P-47D-21-RA.
P-47D-30-RA This block introduced the small dorsal fin like the P-47D-26-RE for the Farmingdale-built aircraft.
P-47D-35-RA This block introduced provision for zero-length underwing rocket launchers. These totaled five on each side (only three if bombs or drop tanks were carried), and could each carry one 5 inch (127 mm) HVAR air-to-surface rockets.


Number built: 12.603, of which 6.510 were built in Farmingdale, 6.093 built in Evansville
Republic P-47G Thunderbolt This was the Curtiss-built version of the Thunderbolt, and all were completed with the original type of framed canopy and rear-fuselage ‘razorback’ fairing. The first 60 aircraft were completed to a P-47C standard, while the last 294 of these 354 aircraft were to the P-47D standard, the final 234 of them with the ventral hardpoint for the carriage of a bomb or drop tank.
Number built: 354
Republic P-47M Thunderbolt In June 1944 the germans started to launch their V-1 (Fiesler FI 103) flying bomb at Great Britain. To be able to catch them very fast aircraft were necessary. The USAAF opted for a speed optimised version of the P-47D, which was based on the XP-47J prototype and powered by 1 × Pratt & Whitney R-2800-57(C) radial, rated at 2,00 hp (1.566 kW) at take-off and 38,750 ft (11.810), fitted with a CH-5 turbocharger. However this engine had an emergency power rating of 2,800 hp (2.088 kW) at 32,500 ft (9.905 m).
The fighter would normally cruise at a medium altitude and, after acquiring its target, accelerate in a dive until it was close to the flying bomb, whereupon it would decelerate with the aid of air brakes and open fire with its fixed forward-firing battery of 6 or 8 × 0.50 inch (12,7 mm) Browning machine guns.
The P-47M was preceded by the YP-47M evaluation type, which were prototype conversions of the P-47D. This showed off course in the final production model, which was similar to the P-47D as far as dimensions are concerned. Differences in technical aspects are: empty weight of 10,423 lb (4.728 kg), normal take-off weight of 13,275 lb (6.022 kg), max take-off weight of 15,500 lb (7.031 kg), max level speed of 470 mph (756 km/h) at 30,000 ft (9.145 m) declining to 400 mph (644 km/h) at 10,000 ft (3.050 m), typical range of 560 miles (901 km) with internal fuel, and maximum climb rate at 5,000 ft (1.525 m) of 3,500 ft (1.067 m) per minute.
Number built: 130
Republic P-47N Thunderbolt This was the final version of the P-47 Thunderbolt. It was preceded by a single prototype, the XP-47N, which was based on the P-47D. Basically it was the P-47M, but with strenthened landing gear and slightly larger wings (span as well as area). This version was meant to be operated in the Pacific theatro, were range was more important tahn in the European Theatre, so the wing increase was used to add two additional fuel tanks of 77 Imp gal (93 US gal, 352 liters) each. Internal fuel capacity thus reached 463 Imp gal (556 US gal, 2.104 liters), optionally supplemented by one 91 Imp gal (110 US gal, 416 liters) underfuselage and two 249 Imp gal (300 US gal, 1.136 liters) underwing drop tanks. The resulting range was 2,350 miles (3.781 km) even without the centerline drop tank, and good for an endurance of 9 hours and 36 minutes (!).
All aircraft were more or less similar, except the first 500 produced. These did not have the underwing zero-length rocket launchers that the subsequent aircraft did have.
Number built: 1.816, of which 1.667 were built in Farmingdale, 149 built in Evansville
Republic Thunderbolt Mk I These aircraft delivered to the RAF were P-47D's from early production blocks lacking the bubble canopy.
Redesignated aircraft: 240
Republic Thunderbolt Mk II These aircraft delivered to the RAF were P-47D's from later production blocks fitted with the bubble canopy.
Redesignated aircraft: 590
Republic F-47D Thunderbolt After 1948 the USAAF redesignated the surviving aircraft, adopting F-for-Fighter, rather than P-for-Pursuit.
Redesignated aircraft
Republic F-47N Thunderbolt After 1948 the USAAF redesignated the surviving aircraft, adopting F-for-Fighter, rather than P-for-Pursuit.
Redesignated aircraft
Republic TP-47G Thunderbolt Two P-47G were modified to accomodate a lenthened two-seat cockpit. This cockpit was lengthened toward the nose.
Number converted: 2

Operational remarks:

The Thunderbolt made a difference during World War 2. It was the first fighter that was a serious candidate for escort duties for the USAAF heavy bombers. Up till then the American Heavies had to deal with the German fighters themselves, suffering unneccessary heavy losses in the process. This was reduced (but not really cured) with the long range version of the Thunderbolt.
Some statistics about the P-47:

As impressive as these destruction figures may be, the main feat was the protection of numerous bombers during their escort duties, enabling the USAAF 8th Air Force to continue it's strategic offensive against the economical targets of Germany.

Strengths:

Weaknesses:

 

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© by Frans Bonné, 2000
Last revision: 5/27/02