Republic P-47 Thunderbolt came into being in response to a tender by the United States
Army Air Corps for a new, high-altitude interceptor, offered in the summer of 1939. Shortly afterwards war broke out in Europe. It soon became obvious that the key to success in modern air combat was altitude advantage and powerful armament. This knowledge prompted Aleksander Kartveli, the chief designer of Republic Aviation Corporation, to choose for his new project one of the most powerful aircraft engines in existence – the 18-cylinder Pratt & Whitney Double Wasp radial engine fitted with turbo-supercharger. It was a daring choice, for the resulting weight and dimensions of his fighter by far exceeded those en vogue at that time (in its final configuration the P-47 was nearly twice as heavy as a standard single-seat fighter of WWII era). Perhaps understandably, many pilots, accustomed to light and nimble machines, had mixed emotions about flying this heavy-weight ‘monster’.
On 6th May 1941 test pilot Lowery L. Brabham took the prototype XP-47B on its maiden flight. Refining such revolutionary design took time, hence P-47B, the first production variant, never saw combat. This distinction went to its successor, P-47C, in production since late 1942, which joined the war in Europe in spring of the following year. P-47C soon phased out in favour of P-47D, the most numerous model of the Thunderbolt (over 12 500 aircraft out of some 15 500 in total), which was eventually produced in 20 successive variants. Since the Republic factory at Farmingdale was no longer able to meet the growing demand for the new fighter, a new P-47 production line was set at another plant in Evansville, Indiana. In order to tell apart the two production series, Farmingdale and Evansville aircraft were given different suffixes (‘-RE’ and ‘-RA’, respectively).
The most notable variants were D-22 and D-25. The former, introduced at the turn of spring and summer 1944, featured a new, paddle-blade propeller (to make full use of the additional power provided by water injection). The new propeller’s blades had wider chord, which made them look like paddles (hence the name), and the prop’s diameter was increased to 13 feet. It added 400 feet per minute to the P-47’s climb rate. P-47D-25, introduced shortly afterwards, was fitted with the distinctive bubble-top canopy, which greatly enhanced vision from the cockpit, and enlarged fuel tanks (total internal fuel capacity increased from 305 to 370 gallons). January 1945 saw the debut of P-47M. Coming from a short production run of only 130 aircraft, it was in fact an interim hybrid of the basic P-47D airframe with R-2800-57(C) engine (designed for P-47N, which came too late to see combat over Europe). The new powerplant, rated at 2,800 hp (war emergency power), gave the P-47M a stunning 470 mph at 30 000 feet, making it the fastest piston-engined fighter in operational service with the Allies during World War Two (the D-25 model, powered by a 2,535 hp engine, could attain a maximum speed of 429 mph at the same altitude).
P-47 Thunderbolt was crucial in overwhelming the defences of Hitler’s Festung Europa, initially as escort fighter, and later mainly as fighter-bomber. It debuted in the former role with the USAAF 8th Army Air Force on 10th March 1943. Until P-51 Mustangs came into play, which happened nine months later, P-47 pilots bore the brunt of fighting with the Luftwaffe for air superiority over western Europe. Initially the American fighter groups, stationed in eastern England, carried out fighter sweeps over the coast of occupied France, Belgium and Holland. At that time Thunderbolts equipped three outfits – 4th, 56th and 78th FG – each with three squadrons on strength. Thunderbolts clashed with German fighters for the first time on 15th April, pilots of 4th FG scoring first ‘kills’ for the P-47. In early May Thunderbolts were relegated to escort duties, even though in this role they were severely hampered by their limited range.
Meanwhile, intense development work was underway to increase P-47’s range by fitting it with disposable drop tanks. For the first time external tanks were used during a mission to Kassel and Oschersleben on 28th July 1943 (notably, it was also the first time when Thunderbolts crossed into Germany). Nevertheless, the bulbous 200-gallon ferry tanks were, among other disadvantages, not pressurized, hence unusable above 23,000 ft. Much more useful were the pressurized, streamlined, teardrop-shaped 75-gallon tanks, and the cylindrical-shaped 108-gallon tanks which came a month later. On 27th September, during a bombing raid to Emden, the underbelly 108-gallon tanks allowed the P-47s to stay with their charges along the bombers’ entire route (600-mile round trip) – for the first time on a mission against a target in Germany. By steadily increasing their range, Thunderbolts forced the Luftwaffe to withdraw their fighter units ever farther to the east. It was particularly true in case of the heavy, twin-engined Bf 110s, which were suffering appalling losses in clashes with the escorts.
On 25th November 1943 Thunderbolts were used for the first time as fighter-bombers – on that day machines of 56th and 353rd FGs, each armed with a single 500 lb bomb, set upon Luftwaffe airfields in St Omer area. By the year’s end Thunderbolt outfits of the 8th AF, their number increased to seven by that time, racked up 405 air victories. The top-scoring unit, with a tally of 167 ‘kills’, was the oldest and the most experienced 56th FG, led by the legendary Col. Hubert Zemke.
Somehow overshadowed at that time by the 8th AF, the tactical 9th AF also steadily grew in strength. The Ninth’s Thunderbolt units, whilst being readied for ground support duties after the invasion, were often temporarily detached to fly escort missions alongside the 8th AF. The first three such fighter groups – 358th, 362nd and 365th – three had their baptism of fire during the momentous air battles in late February and early March 1944.
Even at that stage of the air war, after Mustangs and Lightnings had joined the fray, Thunderbolts were by far the most numerous escort fighters available to 8th AF. For instance, on 20th February 1944, when the Allies commenced a series of massive air strikes against German aviation industry all over the Reich (operation ‘Argument’, better known as the ‘Big Week’), the heavy bombers – over a thousand of them – were shepherded by 73 Mustangs, 94 Lightnings and as many as 668 Thunderbolts. On that day some Thunderbolts for the first time carried underbelly 150-gallon drop tanks. With extra flying time provided by the new tanks, 56th FG ventured as far as Hannover area, some 350 miles from its base at Halesworth.
The ‘Big Week’ was the apogee of Thunderbolts’ service with the 8th AF. Henceforth, their numbers steadily diminished in favour of Mustangs. In February 1944 nine fighter groups of the 8th AF – 4th, 56th, 78th, 352nd, 353rd, 355th, 356th, 359th and 361st – still operated Thunderbolts but this was soon to change. First to go was 4th FG, which converted to Mustangs in late February. In early March the Americans commenced a series of bombing raids against Berlin. By that time some Thunderbolts had been modified to carry auxiliary fuel tanks under wings – initially of 75 gallons, and of 108 gallons starting with April. In summer 1944 the roles somewhat reversed, and the remaining Thunderbolts of the strategic 8th AF were pressed into a tactical, ground-supporting role. Only one fighter group of the 8th AF – 56th FG – continued to operate Thunderbolts by the end of the war. Notably, it remained the top-scoring outfit (in terms of aerial victories) of all American fighters groups in the ETO. After the group had received the so-called ‘Superbolts’ (the P-47D-25 and later models), fitted with enlarged internal fuel tanks and modified to carry 150-gallon drop tanks under wings, it could range out as far as Berlin. Not unduly, it was with this unit that the aforementioned P-47M saw operational service, starting with January 1945. The 56th FG’s last Thunderbolts are famous for, more than anything else, their flamboyant painting schemes. The 61st FS opted for overall dark Midnight Blue with code letters and rudders in red; 62nd FS chose to paint upper surfaces in intermittent broad stripes of Medium Sea Grey and Dark Green (code letters and rudders in yellow); 63rd FS used the composition of dark French Blue and light Azure Blue (rudders blue, code letters left in natural aluminium colour). Apparently there were also some individual variations of these schemes.
Thunderbolts that the 8th AF no longer needed usually ended up in 9th AF, which by the time of Normandy landings could field as many as 13 Thunderbolt fighter groups. This force was split into two Tactical Air Commands: IX TAC under Brig.Gen. Elwood Quesada and slightly smaller XIX TAC under Maj.Gen. Otto Weyland. The former was tasked with providing support to First Army under Hodges, and the latter to pave the way (by all means a challenging assignment) for Patton’s Third Army.
In late 1944 the needs of the western front’s southern sector led to constituting the First Tactical Air Force (1st TAF, also known as the 1st TACAF), a Franco-American air arm created provisionally in the field and commanded by Maj.Gen. Robert Webster. Its mission was to support Franco-American Sixth Army Group (U.S. Seventh Army and French First Army). The 1st TAF comprised, among other units, three Thunderbolt fighter groups of the 9th AF (50th, 358th and 371st) as well as five P-47 groups of the 1st French Air Corps. Moreover, at the turn of 1944/45 Thunderbolts were also flown, albeit temporarily, by 354th FG (the only USAAF fighter outfit which, if only for a short stint, converted from P-51s to P-47s). When the 354th was given back their beloved Mustangs, its Thunderbolts were passed to 367th FG, which hitherto (until February 1945) had flown P-38 Lightnings.
Although 9th AF Thunderbolt pilots, whilst flying mainly fighter-bomber missions, amassed an impressive tally of air victories (quite a few of them became aces), their contribution in the final Allied victory was much more than that. For example, only one group – 368th FG – in the period between 14th March 1944 and 8th May 1945 claimed the destruction of 143 enemy aircraft in the air and 98 on the ground, as well as 499 tanks, 280 other armoured vehicles, 6865 motorised transports, 682 horse-drawn carts, 700 locomotives, 3174 rail cars, 33 bridges and 187 artillery pieces. Furthermore, the group’s pilots blew up 64 ammunition or fuel dumps, sank 31 barges and cut rail tracks 475 times.
The relatively least known role embarked upon the USAAF Thunderbolts in the World War Two was its use as rescue aircraft. During the massive air raids against the Third Reich many crippled machines fell short of England, ditching in the North Sea. Although P-47s obviously couldn’t pick up the survivors, by dropping dinghies and marking the spot with flares helped them enormously to survive until the arrival of the British Air Sea Rescue launches and flying boats. The rescue Thunderbolts equipped the 5th ERS (Emergency Rescue Squadron), which was an integral part of the U.S. 8th Air Force.