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.