The XP-44 was the final stepping stone on the road to the P-47 Thunderbolt. It never progressed beyond the prototype stage, but it gave Alexander Kartveli, Republic’s chief designer, invaluable experience working with the most powerful radial engines then available. This would come in very useful when his original plan to use an inline engine in the P-47 fell through.
The P-44 would have been very similar to the P-43, but with a more powerful engine. On 13 September 1939 Republic received an order for 80 P-44-1s, powered by a 1,400hp Pratt & Whitney R-2180-1 engine. At the same time work was underway on the P-44-2, which would have used the Pratt & Whitney R-2800-7 engine, similar to the engine later used in the Thunderbolt. On 12 July 1940 Republic received an order for 225 P-44s.
Before any of these aircraft were even close to completion, events in Europe demonstrated that the new design was already outdated. On 6 September 1940 Republic had received approval for the radial engined version of the P-47. Three days later the number of P-44s on order was increased to 827, only for the project to be cancelled on 13 September. Republic instead received increased orders for the P-43 while development work continued on the P-47.