escort fighter
Ironically it was the British that 'enabled' one of the best long range fighters albeit not designed for that purpose.
The Allied purchasing commission ordered the North American P51 (with Allison engine) and utilised it as a low altitude tac recon machine as the engine was not designed to be 'blown' for altitude work.
When a Rolls Royce liaison pilot flew one of the original early models he immediately identified its potential if fitted with the new high altitude Merlin.
The Mustang with its new Merlin soared into history as the best single engine long range escort of its time, able to escort American bombers deep into Germany and reduce the appalling previous losses of bomber crews. Such is the way that legends are born 'eventually'.