Not to mention a spot of Hun despatching along the way

Heres the story of it's development.
In 1940, the British Purchasing Commission approached J.H. "Dutch: Kindelberger, President of North American Aviation with a proposal to produce Curtis P-40 War Hawks, under license, for Great Britain. North American's designers, Raymond Rice and Edgar Schmued, responded with a counter proposal that they produce instead a brand new airframe that used the same Allison engine employed by the P-40.
The British agreed, under the condition that the new prototype be ready in an unheard of 120 days. North American, who had never even produced a fighter before, designed, manufactured and flew the NA-73x (P-51) prototype in a truly amazing 102 days.
Despite revolutionary features like a laminar flow wing, an under the fuselage radiator that provided additional "thrust" and a slick, aerodynamic shape, the early P-51A models were hampered by the poor high altitude performance and the mediocre top speed of the original Allison engine. Although good low level attack planes, they did not attract much interest on either side of the Atlantic.
All that changed when the British decided to test a Rolls Royce Merlin engine (used in the Spitfire) in a Mustang air frame. The rest, as they say, is history. Top speed leaped past 400 mph and high altitude performance was a revelation. The result was the P-51B, followed by re P-51C, both of which featured a Packard built Merlin and the flush patterned cage style canopy.
The definitive wartime Mustang was the P-51-D, which introduced a new clear "bubble top" canopy (inspired by the British "Malcom Bubble") that offered an outstanding field of vision and a new 85 gallon fuel tank located behind the pilot's seat. The latter innovation was critical to the Mustang's success as a long range bomber escort fighter because it could now fly all the way from England to Berlin and back -- something no other fighter could do at the time. It also meant that P-51's could roam far into enemy territory as a fighter/bomber to attack roads, air fields, rail lines, depots and communications to cripple the oppositions ability to respond
It was the Mustang's ability to place at or near the top in so many categories that made it an outstanding aircraft and a leading candidate for Best All Around Fighter of World War II: It was among the fastest piston engine planes of the war; it had an outstandingly high Mach number and strong construction so it could out dive opponents; it had a very good roll rate and could use it's "combat flaps" to turn inside many opponents; the P-51's great range meant it could fly farther and loiter longer in the battle zone than it's opponents,
It's six 50 caliber machine guns packed plenty of punch and the Mustang's rugged frame could absorb an unusual amount of damage. Though not "easy' to fly and requiring that the pilot pay attention, the Mustang was predictable, with good stall characteristics and was without any really nasty habits.
About the only short coming of the P-51D was it's relatively heavy weight, which made it only a mediocre climber up to 20,000'. That deficiency would have been more of a draw back in an "Interceptor" than in the roles the Mustang was designed for, and that fault was corrected in the light weight P-51H, which was produced too late in the War to see action. Ironically, it was the World War II work horse, the P-51D, not the newer "H" model, that saw heavy action in Korea because of an abundance of spare parts.
Here's the Daddy (A TF51 actually, so you can actually get to fly this too

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