The greatest American fighter of World War II exists because the British Purchasing Commission came to North American Aviation in 1940 asking for license-built Curtiss P-40s. Company president Dutch Kindelberger refused and promised a superior new fighter in the same time it would take to tool up for the P-40. Edgar Schmued's team rolled out the NA-73X prototype in 102 days, packing in a laminar flow wing developed with NACA and a belly radiator that exploited the Meredith effect to turn engine heat into thrust that cancelled its own drag.

This episode follows the Mustang's serendipitous life: the Allison V-1710's single-stage supercharger that left it gasping above 15,000 feet, Rolls-Royce test pilot Ronald Harker's April 1942 proposal to fit the two-stage Merlin 61 and push top speed past 440 mph at 28,000 feet, the 85-gallon fuselage tan ...