The P-40Q was an experimental project Which Attempted to produce a really modern fighter out of the existing P-40. The Modifications were in FACT That Drastic so there was very little in common with P-40 Earlier versions. Two P-40pcs (serial numbers 42-9987 and 42-45722) and one P-40N (serial number 43-24571) were extensively modified with revised cooling systems, two-stage Superchargers, and structural changes Which Their markedly altered appearance. The project was Assigned the designation XP-40Q. The XP-40Q was built three times. In its final form, with a shallow chin air scoop, clipped wings and a bubble canopy, the Curtiss fighter's appearance was somewhat reminiscent of a P-51D Mustang. The XP-40Q, as the new version was redesignated, was the fastest of the Warhawks. Unfortunately, by the time the XP-40Q was built, the more capable P-51D was already available in large numbers. Only three were built, and only one was Evaluated and rejected by the USAAF.