The US Marine Corp has always provided it’s ground troops with superior support from Marine aircraft. As such they were constantly looking for improvements in those aircraft. Although they were pleased with the performance of all versions of the Corsair in the Korean close support combat they pressed Vought for an attack version of the airplane that would incorporate the lessons being learned from that combat. The F4U-6 (later to designated the AU-1) was Vought’s answer. Employing anly a single stage supercharger, which reflected the “in the mud” nature of the mission, the AU-1 featured extensive added armor plate and many other changes to improve the combat survivability.

The AU-1’s joined six other models of the Corsair engaged in the Korean fighting:  F4U-4, F4U-4B, F4U-5, F4U-5N, F4U-5P and F4U-5NL.

Marine pilots received the last of the AU-1’s in the summer of 1952.

After Korea, the French Navy used 69 of these planes in campaigns in Indochina and Africa.