Chance Vought's F4U-4 came about as a development of the F4U-4XA, which was first flown in early April 1944. It was fitted with an up-rated Pratt & Whitney R2800-18W or -42W engine. This powerplant developed 2,450 bhp with water injection. It was also fitted with a four blade hydromatic propeller which provided the necessary efficiency to utilize the greater power. The carburetor inlet was moved from the wing root leading edge to a duct located under the engine. The exhaust stacks had to be re-routed as a result. Armament remained the same as the F4U-1, with six .50 caliber Browning MGs. The limited production F4U-4B was armed with four M3 20mm cannon. Under-wing load capability was substantial. Up to three 1,000 lb. bombs along with eight 5 inch rockets could be carried. Reportedly, it was not unusual to rig the F4U-4 with as much as 6,000 lbs of ordnance. Apparently the robust structure of the Corsair could bear these loads without undue wear and tear on the airframe. Almost certainly, such overloaded Corsairs did not operate from carrier decks, but exclusively from shore bases. Maximum speed:
F4U-4: 446 mph @ 26,200 ft. | 
