The F6F was equipped with three internal tanks: a left and right tank each carrying 87.5 gallons, and a reserve tank with a capacity of 75 gallons. In addition a droppable belly tank of 150 gallon capacity was added to all F6F's. This provided a total of 400 gallons, or roughly 2400 pounds of fuel. Depending upon the power setting, the engine consumed a minimum of 60 gallons, to a maximum of 270 gallons per hour. Therefore, the plane could remain airborne from a minimum of approximately 1.5 hours to a maximum of 6.8 hours.

 

Original Fighter Doctrine had been to jettison the belly tank upon entering combat, or when the tank was empty. Later it became evident that the difference in performance of the plane, with or without the empty belly tank, was negligible. So belly tanks were to be retained. This certainly helped logistics aboard the carriers, because obtaining and storing a sufficient number of tanks for replacement after each flight was a nightmare.

 

Start, warm up, take off, and the first few minutes of flight was accomplished utilizing the right internal tank. As air pressure changed with altitude, equalization of tank pressure would cause some fuel to be pumped overboard from all tanks. The F6F fuel system was fitted with a bleed system that directed this excess fuel into the right internal tank. Operating on the right internal tank for the first few minutes provided space for storage and conservation of this fuel.

 

After 30-40 minutes of flight, the fuel selector would be switched to the belly tank. The belly tank had no quantity indicator, so the pilot had to note the time use began, and mentally calculate when the tank would run dry. As the time approached for the tank to run dry, the pilot had to keep an eye on the fuel pressure gage. As pressure began to drop, the pilot would switch tanks. Timing was very critical. If the pilot failed to note the pressure drop, the engine would quit when the pressure reached zero. Without power, the propeller would windmill until the engine received new gas and began to fire. Not only did this cause a pilot to drop out of formation, but also sometimes an air lock formed resulting in a delayed or difficult engine restart.