Recollections of Vietnam
Getting assigned a corrosion control mission, though, meant several days in the "world" and it was a coveted prize. The trip consisted of two long overwater legs via Clark Air Base in the Philippines which were beyond the normal range of the Caribou. To increase the range of the Bou, some temporary modifications were made. First, a fuel manifold was installed in the cargo compartment and the cargo compartment was filled with rubber fuel bladders (we called them "blivets"). The deicing pumps were connected to pressurize the bladders with air and fuel line connections were made from the bladders to the wing tanks such that it was possible to transfer fuel in flight from the bladders to the tanks. Next, the engine oil dipsticks were removed and replaced with oil lines which lead to a hand pump on top of a 55 gallon oil drum in the cargo area. Once we loaded enough fuel and oil on board for the trip, the all-up weight of the machine was about 33,000 pounds - much more than its design maximum gross weight of 28,500 pounds. The technique for flying an overweight Bou was simple - take off with no flaps, use a very long runway, and hope for the best. Since we were over the weight at which one engine could sustain flight, our flight mechanic stood guard by the fuel bladders with a sharp fire ax during the takeoff and initial climb. The emergency procedure for an engine failure was to cut the fuel bladders open and let the gasoline spill out the back of the airplane, thus reducing weight. I'm glad I never had to try that procedure, I can't imagine what it must be like to flying an airplane which is spilling 115/145 avgas out of every seam.
Log book entries and notes on the trip