DESIGN, DEVELOPMENT AND EVALUATION OF A CRASH-RESISTANT FUEL SYSTEM INSTALLATION.
ALL AMERICAN ENGINEERING CO WILMINGTON DEL
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A crash-resistant fuel system, utilizing high-strength bladder fuel cells, breakaway fittings, crash-load-actuated shut-off valves, and fiber glass protective liners, was designed and installed in the center section of a DC-7 aircraft wing. The wing was mounted on a wheeled dolly. A jet-propelled car was used to accelerate the wing and dolly to predetermined velocities prior to engaging a decelerator. The decelerator, especially designed for this project, imposed controlled decelerations on the wing ranging from 2 gs to 21 gs 28-g fuel equivalent. There were no failures in either standard or crash-resistant fuel CRF system fuel cells and no inadvertent valve closures in the CRF system during the tests. Hydraulic loads were nominal and were not additive from one cell to another through interconnections. A final destructive test was conducted wherein the wing, at a velocity of 77 knots, engaged two stationary vertical poles, positioned to shear the wing panels at the outboard nacelles. It was demonstrated that, with a more positive means of triggering shut-off valves, the CRF system has a potential for greater chances of fuel containment, with consequent less fire hazard, in case of survivable crashes. The CRF system, as installed in a DC-7, imposes a penalty of 6.97 fuel volume loss for a range loss of 7.6, although it results in a weight decrease of about 1200 pounds. Author