Nonflammable Fluid and 8,000 psi Technology for Future Aircraft Hydraulic Systems (22 CFR 125.4 (b) (13) Applicable)

In the Middle 1970's, the Air Force identified significant damage and losses due to noncombat hydraulic fluid fires. As a result of these fires, a search for a nonflammable hydraulic fluid for use in new aircraft was initiated. A nonflammable fluid, (CHLOROTRIFLUOROETHYLENE, CTFE), was identified, however, its weight was over 2.2 times heavier than conventional fluid. This paper discusses the system design approaches, component design, and test results of an overall program to establish technology for use of this nonflammable fluid in new aircraft. This will include the tradeoff study results for selection of 8000 psi as the pressure level, design approaches to control water hammer pressures, component and system design and evaluation. The status of ongoing programs for investigating dynamic seals, pumps, and low energy consumption hydraulic concepts will also be presented.