Tribology testing for load carrying capacity of aircraft propulsion system lubricating oils

A tribology testing capability has been developed to provide a closer link between bench testing and performance in component hardware. The new test capability enables simulation of lubrication and failure mechanisms that control the life and durability of lubricated contacts in machine hardware. The key feature associated with simulation is the independent control of entraining velocity and sliding velocity. The Wedeven Associates, Inc. test machines (WAM) control the motions and forces of a single contact in 3-dimensional space. The machine software links the operator to the machine with tribologically meaningful parameters. The value of this approach is shown by test protocols developed for the evaluation of aircraft propulsion oils. The test protocol simulates the Ryder Gear Test Method, which is based on a scuffing performance criterion. The inclusion of traction (friction) measurements is found to reflect wear and a superficial form of scuffing (micro-scuffing). The test method illustrates the performance of U.S. Navy oils formulated for corrosion inhibition (CI). In addition to additive chemistry, the results show the chemical contribution of the base stock with respect to wear and scuffing resistance.