A New Laboratory Method of Evaluating Ring-Sticking Tendencies of Aircraft Oils
CONTINUOUS increase in the power output of aircraft engines introduces from time to time lubricating problems including excessive wear and scuffing, excessive oxidation of the oil, and ring sticking. The one problem of ring sticking was chosen and the discussion is limited to the testing of lubricating oils to compare their abilities to prevent this type of failure. Although the best answer as to the ring-sticking tendencies of a lubricant rests with the full-scale engine in service, a simple test is needed during the development period. The development work which led up to the selection of an L-head CFR engine for a ring-sticking test is discussed. Various criteria used for detecting incipient ring sticking are mentioned and a method for direct measurement of incipient ring sticking is described.