RECENT DEVELOPMENTS IN AIRCRAFT ENGINE OIL FILTRATION

The following is a shortened version of a paper presented by Griffith May of Screen Products Inc. at the SAE Annual Meeting at Detroit in January. Until 1949 oil‐in filters were of the cylindrical wire cloth strainer type and their life before blocking did not exceed 20 hours. A significant advance was made with the sequence stack filter which enabled finer screens to be used and increased operating intervals from 3 to 5 times. The author describes the disadvantages of early sequence stack designs and discusses the newer type of composite element stack oil‐in filter which has given good results for scavenge oil systems in flight tests and is also being used on gas turbine engines.