"INTRODUCTION During the past few years@ there have been Incidents with aviation gas turbine engines in which the Standard ASTM Designation Test 0892-63 did not correlate properly with engine experience relative to oil aeration or foaming tendencies. It was desired to develop a dynamic test with parameters which simulated the air entrainment and foaming conditions of a modern aircraft gas turbine engine. Participants on the Sub-Panel had developed dynamic testers for their own particular use and volunteered to evaluate three synthetic gas turbine lubricants. The lubricants selected were identified as RAO-19-67@ RAO-20-67@ and RAO-27-70@ and represented a low foam@ high foam@ and medium to marginal foam lubricant@ respectively. These oils were selected from previous dynamic foam tests and were not related to engine service experience. ASTM Method D892-72 - ""Foaming Characteristics of Lubricating Oils@"" is a specification test for aviation oils."
API 4234-1974 history
1974API 4234-1974 AN INVESTIGATION OF THREE SYNTHETIC GAS TURBINE LIBRICANTS FOR OIL AERATION AND FOAMING TENDENCIES