ABSTRACT
Ester base oil lubricants for aviation and aviation derivative engines consist of a mix of ester molecules to obtain the properties required to meet specifications. The 5 cSt MIL-PRF-23699 remains the mainstay of aviation engines, both military and commercial. These lubricants are based on a mix of even and odd numbered polyol ester molecules to obtain the desired properties. The first United States (US) specification for a 3 cSt and 4 cSt diester-based lubricant was MIL-L-7808A in 1950, which has been revised eleven times and is currently known as MIL-PRF-7808L. The first US specification for a 5 cSt neopentyl polyol ester-based lubricant was MIL-L-23699A in 1960 which has been revised six times and is currently known as MIL-PRF-23699G. The shift from US government control of the gas turbine oil specifications towards the SAE AS5780 specification provided an opportunity to introduce additional quality and safety regulations, as was the objective of the aviation safety authorities that promoted this effort.
