Originally Posted by BrightGarden

My limited knowledge / experience of oil contents in different fuels - definitely depends on what materials your engine is made from, how wear resistant it is, how it is designed. Iron vs steel pistons/sleeves/cylinders, etc. Since getting back in the hobby about 2 years ago, I have been awed by the sheer tenacity of castor oil. It simply does not break down, getting spit out the exhaust about how it went in. I am pretty awed by this comound being produced naturally in nature. I don't think the petroleum based lubricants are as thick (viscous) and perhaps cannot stand up to the heat / oxidation of combustion. The high viscosity may create drag on the engine to limit RPM's (?) Living near Old Rhinebeck Aerodrome, it has been on my mind to ask about what fuel recipe they are using for their radials / rotaries up there. Wondering if they go through gobs of castor oil or if they use synth / modern compounds.