RE: Weston uk & Cool Power 15% ?
Yes, castor oil = rizinus...
I run mostly all synthetic fuel (Aerosave homebrew and Wildcat helimix) in all my engines, but I noticed that for the high revving engines the oil is too "thick" and produces drag. This means good protection of course, but also less power. Castor becomes very thin when heated in the engine, so it produces less drag, which in turn means more power.