Hi fellows: I just found this thread while reading a discussion concerning castor oil in glow fuel.
Since I am from the U-Control era having moved into RC some years ago, castor oil fuel is all
that I use then. When getting into RC, my impression of the oil debate was what oil to use in
4 stroke engines. It became my thought that since I had no reason to purchase any 4 stroke
engines, there was no reason to change from Sig 20% all castor fuels. When purchasing an
ASP .75 engine in 1998, there was a slip of paper in the engine manual that suggested adding
3 ounces of castor oil to a gallon of my fuel to extend the life of the engine. Well, the 5% nitro all castor fuel I was using really well oiled this .75 during the break-in run, and all of my other
2 c engines. Now as to the clean up of the plane, I believe we all love to caress our autos when
washing and polishing them, well, isn't it great to caress a model that has safely flown all day
for you? Well, as the weather turned cold, the high oil content and low nitro began to make
my engines to sage somewhat; so, went to 10% nitro 20% castor plus only one more added
ounce of Sig Castor oil. Now I have great flights with a nice smoke trail from the muffler, and
know if some how the engine should run lean it will not be destroyed by the time the plane lands. Everyone has to make their own choice as to the type and oil content they are willing to fly with. In my case, I chose to think my engines are of the old Fox .35 variety, and enjoy
caressing the plane for cleaning when the flying is done. If I ever become the owner of
a 4 stroke, I will follow the mfg's recommendations on fuel and oil type to use.

May you all have great flying with no engine problems.

Rich S.