RE: Welcome to Club SAITO !
Sarge:
The gasoline two strokes are engineered a little differently from our ordinary glow engines.
The gas engines are usually weed-eater or chain saw engines, either converted or using the same type construction. What you see when you open one up is a roller bearing in the big end of the con rod, and often a roller bearing at the piston end as well. The roller bearings need much less oil than our plain or bushed rod bearings do.
Some model engines have been made with roller bearings in the con rod, and these engines run happily on a much lower oil content than normal glow fuels have. Just for one example, the Technopower radials have a maximum allowable oil content of 5%, and the maker recommends running them on 2% for best results.
Another factor in our model engines is cooling. The excess oil carries a lot of heat out of the cylinder This is largely down played by advocates of synthetic oil, as castor oil is much better at carrying the heat out, the synthetic tends to burn and add heat rather than taking it out.
Many glow engines could be converted to roller bearing, and afterwards would probably run well on the lower oil content, but you’d still have to be wary of overheating. Don’t try this on a Saito, they still have plain bearings on the cam shaft.
One thing in favor of lower oil content is the added flight time with the same size tank – cutting the oil from 20% to 10% would give you another 10% of fuel to burn.
Bill.