Originally Posted by
2W0EPI
This, to me makes sense because with ringless ABC engines, the entire piston contact area forms the seal. Also, with rc ringed hobby engines usually only one ring is used surely a double ring engine would make a better seal?
It’s a catch-22. Two rings will seal better, but at the expense of higher friction. This is why engines that were originally fitted with two rings from the factory are often replaced with a single reproduction iron ring that are rewarded with better power (the better the piston seal the better the power).