ORIGINAL: f650
If metal to metal contact friction causes radio interference then why do all RC things with a internal combustion engines not have problems with interference as the biggest metal on metal friction is the piston,cylinder and crank?
In every fuel/air engine there is a very very thin film of oil between all items in the engine. The only real time you get metal to metal is running it lean. If there was no film of oil, your engine would not last long.
In the gas engine (not nitro) part of this hobby, it's more important to keep everything connected to the receiver as far away as possbile from the engine and electronic ignition if it has one.
Glow engines are self supporting so they need no outside ignition source so the distance between it and the receiver does not need to be as far as gas.