Some people refer to all types of fuel burning engines as gas engines. They are technically correct. But that doesn't clear up what you are looking for, or at least it doesn't to me.

I would never say that Magnum engines are as good as OS engines. I do say that sometimes they are "good enough" for our uses and that there may not be a benefit in spending more money for an OS engine when it is likely that the difference will not be perceived. Clear as mud?

A 1.40 (23cc) to 1.60 (26cc) gasoline/oil (petrol) engine such as the RCS/Moki 1.40 and the MVVS 1.60 gasoline/oil (petrol) engines would provide excellent power for the Joss Stick, if you are looking to escape the high price of glow fuel. I would not use a heavier engine than either of these engines.

A Magnum .61 - 1.20 two-stroke, or .91 - 1.20 four-stroke engine (all glow engines), would pull the Joss Stick with gusto and then some. I have heard from several people that the model even flies well with a .61 two-stroke.