RE: What would a gas engine be compared to a glow
1.80 4-stoke =~ 30cc
1.20 4-stoke =~ 20cc (I have run both in the same plane and found the power to be the same (Saito 120, RCGF 20cc))
3.2 2-st gas =~ 50cc
Rough estimations I use, (10cc =~ .60ci).
Edwin