Really depends on a few factors. If you are scaling it out with lots of bell and whistles (i.e. weight) than you may want to consider something larger. Mine was built light with monocote, non-retractable tailwheel and flew just fine with a Moki 2.10 which is similar in displacement to the BGX 1. It had plenty of power and very few issues other than flooding out due to being inverted. I've seen these planes with 75cc gas engines in them that flew FAST!! You won't get that with a 35cc glow motor, but it will fly just fine.