RE: .30 or smaller 4 stroke engine?
I agree with Red, those little four strokes are great fun and they make very useful power on 10 inch props. The sound is so appealing that it makes the whole flying experience more enjoyable. I swear they make me fly better because they have such a calming effect.
That TF DC-3 flying on 26s is just awesome and I'm sure it is much more realistic in flight than heavier versions with usual larger engines.
Jim