I have an LT-40 with a Saito 56 in the nose. It fly's it beautifully. I am teaching my kids to fly with it now.

I agree that if someone asked me what kind of engine to put in an LT-40 for 1st plane use, I would not recommend a 4-stroke. I would probably recommend a Thunder Tiger 46Pro. Nevertheless, if someone really wants to start out with a 4-stroke, that's great. The Saito 56 is a great choice.

Remember, it's all about having fun.