I wouldn't recommend the 80, personally, I don't think its enough engine. I have a YS91AC in mine. One word - awesome!

Have you considered the Saito 100? I hear lots of good things about it, and have seen several first hand - but I don't own one.

You will want plenty of engine in your Chipper. Although I am partial to 4-strokes, I like the idea posted above about the .91 2-stroke.

Good luck, you are going to absolutely love this plane...