I think that if you can get the plane to 11.5 pounds or less, it would be awesome. The only problem is that most of the post I have seen shey are showing the bare plane out of the box at a touch over 7 pounds. You add 2 pounds for the 180 and that only leaves a pound and a half for servos, reciever and batteries, not to mention a full tank of fuel. The 180 will fly it. Heck at a lower elevation it wil probably even hover it (this engine with 18x6 APC makes 19 pounds of thrust), but you wont have alot of pullout authority. The plane would fly really nice and light though. I think at 15 pounds, which I think is attainable, the plane would fly pretty darn good with a 50cc engine. Lest just see how poeple like it with the 50cc engine before we "assume' that it is not gonna fly good with one. I mean I love the way it looks and it may make an alternate to the 50cc EF Yak since you cant get one of those.