RE: 86cc engine with 18 pound plane?
My wing loading is more in the 32 oz area and the plane still flies great in 3D. I made larger tail surfaces and this thing has by far the strongest control authority I have ever seen. The plane is short so I think that the main reason of that, along with bigger surfaces.
I often get asked what the weight of the plane is and usually, people are surprised to see that its that heavy with such a small wing.