Well, after several months of not using the AT6, I have to admit that it doesn't do a flat spin very well. It does rotate around it's central axis, but the spiral is not very flat and I can't cross control more than say 25% before it flops out. Bummer, I thought it was better than that.

I have increased the size to about 96 inch wing span, set the CG at negative .3 inches, and am using a Supertiger 4500 engine. Oh well,........