Thanks Ed, I guess I shouldn't give up on the foaming theory until I test it with a couple guys holding the wingtips like you say. Luckily I made a removable hatch under the tank so we should be able to observe what's going on. The tank in it now is 12 oz., it's one of those Sullivan slant/oval tanks that's like a hip flask on it's side, tall and narrow. The plane currently has no spinner on it and the 3-blade prop is balanced. I've moved away from the foaming theory after installing the foam and the felt clunk, they made absolutely no difference and you would think that if foaming were really the problem, those changes would make a slight difference at least. I'm starting to think it may be more along the lines of a bad receiver or antenna routing, I'm going to put a different receiver in it tonight and hopefully try it again tomorrow. There's definitely something going on with the elevator at the same time the engine is going to idle, on my last test flight I was chopping the throttle on purpose and didn't have any of the ballooning like I get when it "glitches." Plus it pitched up like that once while I was on approach with the engine already at idle. I think I have an electronics problem somewhere. I just wish it would show up on the ground so I could troubleshoot it without having to fly it!

I really appreciate your thoughts and suggestions, it's a big help!

Dan