I don't know about PP's background but I'm making this up and learning as I go. The aerodynamics of what makes our toys fly has always fascinated me so I've tried to learn as much as I could. This forum has provided a light year jump ahead thanks to the sticky problems and sharing thoughts with some of the minds around here. If I'm ahead of some of you then it's only because I cheated and jumped the start....

But I totally agree that the radio is suspect until proven innocent. If I had seen the model fly I may have a different opinion but since we are doing this over the net nothing is obvious or can be dismissed regardless of what we think. And then there's the chance that we are fighting two problems here. The model may indeed have a stall/snap problem that's just brought on by the radio glitching thanks to an intermittent problem.

Thud Driver. If the model was prone to this problem and he bank and added a little elevator and it glitched to full up in response that would certainly trigger a very nasty snap thanks to the trim I suspect. Or it may have been just plain ol' nasty like that damn Piper Cub from Hell was to me.

But then I don't like the sound of that tail end sorta wandering around. Sounds like it was responding to something other than dihedral. DR, dihedral doesn't make a model do that sort of stuff. But a hunting tail speaks to me of Dutch Roll and very nasty snap possibilities related to that. Dutch Roll is a sign of too little vertical tail area coupled with short moments and too much dihedral. Dutch Roll can also be aggravated into the sort of nonsense that your model is being accused of. AND..... <drum roll-cymbal crash> Dutch Roll is also aggravated by a nose heavy condition in the free flight models where I'm used to seeing it.

I think I'm starting to see a pattern here..... and it's not plaid....

As Thud Driver said it's probably not any of the individual item by itself but add 'em all together and you have a busted model.