Sorry for your loss - that's hard to swallow, I know.

It may have been a TX issue. However, the pots went bad on my 12FG and when they did, they stayed bad. I sent it back to Futaba and they figured out that it was cold solder joints on the surface mount pots. Lots of guys with that radio I know have been sending them back to have the pots resoldered. I don't know if that has been an issue on the 14MZ or not.

Hind sight is 20/20 for sure, but as soon as you had the uncommanded roll in the loop on the flight, you should have put the airplane on the ground. I know there is a desire to try and figure out what is going on with the plane at that time, but as you saw, that didn't go too well. If you suspected the TX, then checkout flights (perhaps many) with a lesser plane would possibly helped nail it down. In addition, using someone else's TX to fly the Viper for awhile would have been a good test. Of course, after the flutter on the first flight, the second flight probably shouldn't have happened. If you were sure it was the rudder, then the rudder servo should have been replaced and the linkage modified to give more torque at the surface. I have never seen flutter occur that did not damage *something* in the control path and I'd bet that was the case here...

Bob