SJN

Thanks for all the very good comments guys.
I still have some time to make up my mind until my next project is done.

I do not know the cause of the failsafe.
Im pretty sure that the plane still had power. I had 2 batt wires from the same battery going into the RX First flight of the day, and the Batt pack was just fully recharged. The plane was at very high speed in a bank, so the elevon servos where deflected quite a bit. Im sure if I had a power loss, that the control surfaces would have been pushed to neutral, or at leeast moved a tiny bit and the plane would have reacted to that.... But it just kept its final track, and the engine shut off.

We where only 2 pilots at the flightline that mornig, so its unlikely that someone shot me down.