Well, somehow I doubt that the RADIO blew up.... Must have been the fuel system!

I did see a completely unexplained one happen to a friend of my brother's at a field in California once. His biplane just quit responding, and started doing big lazy circles in the air. It was very slowly climbing, and drifting with the wind. He just suddenly had no response from his radio at all. We watched it in amazement for a long time. People even had time to go to their cars and get their radios to see if they could get control of it. No deal. It just finally drifted out of sight. It was never found. The only thing I could think of was the battery disconnected or the switch failed. But it was rather amazing that it, being a biplane, was stable enough to keep flying by itself for so long without falling off into a spiral and crashing!

AV8TOR