What makes you think it was radio problems that caused it??? I have crashed two funtanas, ond 40 and one 90 due to mechanical/failure problems. One was my fault, apparently, the rudder failed to act as landing gear while inverted trying to see how low i could go, so that was the mechanical failed crah! haha The other, the 90 size, i fluttered an aileron off while at 1/4 throttle or so in level flight. Those planes are a handful to fly in the air with regards to throttle managment. Maybe yours had a similar fate?