Actually, the full scale piper cub is a good trainer because it isn't really all that easy to fly. It is a low powered tail dragger that will still whip around and bite you if you get complacent. It's a good trainer because it forces the full size pilot to fly. Most Cub models make poor model trainers because they are not as stable as a purpose designed RC trainer. Gets frustrating on the student when the model is always ground looping.

MTC
MrT