My first trainer was a cox 'centurion w QRC .049' engine and 2ch sanwa radio back in the later 70's, fun stuff, first flight lasted a whole 4 seconds which was the time it took to fly into the one tree in the whole area...a bit of epoxy and it was going again. repeat that scene a few times and you'll know why I don't have that plane anymore!  First really successful plane was a Goldberg Eaglet w/ enja .19.   I keep 1 or 2 trainers in my trailer because I'm always training newbies, I let them get flight time on my planes then take-off my plane and once they can line up w/ runway I let them land my planes, needless to say then I have lots of kids show up when I'm flying and I also get to do a bit fixing every 1-2 wks for our 3wkends per month of flying.