Very first was a plastic Testor's Cosmic Wind Christmas present. My parents live across the street from a huge park in Long Beach so I put gallons though it. Eventually tried to stunt it. Glued it back together and tried again. It never did stunt but it flew and flew until it was mostly glue.
First built-up was a Carl Goldberg Lil Wizard with a Cox Babe Bee 049 scavenged from a Cox Shrike prop rod. Put more gallons through that one. Didn't stunt very well (tended to flame out inverted) until I put a Cox Black Widow on it, then it stunted like crazy. Flew it a couple of years until it was nothing but fuel-soaked mush.
Ah those were the days...
Paul W.