I have a Curare and QuickFli III, both built in the 1970's that are both flown several times a year. The Curare still has the original OS .60 but the QF has a new OS in it. Both are fun to fly and seem to fly better every day. A fun airplane from those days is the Mach 1. It had a thin airfoil and nicely tapered wings. I went through 4 due to various malfunctions but the Curare and QuickFli kept motoring on. They have been through a lot of radio gear until I finally got the Futaba 8U system.