I was fortunate in my first radio was a Heathkit digital proportional 2 stick 3 channel with the Heathkit version of the KPS-9 servos. It was the last of a discontinued model with individual sticks for rudder and elevator with a tab on the back behind the elevator stick controlling the throttle. It had been replaced by the new 3 and 4 channel single stick radios were out with the smaller KPS-10 servos. I remember it cost $125 with the third servo. I built for a high school electronic course and got an "A" for the project. My first airplane was a Goldberg Skylane covered with Silkspan and painted with one ver thin coat of white Pactra dope.powered by an OS Max .20 R/C. I would graduate 3 years later spending my tax refund of $235 for a Kraft series 70 radio the previous owner had bought but never used. It was hot stuff back then.