The sound of the Cox .049 Glow-plug engine was the background music of my childhood! It was a great day when I discovered you could buy a spring-starter and thus save hundreds of lacerated index fingers. The smell of the castor-oil fuel burning, the high buzzing of the engine, the smell and feel of the grass you were knelling in in your brown corderoy pants, the taste of the smoke, the U-control lines waiting to pick-up the load as you whirled in a left-handed circle, trying not to crash your still tacky wet red-and-white painted "American Boy" balsa model, the sounds of the kids in the playground as a backdrop... THAT was a rare part of childhood that was bright and shiny and wonderful and all yours for an hour or so. Kind of like the TZ episode, "Walking Distance."
With the Cox .049, flying became my life's work and passion.
Yep, I remember the city park near home had a circular concrete runway with a round concrete pad in the center, where you stood spinning in a circle. The entire area was surrounded by hedges over 20 feet tall. Very cool.
Unfortunately, interest in control-line models waned in the '70s and '80s and that flight area was torn up and became part of a golf driving range.
BTW, that "American Boy" model is available at the link in #3 above. Looks like a total of $100 or so for the kit, engine and all the bits and pieces. Seems pretty inexpensive for a glimpse back into childhood.