I have a couple of Midwest Sniffer free-flight airplane kits in the storage unit. I built one of these as a teen, and it’s a great flyer.
The Sniffer has a ‘dethermaliser’. The front of the tail surfaces is held to the fuselage, which acts like a hinge, by a rubber band and may tilt upward. The trailing edge and the end of the fuselage have wire hooks. A metal tube on the fuselage holds a fuze that passes between the strands of the rubber band that holds the hooks together, and keeps the tail surfaces from tilting upward. If you’ve cut the fuze to the right length, the lit fuze will break the rubber band just after the Cox .020 engine runs out of fuel. The horizontal stab tilts up and causes the model to stall so that it doesn’t climb away in a thermal and get lost. I lived in the desert at the time, so I never lost my airplane – though I did have to ride my Enduro to retrieve it.
Nowadays r/c gear is cheap and tiny. Cox engines have ceased to be, and people use electric motors. But what about back then? What about people who want to fly gas-powered free-flight planes now? Not everyone lives in a desert or farmland. Where did, or do, people fly?