Hey, I still have my Cox 049 engine somewhere. The airplane is gone, smashed up of course. I suppose it was dangerous by modern standards, but not at the time. About the worst it would do would cut your finger if it backfired when starting. Or you could use a cheater stick, or even an electric motor to start it. I once made a car for it out of piano wire. It would take off at high speed down the road, but because I n…
Hm. I don't think "wheels aligned perfectly straight" is the actual solution. I wonder if there's some simple mechanism by which it could be made directionally stable, in the sense of continuously adjusting itself to go forward instead of turn.