Oh, I forgot about cars. I used to race 1/8th nitro on road some time ago. Those were a blast although high maintenance.

As for rockets, an interest in rocketry when I was young developed into RC when a leader in my club built a rc shuttle as a glider with rocket motors in the boosters that launched it. The ejection charge on the motors caused the boosters to separate from the shuttle body. It was all scratch built and quite a sight. The launch was very hit and miss from memory.

Regards,
Garrett