Maybe some details (really hate these secret projects and all the guessing), just spill it!
Are you using an existing R/C transmitter/receiver, or are you hoping to build the whole thing from salvaged parts and Radio Shaft? There are some simple on/off circuits that use the PWM signals from the receiver. Haven't looked in a couple of years, so no quick links today, just remember seeing them for lights, releasing a payload, lighting fireworks... Shouldn't be hard to find.