I have seen some of the larger electric powered CL models and they are using the following parts. I assume you plan on using a brushless motor with a Lipo battery.
brushless motor
speed control
Lipo battery
Zigras timer
You need the zigras timer to start the motor and then shut it off after a predetermined time.
http://www.windyurtnowski.com/#ztron
The electric stunt examples I have seen have been the larger models but the same priciple should apply to the 1/2a electric motor.