I had a toggle switch mounted on the side of the model and a single 2400mah sub C installed inside the airplane.
I flip the switch to start the engine and leave it on during the entire flight; never a flameout and what a beautiful idle!
The 2400mah battery is good for about 40 min of flight. Use a bigger batt if you want more time.
Other fellows have used a servo operated switch for starting and TO and landings.

Used this for about a year with no plug burnout (type F 4-cycle plug)

feihu