If you want to use a brushless motor you'll need a speed controller --
brushless motors need some electronics provide the commutation that
brushes provide on a brushed motor. Even with a brushed motor it's a
good idea to have a speed controller that'll limit current in the event
that the motor gets stalled -- a hard landing that stops the prop is
much less severe than a hard landing that stops the prop, ruins the
motor, and possibly makes the batteries burst into flame.
As the other responder noted, there are timers for control line use. I
don't know who carries them. If you're in the US (or not) a check on
Brodak's website, or a call, may get you an answer.