It depends on the timer I imagine. I use the FM9
on mine, I set the delay time and the flight time.
The delay time establishs the amount of time to get to the handle, the flight time is spool up and fly the pattern.
SO it goes like this, arm the battery,, signal the judges, push the button, ( on my setup I have a 25 second delay set typically)
at the button push the prop spins a partial revolution letting you know that you have triggered the system.
saunter confidently to the handle, prepart,, after the 25 seconds transpires the motor begins the timed run ( 5:10 minutes)
FLy the pattern,, at 5" 05 the motor sags for a second to warn you . At 5:10 it stops and you land...
HOpe that sheds some light,,