The below setup allows to totally forget about switching timers and provides accurate air time information at the end of a flight or the day.
All you need is two triggers to tell OpenTX when to activate (On) and when to deactivate (Off) the timer. Many triggers are imaginable. I used the following for my pure gliders:
On Trigger: Moving rudder and aileron at the same time in any direction
Off Trigger: Vertical speed (TELEx:VSpd) is very small for at least 10 seconds
The off trigger only works if you have a receiver with vario (e.g. G-RX8 / G-RX6) or a separate vario attached to your receiver.
L25 is active if the rudder stick moves at the same time than…
L26 … the aileron stick
L27 is the actual timer switch. It is active (Sticky) if L25 is true. It is deactivated if L29 is true.
L 28 checks if vertical speed is under a certain threshold. VSpd < 0.3m/s works for me.
L29 is active if L28 is true for at least 10 seconds
L27 triggers those timers you want to be running
Special Function (Optional)
Mostly self-explanatory. Just a couple of special functions to announce timers being “on” or “off” and the optional switch to reset timer 1. I keep Timer 2 running to sum up the day and reset Timer 1 after each flight (if I don’t forget).