I have been flying electric, but recently removed Mega brushless and installed OS .15 into my Piper Cub. First flight great, but I am not sure I have the throttle set up correctly.

Full up channel 3 and the throttle is wide open.
Full down channel 3 and the throttle is fully closed.
To keep the plane flying and to avoid dead stick I used channel 3 trim to 80% up.
To kill the engine after landing I quickly lower the digital trim to 40% or so and this kills the engine.

The first question I was asked at the field was if the radio has a "kill switch" and as far as I can tell it does not.

Is this true? I am assuming a kill switch over-rides the trim and closes the throttle immediately.

I have studied the manual and it appears as though throttle cannot be assigned to one of the switches.

Any help appreciated.