ORIGINAL: Pat Roy
Either method works. If the carb linkage is properly adjusted the engine can be killed with the throttle trim on the transmitter, just like a glow engine. Then you simply turn off the ignition switch by hand.
Why is it when people fly glow engines of any size there is no choke servo, optical cut offs, or other extra kill switches but the moment they go to gas there has to be upteen different methods of stopping the engine? Does adjusting the throttle linkage to shut off fuel to the carb limited to glow engines????
Pat,
The only reason I see fit to have a redundant throttle cut-off system is for personal safety concerns. I could not find neither IMAC or AMA regulations that requires a redundant engine kill system (AMA only requires it for Experimental over 55lb. aircrafts).
Some folks don't remove the throttle return spring so if the servo linkage breaks the throttle returns to idle, and if you have removed the idle adjustment screw the engine shuts off. That should be sufficient to satisfy any safety concern. Choke servo actuations is primarily a convenience choice.
Now, this doesn't solve the problem if the servo gets stuck in full throttle. Myself I like to remove the throttle return spring to unload the servo working against the spring pressure, and install a choke servo just for convenience (easy on/off from transmitter) and remove the idle screw so I can shut down the engine with the throttle trim (or transmitter kill switch ) if I need to. That gives me a redundant system, but as you say that's not required or necessary.