Battery into switch
Switch into Rx
Opto-Kill switch leg into LG channel (5)
Opto-Kill input into any Rx spare channel port
Opto-kill output to ignition with one 1N4007 diode spliced into the + lead

Thesingle switch turns on both the Rx and ignition at the same time. This method provides 1 manual and 3 remote means of shutting down the engine.

1) Turn off power switch on plane, shuts off everything.
2) Turn off ignition power with programmed switch on Tx.
3) Programmed throttle kill shuts off engine...NEVER leave home without it.
4) Turn off Tx, Opto-Kill turns off ignition with loss of signal and throttle kill activated as a programmed failsafe.

You could add a 5th if you install a choke servo, if you use 4 cellNicador Nimhbatteries for the Rx you don't need any diodes but I don't recommend 4 cell power suppliesfor anything but ignitionsor small glow powered planes.

I use the 42% Products Opto-Kill.