You're really better off with an optical kill. If the battery dies in the reciever the ignition will shut down. There's no way flying a gas plane I would want the motor running if the receiver battery dies or the radio goes into failsafe.

Also, if our linkage has a problem or the servo dies from vibration you can still kill the engine.

We used to listen to high quality 8 tracks, personally I prefer the sound and picture of a Blu-Ray, because its available to me, its cheap, and its better than some of the time honored way of doing things. Not that they dont work, but this really is better in almost every aspect.