Hi Harry,

Most of us use this:

http://www.smart-fly.com/Products/Ignition/ignition.htm

There is a how-to here on RCU for installing it. Total weight is something like one-half ounce and really simple to use and allows you to kill the engine in the air. If all power is lost to the receiver than it kills the ignition.

http://www.rcuniverse.com/magazine/a...article_id=375