I just finished making a sonic combat module which can be used on all electric planes, and glow planes (if they are not too loud). It is designed by Mr. RC-Cam. I don't think the design is public yet. It uses a sonic combat module from the Figther bird. It takes about 10 small electronic parts to complete. It also requires some computer programing. But, he provides that. If you hurry, he may have some pre-programed chips available. Otherwise, you will have to find a way to program a PIC chip.

The system is awsome. It does not completely cut the throttle on a hit. It stutters the motor as if it were having motor problems. It can use the throttle channel or any extra channel to activate. It has an LED which counts hits. It can also act as a lost plane locator. Each unit costs under $30 complete.

Here is the link from Ezone.
http://www.rcgroups.com/forums/showt...5&pagenumber=1

I am actually going to use this to do combat with my son. He has a Firebird XL. It has a hidden module jack in the same location as the Fighterbird. Just cut a small hole in the fuselage. You will find it.