What I do is:

1. Wrap the battery/receiver in foam.

2. Completely cover the foam (except for the ends) with a minimum of 2 layers of masking tape. Do not pull the masking tape tight or you will lose the effectiveness of the foam.

3. In the general area where you will be putting the battery/receiver make sure there is a sheet of 3/32" - 1/8" balsa.

4. Use self adhesive INDUSTRIAL STRENGTH VELCRO. Fasten one piece to the bottom of the battery/receiver (the built in adhesive will hold quite well to the masking tape ). LIGHTLY attach the other half of the velcro to the part on the battery/receiver. Remove the backing on the 2nd piece and position in place.

5. Move the battery/receiver around as needed until you achieve the balance you want.

6. Once you have found the location for the battery/receiver, VERY GENTLY press the battery/receiver down to LIGHTLY adhere the adhesive on the velcro. This is the tricky/fun part. You do not want to "lock" the 2 pieces of velcro together, just have the 2nd piece adhere. Now, using the tip of a #11 blade, hold the piece of velcro attached to the balsa in place while you remove the battery/receiver.

7. This is the key part. Once the battery/receiver has been removed, firmly press the other piece of velcro in place, the go around the edges with some thin CA. My experiences have shown that without the CA, the piece attached to the balsa will loosen and come off in a couple of months (I presume air getting to the adhesive through graining of the wood).

8. When the CA is dry, firmly press the battery/receiver in place.

This will hold everything in position even through a "lawn dart" (don't ask about that ), yet allow easy access/removal if needed, or changing of CG location if desired (just add some additional velcro pieces to the balsa if needed ).

This sounds complicated, but it really isn't.