This is the electrical and radio section. I believe it is important to keep the radio receiver isolated from the servo circuits. There is an easy way to do this by using a product from ElectroDynamics called the EDR-111. Here is a direct link to an explanation of how this product isolates servos from the receiver. http://www.electrodynam.com/t111.htm  The "Y's" in the diagram below identify how many "Y" servo leads you need.

Here is a block diagram that I used to help myself understand how everything comes together electrically. I also installed all the 14 servos, the optical isolation unit, both batteries and switches on a large test board just to make sure everything would work together before putting any of it into the airframe.

I ended up mounting the receiver on the bottom side of a removable 1/8" plywood plate. I mounted the EDR-111 on the top side.

I use small wire clips from Radio Shack to help keep the wiring away from the retract gear areas.

It's important to mark every servo lead. I use a label maker. The next picture shows why.

You think a big plane has lots of room, but the P-38 doesn't! I use Futaba yellow wire clips to insure that connectors don't come apart in flight.

There are two servos in the each boom, one for each rudder and two for the elevator. I used GWS metal gear, coreless 110 inch ounce servos and heavy duty Nyrods for tail feather linkages.  The hole is covered up by the removable outer radiator.