I recently purchased a phoenix .46-.55 edge 540, nice plane except it doesnt have room for the battery, receiver and battery, or the switch, I need some suggestions as to where to place the battery at 87mm to balance and also where to mount the witch, seems there isn't a place to mount one. Any suggestions would greatly be appreciated.

Can you take a picture of the fuselage/wing area? That might make it easier for us to guide you.

Without knowing what I am talking about, the battery might go under the tank, and the switch can protrude the side of the fuselage (away from the muffler).....you are going with a nitro engine, right?

I think you can place one battery under and near the front by the firewall. You might have to take out the tank first to place it there. It appears like there is a rectangular cutout in the fuselage side that is made for the switch. Your receiver can go in the open space in front of the servos. When all that is in place, then check the CG (87mm you said). If it is still tail heavy, add some dead lead on the firewall (stick-on weights can be found at Harbor Freight) . If it is nose heavy (doubt it), move the battery behind the tank.

Do you have a local club to help you out? Or a hobby shop? You mentioned two batteries, but unless you have a gas engine, only one battery is needed.

Hope this helps,
Jerry

You could also add a plywood tray right behind the fuel tank where you could install both the battery and the receiver. This is likely located close enough to the leading edge of the wing to keep the weight up front.