Just thinking to myself here but if you put a couple of pieces of 3/8" tristock backing up the FW on either side, split them at the thrust line so that you have a 1/16" gap. You can then run a 1/16" ply plate the width of the FW on the thrust line back to F3 and support it with the opening in the former. Another piece of tristock running horizontally in front of F3 under the opening would provide a little added support or you can use some square hardwood and screw the plate into it. This would make access to the ESC easier. Might also need a cross section of square hardwood in between for a nice solid LIPO/ESC tray.

You might also want to check out Frank's retract wing build starting with post #107 here:

http://www.rcgroups.com/forums/showt...tsunami&page=8

David.