I am finishing the build on an AV8R turban jet. It has a foam core wing that is sheeted with balsa. It has flaps and ailerons, so it needs 4 servos in the wing totoal. But HOWDOIMOUNTTHEM!? There is nothing but the 1/16" balsa sheet and foam to screw them into. Sence this thing will fly at 150-200mph I want them to be very strong! Im not much of a scratch builder, so I dont kow many little tips and tricks. The only thing i've thaught of is to epoxy a hardwood block into the foam and screw the servo to that. But im worried about fatige of the foam being able to hold the wood after a while.

Anyone had any experiance with this plane or have any ideas?

Thanks!
-Jake

Epoxy in a plywood or liteply servo boxs then screw the servos to the boxes.

Do the blocks as you described, but sink them deep into the foam

If you would like a stroger solution, just extend the front and back wood pieces as shown by MinnFlyer up to the opposite wing skin and glue them to a frame built on it.
In that way, both skins will work as structural elements, liberating the core foam from any load.

I think, Lnewqban, has the easyest and fastest solution.   Mike B., got my discription exactly.  I think that is what I need to do, as well as useing LOTS of epoxy.

I appreciate the help, guys!   This little issiue had held up a year's build for a month!