I cut 1/2 way through the leading edge, then added plywood backing on it for some support. I also added a floor for the battery to sit in. And as you can see in the pic, a plywood top to the fuse, then hold it all in with a velcro strap. My first attempt I used 3/16 balsa on the top. Bad plan. Shot the battery out on the first outside loop.
The elect clown actually totally removes the leading edge, and bits of the spar get chipped away every time you insert the battery. I keep waiting for the outboard wing to fold. But so far, so good.