Bill
you may know this but....
To make the wings nearly bullet proof I use Kevlar cord (or Carbon TOW) around the wing tip back to center of TE and wrapped around the arrow shaft set with thick CA....
I start the cord just in front of the Tip on the LE, set into a shallow slit in the wing tip to "bury" the cord, then along the outside of the TE to the center...In a direct nose plant this lash up keeps the foam wing from torquing forward and breaking
I also use .75 fiber glass cloth on each wing tip as well as engine mount area... generally glued on with thinned White glue...makes the tip and glue area of the engine mount tougher
I also fix flattened carbon TOW Under each spar top and bottom....layer of tinned White glue...TOW set in the glue... fresh glue, set spar, light clamp, when dry, razor plane spar to taper at wing tip
1 inch and 2 inch wide strapping tape is also used...the 1 " is folded over equally above and below TE perimeter
The 2" a strip on top and bottom of wing near 1/2 chord out about 10" either side of center, ironed down and then covered with SLC on the whole wing
These planes will take a direct full speed nose plant and survive with the only issue being digging all the dirt out of the broken prop engine
each of these ....carbon TOW, Kevlar thread, and strapping tape have very good tension strength vs weight
virtually impossible to fold or break a wing this way