Fred:

One thing I need to mention before getting back to work... : ) Be very careful in the use of this or any spackle product as it has no load bearing property.


There are appropriate leveling products which are EPS foam safe and cure to a durable, light weight, and load bearing surface that will not easily break out on you or be soft beneath either a balsa laminate or a direct application of fiber glass and Z-poxy to your P-51 foam or wood components. One need only experience this once to suffer tremendous $ and time vestment in projects. Spackle as the directions state is meant as only a cosmetic item...not structural.

With respect to the Byron wing components I would suggest lightly sanding the entire foam surfaces to remove any sheen imparted by the molds the wings were created in. This permits wicking into the foam when Z-poxy is appropriately diluted with denatured alcohol as described above. This is not to say sand the surface in any fashion or force which will alter its shape... ;^)

The interior foam surfaces of your wing retract mounting wells can be laminated with inexpensive carbon fiber vail and diluted Z-poxy to create an exceptionally strong substrate onto which the actual retract mounting frames can be adhered. This will distribute the load of the landing impact over as wide a portion of the wing as possible to assist in eliminating gear breakouts... :^) Just an idea...