(JJ Sinclair) wrote in message ...
As I write this, I am looking at a cross-section of an ASW-22 wing, taken from
a ship that has met with misfortune, It has styrofoam dams at the leading edge,
on both sides of the upper spar cap and at the forward edge of the drag spar.
These styrofoam dams were set just high enough to allow for a 10% excess of
glue (epoxy resin, chopped fibers, micro-balloons) that were trawled in from
the edge of one dam to the edge of the other dam. In this way, the construction
crew was 100% sure that the proper amount of glue had been spread along the
spar cap. When the upper skin was mated, all voids were filled and the excess
10% of resin was forced out each side into the styrofoam dams.
The inside of this wing is a work of art. I would expect nothing less from all
sailplane manufactures.
JJ Sinclair

It is interesting that you mention dams on BOTH sides of the upper
spar cap, as the AD for the Duo Discus had an inspection of the rear
side of the upper spar cap only. There must be an assumption that if
epoxy resin oozed out the back it equally oozed out the front side.
How good is that assumption? If it is possible to have voids where
there is no bonding of the cap to the shear web it must also be
possible to have a partial bonding of the upper aft corner of the web
but not the top and front side. How strong would this spar be? Would
it fail after 1000 hours and only in "extreme turbulance"? Why
wouldn't they have checked both sides of the spar?