High Quality Plan Sets and Laser Cut Partial Kits for Radio Control
Aircraft
Page 11
Henry Struck's 1937 Benny Boxcar in 108 inch span
The front ply shear web is next tack glued
to the spars with the joiner blocks installed and also the paper
shims. Then remove the joiner blocks and paper and glue the front
plate securely with thin CA from the inside.
Test fit the joiner blocks, then remove them again and attach the rear ply
web with 30 minute epoxy. The next step is to make the final fit of
the joiner blocks. Make sure there is no glue inside the pockets in
the way of the joiner blocks. Sand a radius on the
corners of the joiner blocks to clear any glue forming a radius inside the
pockets. I used a belt sander to finish the joiner blocks until they fit in with minimum resistance but still
were snug enough to have almost no movement in
the vertical dimension. The side movement is less critical. It is
important that the wings can be separated without too much effort as once the covering is on it more
difficult to grip the panels than it is when you can
grab them by the spars.
100 pound Kevlar string was wrapped around
each end of the pockets to increase strength. It was embedded in 30
minute epoxy.
