Twisted Hobbys CRACK PITTS Assembly Manual page 23

And the one with the blunt end installs
on the upper part of the fuselage.
Correct postion for the lower doubler.
As with the upper doubler, the edges of
the wood should match the edges of the
foam and the slots should be aligned.
Let these dry before proceeding.
Rev: 2015.09.18.v01a
Apply a medium coat of glue to each or
the parts and install them into their
appropriate positions as just
mentioned.
Once the glue has dried on the
doublers, test t into the cut out in the
wing. The slot will need to be widened a
little to account for the thickness of the
doublers. Do not remove too much.
Correct position is such that the edges
of the wood match the edges of the
foam and that the slots are aligned.
Size the cut out in the top wing as well.
Ideally it should be a snug t.
page 23