Great Planes Piper J-3 Cub 60 Kit - GPMA0162 - Manual (Page 22)

D 1. Locate the die-cut 1/8" birch plywood dihedral
brace (A) and the two die-cut 1/8" birch plywood dihedral
braces (B). With (A) in the middle, use the centerlines to
align the parts and glue them together with 30-minute
epoxy. While the epoxy is curing, proceed to the next step.
D 6. After the epoxy on the dihedral brace laminations
from step 1 has cured, trial fit it between the main spars.
The brace should fit between the spars without forcing
them apart. Make adjustments to the brace if necessary.
D 2. Test join the wing panels with the die-cut 1/8" plywood
forward dowel plate, forward spar joiner and aft spar
joiner. This is just a test fit - do not glue at this time.
Make adjustments if necessary. It is typical to trim 1/16"
from the ends of the spar joiners to allow the spars to come
together and it may be necessary to deepen the notches in
the ribs. Test fit both die-cut 1/8" balsa sub
ribs R1A
D 3. Refer to the dihedral drawing on the plan. With one of
the wing panels flat on your work table, prop up the main
spar at the other tip rib R8 1-3/8" to set the dihedral angle
(1-1/4" for the clipped wing). Check the fit of the spars,
joiners and trailing edge. They should all fit evenly with
no gaps.
D 4. Chamfer both ends of the 5/16" x 2-1/2" hardwood
wing dowels and test fit. If you have to make adjustments
don't modify the forward dowel plate but adjust the
position of the forward spar joiner instead.
D 5. Make sure you have not built any "sweep" into the
wing by cutting the spars or trailing edge too long or too
short. Make adjustments if necessary.
NOTE: Before performing the following next two steps with
glue, "dry fit" the entire assembly to become familiar with
the procedure and decide where you will fasten
your clamps.
D 7. Prepare to permanently join the wing halves with the
laminated dihedral brace, front and rear main spar joiners,
the forward dowel plate, and the two R1A ribs. 30-Minute
epoxy must be used for this step. Place waxed paper on
your work surface and mix up a batch of epoxy. The 1A ribs
must be in position but no glue need be applied at this
time - you can add CA to them later. Apply epoxy liberally
to all mating surfaces. Slide the parts together and wipe off
any excess epoxy. A paper towel easily removes uncured
epoxy. Immediately proceed to the next step.
D 8. Make sure the dihedral angle is set as described in
step 3. Align the spars and trailing edge of the panels,
being careful not to build in any twist. Clamp the spar
joiners and the forward dowel plate to the wing. Small C-
clamps work well for this. Wipe away excess epoxy that
oozes out. Allow the epoxy to fully cure before
disturbing the wing and removing the clamps.
D 9. Remove the wing from the building board and take off
all the clamps. Sand off any excess epoxy that may
interfere with installation of the wing sheeting and
shear webs.
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