Great Planes Piper J-3 Cub 60 Kit - GPMA0162 - Manual (Page 38)

D D 3. As a precaution, tightly wrap the end of each strut
with masking tape to help prevent the wood from splitting
while tapping the threads or inserting the studs with epoxy.
Thread the holes with a 6-32 tap.
D D 4. Use music wire or a toothpick to force 30-minute
epoxy into the holes. Proceed to the next step immediately.
D D 5. Apply epoxy to one end of four 6-32 strut
attachment studs and thread them in so 3/4" is exposed.
If you have done a thorough job of filling the holes with
epoxy, the wood may split while threading in the 6-32
studs. This is why we have tightly wrapped the struts with
masking tape. A small crack or a split in the wood presents
no danger as the studs are inserted in the strut ends until
3/4" sticks out and are held with epoxy — they're in there
to stay! Skip to the next section while the epoxy cures.
D D 6. After the epoxy has fully cured, thread four strut
end attachments 7/16" onto the studs.
D D 7. Drill 1/8" holes in the strut blocks in the fuselage
for the #8 x 3/4" sheet metal screws. The hole locations
in the strut blocks in the wing have been previously drilled.
See the sketch above for the hole locations in the fuselage
strut blocks.
D D 8. Temporarily mount the remaining four strut end
attachments to the fuselage with four #8 x 3/4" sheet
metal screws.
D D 9. Bolt the wing to the fuselage. Install the struts on
the wing with four #8 x 3/4" sheet metal screws.
D D 10. Match each wing strut with its prospective strut
attachment mounted to the fuselage. Mark where the strut
meets the strut attachment.
D D 11. Remove the wing struts and cut each one 1/4"
shorter than the mark. Repeat steps 1 through 6 for the
other end of each wing strut.
D D 12. Cut a bevel on the bottom (fuselage end) of only
the front right and left wing struts as shown in the plan.
D D 13. Reinstall the wing struts on the airplane. Make
final adjustments to the length of each wing strut by turning
the strut end attachments in or out (it's helpful to support
the model upside-down for this operation).
Note: After covering your Cub 60 you will check for wing
twists using an incidence meter and you will twist the wing
panels and reheat the covering to remove any twist. After
doing this you must repeat Step 13, readjusting the strut
end attachments to lock the wing in its straight, untwisted
position. If you fail to do this, you may inadvertantly twist
the wing when attaching the struts.
D D 14. The wing struts may be finished by any of several
methods. MonoKote covering was applied to the wing
struts on our prototype Cub 60. 3/4 oz. Glass cloth with
resin and paint is another highly recommended method.
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