Great Planes Piper J-3 Cub 60 Kit - GPMA0162 - Manual (Page 21)

D D 16 Trim the excess bottom sheet and blend the
leading edge to the wing tip. Refer to the plan for the
correct shape.
D D 17 Back to the top sheet for a moment If the sheet
still bows upward too much between rib R8 and tip rib R9,
wet the balsa in this area and pull it down with masking tape
until all the water has evaporated from the wood Nearly all
the excess bow will be eliminated The rest can be sanded
out.
D D 18 Rough sand the completed wing tip with 150-grit
sandpaper, carefully rounding the edges and blending the
tip sheet to the outer tip Blend the leading edge to the
sheeting all along the wing panel A razor plane works well
to cleanly remove material until you get close enough to
use sandpaper Be careful with the razor plane — it's a
fun tool to use but shave a little off at a time. Fill the rib
notches with filler.
D 1. Gather the parts you'll need right away .
2 pc die-cut 1/16" plywood aileron servo hatch
1 pc. 1/4" x 1/4" x 36" balsa rib stiffener
1 pc 1/32" x 1/4" x 16" plywood aileron servo
hatch shim
1 pc. 3/32" x 1/4" x 24" cap strip
D D 2 Cut two pieces from the 36" rib stiffener to fit
between the 1/8" shear web and the trailing edge sheet
The top of these stiffeners must be flush with the top edge
of the ribs, and blend with the TE sheet Glue them into
position with medium CA Add a piece of 1/8" scrap
between the stiffener and the main spar.
D D 3 From the 1/32" x 1/4" x 16" aileron servo hatch
shim, cut two strips to fit on top of the servo rails between
the 1/4" square stiffeners Using medium CA, glue the shims
into position flush with the inner edges of the servo rails (See
photo at Step 5 below.)
D D 4. Position the hatch. The rear edge of the hatch
should meet the front edge of the TE sheet Leave a small
gap to allow for the thickness of the covering.
D D 5. Cut a length of cap strip to fit in front of the hatch,
and between the 1/4" square hatch compartment stiffeners.
It will have to be sanded to a width that allows the hatch to
fit (remember to leave a gap for your covering) Glue the
strip to the servo rails with medium CA.
D D 6 Drill six 1/16" holes through the punch marks in
the die-cut 1/16" plywood aileron servo hatch. Place the
hatch cover in the aileron hatch compartment so the servo
arm hole is toward the front and outboard edge of the
hatch Transfer the position of the holes in the hatch to the
rails and drill 1/16" holes in the servo hatch rails
D D 7 Enlarge the holes in the hatch only to 3/32"
Countersink the holes for the six #2 x 3/8" flat head sheet
metal screws by using a countersink bit or carefully use a
7/32" drill bit to drill part way into the hatch Don't drill all
the way through! Temporarily mount the hatch to the wing.
D Return to step 2 on page 14, and build the other
wing panel.
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