Top Flite J-3 Piper Cub - Manual (Page 12)

4. Clean-up each of the solder joints with a wire brush and make
sure that the joints are strong. With the 1/4" sheet provided,
make two inserts to fill the triangle created by the front and
rear main wires. Epoxy these in place, centering them on the
front and rear wires. When dry, sand them to shape using the
front and rear wires as the "leading and trailing" edges. Slip
your wheels in place and secure with wheel collars (not fur-
nished). Cut off the excess axle wire and except for covering
the fillers, the landing gear is ready for use.
5. Again place the landing gear assembly on the fuselage. Lo-
cate and drill 1/16" guide holes for the four metal landing
gear clips (see plan for position). Leave the landing gear in
position and make the two wing strut supports as shown on
the plans from the material provided. With the two rear land-
ing gear clips in position, drill the guide holes for these sup-
ports. Remove all hardware from the fuselage and set aside
for final assembly.
FINAL ASSEMBLY
1. Remove both W-1 (PLY) "cap" ribs from their sheet. Re-
move the four (4) holes stamped on their surface. An X-acto
knife does this best. Accurately tack-glue these two ribs to-
gether. Use a sanding block to "match" their outlines — they
must be identical. Use a 1/4" dia. drill bit to "match" the
four holes. These too, must be the same. Once satisfied,
separate the two ribs and clean off any dried glue with a
sanding block.
2. Tack-glue each W-1 (PLY) to each side of the fuselage,
matching the top of the rib to the same edge as the cabin.
This must be accurate to insure proper wing/fuselage mat-
ing. "Eyeball" the two holes at each end of the W-1 (PLY)'s
to be sure that the 1/4" dowel holes you are about to drill
will clear F-10 (PLY) and F-11 (PLY) as shown on the plans.
Use an electric drill and a 1/4" dia. bit to drill the four holes
into each fuselage side, using the W-1 (PLY)'s as a template.
NOTE: drill these holes at right angles to the fuselage sides
and all the way through the inner F-17 (PLY)'s. Use a pencil
to mark the left W-1 (PLY) "L" and the right one "R". Re-
move them from the fuselage.
3. Cut two 6-1/4" lengths of 1/4" dia. dowel provided. Slightly
round their ends and insert them in place through the fuse-
lage. Center them as shown on the plans. These are the for-
ward and aft wing panel supports and will NOT be epoxied in
place until after the fuselage is covered. Leave them in place
for now for positioning wing panels.
4. Thread the outer nyrod tube through the wing ribs to just
inside the W-6 rib as shown on the plans. Leave the excess
sticking out of the root rib W-2. Epoxy these tubes in place
on each rib. Make the "L-bend" linkage for the inner nyrod
tube to connect the 90° bellcrank to the inner pushrod.
5. Drill holes for, and press in place, the wing strut blind mount-
ing nuts (No. 4-40 provided) into W-14A (PLY) and W-15A
(PLY), as shown on the plans. Drill holes for the interplane
strut eyelets in the W-13 (PLY)'s. DO NOT glue eyelets in
place until after the wings are covered.
6. Place the wing panels on a FLAT surface, using weights to
keep them that way. Epoxy the W-1 (PLY) "cap" rib, that
you makred "L", to the left wing panel root, over the nyrod
tube and flat against W-2 rib. Both the W-1 (PLY) rib and the
wing panel must be flat against a common surface for align-
ment. Repeat this step with the right panel. When these
assemblies are dry, use the drill and 1/4" bit to drill all four
holes in W-1 (PLY) through the wing root W-2/W-3(PLY) lam-
inate. Like the fuselage, drill these holes at accurate right
angles to the wing root surface.
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7. Slightly enlarge the hole in the W-1 (PLY)/W-2/W-3 (PLY)
wing roots to accept the outer diameter of the 1/4"-20 blind
mounting nut that will serve as the wing bolt attach point.
Epoxy these nuts in place as shown on the plans. Keep epoxy
away from the threads, but use enough to keep the nut from
coming loose.
8. With the 1/16" balsa sheet provided, cover the top center
section of each wing panel and allow to dry. Trim the excess
outer nyrod tube flush with W-1 (PLY).
9. Join the two wing panels together on the work surface using
some scrap 1/4" dia. dowels at the W-1 (PLY)'s for alignment.
Use a sanding block to final sand the leading edges to the
finished shape. Once satisfied that the panels have the same
leading edge shape, sand the rest of the panels to final shape,
including the wing tips.
10. Drill the 1/16" guide holes in each aileron horn mounting
plate, W-19 (PLY). Mount aileron horns with No. 2 screws
provided. As shown on the plans, bend to correct length and
install the aileron pushrod — provided — to the 90° aileron
bellcrank. Since the ailerons have not yet been cut free from
the wing, neutral is easy to achieve. Turn the wing panels over
and epoxy the bellcrank nut to the bellcrank tray W-20 (PLY).
Remove the aileron horns from the ailerons and set aside for
assembly after covering.
11. Carefully cut ailerons free from wing at the inboard trailing
edge. Break free the tack-glued joint between the aileron
spar and the aileron leading edge. Lightly sand the leading
edge of each aileron to the cross-section shown in Section
B-B on the plans, using a flat sanding block and medium
paper. Cut the hinge slots in each wing panel and aileron and
trial-fit. The ailerons and panels are now ready for covering.
12. The bottom door on the right side of the fuselage can now be
cut free. Pin holes made from the inside at each corner of
the door between the 1/4" square frames will mark it's lo-
cation accurately. Once the door is free from the fuselage, use
a sanding block to smooth it's edges. Set aside for covering.
13. Remove the 1/4" spacer that is between the F-19 and F-21
pieces at the tail of the fuselage. When the fuselage and fin
are covered, remove the material from around the stabilizer
slot and cut-away the small piece of wood at the tailpostto
facilitate installing the stabilizer. The stabilizer should be
first covered separately, trial-fitted in place and then have the
fabric removed from the center-section where it contacts the
upper F-21's and lower F-19's to create a good glue joint.
Only then should it be glued in place. Then the covered ele-
vators are hinged to the stabilizer followed by hingeing the
covered rudder over the tailwheel steering wire to the fin.
14. The top and bottom access doors are meant to be fully func-
tional and provide access to the radio equipment as well as
the nylon 1/4"-20 wing attach bolts. Therefore provisions for
hingeing these doors as well as being able to "lock" them in
place should now be considered. On plan sheet No. 2 we show
a scale-like method of being able to open and lock these two
doors. This is the method we used on our prototype and it
works well. We hinged our doors with regular model aircraft
hinges. If this method does not appeal to you, we suggest
hingeing the doors with yellow Super Monokote strips and
using tape or Trim Monokote at the center to keep the doors
closed.
15. The aileron, rudder and elevator servos should now be in-
stalled. The installation shown on the plans is exactly what
we used on our prototypes and works very well. Install the
rudder and elevator nyrods as shown. Be sure to anchor the
outer nyrods in place at various points in the fuselage to pre-