Great Planes Piper J-3 Cub 40 Kit - GPMA0160 - Manual (Page 12)

first two #3 ribs. Keep the plans aligned and tape the
inner and outer halves together. The plans are now
ready to use for the clipped wing version.
❏
1.Tape the plan to your flat work surface. Align a straightedge
on the wing centerline and draw a continuous line extending out
past the leading and trailing edges. Do this for both the right and
left wing panel plans. This centerline will be used at various
times during the wing construction. Cover the wing drawing with
waxed paper (so you won’t glue the wing to the plan!).
❏
2. Before using the 3/8" x 3/8" x 33-1/2" basswood Spars
(CUB4W06), examine them carefully for possible
imperfections. Look for knots, soft spots, diagonal grain and
any other imperfections. If possible, position each spar so
the imperfections are on the outer half of the wing panel
(toward the tip), where they will be least affected by high
stress. If the spars are warped slightly, try to “balance them
out” by installing the warped spars in opposite directions.
❏
3. Carefully punch out all the die-cut 3/32" balsa #3 and
#5 ribs (CUB4W02) and the die-cut 1/8" balsa #2, #4, #6, #7
and #8 ribs (CUB4W01, CUB4W03 and CUB4W04). Sand
the edges slightly to remove any die-cutting irregularities.
❏ ❏
4. Place one of the 3/8" x 3/8" x 33-1/2" Basswood
Spars (CUB4W09) on the wing plan and pin the spar down
with crossed T-pins as shown in the following sketch. NOTE:
Align the end of the spar with the outboard edge of rib #7.
The spars are cut slightly too long, and the excess will be
cut off later at the center of the wing.
❏ ❏
5. Place the 1/16" x 1-3/8" x 36" balsa TE Sheeting
(CUB4W13) on the plans but do not pin it yet. Align one end
of the sheeting with the wing centerline.
❏ ❏
6. Place three of the #3 ribs and one of the #4 ribs on
the spar in their locations shown on the plans, but do not
glue. Slide the TE sheeting to the forward edge of the
notches in the bottom of the ribs. The TE sheeting is used
only as a shim for the rib ends at this point.
❏ ❏
7. Carefully check the notches on the TE (CUB4W11).
The 1/8" wide notches are to be positioned over the #1 and
#2 rib locations on the plans. Align the outboard end of the
TE with the aft end of the #4 rib. Insert the aft ends of the #3
ribs into the notches in the TE. Make sure the ribs are down
against the sheeting and building board and glue the ribs to
the spar and the TE with thin CA. The TE sheeting should
hold the ribs 1/16" above the work surface.
❏ ❏
8. Slide the bottom sheeting back against the TE and
align it with the inboard end of the TE. Glue the bottom
sheeting to the TE and the ribs.
T-Pin
Spar
Work Surface
NOTE: Follow steps 4 through 30 to build the LEFT
wing panel, then repeat these steps to build the
RIGHT wing panel.
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