Top Flite TOPA0410 - Manual (Page 20)

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[3.2mm] plywood wing jigs under the wing tips at T-7 and
the 1-1/4" x 1-3/4" x 3-1/4" balsa block under the wing
center section TE. The wing tips must be seated on the
wing jigs and the jigs against the building table in order to
provide the proper amount of washout in the wing tips,
when sheeted. Note: The wing jigs can be tack glued to
the excess bottom sheeting, 1/16" [1.6mm] past rib T-7.
❏ 9. Before applying the top skin, rough cut the bottom
skin from over the aileron hatch openings.
❏ ❏ 10. Hold an outer wing panel skin over the top of the
outer wing panel. The wood grain of the skin runs parallel
to the main spar. Mark the shape of the wing on the skin,
allowing about 3/16" [4.8mm] extra on all sides. On the
wing top, the outer wing panel is skinned from rib T-7 to
the center of R-1. We again, suggest adding a piece of left
over balsa to each side of R-1A.
❏ ❏ 11. Use thick CA to glue the wing skin to the LE first.
Use masking tape to hold it in position until the CA cures.
Next, wet the outside of the skin with warm water. Apply
thick CA to all the structure that will contact the bottom of
the wing skin from the main spar forward. Carefully press
the wing skin onto the structure and hold it in place until
the glue cures. Finally, carefully lift the aft edge of the
wing tip sheeting and apply thick CA to the remaining
structure and press the sheeting against the structure until
the CA cures. Use the remaining 3/32" x 3" balsa sheet
from step 4 to complete the sheeting at the TE .
Repeat steps 10 and 11 for the other wing tip panel.
❏ 12. Trim and sand the top and bottom wing tip skin flush
with the LE, TE and wing tip rib T-7.
❏ ❏ 13. The forward bent section of the wing is skinned
with the 3/32" x 5-7/8" x 7-1/2" balsa forward LE skin
assembled in step 3. The grain of the wood runs parallel
to the LE of the wing. The edge of the LE skin that fits
against the wing tip panel skin will need to be trimmed to
a curved shape. The best method to accomplish this is to
rub chalk along the edge of the wing tip skin. Wet the top
of the LE skin with warm water and carefully press the
forward LE skin into position. Remove the LE skin and trim
it along the chalk line. Check the fit and trim as necessary
to achieve a good fit.
❏ ❏ 14. Don’t worry about trimming the other edges of the
forward LE skin until after it is installed. Put a mark on the
edge of the wing tip panel skin, at the middle of the main
center spar. Wet the top of the LE skin again. Apply
medium or thick CA to the top of rib R-1, R-2, the forward
half of the center main spar and LE, from rib R-1 to
R-3. Press the LE skin onto the ribs, LE and center spar
starting at rib R-1 and working toward R-3.
❏ ❏ 15. Use a flexible straightedge to trim the LE skin
along the middle of the main center spar and along the
center of rib R-3. Glue the LE skin to R-3.
❏ ❏ 16. Use the chalk method to trim a second piece of
3/32" x 5-7/8" x 7-1/2" balsa sheeting to fit from R-3 to the
center of R-5.
Repeat steps 13 and 16 for the other end of the wing
center section
❏ ❏ 17. With the wood grain running diagonally to the TE,
use the chalk method to fit the previously assembled 3/32"
x 10- 1/8" x 10-1/8" top TE skin, to the TE of the wing
center section, between ribs R-1 and R-5. You will need to
wet the wood before trying to fit it in position.