Top Flite TOPA0220 - Manual (Page 26)

crisscross fashion. Place an additional pair of pins
beside the spar between ribs W5 and W6. Do not
crisscross these as it would interfere with the spar web.
Stick them into your building board vertically so that
they keep the spar in position.
❏ ❏ 12. Position the spar web, with ribs, onto the
bottom spar. Align the ribs over their locations on the
plan. Install W1 and W10 on the spar and spar web.
Make sure each rib is seated onto the bottom spar
and that the spar web is against the forward part of
the cutout in each rib. DO NOT apply glue until
instructed to do so.
Note: Do not be concerned if the ribs do not exactly
align spanwise with the plans. Paper plans can
expand and contract as much as 1/8" [3.2mm] due
to moisture.
❏ ❏ 13. Position the TE spar/jig flat on the building
board, under the TE notches in the ribs. The jig tabs
must be facing the bottom spar and the widest
part of the TE spar/jig must be at W1.
❏ ❏ 14. Carefully rotate the TE spar/jig so that the jig
tabs are facing up, while also sliding each rib into the
slot in the TE spar/jig. Make sure that each rib is seated
in the notch in the TE spar/jig and that the TE spar/jig is
seated in the notches in the ribs. Pin the TE spar/jig in
location over the plan. DO NOT glue yet.
❏ ❏
15. Put the 1/8" x 1/4" x 24" [3.2 x 6.4 x 610mm]
basswood top spar into position on the spar web,
seating it in each rib. DO NOT glue yet.
❏ ❏ 16. Time to get the thin CA. Starting with W3
and working towards W10, glue each rib to the
bottom spar and the spar web. While doing so, press
the rib and spar web firmly onto the bottom spar until
the CA cures. Make sure the rib is firmly seated
against the front face of the spar web and also that
the TE spar/jig and rib remain in place.
Important: For maximum wing strength it is
essential that the joint between the spar web and
the top and bottom spars, as well as the joint
between the spar web and each rib, be securely
glued with no gaps. When you remove the wing
panel from the building board in a later step, be sure
to touch up any joints that need additional glue.
❏ ❏ 17. Tack glue W1 and W2 in place to the spar
web. There is a 1/16" [1.6mm] gap between the spar
web and the top and bottom spars. Do not get any
excess glue into this gap as the 1/16" [1.6mm] ply
spar joiners fit into the gap.
❏ ❏ 18. Remove the top basswood spar. Spread a
bead of medium CA along the top of the spar web
between W2 to W10 and on each rib where the top
spar will contact them. Re-install the top spar and
hold it firmly in place against the spar web until the
CA cures.
❏ ❏ 19. Glue each rib to the TE spar/jig with thin CA.
Make sure each rib is properly seated in the TE
spar/jig. The top of each rib should be even with the
top of the TE spar.
Note: Use the CA sparingly. If you apply an
excessive amount of CA it will be difficult to remove
the bottom of the jig under the ribs. Use the included
CA applicator tip.
❏ ❏ 20. Glue the 1/8" x 3/16" x 24" [3.2 x 4.8 x
610mm] balsa trailing edge to the rear of the ribs
with thin CA. The top of the trailing edge should be
even with the tops of the ribs.
❏ ❏ 21. Glue the tapered 5/32" to 1/2" x 1/4" x 24"
[4 to 12.7 x 6.4 x 610mm] balsa leading edge to the
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