Top Flite TOPA0310 User Manual
Page 18
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6. Cut four 17"
joiner box rails
from two 1/4" x
3/8" x 36" basswood sticks. Refer to the note at the
end of this step
(you’re reading the steps all the way
through before proceeding, aren’t you?), then use
epoxy to glue two of the rails to the 1/8" x 1-11/16" x
14" ply
joiner box top.
Use the die-cut 1/8" balsa
and ply
rail spacers
to maintain the correct spacing
of the rails. Use C-clamps or weights to hold the rails
to the joiner top until the epoxy is fully cured. From
now on this assembly will be referred to as the
joiner
box top
.
Note:
The root end of the rails extend
beyond the 1/8" ply joiner box top by 3/32".
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7. After the epoxy has fully cured, remove the
spacers and sand the edges of the rails and ply box
top even. Use a ballpoint pen to write “top”
somewhere on the joiner box top.
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8. Make an identical assembly the same way.
Mark it as the “bottom.”
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9. One rib at a time, test fit the joiner box top
through the slot in the top of ribs 2 thru 7. Make
adjustments to the slots in the ribs as necessary so
the joiner box top can slide all the way through.
Hint:
The joiner box top passes through the ribs at an
angle. A thin sanding tool such as a Perma-Grit
(F-102) makes sanding the angle in the slots easy.
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10. Test fit the joiner box bottom through the slot
in the bottom of ribs 2 thru 7 the same way.
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11. Cut the
bottom outer main spar
from a
1/4" x 3/8" x 36" basswood stick to the length shown
on the plan (between ribs 15 and 5).
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12. Following the dimensions in the sketch, cut
the
bottom inner main spar
that fits between rib 5
and rib 2 from a 1/4" x 3/8" x 36" basswood stick (or
use the remainder of the same stick you used for this
step if you are building the second (right) wing panel).
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13. As you can see by observing the wing plan,
the spar web, outer TE spar, top main spar and
bottom main spar join the ribs at an angle. However,
the notches in the ribs for the spars can only be die-
cut straight through. Therefore, you must bevel the
notches in ribs 4 thru 15 to allow the spars to pass at
the required angle. Use a single-edge razor blade, a
sharp hobby knife or a Perma-Grit sander to bevel
the notches in the ribs. Study the ribs and the spars
for the wing panel you are building to be certain you
are cutting the bevel in the correct direction.
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14. Bevel the notches of the die-cut 1/8" balsa
spar web
and the outer TE spar the same way.
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15. Bevel the aft edge of the outer TE spar to
the angle at which it will meet the inner TE spar 1"
from the end.
Clean all the balsa dust and wood chips off your
workbench and put away the CA. We still have more
work to do before it’s time to start gluing (but at least
we’re finally going to start fitting parts together!).
Frame the panel
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1. Without using any glue until instructed to do
so, fit ribs W5 through W15 on the spar web, then
add the bottom outer main spar and the outer TE
spar. Cut the
top outer main spar
from a 1/4" x 3/8"
x 36" basswood stick and add it to the assembly.
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