Dynaflite GPMA0090 Butterfly - Manual (Page 12)

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15. Slide the composite wing joiner tube
into the holes of W-1, W-2 and W-3. The holes in
the ribs are slightly oversize so you can accurately
position the tube when you permanently glue it
into the wing. Position the joiner tube so it rests
against the forward edge of the holes in the ribs,
then position the shear webs so they contact the
tube yet remain vertical. Glue the shear webs to
the wing (not the joiner tube) in this position.
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16. Remove the joiner tube, then test fi t the
1/8" x 3/8" x 21" basswood inner upper spar in
the notches of the ribs. Make sure none of the
crossed T-pins interfere with the top spar and you
will be able to remove them after you permanently
glue the spar into position. If necessary, trim the
shear webs that do not allow the spar to rest fully
into the notches of the ribs. Use medium or thick
CA to glue the upper spar to the assembly so the
end is even with the outer rib W-4.
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17. Make two gussets from the 3/16" x 3/4" x
12" balsa sheet, then glue them in position. If you
have one, use a small building triangle to accurately
cut the gussets. Note the grain direction as shown
in the photo.
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18. Remove the T-pins and lift the wing panel
from your building board. Trim the ends of the spars,
LE and TE, then use your bar sander and 150-grit
sandpaper to make the spars, LE, TE and bottom
sheeting fi t perfectly fl ush with W-1.
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19. Glue W-1A into position with medium CA.
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20. See the Tip that follows, then use a razor
plane, a hobby knife with a carving blade or a #11
blade to
roughly carve the leading edge according
to the sketch.