Dynaflite GPMA0090 Butterfly - Manual (Page 18)

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6. After the epoxy has fully cured, carefully
prop the wing up on its leading edge, then apply
30-minute epoxy to the wing joiner wires to securely
glue them to the shear webs and spars. Use T-pins if
necessary to hold the joiner wires against the spars.
Do not disturb the wing until the epoxy cures.
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7. Return to step 2 and join the panels of the
other wing half the same way.
Finish the Wing
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1. Drill a 1/16" hole in the bottom spar of both
wing halves where shown on the plan for the #2 x
3/8" screws to secure the wing halves with rubber
bands. We will instruct you to install the screws
after you cover the wings.
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2. See the Tip that follows, then shape the LEs
of both wing panels.
Tip: How To Final Shape The LEs
The Butterfly is a motor glider not a high
performance aerobatic model – it’s named the
“Butterfl y” after all! It is not critical that you shape
the leading edges with the greatest precision. You
probably would not notice any difference in the
fl ight performance of a Butterfl y with a leading
edge accurately fi nished by an expert builder and
a Butterfl y with a leading edge roughly carved to
shape with a hobby knife. This isn’t to say that
you should not always strive for building accuracy
and a good fi nish, but don’t worry if your LEs
don’t look perfect. Building a straight fuselage
and fl at, warp-free wings are where you should
concentrate most your building efforts.
Here are some tips that can make shaping your
LEs a little easier and faster:
A. While you shape the LEs, frequently reference
the cross-section on the plan and the drawings
of the
LE gauges on the plan. If you are a
perfectionist, cut the gauges from the plan, then
use rubber cement or spray adhesive to glue
them to leftover 1/8" plywood or thin cardboard
(such as a cereal box). Cut the gauges from the
wood or cardboard you glued them to, then test
fi t the gauges to the appropriate sections of the
wing to arrive at the correct shape.
B. We highly recommend a razor plane to shape
the LEs until they are nearly the shape shown on
the plan – leave enough material to fi nal shape
by sanding.
C. Shape the LEs of the inner panels fi rst since
they have a constant shape from W-1 to W-4.
D. After you roughly shape the LE’s by carving
(or using the razor plane), fi nal shape the LE’s
with a bar sander and 220-grit sandpaper. Wrap
a piece of 220-grit sandpaper around the LE and
fi nal sand by hand.
E. Once you shape the inner LE’s, use the gauges
to fi nal shape the outer LE’s and blend the two
together where they meet.
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3. Inspect all glue joints of both wing panels. Add
CA to all glue joints that don’t look strong.
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4. Final sand the wings with your bar sander
and 320-grit sandpaper and blend all the ribs with
TE, LE and spars.