Build The Flaps - Top Flite Douglas DC-3 User Manual

This is what the bottom of your wing will look like if
you're installing fixed landing gear. Disregard the
sheeting on the outer panel in this photo.
3. Test fit an outer panel skin to the bottom of your
wing. Trim where necessary but make sure you leave the
skin a little oversize to allow for positioning and trimming
later. Temporarily hold the skin to the wing with a few
T-pins, then flip it over and start gluing. Do not glue the
sheeting to the aileron servo hatch rails or to the ribs on
both sides of the servo hatch. As you glue, handle your
wing carefully so you don't build in any twist. We used
thin CA to glue the skin to the ribs and main spar and
used medium CA to glue the skin to the LE.
4. Trim the sheeting even with the LE, the wing tip
and the outer TE spar. If you are building working
flaps, trim the sheeting even with the inner TE spar, but
if you are not building working flaps, trim the sheeting to
the middle of the inner TE spar making a small ledge to
accommodate the bottom flap skin.
5. Sheet the bottom of the other panel the same way.

BUILD THE FLAPS

Follow these instructions even if you are not
building working flaps. You still need to make the
flap skins.
1. Refer to the sketch above. Use medium or thick CA to
glue a 1/32" x 3/4" x 21-9/16" plywood strip on top of a
1/16" x 3" x 24" balsa sheet. Trim the balsa even with all
edges of the plywood strip. Glue one edge of the balsa/ply
sheet to the edge of a 3/32" x 3" x 24" balsa sheet.
2. If you are building working flaps, trim the glued
together pieces to make a bottom center flap skin that
is 2-1/4" wide. If you are not building working flaps, trim
the glued together pieces to make a bottom center flap
skin that is 2-3/8" wide. Sand the bottom flap skin flat
and even.
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Perform step 3 only if you are building working flaps.
3. Place the bottom center flap skin over the plan and
mark the location of the flap ribs. Cut the flap LE from a
1/4" x 3/8" x 24" balsa stick and glue it to the inside (top)
of the flap skin. The inside of the skin is the side without
the ply strip.
4. Wrap a piece of masking tape around your bar
sander so you do not sand the flap LE, then bevel the
TE of the flap skin using the flap LE as a guide. If you
are not building working flaps, just position but do not
glue the flap LE (see previous step) on the flap skin and
use it as a guide for sanding the bevel. Stop sanding
when you get to the plywood leaving the trailing edge of
the flap 1/32"—the thickness of the ply.
Perform step 5 only if you are not building
working flaps.
5. Glue the bottom center flap skin to the bottom of
the wing. Proceed to step 10.
6. Cut the 1/4" x 1/2" x 1" flap hinge blocks from
leftover 1/4" x 1/2" balsa. Glue the die-cut 3/32" balsa F1
flap ribs and the flap hinge blocks to the flap skin. This
assembly is now called the center flap.