
.
WING CONSTRUCTION
IMPORTANT NOTE: Refer to the KEY TO LASER-CUT BALSA PARTS to find the correct TOP and BOTTOM wing
sheeting pieces. You will assemble two TOP and two BOTTOM wing sheets. It is important that you understand this.
40.
Assemble both right and left top and bottom wing panel sheeting skins, including the center section sheets. Start by gluing
the front and rear center section sheets together to make a single piece. Glue the leading edge of the center sheet piece to
the rear edge of the leading edge. Now glue the curved trailing edge piece to the rear edge of the leading edge, at the wing
tip. Finally, glue the rear of the center section piece to the front edge of the trailing edge sheet. Once the sheet is
assembled, use a flat sanding block, with 220 sandpaper, to lightly sand the top and bottom smooth at the glue joints.
41a.
The two shaped 5/32"x5/16"x24" leading edges are now trimmed to match the tip shape, using the laser cut wing spar as a
guide. Hold the spar against the back face of the leading edge, as shown, and use a pencil to trace the bottom tip edge of
the spar onto the leading edge.
b.
Use a sanding block to sand the end of the leading edge to match the line just drawn. Do this to both leading edge pieces.
42.
Position and pin bottom wing sheet assembly in place over plans. Cut, fit and glue
the 1/16"x1/4" balsa cap strips in place between the leading and trailing sheets at
each rib station. Locate the laser-cut 1/16" sheet balsa spars from your kit
contents. As shown on the plans, the spar is glued in place over the back edge of
the forward wing sheeting. Apply glue to the bottom edge of the spar all the way
out to the outer W-8 rib location - do not apply glue past this point. Accurately
position the spar in place, making sure it is 90 deg. upright. Pin in place.
43.
Note that the wing root ribs are lasered into two parts: W-2 and W-2A. Separate
these parts with a razor blade. Position the already built wing center section in
place against the inboard edge of the bottom wing panel sheet. Hold the plywood
dihedral brace arm firmly against the front face of the wing spar with a clamp or
clothespin. The center section assembly will be off the work surface when the
dihedral brace arm is clamped in this position. Apply a small bead of thick CA glue
to the bottom of W-2 and glue it in place to the bottom edge of the wing sheet and
the inboard end of the spar. Hold W-2 in place against the center section to
provide it with the correct dihedral angle. When the glue sets, remove the center
section.
44a.
Slip a length of 1/8" sq. scrap balsa directly underneath the wing sheeting at the
leading edge. This provides the sheeting with the correct bottom leading edge
curvature to match the wing ribs and supports it when the leading edge is
installed.
b.
Starting with wing rib W-3, carefully glue each wing rib in place over the spar and
onto the bottom wing sheeting. Be sure each rib is centered on its cap strip and is
in complete contact with the bottom sheeting and cap strip. With all ribs glued and
pinned in place, again position the center section structure in place as before, with
the dihedral brace arm clamped to the spar. Glue the forward half-rib W-2A in
place to the bottom leading edge sheet only - not the dihedral brace. Make sure
W-2A is against the center section to give it the correct dihedral angle - avoid
getting glue on the center section. With W-2A in place, remove the center section.
Summary of Contents for SIGRC80 Rascal C
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