Top Flite TOPA0405 - Manual (Page 20)

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21. See the cross-section at W-1 on the fuselage
plan for the proper orientation of the angle on the
front of the W-1A ribs. Use 6-minute epoxy to glue
the forward assembly between the two W-2 ribs.
The aft edges are centered on the front face of the
dihedral brace (the W-1A ribs are undersize to allow
for double sheeting). The front of the assembly is
located by placing the center of the 1/4" wing bolt
plate 1/16" below the centerline of the W-2 ribs
(toward the bottom surface of the wing).
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22. Glue the two die-cut 1/4" balsa center LE’s
(CLE) together. Trim the CLE to fit between the
two wing LE’s in front of the wing bolt plate. Glue
the CLE in place. You may rough contour them
now, but wait to do the final sanding until after the
wing has been sheeted.
SHEET THE BOTTOM OF THE WING
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1. Sort through the remaining 3/32" x 3" x 30"
wing sheeting. Pick out the best 3 sheets and set
them aside for the top of the wing. Also, from the
3/32" x 3" x 42" balsa wing sheeting, pick out the
best 6 sheets and set them aside for the top of
the wing.
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2. Notice that the center wing rib W-1 is 3/32"
undersize everywhere but on top of the center tray.
This is to allow you to put 3/32" center sheeting
over the W-1 ribs to reinforce the center-section.
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3. Use a piece of 3/32" x 3" x 30" balsa sheet to
sheet the top and bottom of the two W-1 ribs
(except on top of the center tray).
NOTE: This is a somewhat unique way of joining
the sheeting in the center of the wing that eliminates
the need for glassing the center-section. Do not try
to sand the center sheeting so the wing skin will
have 100% contact with it. If the skin is left a little
high on the top surface of the wing, it is fine, since
this part of the wing is hidden inside the fuselage.
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4. Glue the 1/4" x 1/4" balsa wing TE spars and
the flap LE’s to the radiator frame. Make sure the
TE’s and LE’s are flush with the center sheeting.
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5. Glue 3/32" balsa shear webs to the front of
the 1/4" x 1/4" balsa wing TE spars, between the
radiator frame and W-2 ribs.
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6. Sand the center sheeting slightly, particularly
on the bottom, to blend it with the shape of the
other wing ribs.
NOTE: The wing sheeting process described here
involves first making a skin that covers most of the
wing before gluing it to the structure. This skinning
process requires fairly quick and accurate work
when you apply the skin to the wing. We
recommend you read through the entire sheeting
section before proceeding.
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7. Cover your flat, smooth building surface with
waxed paper or Plan Protector. You will join the
wing skins on this surface.
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8. Use a long sanding bar with 150-grit
sandpaper to sand the tops of the bottom spar,
wing TE spars and ribs so they all smoothly blend
together. Make sure the tops of the TE spars
match the tapering angle of the ribs sanding the
ribs lightly to maintain the designed airfoil shape.
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