Top Flite TOPA0140 - Manual (Page 24)

SHEET THE BOTTOM OF THE WING
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1. If you haven’t done so already, remove your
retracts from the wing.
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2. Make sure all the ribs, spars, rails and trailing
edges smoothly blend. Sand where necessary.
Sheet the left wing panel first.
❏ ❏
3. Put your wing upside down on the upside
down jigs. They make a handy platform for working
on your wing in the next few steps.
❏ ❏
4. Trim one of your wing skins to fit the left
wing panel. Make sure you trim the skin slightly
oversize to allow for positioning and trimming.
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5. Position the bottom wing skin on the wing
to determine where the landing gear rail contacts
the skin. Cut a slot in the bottom skin to
accommodate the landing gear rail. Proceed to
step 8.
Perform step 6 only if you are installing
retracts.
❏ ❏
6. Use leftover 1/16" [1.6mm] balsa sheeting
(you should have plenty of leftover sheeting by
now!) to make wing skin doublers that fit inside
the wheel and retract openings in the bottom skin.
The doublers fit between the ribs as shown in the
photo. Set these pieces aside for now. You will be
instructed to glue them inside the wing after you
sheet the bottom.
❏ ❏
7. Glue the bottom skin in position. There
are several methods to do this but one we prefer is
to apply a bead of medium or thick CA along the
bottom spar and rib 4. Quickly position the bottom
skin on the wing and lightly press it down to the
spar and rib 4.
❏ ❏
8. After the CA on the spar and rib 4 cures,
lift the skin and apply a bead of CA to the outer
trailing edge and rib 13. Press the skin down over
these areas.
❏ ❏
9. After the CA cures, remove the wing from
the jigs and turn it upright. Carefully, holding the
wing in your hand (and without adding any twist to
the wing), one rib at a time apply a light bead of
medium CA to each rib and press the bottom skin
to it. Glue the skin to the sub leading edge the
same way. Do not glue the skin to the inner
trailing edge at this time.
❏ ❏
10. Trim the bottom skin along the sub
leading edge, tip rib 13 and the outer trailing edge.
Trim the trailing edge of the skin between ribs 12
and 13 at least 1/8" [3mm] past where shown on
the plan (to allow for trimming later).
Perform steps 11, 12 and 13 only if you are
installing retracts.
❏ ❏
11. Working quickly, apply thick or medium CA
to the inside of the bottom skin in the area of one of
the bottom skin doublers. Slip the doubler into place
and press it to the bottom skin. Glue the other two
bottom skin doublers in place the same way.
Perform step 5 only if you are installing fixed
landing gear.
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