Great Planes SlowPoke Sport 40 Kit - GPMA0492 - Manual (Page 10)

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3. Pin the 17-1/8" skin over your protected plan. Use the
tic marks on the plan to draw the location of the ribs and
spar on the surface of the balsa skin.
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4. Locate two 1/2" x 3/8" x 36" balsa main spars. Cut one
8-5/8" piece from each stick to use for the center section
main spars. Cut four 1/4" x 1/4" x 8-5/8" auxiliary spars from
two 24" sticks. Without using glue, pin the bottom 8-5/8"
main spar onto the sheeting where marked. Lay the two
1/4" x 1/4" auxiliary spars in position.
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5. From a 1/8" x 1/4" x 24" balsa stick cut two 8-5/8" aft
auxiliary spars. Lay one of these in position.
❏ 6. Without using glue, position the W-1 rib on the spars
and along the W-1 reference line. The forward edge of the
W-1 rib should be 1/16" behind the forward edge of the
sheeting to allow for the sub-leading edge. Position the W-2
ribs over the spars and aligned on the marks you made.
When everything is aligned, wick thin CA into all joints and
under the spars. Use a builders square or drafting
triangle to be sure all ribs are vertical.
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7. Install all of the top spars and glue them in place while
checking that the ribs remained vertical.
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8. From two 1/16" x 3/4" x 36"
balsa sub leading edges cut a
piece 4-3/8" long from each.
Glue this piece to the forward
edges of the ribs (save the
remaining pieces for the wing
panels). Sand the top edge of
this strip to match the contour of
the airfoil on top of the wing.
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9. Use the 1/2" x 2-1/2" x 9" balsa block to make a filler
between the W-1 and W-2 ribs at the aft edge of the panel
to support the wing bolts. The block needs to be carved to
match the ribs. The easiest way to shape the blocks is with
a long blade hobby knife followed by a power sander.
Perform the shaping before you glue the fillers in position.
❏ 10. Sand everything flush with the outer edges of the
W-2 rib. Measure and mark a line 1/16" on each side of the
spar on the outer side of the W-2 ribs. Carefully cut away the
balsa on the inside of those lines.
❏ 11. Test fit the wing joiners in position on both sides of the
main spars. Be sure the joiners are flat on the bottom
sheeting and that the square inboard ends are against W-1.
When satisfied with the fit, use 30-minute epoxy to glue all
four joiners to the spars on both sides of the wing panel.
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