Great Planes Extra 300S 40 Kit - GPMA0235 - Manual (Page 13)

❏ ❏
5. Place a 5/16" x 5/16" x 30" bottom spar in the
notches of the ribs. Approximately 1/2" of the bottom spar
should extend past the wing centerline.
❏ ❏
6. Glue the main spars to the ribs with thin CA. As
you glue each rib to the spars, simultaneously pull the top
spar up into the rib and push the bottom spar down into the
rib to make sure the spars are fully seated in the notches.
Make sure all the jig tabs are contacting the work surface.
❏ ❏
7. Position the 27" shaped balsa leading edge (LE)
on the front of the ribs. The LE should be centered on all
the ribs and the root end should extend past rib R-2 by
about 1/16". Make sure all the jig tabs are contacting the
work surface, then use thin CA to glue the LE to the front of
the ribs.
❏ ❏
8. Use thin CA to glue the shaped 30" balsa trailing
edge (TE) to the ends of the ribs so approximately 1/2"
extends past the centerline of the wing.
❏ ❏
9. Use medium CA to glue the 3/32" x 7/8" x 30" balsa
trailing edge sheeting to the TE and wing ribs so the end
extends past the wing centerline by approximately 1/2".
❏ ❏
10. Starting at ribs R-8 & R-7 test fit, then glue the
die-cut 3/32" cross grain balsa shear webs to the front of
the spars. Note that the shear webs increase in height as
they get closer to the root and there are two shear webs
that are the same height between ribs 2 & 3 and 3 & 4.
❏ ❏
11. See the Expert Tip that follows, then glue two
3/32" x 3" x 30" balsa sheets together to make one 6" wide
sheet for the top and bottom leading edge wing sheeting.
HOW TO MAKE WING SHEETS
A. Use a metal straightedge as a guide to trim one edge of
both sheets.
13