Great Planes Extra 300S 40 Kit - GPMA0235 - Manual (Page 15)

Working quickly, pull the sheeting back toward the main
spar as you press it down to the ribs and spar, then glue
the aft edge of the sheeting to the main spar with thin CA.
Use masking tape, T-pins or weights to hold the sheeting to
the ribs until the CA cures.
❏ ❏
17. Use the die-cut 1/8" plywood dihedral gauge
and a ballpoint pen to accurately mark the wing centerline
on the spars, TE and bottom TE sheet.
❏ ❏
18. Remove the T-pins, then take the wing off your
building board.
Repeat steps 1 through 18 to build the left wing panel over
the right wing panel drawing on the plan.
❏
1. Use a razor saw to accurately cut the spars, TE and
bottom TE sheeting of both wing halves along the lines you
marked at the wing centerline. At the wing tips, trim the spars,
LE and bottom sheeting so they are even with rib R-10.
❏
2. Trim the bottom LE sheeting and the LE so they are
even with rib R-2.
❏
3. Without using any glue, test join the wing panels by
laying them upright (on the tall jig tabs on the bottoms of
the ribs) on your flat building table and join the ends of the
spars and TE.
❏
4. Test fit the 1/8" x 1-3/8" x 5-3/8" ply spar joiners on
the front and rear of the spars and temporarily clamp them
in position.
❏
5. Make sure the ends of the spars and TE's join without
any gaps. If there are any gaps, use your bar sander to
make small adjustments to the ends of the spars. Whatever
adjustments you make, the lengths of the spars and TE's
must be identical so you do not build any “sweep” into the
wing. In other words, when you temporarily clamp the spar
joiners to the spars, you should not have to pull the TE's
together, nor should they be pushing against each other.
❏
6. Glue the spar joiners to the spars with 30-minute
epoxy by spreading a film of epoxy on both the spars and
the spar joiners. Once the C-clamps are tightened wipe
away excess epoxy. Place waxed paper under the center of
the wing to catch excess epoxy and place weights on top of
your wing to hold the jig tabs down. Glue the TE's together
with thin or medium CA. Do not disturb the wing until the
epoxy cures.
❏
1. Glue the two R-1 ribs together with medium CA. Fit
the laminated R-1 rib between the aft spar joiner and the
Sheet the Wing
Join the Wing Panels
15