Great Planes Extra 300S 60 Kit - GPMA0236 User Manual
Page 12
Note: The following instructions explain how to build the
wing directly over the plans. We’ll start by building the left
wing panel upside-down over the left wing panel plan so
your progress matches the photos.
❏
1. Before using the 1/4" x 3/8" x 32" basswood spars,
examine them carefully for possible imperfections. Look for
knots, soft spots, diagonal grain and any other
imperfections. If possible, position each spar so the
imperfections (if any) are on the outer half of the wing panel
(toward the tip), where they will be least affected by high
stresses. If the spars are warped slightly, try to “balance
them out” by installing the warped spars in opposite
directions (see sketch).
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2. Find the 1/8" x 3/8" x 18" basswood sticks. Cut the
sticks down to 15-3/4" making the spar doublers. Sand
one end of each of the four spar doublers to a taper as
shown on the plan. Glue the spar doublers to the spars and
sand off any excess glue.
❏
3. Carefully press out all the die-cut 3/32" balsa wing
ribs. Sand the edges slightly to remove any die-cutting
irregularities.
❏ ❏
1. Tape the left wing plan to your flat work surface,
and cover the wing drawing with Great Planes Plan
Protectors (so you won’t glue the wing to the plan!).
❏ ❏
2. Cross pin a top spar to the plan with the doubler
up and toward the root. Note: The spars are cut slightly too
long. Align them at the root and leave the excess past the
tip rib.
❏ ❏
3. Glue ribs R3 to R10 to the top spar over their
locations shown on the plan, using rib gauge G1 to set the
ribs at the correct angle. Note: One angle on G1 is used as
a rib angle guide and the other angle on it is used for
setting the cockpit rear former at the correct angle.
❏ ❏
4. Place the bottom spar into the rib notches, and use
G1 to position the root end of the spar. When satisfied with
the fit, glue the spar to the ribs with thin CA.
❏ ❏
5. Glue R1, R2 and R2A in place using a leftover
piece of 1/16" ply as a spacer to locate the ribs 1/16" away
from the spars. Do not glue the spacer while gluing the ribs.
Build the Wing Panels
Build the Wing Spars
BUILD THE WING
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