Construction Manual
www.oldschoolmodels.com
Page 5
Step 15 - Wing Assembly (cut leading edge)
Measure and cut one of the
1/4” square balsa strips to
create the leading edge. Press
it into position and glue to all
the ribs.
Once the glue has cured,
make a cutout in the leading
edge between the two already
installed R1A pieces, so the wing dowel will be able pass through
after the wings are sheeted and sanded.
Step 16 - Wing Assembly (cut upper sub-spar)
Measure and cut a 3/16”square balsa strip to create the upper sub-
spar. Press it into position and glue to all the ribs.
Step 17 - Wing Assembly (create dihedral box)
Carefully cut away the center of
the R1, R2 ribs, leaving a box as
shown in the photo. Carefully
sand the inside of the box so
the edges are smooth and flush.
This forms three sides of the
dihedral box and needs to be
smooth and free from edges so
the dihedral braces will slide in
smoothly when joining the wing
halves later.
Note that a Japanese saw is the
perfect tool for this job.
Step 18 - Wing Assembly (cut upper spar)
Lightly sand the edges of the bottom face
of the spar as shown in the drawing to the
right. This will help the spar slide in easier.
This next part takes a bit of time, so we
recommend against using an instant
setting glue. If you are using CA, use a
thicker formulation that gives you a bit of working time.
Measure and cut one of the 3/16” x 3/8” basswood strips to use
as the upper spar. Apply glue to
the top of the ribs where they
will contact the upper spar.
Working from the tip rib (R5),
carefully press the upper spar
into position. This will be a tight
fit and might require “wiggling”
the spar from side to side to slip
in-between the sheer webs. Be sure to press the spar completely
into the slot in each rib, making it flush with the sheer webs.
Once the spar is in place, wick thin C/A along the spar to sheer
web joints (front and back) along the entire length of the spar
When fitting the upper spar to the top of the dihedral box, be
careful not to drip excess glue into the box formed between R2
and R1.
Step 19 - Wing Assembly (sanding)
Lightly sand the area between R1 and R2. Pay a bit of attention to
sand WH2 so that it will be flush with the curvature of the wing. This
will pay dividends when applying the sheeting in the next step.
Step 20 - Wing Assembly (sheeting)
Using a bit of the leftover sheeting
from the BP6 sheets, measure, cut
and glue together the sheeting to
cover the area between R1 and
R2.
When measuring, make sure that
the grain is crosswise (flowing
from R1 to R2). Also measure so
the sheeting extends about 1/16”
past R2.
When edge gluing the sheeting
pieces together, first make sure
the edges are flat (give a quick,
swipe or two with a sanding
block). Then tape the two pieces
together as shown here with
a piece of tape. As you lift the
sheeting from the board you’ll
see that the tape will act as a
hinge allowing you to put a small amount of adhesive in the joint.
When the adhesive is applied, place the sheeting back down on
the waxed paper, so that it’s flat (as shown in the photo). When
cured, you’ll now have a single, longer piece of sheeting.
You’ll need to join a few pieces together to make it long enough to
reach from the leading to the trailing edge.
It’s easier to join the shorter lengths of sheeting together on a flat
surface, then when the glue has cured, trim and glue the sheeting
in place on the wing. Start at the leading edge and gluing a little
at a time. Press the sheeting firmly against the ribs and wait for
the glue to cure before gluing the next section of sheeting - slowly
working your way back to the trailing edge, being careful not to
put a bend (warp) in the wing.
Step 21 - Wing Assembly (top cap strips)
Cut several 1/16th x 1/4” x 36”
balsa strips from BP10. Carefully
measure and cut cap strips to
cover each R3, R4 and R5 rib.
These strips should be centered
on each rib. When it comes to
R5, you’ll see that there are
recesses pre-cut into the T1, T2
and T3 pieces to accept the cap strip sheeting.
Note: it may be necessary to soak these strips in water to soften
them up, allowing them curve around the sharper curve of the ribs,
from the spar to the leading edge.
Step 22 - Wing Assembly (reinforce glue joints)
Remove the wing from the building board and make sure that all
of the wood to wood joints are securely glued together. Especially
check that all of the Sheer Web pieces are glued to the ribs. If not,
run a thin bead of glue where needed.
Step 23 - Wing Assembly (W3 assembly)
Remove the wing from the building board and flip it over. Locate
one WH3 and 4 WH3A pieces from LP1.
The 4 WH3 pieces are glued, one on top of the other. Then this
assembly is glued to WH3 - making sure that they are glued to the
inside surface of WH3, centered on the pre-cut hole.
Lightly
sand here.
Lightly
sand here.
