Construction Manual
www.oldschoolmodels.com
Page 7
After test fitting, it’s time to install it permanently with the help of
some 30 minute epoxy. Remove the DH2 and DH1 parts, then mix
up some 30 minute epoxy. Carefully spread a thin layer of epoxy
on the inside of the dihedral box of one wing half, and both sides
of one half of DH1.
Put a DH2 on the front and back of DH1 where you applied the
epoxy. Be careful to note the circle’s position on each DH2. Then
slide the DH1/DH2 sandwich into the wing’s box, making sure that
DH1 is angled upwards, toward the top of the wing. Push it in so
exactly half of DH1 is inside the wing half (both DH2’s should be
flush with R1 when seated properly).
Wipe off any excess epoxy with the paper towels and rubbing
alcohol mentioned earlier in this step.
Step 34 - Wing Assembly (join 2 wing halves)
Once the epoxy has cured from the previous step, it’s time to join
the two wing halves. Locate the other DH2’s from BP3 and test fit
them into the right wing half, as you did before. Note that when
you test fit the pieces, together, the wing halves should touch in
the middle, with both R1 ribs lining up with no twists. Carefully
sand as necessary to make sure everything fits properly and the R1
ribs in each wing half are touching along their entire length.
After test fitting, it’s time to join the wing halves permanently with
a bit more 30 minute epoxy. Remove the DH2 and DH1 parts and
apply the epoxy as you did in the previous step, but also coat the
joining face of R1.
Now repeat the process you used in the previous step to attach the
DH1/DH2 sandwich in the right wing’s box.
Any twist in the alignment of the panels cannot be fixed after the
epoxy cures and will lead to a poor flying model.
Using a couple of clamps, hold wing halves firmly together. Wipe
off any excess epoxy and remove the clamps only after the epoxy
has fully cured.
Step 35 - Wing Assembly (Optional strings)
This step is optional, but could make the aileron servo installation
a bit easier, once the wings are covered. Cut two 12” lengths of
string, one for the left wing, and one for the right. Remember that
hole cut in the upper sheeting? Starting with the left wing panel,
push the thread through this hole, then through the circular holes
in R2, R3, and R4. The string will now extend from the servo bay,
out through the bottom of the wing. Tape both ends of the string
so they won’t easily pull out. Do the same for the right panel.
Step 36 - Cut and hinge the ailerons
Measure and cut the correct length and shape for each 5/16” x
1-1/4” x 36” strip to make the ailerons.
Round the leading edge of both ailerons. When finished shaping,
make the necessary slots/holes needed to hinge the ailerons to
each side of the wing. We recommend 4 hinges per aileron.
Step 37 - Aileron servo hatches
From leftover 3/16” x
3/8” x 36” basswood
strip, cut eight 3/4”
pieces. Make a
mounting post by
laminating two pieces,
gluing the 3/8” sides
together to make a
3/8 x 3/8” square post. Make 3 similar posts from the remaining
pieces, sanding the ends flat.
Position your aileron servo on the inside of the aileron hatch so the
servo arm output shaft is centered in the opening.
On the inside of each aileron hatch, glue one post on each side of
the servo as shown in the photo.
Note that the left hatch is a mirror image of the right hatch.
Now fit the servo hatches into position on the bottom of the wing.
Using the pre-cut holes as a guide, drill four 1/16” mounting holes
into the 3/16” x 3/8”basswood mounting strips installed earlier.
Harden the wood with a bit of thin CA and you can use the supplied
2-56 x 3/4” self tapping screws to secure the hatches in place.
This completes assembly of the Sky Ranger 40 wing.
Now it’s time to start construction of the tail and fuselage.
Prepare your work area
Now tape the fuselage side plan and a fresh piece of waxed paper
on your building board.
Step 38 - Horizontal Stab Assembly
Locate S1
from BP8 and
S2 from BP9.
Glue these
two pieces
together as
shown.
Step 39 - Vertical Fin Assembly
Locate VF1 and VF2 from BP7. Glue
these two pieces together as shown.
Cut a length of leftover 1/4” x 1/4”
balsa stick to snugly fill the slot in the
vertical fin, then glue in place.
Step 40 - Rudder Assembly
Locate R1 and R2 from BP7. Glue these
two pieces together as shown.
Cut a length of leftover 1/4” x 1/4”
balsa stick to snugly fill the slot in the
vertical fin, then glue in place.
Step 41 - Fuselage Assembly (FS2 and FS3 assemblies)
Fuselage construction begins
by assembling the fuse sides.
Locate both FS2s and FS3s from
BP5s. FS3 fit on the bottom of
FS2. Glue this in position, then
do the same for the other FS2 and FS3.
Step 42 - Fuselage Assembly (FS1 assemblies)
Locate both FS1s from the LP2s.
Glue one FS1 to one of the FS2/FS3
assemblies from the previous step. Then
do the same for the other FS1 to create
both fuselage sides. Make sure that the
top edges of FS1 and FS2 are in line -
use a straight-edge if necessary.
