.
42.
a. The balsa cowl is made of several parts that are basically built up around the engine. Install the engine mounts and
your engine with the spinner that you intend to use. Cover any openings in the engine (carb, exhaust) with tape to
protect it from dust.
b. Begin the cowl construction by gluing the 1/4"x3"x3" balsa cowl bottom to the front of F-1 so that it's flush with the
fuselage bottom. Sig-Bond is recommended for all of the cowl parts because it will be easier to sand later.
c. Add two of the 3/16" pre-cut balsa cowl sides leaving about 1/16" between them and the engine mounts. Depending
on the width of your engine, the cowl sides may or may not blend into the spinner backplate. If not, cut off the front
end of the two remaining cowl sides and glue them in front of the engine mounts.
43.
Remove the engine and the mounts,
then fill the bottom inside corners of the
cowling with pieces of 1/2" or 1/4" balsa
triangular stock. Taper the triangular
stock towards the rear so it doesn't
interfere with the engine mounts.
44.
Bolt the engine back in place and
carefully sand the front edge of the cowl
with a narrow sanding stick. Sand until
the gap between the cowl and the
spinner backplate is about 5/32".
WONDER WHY...
...the Wonder cowl is made of balsa instead of plastic?
Answer: Flexibility. The Wonder uses lots of different engines which all have
different lengths, which all require something of a custom cowl. Besides, a
balsa cowl allows you to cover the fuselage right up to the spinner ring with no
seams. Actually, you can leave the cowl off with no adverse effects on flight
performance - it just won't look as good!
45.
a. Glue the die-cut 1/8" lite-ply spinner ring to the front of the cowl, making
certain it is aligned with the spinner backplate. Notice that the spinner ring
is cut oversize to allow for a bit of sanding.
b. Prepare the spinner backplate for the cowl sanding process by protecting
the edge with tape.
c. Carve and sand the cowl to blend in smoothly with the spinner at the front
and the fuselage at the rear. Now's a good time to round off the bottom
corners of the fuselage (forward of F-4) as well. Do the rough sanding with
80-grit sandpaper, then smooth it down with some 150-grit.
46.
The landing skid is constructed by
gluing two 1/2" lengths of 1/4" balsa
triangle stock to the sides of the
1/8"x5/16"x12" spruce skid. Sand the
spruce round on the bottom and shape
the ends as shown on the plans.
WONDER WHY...
...there's no landing gear on this design?
Answer: Well, let's look at the pros and cons of going with a skid instead of wheels on the Wonder. On the positive
side, without landing gear the Wonder is lighter, simpler, costs less, flies faster, performs better, and simply looks
sleeker. The negative is you can't land on concrete (technically you can, but it's certainly not recommended!). Even if
it had wheels, the Wonder would still require a hand launch because there's no ground steering without a rudder. So
find a field and have at it!
.
