Dacron 1/2A control line is used for sewn hinges. A simple Z-bend is sufficient for the pushrod,
although a clevis can be used.
I like using Colorline DC540 gray spray-can primer from
Napa Auto Parts. It is easy to use, compatible with epoxy glue
and paint, dries quickly, and sands beautifully.
Prime the entire airplane, and look for any areas that could
benefit from a bit of spot putty or additional attention. I prefer
to use Squadron white putty because white is easy to cover.
This is primarily a product for plastic models.
Sand the entire model with 220-grit then 400-grit
sandpaper. Prime and sand again any areas that may require it.
The idea is to sand almost all of the primer off, leaving it only
in low or uneven areas.
Blow the dust off the model, paying particular attention to
the mounting holes. Clean the model with Windex, allow it
to dry, and wipe it with a tack rag. The model is now ready for
I use Klass Kote two-part epoxy paint. It is durable, glossy,
and fuelproof. Its instructions are good, so I won’t repeat them.
For the base color, I spray with an 8-ounce automotive-type touchup gun at 35 psi. Roughly 50ccs of paint, 50ccs of
catalyst, and 60ccs of reducer should be a sufficient quantity
to paint the airplane. For trim colors, numbers, and the canopy,
I use a basic siphon-type airbrush, also at 35 psi. This may
require more reducer for optimal spraying.
I don’t always clear coat the model, but go ahead if you
prefer. Let the paint cure for 24 hours before handling or
beginning final assembly.
The elevators are sewn to the
stabilizer with 1/2A Dacron flying line.
Cut six 2-foot pieces and saturate one
end of each piece with thin CA. This
will harden the line and let it function as
a sewing needle.
Starting at the hinge location closest
to the fuselage, pass the line through
the stabilizer, leaving approximately 8
inches. Temporarily tape this end to the
bottom of the stabilizer and sew four or
five figure-eight stitches to connect the
stabilizer and elevator. Pull both ends of
the line tight and tie a knot underneath
Thread the CA-hardened end up
through the stabilizer again and pull
the knot up into the hole. Sew the rest
of the hinges in a similar manner. Pull a
little tension on the elevators to align the
hinges. Using a toothpick, apply a drop
of medium CA into each hinge hole in
the stabilizer and elevator, being careful not to get the glue in
the hinges. Cut off the excess thread with a new #11 blade.
Engine, Tank, and Landing Gear Installation
Fasten the tank and engine plate to the airplane with #2
sheet-metal screws. Attach the engine and landing gear with
4-40 screws. Install the fuel line between the engine and tank.
Always use a filter. I prefer the Sullivan #204 silicone tubing
because it is softer and easier to pinch.
Begin with an APC 6. 5 x 5.0 propeller. This is generally the
fastest, but an APC 6. 5 x 5. 5 might be slightly faster, so don’t
be afraid to try it as well. If you prefer a spinner nut over the
stock hex nut, the O.S. 10 spinner nut (#OSM20824005) has
the correct thread size.
The fuel shutoff is composed of a pedestal made from a 1/2A
control horn and a 1/16-inch music-wire trigger. Fabricate these
parts as shown on the plans and install them on the airplane.
The trigger wire is held away from the fuselage by the
pedestal, and the fuel line is captured between the trigger wire
and the fuselage. When the trigger wire is pulled aft by the
shutoff cable, it comes off the pedestal and pinches the fuel
line against the fuselage, stopping the engine.
Use a 2-inch Fox metal bellcrank. I attach the lines directly
to the bellcrank primarily to eliminate the chance of line
connectors becoming fouled, but it also decreases drag. The line
ends are constructed in the usual manner.
I use Brodak BH321 large-thimble eyelets. They perfectly
match with the Du-Bro #135 4-40 blind nuts that serve as the
line-attachment buttons. I also used 4-40 x 1/4-inch button-head
cap screws because their low profile eliminates interference.
Drill and tap the leadout holes in the bellcrank 4-40 then
install the screws. Be sure to use Loctite. To make the buttons,
thread a blind nut onto a long 4-40 bolt (to use as a handle).
Screw a regular 4-40 hex nut down on top of the blind nut,
and “jam nut” them together so they don’t move.
With a Dremel tool and cutoff wheel, file the round flange
of the blind nut down to match the hex nut. The idea is to
MJ 4 Model Aviation JUNE 2015 www.ModelAviation.com