Great Planes Piper J-3 Cub 20 Kit - GPMA0158 - Manual (Page 37)

D 2 Connect the fuel tube marked "P" to the nipple on the
carburetor Install the cowl over the engine and attach it to
the fuselage with the #2 x 3/8" sheet metal screws Install
the muffler on the engine and attach the fuel tubing marked
"V" to the nipple on the muffler
D 1 Roughen the elevator joiner wire with 150-grit
sandpaper, then clean the wire thoroughly with alcohol and
a paper towel to remove any oil residue
D 2 Glue the joiner wire in the elevators with 6-minute
epoxy After applying the epoxy, lay the elevators on a flat
surface with the leading edge along a straightedge to
ensure perfect alignment
Note: Cut 17 hinges 5/8" x 1" from the 2" x 9" supplied
hinge material
D 3 Attach the elevator assembly to the stabilizer with six
hinges using the technique described in the Expert Tip
section that follows After the CA has cured, flex the
elevators to "break them in "
The hinge material supplied in this kit consists of a 3-
layer lamination of mylar and polyester It is specially
made for the purpose of hinging model airplane control
surfaces Properly installed, this type of hinge provides
the best combination of strength, durability and ease of
installation We trust even our best show models to
these hinges, but it is essential to install them correctly
Please read the following instructions and follow them
carefully to obtain the best results These instructions
may be used to effectively install any of the various
brands of CA hinges
The most common mistake made by modelers when
installing this type of hinge is not applying a sufficient
amount of glue to fully secure the hinge over its entire
surface area, or, the hinge slots are very tight,
restricting the flow of CA to the back of the hinges This
results in hinges that are only "tack glued"
approximately 1/8" to 1/4" into the hinge slots The
following technique has been developed to help ensure
thorough and secure gluing.
A Cut the hinge slot using a #11 blade in a standard #1
knife handle The CA hinges provided have a thickness
that fits this type of slot very well Trial fit the hinge into
the slot If the hinge does not slide in easily, work the
knife blade back and forth in the slot a few times to
provide more clearance (it is really the back edge of
the blade that does the work here in widening the slot)
B Drill a 3/32" hole, 1/2" deep, in the center of the
hinge slot. If you use a Dremel® Moto-Tool for this
task, it will result in a cleaner hole than if you use a
slower speed power or hand drill Drilling the hole will
twist some of the wood fibers into the slot making it
difficult to insert the hinge, so you should re-insert the
knife blade, working it back and forth a few times to
clean out the slot
C Trial fit the hinges into the slots and temporarily
attach the control surface, to verify the fit and operation
D Rather than just making a single slit, it is better to cut
away a narrow rectangle of covering to provide an
adequate opening for the CA glue to wick into the slot.
E Insert the hinges and install the control surface
Verify the left-right positioning of the control surface,
and close up the hinge gap to 1/32" or less It is best to
leave a very slight hinge gap, rather than closing it up
tight, to help prevent the CA from wicking along the
hinge line Make sure the control surface will deflect to
the recommended throws without binding If you have
cut your hinge slots too deep, the hinges may slide in
too far, leaving only a small portion of the hinge in the
control surface To avoid this, you may insert a small
pin through the center of each hinge, before installing
This pin will keep the hinge centered while installing the
control surface Remove the pins before proceeding.
ASSEMBLE THEN APPLY 6 DROPS
OF THIN CA TO CENTER
OF HINGE ON BOTH SIDES
F Apply 6 drops of thin CA adhesive to both sides
of each hinge, allowing a few seconds between drops
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