Great Planes Piper J-3 Cub 60 Kit - GPMA0162 - Manual (Page 45)

D 1 Cut a slit in the tapered tail wedge for the tail wheel
wire bearing Test fit the rudder with the tail wheel wire
assembly to the fuselage and fin Make adjustments
if required.
D 2 Apply a dab of petroleum jelly to the top of the rudder
bearing where the wire enters to keep the epoxy out Glue
the tail gear wire into the rudder with 30-minute epoxy
Wipe away excess epoxy that oozes out of the rudder Do
not glue the plastic tail gear bearing to the rudder.
When permanently hinging the rudder, refer to the hinging
technique below but use 30-minute epoxy to glue the tail
wheel wire hinge bearing into the fuselage.
D 3 Cut a slit in the covering where each hinge slot is
located Insert the hinges and install the control surface
Adjust the hinge gap to 1/32" or less It is best to leave a
slight hinge gap, rather than closing it up tight This
prevents 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 to 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
D 4 Apply 6 drops of thin CA adhesive to both sides of
each hinge, allowing a few seconds between drops for the
CA to wick into the slot NOTE that the small "tunnels" you
created by drilling the 3/32" holes allow the CA to freely
travel in to the entire surface of the hinge, producing an
extremely secure bond
NOTE: This section is VERY important and must not be
omitted! A model that is not properly balanced will be
unstable and possibly unflyable.
Our Cub 60 required the servo tray to be positioned 2-3/8"
ahead of former F3 No additional weight was required to
adjust the C G Final checking of the C G and positioning
of the servo tray will be done after the model is covered
and all systems installed (engine, receiver, battery).
D 1 Trial fit your servos in the die-cut 1/8" plywood servo
tray and make adjustments if required From the remainder
of the 1/4" x 1/4" x 36" stick used earlier for the rib
stiffeners, cut two more sticks 5" in length and glue them to
the bottom of the servo tray for the servo mounting screws.
D 2 "Mock up" the completed model in order to closely
represent the finished weight distribution Install the engine,
landing gear, wheels, cowl, control pushrods, fuel tank,
propeller, etc Each of these items may be temporarily
installed if they are not ready for final installation - we are
just approximating final weight distribution
D 3 Install the servo tray, receiver, and battery The
recommended location for the battery is beneath the fuel
tank just ahead of former F2 For now it is not necessary to
permanently mount the battery and receiver - just place
them in the locations for estimated weight distribution.
D 4 Accurately mark the balance point on the bottom of
the wing on both sides of the fuselage The balance point
is shown on the plan (CG), and is located approximately
4-1/2" back from the leading edge This is the balance
point at which your model should balance for your first
flights Later, you may experiment by shifting the balance
up to 3/8" f o r w a r d or back to change the f l y i n g
characteristics Moving the balance forward results in a
model that tends to resist stalls and spins but may act
sluggish and require more speed for takeoff and landing.
Moving the balance aft makes the model more agile with a
lighter and snappier "feel " In any case, do not balance
your model outside the recommended range.
Note: The best balance point for a Cub 60 on floats is
4-1/4" back from the leading edge
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