This also makes sure that you don’t scrape all the epoxy/microballoons mix off when inserting
the fin post into the fuselage. (See photo)
Hold the fin post against the rudder LE, mark through the holes to give you the hinge positions
and drill 4.5mm Ø. Open up slots either side of the holes for the
hinges with a round permagrit file, or similar, as shown.
Oil the hinge pins on the hinges so that they don’t get stuck,
and glue the hinges into the balsa L.E of the rudder with 30
minute epoxy and micro-balloons mix. Make sure that the
hinge axis is exactly on the front edge of the false balsa L.E.
for all 4 hinges. When cured push the hinges into the milled
holes in the fin post (with about a 4mm gap between the rud-
der and fin post) and trial fit in the fuselage to check for enough
movement. When correct, epoxy the hinges into
the fin post.
Important Note:
The bottom rudder hinge, especially, is an
extremely important
glue joint, as there will be
constant pressure on it when a pull-pull closed-
loop system is used. Please make extra sure
that this hinge is scuffed up, and glued into both
the rudder and fin post in the fuselage properly.
Do NOT use CA to glue the hinges into the rud-
der or fin post! If this hinge becomes loose and
you have rudder flutter this can damage or
destroy the back of the fuselage. The composite
balsa/glass bulkhead, which is factory-installed
in the fuselage, at the front of the vertical fin will
help to prevent any serious damage if flutter
should occur. If you have an early kit, without
this bulkhead, we
highly recommend
that you
make and install it. The paper pattern to make it
is provided at the end of these instructions.
Make from 3mm balsa, prepare inside surfaces
of fuselage carefully, and glue in with 30 minute
epoxy and micro-balloons.
Finally scuff up the inside surface of the fuse-
lage, and epoxy the fin post into the fuselage,
with a 1mm spacer on top of the fin (as shown)
and tape the rudder into position until the glue
has cured. Check the alignment of the rudder
very carefully by eye, to make sure it is lined up
with the centre of fin before the glue hardens.
Servo:
We recommend a hi-torque digital servo,
like the JR/Graupner 8411, for rudder control.
The rudder servo mount construction is up to
you. We show the normal position, but it can be
changed if you need due to Centre of Gravity
Composite-ARF IMPACT
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