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Composite-ARF SuperXtra 330L (3.1m span)
The rudder tray is supported on the 2 carbon-balsa formers
supplied, and it's exact position is your choice. However,
the back former is usually installed vertically in line with the
rear wing dowels, as seen here. Notch both ends of the rud-
der tray to fit into the slots in the formers (photo right).
Prepare the inside surface of the fuselage carefully, and
glue the complete assembly in place with epoxy and micro-
balloons mixture, with a nice fillet on all joints.
Install the 4 servos into the rudder tray using the 2.9mm Ø
x 13mm screws supplied, with the servo output shafts
towards the tail of the plane, as shown in the photo.
Rough sand the top surface of 4 standard 25mm (1") diam-
eter plastic output arms with 60 grit, or a Permagrit, and the
bottom surface of the 4 phenolic rudder servo arms provid-
ed to ensure good glue adhesion. Then fit the plastic output
discs to the servos and connect all 4 servos to your R/C
system (through the Powerbox) to centre them.
With the R/C still switched 'ON' place the C-ARF rudder
servo horn with the 2 hooks in it on the back servo (hooks
facing forwards, of course !) and align so that it is at 90° the
the rudder servo structure, and glue in place either with a
few drops of CA, or with a slow thixotropic epoxy. You can
do this using a plastic 90° set-square, and aligning one
edge of it with the centre of all the servo arm bolts. The
more accurately you do this, the easier it will be to set up
the linkages later, but 3° or 4° 'out' will still be OK. Then do
the same with the other 3 horns. When the glue has cured,
remove all 4 and secure the phenolic arms to each output
disc with 4 of the small (2.2mm Ø) sheet-metal screws sup-
plied. It is a very good idea at this point to number the phe-
nolic horns so that you know which one goes on which
servo, and which is the front of the horn !
Now connect the horns together with the 45mm long M3 all-
thread, ball-links, quick-links, M3 x 16mm bolts and lock-
nuts provided. The easiest way to do this is to firstly con-
nect the back 2 servos together, and adjust them so that
there is no servo 'buzzing' at idle or full throw. Then connect
the next servo, and do the same adjustment, and finally
connect the last servo.
In this way you always know which linkage to adjust when
you have 'buzzing', but if you just connect all 4 servos
together immediately it can take for-ever to get them right!
Note that you will need to re-drill the inner holes (2nd hole
from the end) in each phenolic arm 2.9 or 3mm Ø for the
M3 bolts. Don't forget to put the M3 nuts on each threaded
rod and tighten them up against the quick-links when you
have finished the adjustment, and add a drop of Loctite to
the locknuts to make sure the ball-links cannot come loose.
techsupport@composite-arf.com
(above) Glue plywood doublers to
the bottom of the servo rails.
(below) The completed rudder
servo tray is light and very stiff.
(above) Notch the ends to fit into
the slots in the formers.
(below) Completed Rudder tray
and sub-formers glued in the
normal position, with rear former
in line with rear wing dowels.
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