Carf-Models Ultra Flash, Instruction Manual

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The openings for the servos (and retracts) in wing have
been roughly cut out at the factory, but you need to finish
trimming these. Using the servo mounts and servo hatch
covers as templates, trim around the edges, reducing the
width of the lip between the tabs for the hatch securing
screws to just 1 - 2mm wide, and mark the holes for the
cover fixing screws. Check that the servo mounts fit inside
with a little clearance all round. You may need to sand the
angle on the front outer edge of the mount a little for a per-
fect fit (photo above).
Assemble the servo mounts from the milled plywood as
shown. Make a ‘left’ and ‘right’ servo mounts! Tack them
together with thin CA, and then reinforce all joints with a
good fillet of 30 minute epoxy.
Servo Choice: We strongly recommend that you install the
metal-geared digital JR8411 servos for the ailerons, as
they are such a large surface, and either JR8311 or 8411
servos for the flaps.
Fit a heavy duty servo arm to the aileron servo and install
in the mount using the Ø 2.9 x 13mm sheetmetal screws
as shown. With the servo arm in the middle of the milled
slot, carefully mark the position of the mount on the servo
cover. The back edge of the plywood mount should be 3 -
4mm (1/8” - 3/16”) from the back edge of the servo hatch.
Sand and clean the surface of the servo hatch carefully
where it will be glued on (see also photos P15 and P16)
Remove the aileron servo, and glue the servo mount to the
hatch using
slow epoxy (Hysol 9462 recommended), and
clamp firmly in place until the glue has cured. Now install
both the flap and aileron servos, with the output shafts at
the back. Centre both servo arms using your R/C. The flap
servo arm only needs the inner 2 holes for the clevise, so
you can cut the end off. Protect and secure the servo
cables as shown (P15), so that they cannot get trapped
when installing the servo covers.
If using the recommended servos, you will need to extend
all 4 cables with a 550mm long extension lead, and secure
the plug and socket connections using a short length of
heatshrink tube or equivalent (photo right). The servo
cables are routed through the large oval hole in the spar in
front of the servo bay, and then to the tank bay in the cen-
tre of the wing.
Make up the aileron and Flap linkages from the hardware
supplied. The Flap linkage uses the 75mm length of M3
all-thread, with a steel clevise and nut on both ends, con-
nected to the inner hole of the servo arm. The aileron link-
age uses a clevise and nut at the servo end, on the outer
25
(above) Servo mount used as
template for trimming servo bays.
(below) Servo hatch used as tem-
plate to mark fixing holes.
(above) CNC Milled plywood parts
for the servo mounts. Make a left
and right handed versions!
(below) Sand covers for good
glue bond with slow epoxy.