already the correct thickness for the M3 alu-
minum clevises provided. Drill out the thread-
ed holes in the SWB arms to 3.0mm diameter
for the clevise pins, and apply a little grease to
the hole to make sure there can be no binding
of the Ø 3mm pin in the servo arm.
Secure your chosen metal servo arms to the
servos, centering them all with your R/C so
that the arms will be at 90 degrees to the bot-
tom wing surface (not to the servo case).
Connect the outer hole on the front inner
servo arm (if used) to the 2nd hole from the
centre on the rear 1.5” arm as shown, and
adjust the linkages between the 2 inner ser-
vos carefully to eliminate any buzzing, or fight-
ing between them.
Install the completed outer servo mounts into
the wing first, screwing them to the plywood
rib using 6 of the Ø 2.9 x 13mm sheetmetal
screws provided in the hardware pack, as
shown. The rib has small ply doublers factory-
installed on the outer face of it. It does make
the outer servo fixing easier if you make up a
very long x-head screwdriver so that you can
access the screws from the wing root. Install
the inner mount in the same manner, using 10
screws.
If using dual ‘ganged’ servos in the inner phe-
nolic mount you will need to lengthen the
small servo arm slots that we have already
made in the bottom wing skin.
Check that the servo output arms are aligned with the dual phenolic aileron horns, and correct
any misalignment by adding thin plywood shims under the phenolic mounts if necessary.
Mill a slot in the servo hatch covers for the outer servos, to suit your servo arm, and secure in
position using the Ø 2.9 x 10mm screws provided. The small slots in the wing underside for the
inner servos will need to be made larger - to suit the exact location of your servo arm.
Make up the linkages as shown, using the M3 x 90mm threaded rod supplied, with the aluminum
clevise and a plain nut at the servo end, and the M3 ball-link at the aileron end. Ensure that the
threaded rod is screwed fully into the shank of the plastic ball-link. The ball-link is secured
between the dual phenolic aileron horns using the M3 x 20mm allen bolts and lock-nuts provid-
ed in the hardware pack. Add a drop of Loctite for extra safety.
Composite-ARF YAK 55SP
(3m span)
22
(above) Inner servo linkage shown using a single
servo, installed in the rear of the phenolic
mount. If using dual ‘ganged’ servos you will
need to extend the servo arm slot forwards for
clearance on the front servo arm.
(below) Aileron linkages are assembled using
the provided hardware. Outer servo hatch is
secured with Ø 2.9 x 10mm screws. Mill the slots
in the hatches to suit your metal servo arms.
