Make up the linkages to your choice - we have
used M2.5 clevises and 2.5mm steel wire, with
the clevise soldered onto one end, and a locknut
on the other end to prevent accidental move-
ment. However, If using a gas or glow motor with
higher vibration levels, then we recommend that
you use 3mm Ø hardware for the elevator link-
ages. A couple of short lengths of tube over the
clevises to prevent them opening accidentally.
If using the supplied phenolic control horns (or
plastic or phenolic servo arms) do
NOT
use sin-
gle-sided ball-links for the linkage, because they
can twist the horns/arms and cause flutter! You must
only
use single-sided ball-links when using
metal horns and arms. This is a solid experience and you should consider it a
FACT
.
Tip:
At this point we recommend that you install the extension cables for your elevator servos,
as it is very difficult to secure them in place to the fuselage sides after the fin post and rudder
are installed.
Wings
The wings are also 95% completed at the facto-
ry, and only need the aileron horns, servos and
linkages installing.
Install the milled phenolic horns into the ailerons
in exactly the same way as the elevator horns,
described above. The servos are installed in the
composite rib (with a plywood doubler on the
back) that have already been milled to suit a
standard size servo. Note that you will need a
400mm (16”) long cross-head screwdriver to
install the servos, which can easily be made by
extending an old screwdriver shaft with a length
of brass tube, either soldered or CA’d together.
You should use 2.9mmØ screws to mount the
servos into the milled ribs, not the standard
screws supplied with most servos as they are
too small. Our production process does not
allow us to mill holes smaller than 2mm Ø in
these CNC milled wood parts.
Servos:
The large ailerons can travel more
than 40 degrees, and if you are going to use the
maximum throw for 3D manoeuvres, we definite-
ly recommend hi-torque digital servos like JR8411, as used here.
Finally make up the linkages from your choice of hardware. We use M3 all-threaded rod with an
M3 clevise and locknut at both ends. Don’t forget to ‘Loctite’ the clevise and lock-nut on one end
of each linkage, and fit short lengths of tube to prevent clevises from opening accidentally. You
Composite-ARF IMPACT
18