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Composite-ARF YAK 55SP (3m span)
Elevator
On high rate the elevator should really be at
maximum, up to 50 degrees both sides
(approx. 130mm), but in this case with 50%
exponential. Low rate should be no more than
50mm (2") both sides. This is the perfect
throw for nice and crisp snaps. If you like you
can add about 20% exponential to the low
rate setting as well.
Rudder
Set the high rate to maximum throw (about
170mm) both sides, and at low rate reduced
to about 110mm. These throws are measured
at the widest chord of the rudder.
Check your linkages and closed-loop cables
again and make sure that there is NO slop at
all in the rudder set-up!
Ailerons
Aileron throw for high rate is 75 - 80mm up
and down (measured at root). Use at least
30% exponential at high rate. For low rate you
should decrease the throw to the TOP
to 50mm, to the BOTTOM to 55mm.
Yes, you're right - this is a reversed
differential due to the hinge line being
in the top skin instead of on the cen-
tre line. You will have to finalise this
differential figure during flight, as
mentioned earlier in this instruction
book. At high rate, for 3D maneou-
vers, this doesn't effect the rolling too
much, so you can maximize the
throws to whatever is mechanically
possible, even more up than down if
you wish.
General
Your Yak has very large control surfaces. This makes it very sensitive and reactive. It is always
possible that these huge control surfaces can flutter at high speeds if the assembly, servo instal-
lation and linkages are not made perfectly, and if a servo gear or output disc/arm strips the flut-
ter will not stop until the plane hits the ground....
So please do yourself a favour, and make sure that you only use the best servos available, and
take the utmost care making your linkages. Check every linkage for slop, and rather reduce the
maximum throw than risking a high speed flutter due to sloppy servo gear or linkages. To pre-
vent this for sure, we recommend reduced control travels (reduced by using shorter servo arms,
not by using electronic settings). Using 2 servos per aileron as described in this manual will
never overload or damage high quality servos, even if the maximum travel of each servo is slight-
techsupport@composite-arf.com
ELEVATOR THROWS
RUDDER THROWS
AILERON THROWS
32
high rate: 130mm (max.)
low rate: 50mm
low rate: 50mm
high rate: 130mm (max.)
high rate: 170mm (max.)
low rate: 110mm
low rate: 110mm
high rate: 170mm (max.)
high rate: 80mm up (max.)
low rate: 50mm up
low rate: 55mm down
high rate: 80mm (max.)
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