Centre Of Gravity - Carf-Models Composite-ARF Yak-55 SP Instruction Manual

Composite-ARF Yak-55 SP (2.6m span)

Centre of Gravity:

The Centre of Gravity should be set on the
back edge of the wing spar tube, with the
plane assembled. The easiest way to check
and set this is to insert the wing tube in the
completed fuselage without the wings
attached, and set the balance point on the
centre of the wing tube, so that plane bal-
ances horizontally. When you then fit the fin-
ished wings it will move the actual Centre of
Gravity back about 10 - 20mm (3/8" - 3/4") to
the back edge of the 40mm Ø wing tube which
is perfect.
After you are confident you can move it further
backwards by up to 10mm behind the back edge of the
wing tube, but this is definitely a '3D/Freestyle' CG setting
and should not be used for the first flights. With this rear-
ward CG you will need to use the high rate control throws
shown below.
Don't forget to balance the plane laterally, holding the spin-
ner central bolt and a fingertip under the rudder, and if
needed add a small weight to the light wing tip to make it
track correctly.
Engine Thrustline:
Already given in the instructions, down thrust should initial-
ly be set at 0.5° - 1° degree and right thrust 1 - 1.5°
degrees, depending on the prop used. The Composite-ARF
Yak-55 SP really only needs this small amount of side and
downthrust with the DA-100 and recommended propeller.
We recommend a 2-blade 28" x10" carbon prop for any
100cc engine. It is a very quiet and powerful solution. They
are normally CNC-designed, so the prop is balanced per-
fectly statically, dynamically and aerodynamically, which
keeps the vibration down to a minimum.
Control Throws:
All measurements are at the root/trailing edge
position.
Elevator
All controls should be set with a dual rate
switch. On high rate the elevator should really
be at maximum, up to 50 degrees both sides ,
but in this case with 50% exponential. Low
rate should be no more than 40mm (1 1/2")
Setting Up Your Aircraft
35
techsupport@composite-arf.com
C of G: At the back edge of
the wing spar tube.
CENTRE of GRAVITY
1 - 1.5° depending on propeller
SIDETHRUST
High-Rate throws shown
high rate: maximum
low rate: 40mm
low rate: 40mm
high rate: maximum
ELEVATOR THROWS