At this stage the model should be in ready-to-fly condition
with all of the systems in place including the motor, landing
gear, battery pack, and the radio system.
❏
1. Use a felt-tip pen or 1/8" [3mm]-wide tape to accurately
mark the C.G. on the top of the wing on both sides of the
fuselage. The C.G. is located 3-1/8" [79mm] back from the
LE of the wing.
❏
2. With all parts of the model installed (ready to fly) and
the battery pack installed, place the model upside-down on
a Great Planes CG Machine
™
, or lift it at the balance point
you marked .
❏
3. If the tail drops, the model is “tail heavy” and the battery
pack and/or receiver must be shifted to balance. If the nose
drops, the model is “nose heavy” and the battery pack
and/or receiver must be shifted aft to balance. If possible,
move the battery pack and receiver to minimize or eliminate
any additional ballast required.
❏
4. IMPORTANT: If you found it necessary to move the
battery pack or receiver for the Yak 54 EP ARF to balance,
recheck the C.G. after this has been done.
❏
1. With the wing level, have an assistant help you lift the
model by the motor propeller shaft and the bottom of the
fuse under the TE of the fin. Do this several times.
❏
2. If one wing always drops when you lift the model, it means
that side is heavy. Balance the airplane by adding weight to the
other wing tip. An airplane that has been laterally balanced
will track better in loops and other maneuvers.
Balance the Model Laterally
This is where your model should balance for the first
flights. Later, you may wish to experiment by shifting the
C.G. up to 1/2" [13mm] forward or 1/2" [13mm] back to
change the flying characteristics. Moving the C.G. forward
may improve the smoothness and stability, but the model
may then require more speed for takeoff and make it more
difficult to slow for landing. Moving the C.G. aft makes the
model more maneuverable, but could also cause it to
become too difficult to control. In any case, start at the
recommended balance point and do not at any time
balance the model outside the specified range.
More than any other factor, the C.G. (balance point) can
have the greatest effect on how a model flies, and may
determine whether or not your first flight will be
successful. If you value this model and wish to enjoy it for
many flights, DO NOT OVERLOOK THIS IMPORTANT
PROCEDURE. A model that is not properly balanced will
be unstable and possibly unflyable.
Balance the Model (C.G.)
IMPORTANT: The Yak 54 EP ARF has been extensively
flown and tested to arrive at the throws at which it flies
best. Flying your model at these throws will provide you
with the greatest chance for successful first flights. If, after
you have become accustomed to the way the Yak 54 EP
ARF flies, you would like to change the throws to suit your
taste, that is fine. However, too much control throw could
make the model difficult to control, so remember, “more is
not always better.”
These are the recommended control surface throws:
High Rate
Low Rate
ELEVATOR:
1-1/8" [28mm] up
5/8" [16mm] up
1-1/8" [28mm] down 5/8" [16mm] down
RUDDER:
2-1/2" [64mm] right
1-1/4" [32mm] right
2-1/2" [64mm] left
1-1/4" [32mm] left
AILERONS:
7/8" [22mm] up
1/2" [13mm] up
7/8" [22mm] down
1/2" [13mm] down
3D RATES
3D ELEVATOR:
2" [51mm] up
2" [51mm] down
3D RUDDER:
3-1/2" [89mm] right
3-1/2" [89mm] left
3D AILERONS:
1-1/2" [38mm] up
1-1/2" [38mm] down
21
