Set The Control Throws; Balance The Model (C.g.) - GREAT PLANES Sukhoi SU-31 Instruction Manual

Set the Control Throws

Use a Great Planes AccuThrow
measure and set the control throw of each control surface as
indicated in the chart that follows. If your radio does not have
dual rates, we recommend setting the throws at the low rate
setting. NOTE: The throws are measured at the widest part
of the elevators, rudder and ailerons.
These are the recommended control surface throws:
High Rate
ELEVATOR: 2-3/4" [70mm] up
2-3/4" [70mm] down 1-1/4" [32mm] down
AILERONS: 1-1/2" [38mm] up
1-1/2" [38mm] down 3/4" [19mm] down
RUDDER: 4" [102mm] right
4" [102mm] left
IMPORTANT: The Sukhoi SU-31 3D Park Flyer 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 Sukhoi SU-31 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."

Balance the Model (C.G.)

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.
(or a ruler) to accurately
™
Low Rate
1-1/4" [32mm] up
3/4" [19mm] up
3" [76mm] right
3" [76mm] left
At this stage the model should be in ready-to-fly condition
with all of the systems in place including the motor, battery,
landing gear and the radio system.
1. Use a felt-tip pen or 1/8"-wide tape to accurately mark
the C.G. on the bottom of the wing on both sides of the
fuselage. The C.G. is located 4-1/4" [108mm] back from
the leading edge of the wing.
This is where your model should balance for the first
flights. Later, you may wish to experiment by shifting the
C.G. up to 5/16" [8mm] forward or 5/16" [8mm] back to
change the flying characteristics. 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.
2. Place the model 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 must be shifted forward or weight must be added to the
nose to balance. If the nose drops, the model is "nose heavy"
and the battery pack must be shifted aft or weight must be
added to the tail to balance. If possible, relocate the battery
pack to minimize or eliminate any additional ballast required. If
additional weight is required use Great Planes (GPMQ4485)
"stick on" lead. A good place to add stick-on nose weight is just
behind the motor. Begin by placing incrementally increasing
amounts of weight on the top of the fuse above the motor until
the model balances. Once you have determined the amount of
weight required, it can be permanently attached. If required,
tail weight may be added by cutting a slot in the bottom of the
fuse and gluing it permanently inside.
4. IMPORTANT: If you found it necessary to add any
weight, recheck the C.G. after the weight has been installed.
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