Great Planes Extra 300S 1.20 ARF Patty Wagstaff - GPMA1305 - Manual (Page 28)

diagram. If any of the controls respond in the wrong
direction, use the servo reversing in the transmitter to
reverse the servos connected to those controls. Be certain
the control surfaces have remained centered. Adjust if
necessary.
Use a Great Planes AccuThrow ™ (or a ruler) to accurately
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
somewhere between the low rate and the high rate setting.
Note: The throws are measured at the widest part of the
elevators, rudder and ailerons.
At this stage the model should be in ready-to-fly condition
with all of the systems in place including the engine, landing
gear, covering and paint, and the radio system.
❏
1. Use a felt-tip pen or 1/8"-wide tape to accurately mark
the C.G. on the top of both wing tips. The recommended
C.G. is located 3-13/16" [97mm] back from the leading edge
of the wing tip.
❏
2. With the wings attached to the fuselage, all parts of the
model installed (ready to fly) and an empty fuel tank, lift it at
the balance point you marked on the wing tips.
❏
3. If the tail drops, the model is “tail heavy” and the
battery pack and/or receiver 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
and/or receiver must be shifted aft or weight must be added
to the tail to balance. If possible, relocate the battery pack
and receiver to minimize or eliminate any additional ballast
required. If additional weight is required, nose weight may
be easily added by using a “spinner weight” (GPMQ4645 for
This is where your model should balance for your first
flights. Later, you may wish to experiment by shifting the
C.G. up to 1-3/16" [30mm] forward or 3/8" [9.5mm] back
to change the flying characteristics. Moving the C.G.
forward may improve the smoothness and stability, but it
may then require more speed for takeoff and make the
airplane 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 for you to control. In any
case, start at the location we recommend and do not at any
time balance your model outside the recommended 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 Extra 300S 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 Extra 300S 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: 3/4" [19mm] up 9/16" [14mm] up
3/4" [19mm] down 9/16" [14mm] down
RUDDER: 4-1/2" [114mm] right 3" [76m] right
4-1/2" [114mm] left 3" [76mm] left
AILERONS: 1-1/4" [32mm] up 3/4" [19mm] up
1-1/4" [32mm] down 3/4" [19mm] down
Set the Control Throws
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