Finish The Model; Balance The Model (C.g.) - GREAT PLANES Eagle 580 Instruction Manual

Finish the Model

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1. Slide the cowl in position on the front of the fuselage.
The cowl is held to the fuselage with magnets. In our testing
we have found the magnets to be very secure but if you
will be fl ying very aggressive aerobatics you may want to
consider applying a piece of clear tape to each side of the
cowl and fuselage. If you fi nd that the motor is not aligned
with the opening in the cowl, remove the cowl, loosen the
motor mount bolts and adjust the position of the motor.
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2. Install the spinner back plate, propeller with washer and
prop nut and the spinner cone. Secure the spinner cone to
the back plate with two 3 x 10mm sheet metal screws.
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3. As you have seen, the canopy slides back and forth to
lock in place. The magnets at the rear of the canopy keep it
locked in place.
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4. Insert a fl ight battery in the fuselage and use the hook
and loop material to hold the battery in position. Do not
connect the battery to the ESC while balancing the model.
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5. Install the canopy.

Balance the Model (C.G.)

More than any other factor, the C.G. (balance point)
can have the greatest effect on how a model fl ies, and
may determine whether or not your fi rst fl ight will be
successful. If you value this model and wish to enjoy it for
many fl ights, DO NOT OVERLOOK THIS IMPORTANT
PROCEDURE. A model that is not properly balanced will
be unstable and possibly unfl yable.
At this stage the model should be in ready-to-fl y condition with
all of the systems in place including the motor and battery,
landing gear, covering and paint, and the radio system.
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1. Use a felt-tip pen or 1/8" [3mm]-wide tape to accurately
mark the C.G. on the top of the wing at the side of the
fuselage. The C.G. is located 3-1/4" [83mm] back from the
leading edge of the wing at the side of the fuselage.
This is where your model should balance for the fi rst
fl ights. Later, you may wish to experiment by shifting
the C.G. up to 3/16" [5mm] forward or 3/16" [5mm] back
to change the fl ying 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 diffi cult to slow for landing. Moving the C.G.
aft makes the model more maneuverable, but could also
cause it to become too diffi cult to control. In any case,
start at the recommended balance point and do not at
any time balance the model outside the specifi ed range.
3-1/4" [83mm]
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2. With the wing attached to the fuselage, all parts of the
model installed (ready to fl y) and an empty fuel tank, lift it at
the balance point you marked.
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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 must be shifted aft or
weight must be added to the tail to balance. If additional
weight is required, use Great Planes (GPMQ4485) "stick
on" lead. A good place to add stick-on nose weight is to the
motor box (don't attach weight to the cowl—it is not intended
to support weight). Begin by placing incrementally increasing
amounts of weight on the fuse over the motor box until the
model balances. Once you have determined the amount of
weight required, it can be permanently attached.
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