16
Balance the Model
(C.G. - Center of Gravity)
More than any other factor, the Center of Gravity (C.G. a.k.a.
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 disregard this step. 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 batteries.
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1. There is a decal with two black lines on the underside
of the wing. Those mark the forward and aft C.G. limit for the
NexSTAR EP Select. The forward C.G. limit is 3-1/4" [83mm]
from the LE. The aft C.G. limit is 3-5/8" [92mm] from the LE.
❏
2. Make certain the model is in “ready-to-fl y” condition with
all components mounted and installed (propeller, spinner,
landing gear, motor batteries, etc.).
❏
3. Mount the wing to the fuselage with the nylon wing
bolt. Lift the model on both sides of the fuselage with your
fi ngertips between the two lines on the bottom of the wing.
❏
4. If the fuselage is level when lifting the model with your
fi ngers anywhere between the lines, the C.G. is correct.
Proceed to the
“At-the-Shop Check List”
section on page
20. If you cannot fi nd a spot between the two lines where
the airplane balances, then either one of the following will
happen: If the tail drops when lifting the model, the plane is
tail heavy and will require nose weight to balance. If the nose
drops, the plane is nose heavy and will require tail weight.
Do not be concerned if your model requires a few ounces
of nose or tail weight. Almost all models require additional
weight to balance and fl y correctly!
If additional weight is required to balance the plane, purchase
Great Planes Self Adhesive Lead Weights (GPMQ4485). The
weight is segmented in 1/4 oz. increments and is easy to
work with. If adding weight to the tail, attach it to the side
of the fuselage under the stab. If adding weight to the nose,
attach it to the fi rewall so that it is concealed by the cowl.
Note:
Shifting the motor batteries fore or aft will have some
effect on the C.G. Make sure that there is some space
between the motor batteries and ESC as the motor batteries
can get quite hot.
❏
5. If you found it necessary to add weight, recheck the
C.G. after doing so.
Balance the Model Laterally
❏
1. With the wing level, have an assistant help you lift the
model by the prop shaft and the bottom of the fuselage under
the TE of the vertical fi n. 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.
Setting Up the Futaba PA-2
Pilot Assist Link
Airplane set-up is complete at this point except for the Futaba
PA-2 Pilot Assist Link. To Activate the PA-2 module you need
to connect the wire labeled as “PA-2 A” with the one labeled
“PA-2 B.”
The PA-2 sensor operates by sensing the strength and contrast of
sun light. This unit works best when the sun is at least 25 degrees
above the horizon, and on partially cloudy days or overcast.
Extremely strong sunlight or light contrast between the sky and
the ground may prevent the module from working at its optimum.
The unit’s performance decreases as the sun gets lower on
the horizon and on extremely bright days. You should also be
cautious when fl ying over snow or water. In these conditions it
is best to disable the unit by setting the gain to zero or simply
disconnecting the PA-2’s sensor wires. After doing this your radio
system will work like any other radio system.
