22
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, landing
gear, radio system, and battery. Place the battery in the
battery compartment but do not connect it.
❏
1. Assemble the balance stand as shown.
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2. Use a felt-tip pen or 1/8" [3mm]-wide tape to accurately
mark the C.G. on the bottom of the top wing on both sides
of the fuselage. The C.G. is located 3-7/16" [87.5mm] back
from the LE of the wing.
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3. With all parts of the model installed (ready to fl y) and a
battery pack in place, place the model on the balance stand
as shown and align it on the marks.
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4. 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 additional weight is
required, use Great Planes (GPMQ4485) “stick-on” lead.
A good place to add stick-on nose weight is to the fi rewall
(don’t attach weight to the cowl–it is not intended to support
weight). Begin by placing incrementally increasing amounts
of weight on the top of the fuselage over the fi rewall 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 open the bottom of the
fuselage 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.
Balance the Model Laterally
❏
1. With the wings level, lift the model by the engine
propeller shaft and the bottom of the fuselage under the TE
of the 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 wingtip. An airplane that has been laterally balanced
will track better in loops and other maneuvers.
PREFLIGHT
Identify Your Model
No matter if you fl y at an AMA sanctioned R/C club site or
if you fl y somewhere on your own, you should always have
your name, address, telephone number and AMA number
on or inside your model. It is required at all AMA R/C club
fl ying sites and AMA sanctioned fl ying events. Fill out the
identifi cation tag on page 26 (or on the decal sheet) and place
it on or inside your model.
Summary of Contents for REACTOR BIPE
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