At this stage the model should be in ready-to-fly
condition with all of the systems in place including
the motor and prop, electronic speed control,
motor battery, radio system and wing.
❏
1. Use a felt-tip pen or 1/8"-wide tape to
accurately mark the C.G. range on the bottom of
the wing on both sides of the fuselage. The C.G.
range is located between 2-1/2" [63.5mm] and
2-7/8" [73mm] back from the leading edge of
the wing.
❏
2. With the wing attached to the fuselage and all
parts of the model installed (ready to fly), place the
model right-side up on a Great Planes CG Machine
™
,
or lift it right-side up within the balance range
you marked.
❏
3. Have an assistant stand 6' to 8' to the side of
the model. As you lift the model, have the assistant
observe the stabilizer. If the plane is properly
balanced, the stabilizer will be level. If the tail drops,
the model is “tail heavy” and weight must be added
to the nose to balance. If the nose drops, the model
is “nose heavy” and 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 beside the
motor on the fuselage side. Begin by placing
incrementally increasing amounts of weight on the
fuse 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 to the underside of the stabilizer.
❏
4. IMPORTANT: If you found it necessary to add
any weight, recheck the C.G. after the weight has
been installed.
❏
1. With the wing level, have an assistant help you
lift the model by the motor shaft and the bottom of
the fuselage, under the TE of the stabilizer. 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.
Balance the Model Laterally
2-11/16"
Your model must be balanced within this C.G.
range. Balancing your model forward or aft of the
C.G. range will change its flying characteristics.
With the plane balanced at the forward C.G. the
plane will fly smoother and be more stable, but it
may require more speed for takeoff and make it
more difficult to slow for landing. This is the best
location for the C.G. if you are new to R/C flying.
With the C.G. at the back of the C.G. range the
plane will be more maneuverable, but could also
become too difficult for you to control. In any
case, do not 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.)
17
