Top Flite TOPA0400 - Manual (Page 54)

BALANCE YOUR MODEL
NOTE: This section is VERY important and must
NOT be omitted! A model that is not properly
balanced will be unstable and possibly unflyable.
❏
1. The balance point (C.G.) is located 4-9/16"
(116mm) back from the leading edge at the “LE
break” as shown in the sketch and on the plan.
Accurately mark the balance point on the top of the
wing on both sides of the fuselage. Use thin strips
of tape or a felt-tip pen to make the marks.
Hint: Reference the fuse plan to help you locate
the proper balance point. This is the balance point
at which your model should balance for your first
flights. After initial trim flights and when you
become more acquainted with your P-51, you may
wish to experiment by shifting the balance up to
5/16" forward or backward to change its flying
characteristics. Moving the balance forward may
improve the smoothness and stability, but the
model may then require more speed for takeoff
and may become more difficult to slow for landing.
Moving the balance aft makes the model more
agile with a lighter, snappier “feel” and often
improves knife-edge capabilities. In any case,
please start at the location we recommend. Do not
at any time balance your model outside the
recommended range.
❏
2. With the wing attached to the fuselage, all
parts of the model installed (ready to fly) and an
empty fuel tank, hold the model upside down with
the stabilizer level. The Great Planes CG Machine
™
balancer works great for balancing the model.
❏
3. Set the model on the balancer at the balance
point. If the tail drops, the model is “tail heavy” and
you must add weight to the nose to balance the
model. If the nose drops, it is “nose heavy” and you
must add weight to the tail to balance the model.
If possible, first attempt to balance the model by
changing the position of the receiver battery. If you
are unable to obtain good balance by doing so,
then it will be necessary to add weight to the nose
or tail to achieve the proper balance point.
Note: Nose weight may be easily installed by
using a “spinner weight” or gluing lead weights to
the firewall. Tail weight may be added by using
Great Planes (GPMQ4485) “stick-on” lead weights.
Later, if the balance is O.K., you can glue the
weights inside the tail wheel compartment.
PREFLIGHT
CHARGE THE BATTERIES
Follow the battery charging procedures in your
radio instruction manual. You should always
charge your transmitter and receiver batteries the
night before you go flying and at other times as
recommended by the radio manufacturer.
BALANCE THE PROPELLER
Carefully balance your propellers before flying. An
unbalanced prop is the single most significant
cause of vibration. Not only may engine mounting
screws vibrate out, possibly with disastrous effect,
but vibration may also damage your radio receiver
and battery. Vibration may cause your fuel to
foam, which will, in turn, cause your engine to run
lean or quit.
We use a Top Flite Precision Magnetic Prop
Balancer (TOPQ5700) in the workshop and keep a
Great Planes Fingertip Balancer (GPMQ5000) in
our flight box.
At this time check all connections including
servo horn screws, clevises, servo cords and
extensions. Make sure you have installed the
nylon retainer on the Screw-Lock Pushrod
Connector and the silicone retainers on all
the clevises.
- 54 -