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This is where your model should balance for the first
flights. Later, you may wish to experiment by shifting the
C.G. up to 1/4" [6mm] forward or 1/4" [6mm] back to
change the flying 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 difficult to slow for landing. Moving the C.G.
aft makes the model more maneuverable, but could also
cause it to become too difficult to control. In any case,
start at the recommended balance point and do not at
any time balance the model outside the specified range.
2. With the wing attached to the fuselage, all parts of the
model installed (ready to fly) and an empty fuel tank, place
the model upside-down on the Great Planes C.G. Machine,
or lift it upside-down at the balance point you marked. You
should be able to feel the tape lines with your fingers.
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 and/or receiver
must be shifted aft or weight must be added to the tail to
balance. If possible, relocate the battery pack and receiver
to minimize or eliminate any additional ballast required. If
additional weight is required, nose weight may be easily
added by using a "spinner weight" (GPMQ4645 for the 1 oz.
[28g] weight, or GPMQ4646 for the 2 oz. [57g] weight). If
spinner weight is not practical or is not enough, use Great
Planes (GPMQ4485) "stick-on" lead. A good place to add
stick-on nose weight is to the firewall. Begin by placing
incrementally increasing amounts of weight on the bottom of
the fuselage over the nose or tail 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.
Note: Do not rely upon the adhesive on the back of the lead
weight to permanently hold it in place. Over time, fuel and
exhaust residue may soften the adhesive and cause the
weight to fall off. Use #2 sheet metal screws, RTV silicone
or epoxy to permanently hold the weight in place.
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 wing level, lift the model by the engine
propeller shaft and the bottom of the fuselage under the
trailing edge of the fin. 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.
IDENTIFY YOUR MODEL
No matter if you fly at an AMA sanctioned R/C club site or if you
fly 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 flying sites
and AMA sanctioned flying events. Fill out the identification tag
on the back cover page and place it on or inside your model.
CHARGE THE BATTERIES
Follow the battery charging instructions that came with your
radio control system to charge the batteries. 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.
CAUTION: Unless the instructions that came with your
radio system state differently, the initial charge on new
transmitter and receiver batteries should be done for 15
hours using the slow-charger that came with the radio
system. This will "condition" the batteries so that the next
charge may be done using the fast-charger of your choice.
If the initial charge is done with a fast-charger the batteries
may not reach their full capacity and you may be flying with
batteries that are only partially charged.
BALANCE THE PROPELLERS
Carefully balance your propeller and spare propellers before
you fly. An unbalanced prop can be the single most
significant cause of vibration that can damage your model.
Not only will engine mounting screws and bolts loosen,
possibly with disastrous effect, but vibration may also
damage your radio receiver and battery. Vibration can also
cause your fuel to foam, which will, in turn, cause your
engine to run hot or quit.
17
PREFLIGHT
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