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This is where your model should balance for the fi rst fl ights.
Later, you may wish to experiment by shifting the C.G. up
to 1/4" [6mm] forward or 1/2" [13mm] back to change the
fl ying 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 diffi cult
to slow for landing. Moving the C.G. aft makes the model
more maneuverable, but could also cause it to become too
diffi cult to control. In any case, start at the recommended
balance point and do not at any time balance the model
outside the specifi ed range.
❏
2. With the wing attached to the fuse, all parts of the
model installed (ready to fl y) and an empty fuel tank, place
the model upside-down on a Great Planes CG Machine, or
lift it upside-down at the balance point you marked.
❏
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 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
bottom of the fuse 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 fuse 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, have an assistant help you lift the
model by the engine propeller shaft and the bottom of the
fuse 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 wing tip. An airplane that has been laterally
balanced will track better in loops and other maneuvers.
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 the decal sheet 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 fl ying, 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 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 fl ying with
batteries that are only partially charged.
26
PREFLIGHT
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