At this stage the model should be in ready-to-fly condition
with all of the systems in place including the engine, landing
gear, covering, and the radio system.
❍
1. Use a felt-tip pen or 1/8" [3mm]-wide tape to accurately
mark the C.G. on the top of the wing on both sides of the
fuselage. The C.G. is located 3-1/8" [80mm] back from the
leading edge of the wing, where it meets the fuselage.
❍
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 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 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, nose weight may
be easily added by using a “spinner weight” (GPMQ4645 for
the 1 oz. weight, or GPMQ4646 for the 2 oz. 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 (don’t attach weight to
the cowl–it is not intended to support weight). Begin by
placing incrementally increasing amounts of weight on the
fuse over the firewall 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 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 page 23 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.
Note:
Checking the condition of your receiver battery pack is
highly recommended
. All battery packs, whether it’s a trusty
pack you’ve just taken out of another model, or a new battery
pack you just purchased, should be cycled, noting the
discharge capacity. Oftentimes, a weak battery pack can be
identified (and a valuable model saved!) by comparing its
actual capacity to its rated capacity. Refer to the instructions
and recommendations that come with your cycler. If you
don’t own a battery cycler, perhaps you can have a friend
cycle your pack and note the capacity for you.
PREFLIGHT
This is where your model should balance for the first
flights. Later, you may wish to experiment by shifting the
C.G. up to 1/8" [3mm] forward or 7/8" [22mm] 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.
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