7
Balance the Model
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.
At this stage the model should be in ready-to-fly condition with all of the systems in place including the receiver, ESC, and battery
pack.
❏
1.
The C.G. is located 1-15/16" [49mm] back from the leading edge of the wing at the fuselage
(the seam where the
wing panels have been joined to the fuselage). Place pieces of masking tape onto the top of the wing where you will mark the
C.G. positions. Use a fine-point felt tip pen to mark lines on the pieces of masking tape at the recommended C.G. If you aren’t
using a C.G. Machine, apply narrow (1/16" [2mm]) strips of tape over the lines so you will be able to feel them when lifting the
model with your fingers.
This is where your model should balance for the first flights. Later, you may wish to experiment by shifting the C.G. up to 3/16
"
[4.8mm] forward or 1/8
"
[3.2mm] back to change the flying characteristics. Moving the C.G. forward may improve the smoothness
and stability, but the model may be 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 all parts of the model installed (ready to fly), 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 to balance. If the nose drops, the
model is “nose heavy” and the battery pack and/or receiver must
be shifted to balance. This model is very weight sensitive. We
do not recommend adding any additional weight to achieve the
suggested balance point unless absolutely necessary. Instead,
shift the battery pack and receiver forward or aft to alter the C.G.
❏
4. If you have more than one type of battery you plan to use in
the L-39, be sure to check the balance of each unique pack and
mark the packs’ locations in the radio compartment to achieve
the proper balancing point.
PREFLIGHT
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 of this manual 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 motor batteries the night before you go flying, and at other times as recommended by the 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 flying with batteries that are only partially charged.
Range Check
Follow the range check procedure as it is described in your transmitter’s instruction manual.
