Great Planes L-39 EP Ducted Fan RxR - GPMA6002 - Manual (Page 9)

9
Set the Control Throws
Use a Great Planes AccuThrow ™ (or a ruler) to accurately
measure and set the control throw of each control surface
as indicated in the chart that follows. If your radio does not
have dual rates, we recommend setting the throws at the
low rate setting.
These are the recommended control surface throws:
ELEVATOR (High Rate): 5/16" [8mm], 10° up
5/16" [8mm], 10° down
AILERONS (High Rate): 3/16" [4.8mm], 8° up
3/16" [4.8mm], 8° down
ELEVATOR (Low Rate): 1/8" [3.2mm], 4° up
1/8" [3.2mm], 4° down
AILERONS (Low Rate): 3/32" [2.4mm], 4° up
3/32" [2.4mm], 4° down
NOTE: The throws are measured at the widest part of
the control surfaces.
IMPORTANT: The L-39 RXR has been extensively fl own
and tested to arrive at the throws at which it fl ies best. Flying
your model at these throws will provide you with the greatest
chance for successful fi rst fl ights. If, after you have become
accustomed to the way the L-39 RXR fl ies, you would like
to change the throws to suit your taste, that is fi ne. However,
too much control throw could make the model diffi cult to
control, so remember, “more is not always better.”
Balance the Model (C.G.)
More than any other factor, the C.G. (balance point)
can have the greatest effect on how a model fl ies, and
may determine whether or not your fi rst fl ight will be
successful. If you value this model and wish to enjoy it for
many fl ights, DO NOT OVERLOOK THIS IMPORTANT
PROCEDURE. A model that is not properly balanced will
be unstable and possibly unfl yable.
At this stage the model should be in ready-to-fl y 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).
If you mark the C.G. position onto the top of the wing, be
very careful if using tape as it could damage the paint when
removed. Also, do not attempt to remove felt-tip pen marks
with alcohol. We suggest making small marks on the wing
beneath the ducted fan inlets.
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 3/16" [4.8mm] forward or 1/8" [3.2mm] back to
change the fl ying characteristics. Moving the C.G. forward
may improve the smoothness and stability, but the model
may be 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 all parts of the model installed (ready to fl y), 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