GRAUPNER MC-20 HoTT Programming Manual page 185

vertical axis, observe the following:
• The controls should have as little friction and
"play" as possible.
• There should be no "spring" in the control linkage.
• Use a strong and comparably fast servo.
When the gyro sensor detects a model rotation, the
faster its response – a corresponding corrective
change to tail rotor thrust – takes effect, the further
the gyro gain adjuster can be moved without causing
the tail of the model to start oscillating, and the better
the model's stability about its vertical axis. If the
response is slower, there is a risk that the model's tail
will start to oscillate even at low gyro gain settings.
Here, further reductions to gyro gain will need to be
made to eliminate the oscillation.
If the model is fl ying forward at high speed or
hovering in a powerful headwind, the net result of the
stabilizing effect of the vertical fi n combined with the
gyro may also lead to an overreaction that once again
manifests itself through tail oscillation. To achieve
optimum gyro stabilization under all conditions, you
can make use of the option to adjust gyro gain from
the transmitter using a transmitter control assigned to
input "7", in connection with gyro suppression and/or
the two settings on the Gyro NEJ-120 BB.
Further notes on gyros with confi gurable multilevel
gyro gain (e.g. NEJ-120 BB)
Since you cannot specify the gyro gain from the
transmitter proportionally via the transmitter control,
the gyro's own control 1 must be used to set the
(weaker) gyro gain (e.g. for aerobatics) and control
2 the stronger gyro gain (e.g. for hovered fl ight).
Even though a proportional control is used for control
function 7, only a switch-over between these two
values takes place and the setting is therefore not
proportional.
You should therefore advance control 2 to the point
where the model is on the brink of oscillating when
hovering in calm conditions, and advance control 1 to
the point where the model does not oscillate with its
tail even when fl ying at maximum speed into a strong
headwind. Depending on the state of the weather
and the fl ight program planned, you can also switch
over the gyro gain from the transmitter – also with
gyro suppression dependent on tail rotor defl ection if
required.
Gyro offset
Important notice:
The value of this option is identical to the offset
value set in the "Gyr7" line of the »Control
adjust« menu, page 116. For this reason, any
changes made always affect the other menu
directly – and vice versa.
Most of the latest gyro systems not only feature
infi nitely variable proportional gyro gain setting, but
also offer a choice of two separate types of gain
mode on the transmitter.
If the gyro in use has at least one of these features
then this alternative offset setting provides an
opportunity to preset both "normal" gyro gain as well
as, as appropriate, to specify a "heading-lock mode"
whereby, even within this pre-selection, gyro gain can
be reduced by a particular gain type for normal, slow
fl ight with maximum fl ight stabilization, fast circuit
fl ights and aerobatics.
To proceed as described above, use fl ight phase
switching to enter different settings on the "Gyro
offset" line. Values between -125 % and +125 % are
possible:
Roll Tail rot.
Nick Throttle
Nick Tail rot.
Gyro suppression
Gyro offset
Normal
Based on these fl ight-phase specifi c (offset) settings,
gyro gain can also be infi nitely varied by a transmitter
control assigned in the "Gyr7" line of the »Control
adjust« menu, page 116.
Swashplate rotation
Nick Throttle
Nick Tail rot.
Gyro suppression
Gyro offset
Swashplate rotation
Normal
Some rotor head control systems make it necessary
to incline the swashplate in a different direction from
the intended inclination of the rotor plane when
a cyclic control command is given. If your model
features a four-bladed main rotor, for example, you
may need to use this menu to set up a software-
driven 45° rotation of the control linkage to the right,
so that the pushrods from the swashplate to the
rotor head can be set exactly vertical, ensuring that
the blade control system works correctly, without
unwanted differential effects. This eliminates the need
to make mechanical changes to the control linkages.
Negative angles equate to a virtual rotation of the
rotor head to the left; positive angles a virtual rotation
to the right.
Detail program description - Helicopter mixer
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