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As an example, the option to configure flight phase-
specific – and static – gyro gain gives you the opportu-
nity to exploit maximum stabilization for normal, slow
flying, but to reduce gyro gain for fast circuits and
aerobatics.
Samples of various gyro settings and configuration
notes
•
Linear gyro suppression: 0 % to 199 %.
With the tail rotor stick in the centre position, the
resulting gyro effect is set using the selected
transmitter control. Using a proportional rotary
control or slider, the effect is infinitely variable
between zero ("min") and maximum ("max"),
provided transmitter control travel is not restricted.
With full tail rotor deflection, the effective gyro gain
is as follows:
"current control position
minus
gyro suppression value".
This means that at 0 % gyro suppression, gyro
gain is constant for tail rotor stick movement; at
50 % suppression, gyro gain is reduced to half if
the assigned transmitter control is moved to the
+50 % position (as shown here); and only at >150 %
suppression is gain reduced to zero with the slider
at this position, well before full tail rotor deflection.
Exemple:
+50 %
left
centre
Stick deflection tail rotor
•
Linear gyro suppression with reduced control
travel, e. g. -50 % to +80 % of full travel.
Gyro gain is infinitely variable within these transmitter
control limits. Here too, for purposes of illustration,
we plot gyro gain values in relation to tail rotor
deflection for various parameter values of gyro
suppression.
Exemple:
+80 %
left
centre
Stick deflection tail rotor
Adjusting the gyro sensor
To achieve the maximum possible level of stabilization
for the helicopter with the gyro along the 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, fur-
right
ther reductions to gyro gain will need to be made to
eliminate the oscillation.
If the model is flying forward at high speed or hov-
ering in a powerful headwind, the net result of the
stabilizing effect of the vertical fin 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 configurable 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 flight).
right
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 flying at maximum speed into a strong
Program description - Helicopter mixer
199
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