The attitude stabilization („head gyro“) for the flybarless head maintains any attitude and prevents disturbances, such as ballooning,
if the pilot does not apply any further control input. On the ground, the function is visible on the swashplate: when giving control input
and subsequently letting go of the stick, the swash moves slowly back to level, maybe even staying in the controlled position for a
short moment.
This head gyro function can also be used for flybared heads, to assist the the mechanical stabilization, but with a caution not to set the
gain too high. An unmatched interaction between mechanical and electronic stabilization is definitely not desired.
AN EFFICIENT WAY TO OPTIMIZE THE RIGID SETTINGS
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We suggest to initially use a pot or slider on the radio for gain tuning. Use the head gyro channel or, in case no signal is supplied
from the radio, the corresponding gain parameter in the HEAD/TAIL menu, to set the gain as high as possible, approx 5-10% below
any oscillations occurring. For safety reasons, begin with low values. Too high a gain may provoke oscillations, for example like a shiver
on aileron or a fast wobble on elevator.
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Then set the desired agility in the software.
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Usually at this point, the performance is close to the optimum or even perfect. If further improvement is necessary, you can test sudden
stops (lock-in) after abrupt and fast stick control stops:
In case of a tendency of wagging in elevator axis:
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increase ‚Elevator Filter‘.
In case of slight bounce-back after abrupt stick control stop:
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Reduce ‚Direct Control Portion‘, increase head gain.
In case the tail continues to move on a short while, even after the end of stick input:
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for avoiding a sluggish reaction: increase ‚Direct Control Portion‘, possibly also increase the head gain and/or carefully increase the travels
in the SERVO TRAVEL menu.
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for avoiding harsh reactions: reduce ‚Agility‘ in the HEAD menu, and carefully increase the travels in the SERVO TRAVEL menu.
If aileron and elevator impulses cause mixed movements, this might be caused by an incorrect ‚Swash Phasing‘ setting. Test with
reduced head gain. For example, if the tail moves downwards when ‚right‘ aileron is input, then increase ‚Swash Phasing‘ in the
positive direction.
Test response to long stick inputs
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In the case of a fast first reaction and then decreased turn rate: reduce ‚Direct Control Portion‘ and, if needed, increase ‚Agility‘.
Test high-speed flight
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Against slow ballooning or undercutting: reduce or respectively increase ‚Decay Rate‘.
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Against temporary nose-up („dolphin“) during sharp coll.pitch inputs: increase head gain as far as possible.
Make sure the servo travel is set optimally (value between 65 and 85 in SERVO TRAVEL menu).
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Against lasting ballooning after hard coll.pitch input: use ‚Attitude Hold Range‘.
In case of tilting or tumbling motion during pirouettes:
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Align the sensor perfectly in all 3 axes.
Trim the swashplate exactly level while there is a connection to the DIAGNOSE/TRIM menu (necessary to have all servos at
neutral), and trim the heli mechanically to the optimum during the first flight.
HEAD GYRO OPTIMIZATION
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