The General parameters
(Dark green panel)
The parameters under this menu influence the overall operation of the gyro and are common to both the flight modes.
Mid Stick pulse length
This must correspond to the channel output pulse width of your radio system with a channel set to its centre position. It is used
to set the zero yaw rate point and also the switchover point for the Mode 0 to Mode 1 switching. Most RC manufacturers use
either 1500
µ
s (e.g. Sanwa, JR) or1520
µ
s (e.g. Futaba, Hitec). The gyro's factory default is 1510
µ
s but this value is
automatically adjusted to the value for your radio system as part of the Quick-setup routine. It is therefore not normally
necessary to adjust its value via the PC interface. However its value is useful for diagnostic purposes. If having done the
Quick-setup you find the value is not close to either 1500
µ
s or 1520
µ
s then you may have some trim offset or sub trim set on
the rudder channel. Alternatively, some unwanted mixing (e.g. revo, or ATS) may be active.
Throw limit 1 and Throw Limit 2
These are the servo throw limits set during the Quick-Setup procedure and are expressed as a percentage of the normal full
travel of the servo. These values are set as part of the Quick-setup routine and so will not normally need adjustment via the PC
interface. However, it is useful to see the actual values as they can help to trace problems with the set-up of the tail linkage. If,
for example, the limits are both greater than 120% it suggests that a better set-up could be obtained if a longer servo arm were
fitted and the throw limits reduced correspondingly. If the values for the two directions are very different this could simply
indicate that the helicopter tail linkage has a very asymmetric pitch capability but it may also point to an incorrect tail centre
pitch value. The quick-trim offset moves the hover pitch point away from the Mid Stick value so a large quick trim offset will
require a difference in the two throw limits in order to give nearly equal servo throw in the two directions. If in doubt turn on
the gyro in Mode0 and observe the throw of the servo for left and right stick deflections. If they are obviously different you
should investigate the reason for it.
Quick-trim offset
This is the servo offset that the gyro has set during the Quick-trim procedure to counter any error in the tail linkage length. It
is limited to
±
30% of the total servo travel. Since it is set by the Quick-trim procedure you will not normally need to adjust it
via the PC interface but it is useful to know the value. If the value is 30% or -30% then the linkage error is probably too great
to have been fully corrected by the gyro and you should adjust the tail linkage length and repeat the quick-trim.
Servo speed
This parameter matches the gyro’s expectation of the ability of the servo to match its commands to the actual performance of
the servo. Our software allows for typical servo loads so simply set this value to match the servo manufacturer’s quoted speed
of the tail servo at the operating voltage you are using.
Stop-Tracking
(Light green panel)
This panel gives access to two independent gain tracking values;
Left Stop Gain
and
Right Stop Gain.
These can be used in
conjunction with the transmitter gain to optimise the gyro performance separately for fast forward flight, left pirouette stops,
and right pirouette stops.
Set up these values as follows:-
Initially leave both stop gain values at the default values and set up the gyro and helicopter as described in the main gyro
manual. These controls should only be adjusted once the stops from fast, full stick pirouette speeds have been equalised by
adjustment of the throw limits and, if needed, the tail blade sizes. Remember that the stop times from fast pirouettes are
dominated by the maximum available tail thrust that the helicopter can produce at full tail servo travel and if this is lacking it
will be impossible to obtain good stop performance from gyro adjustment. You should ensure that the available throw either
side of hover pitch is similar before attempting to trim the stops with these controls.
Before setting the stop gains establish by flight tests the highest mode 0 and mode 1 gains (set at the transmitter) that do not
cause wagging in fast forward flight. You can then use the stop tracking to optimise the quality of the stop from modest
pirouette speeds. To aid in this test it is useful to set a temporary rudder rate switch option that when active limits the
pirouette speed to about 180 per second (equal both ways)
Test the stop from 180 deg/s left pirouettes and adjust this stop quality using the
Left Stop Gain
.
Increase the Left Stop Gain to make the stop crisper.
Decrease the Left Stop Gain to eliminate any bounce in the stop.
Repeat this process for 180 deg/s right pirouettes to achieve the best value for the
Right Stop Gain.
If you find that very different values for left and right stop gains are needed or that good stop quality is not obtainable
in both directions you should inspect the geometry of your tail linkage and correct as needed.
The options panel
(Blue panel)
Gyro sense
This is a parameter that is also set in the Quick-setup routine and should not normally need changing via the PC interface.
However, if you do change it please check that the gyro is operating in the correct sense before the gyro is next flown.
