In Auto, the gain will be controlled by the Flight Mode Switch unless you have chosen to use the RUDD D/R switch (in which case, you'd see "RUDD D/R" displayed in the Gyro Sense menu). Since you see "Auto", gain is controlled by the Flight Mode Switch through Channel 7 of your receiver.
Auto - the gyro gain is controlled by the Flight Mode Switch and the GAIN lead MUST be plugged into channel 7 of your RX (AUX 2).
AT 50% on the 9303 you have essentially disabled the gyro, as it's gain is ZERO and its operating mode is indeterminate. The gyro won't correct the tail servo when you move the nose of the heli.
With the 401 controlled by the Gyro Sense menu, gain numbers greater than 50 select HH mode. Numbers less than 50 select Normal/Rate mode. Numbers close to 50% select nearly zero gain, the gyro won't do much for you here whether it's operating in normal or HH mode.
The picture below is the GYRO SENSE setting menu, and it is set for AUTO (gyro gain controlled by Channel 7/Aux 2 and selected by the Flight Mode Switch).
Those numbers located in the center of the screen in the picture above, are all set to 50% (the default setting, and essentially zero gain and No Man's Land for the 401).
The values at the right of the screen allow you to associate the gain set by the three "POS" values with the position of the Flight Mode Switch.
NORMAL flight mode is with the flight mode switch positioned toward the rear of the TX. ST-1 is the flight mode when the switch is centered. ST-2 is the flight mode when the switch it forward, toward the front of the TX. HOLD, when enabled, selects the value for gyro gain in Throttle hold mode when active.
In the picture, the values at the right show POS 0 gain selected for Normal, ST-1 and ST-2 flight modes. If you have Throttle Hold enabled, you'll see a fourth entry, "Hold" in that list and it will be associated with POS 0, POS 1 or POS 2 -- your choice.
Assume that you set the middle set of numbers as follows:
POS 0: 25
POS 1: 75
POS 2: 60
And on the right-hand set of numbers, you set:
Norm: POS 2
ST-1: POS 0
ST-2: POS 1
The picture below will apply when using the GYRO SENSE menu:
With the flight mode switch in NORMAL position (toward the rear of the TX) the gain number of 60 associated with POS 2 would be applied to your gyro. You would be in heading hold with a gain somewhere close to 20%.
With the flight mode switch in its center position for ST-1 mode, the gain associated with your gyro would be the value for POS 0, or 25. This would put your gyro in Normal/Rate mode, with a gain of 50%.
With the flight mode switch forward, towards the front of the TX to select ST-2 mode, the value associated with POS 1 ("75" ) would be associated with the gyro gain. This would put your gyro in HH mode with a gain of about 50%.
The number you see displayed just to the right of the words "GYRO SENSE" simply tells you which of the three POS values are associated with the flight mode switch position.
You can set these values however you wish, and then switch over to your 9303's monitor screen and see how the gyro gain channel (AUX2) responds to the flight mode switch and the values you chose for this menu.
If you're using a six channel receiver, you MUST plug the gyro gain lead into Channel 5 of the RX, enable the GEAR switch in your TX Device Select menu, and use the GEAR channel endpoints to set gain. You CANNOT USE the GYRO SENSE menu if you have to run the gyro gain out of channel 5 of your receiver.
This picture applies when using the GEAR switch:
If you use the GEAR switch for gyro gain control along with Channel 5, you'll have one gear switch position that selects HH mode and one position that selects Normal/rate mode operation.
Gain for each switch position is set by the GEAR channel endpoint settings, and you'll have one gain in HH mode, one gain in Normal mode, depending upon the position of the GEAR switch.
Note that the endpoint settings must be in the range of 10 to 90% for each endpoint setting in the GEAR menu. Numbers between 0 and 10, or greater than 90 are No Man's Land for the 401, its mode will be indeterminate.
Usable gain numbers go from 11 to 90 in the endpoint menu, and as can be seen in the picture, the number in the endpoint menu isn't necessarily the gain divided by 2 (a setting of 45 gets you 50% gain, a setting of 90 gets you 100% gain).
Even if you have the gain dialed down to zero, you should still have rudder control as long as the rudder input on the 401 is plugged into the RX rudder port.
You will HAVE to set up the 401 for it to initialize in HH mode (red LED must come on solid after the gyro finishes its power-up sequence. If the light isn't ON solid, then you have initialized in the wrong mode and the gyro may or may not work very well.
In any event, if you have everything plugged in correctly you should still be able to control the servo from the transmitter using the rudder stick.
The best way to actually SET your gain is to fly the heli in fast forward flight. Increase gyro gain until the tail of the heli begins to oscillate, then back the setting down until that oscillation in fast forward flight goes away.
Enjoy that 9303.
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