Specifications

Do not set this switch if you are using a tail motor ESC.
30.1.8.1.3. GY401 delay trimmer
The Delay adjustment is on the gyro itself, and allows you to configure the gyro for the re-
sponse of the tail rotor system. This is only used in heading hold mode.
The delay setting of 0 is used for very fast servos such as the S9253/S9254. The delay setting
of 100 is used for very slow tail servos and for tail motor ESCs. A tail motor ESC requires at
least half a second to go from half throttle to full throttle, which is about twice as slow as the
slowest tail servos ( 0.25 sec/60 degrees)
For a heli with a tail servo, if the delay setting is too low, then the gyro will assume the servo is
faster than it really is. So the gyro will send commands to the servo to move very quickly, and
the servo will try to move to the new position but it will be too slow, and it will lag behind the
gyro commands.
For a heli with a tail motor ESC, if the delay setting is too low, the gyro will assume the tail mo-
tor can change RPM very fast. So the gyro will try to change the speed of the tail motor very
quickly but the tail motor RPM will lag behind the gyro commands.
This delay setting seems to affect the end of a turn (yaw). At the end of a turn, the gyro needs
to increase the tail thrust to slow down the tail then decrease it to maintain a steady tail posi-
tion.
For example, imagine you are performing turning the heli (yaw) and you suddenly stop. If the
delay setting is too low in this situation, the tail will wag a few times before settling down be-
cause the gyro will overshoot the end of the turn and need to correct the heading a few times.
If you increase the delay, this may allow you to increase the gain, although you may not need
this as a beginner.
30.1.8.1.4. GY401 limit trimmer
The limit adjustment is on the gyro itself, and allows you to set the endpoints of the servo
travel.
For a heli with a tail servo, if the limit setting is too high, then the gyro will attempt to move the
tail servo too far in one or both directions. This will cause the servo to bind and emit a buzzing
noise, which creates accelerated wear on the servo motor and early servo failure.
If the limit setting is too low, then this will decrease the range of the tail blade pitch. This will re-
duce your pirouette rate and may cause tail control problems.
For a heli with a tail motor ESC, if the limit setting is too low, then the tail motor ESC may fail to
arm when holding the rudder stick full left. Therefore you cannot set the limit too low when us-
ing a tail motor ESC, but this is dependent on the tail ESC.
For a heli with a tail motor ESC, if the limit setting is too high, then this causes severe prob-
lems. The tail motor ESC will not arm because holding left rudder will cause the gyro to emit a
signal that is too low for the tail motor ESC to arm. Also, if you hold extreme right rudder, the
tail motor ESC may shut down because the signal is outside the valid range.
Therefore, for a heli with a tail motor ESC, the limit trimmer should be set to 100%.
30.1.8.1.5. GY401 gain setting
The gain adjustment is done at the transmitter via the gyro gain connector on the channel. This
Technical Appendix
176