Align T-REX 450SA ARF Manual page 42

12.4 To test gyro control and response, it is usually helpful to watch the tail servo arm for reference.
While observing the tail servo arm, give a right rudder input on the transmitter. Note the direction
that the servo arm moves. Then, move the nose of the helicopter quickly to the left while still
observing the tail servo arm (it may take a few attempts to observe the tail servo arm movement
properly). If the servo arm moves in the same direction as it did when you gave the right rudder
input before, then the gyro is responding properly by attempting to counteract the left-hand
movement of the nose with a right rudder input.
If, however, the tail servo arm is moving opposite the direction it did when you gave the right rudder
input before (for example, offering a left rudder input when you move the nose of the helicopter
quickly to the left, further exaggerating the effect rather than counteracting it), you will need to
use the Reverse switch located on the gyro to reverse the direction of response. Please see the gyro
manual for more information if required.
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