Smooth Tail Slider and Pivot

If you are having problems with the tail wagging, check the tail slider control arm. If there is too much friction from either the control arm or from the servo control rod, the tail will wag.

What is happening is that the gyro tells the tail pitch control servo to move. Nothing happens because of friction in the mechanism. The gyro increases its control output to get the tail to move. Eventually, the gyro's output forces the servo to overcome the mechanism's friction. Once in motion, the tail pitch mechanism will move too far, forcing the tail to wag in one direction. The process repeats in the opposite direction when the gyro senses too much tail motion.

Remove the control rod from the tail pitch control arm and check that the control arm and the servo's control rod have no friction. Blowing on the control arm should cause it to move, yet it should not be loose on the pivot.

If it is tight, remove the control arm from the pivot. The photo below shows that the pivot has some ridges in it from the molding process.

Using a thin piece of 600 grit sandpaper, lightly polish the pivot until the control arm rotates smoothly on the pivot. Be careful to not polish too much or in one spot. The control arm should not wobble. The right amount seemed to be when the ridges disappeared.