Tail letting go can it be the servo?

[stunks]

Yesterday when i was flying my 600 nitro v bar i notice like when i flip or do any sudden collective input the tail lets go really bad doing like 360 etc, at one point it was doing a continues 360 piro with out me putting in any input so i had to hit TH, the servo thats on there is the futaba bls 254 that has been on there for over 2ys now.

[cjcj1949]

It could be the servo, but all you really know is that the tail goes out of control. That could be anything in the loop that moves the tail back when its been moved by other forces. You've got the gyro itself, the gyro mounting pad, the servo itself, the servo mounting, the control links, the tail mechanical. I'd try turning the heli the heli on the ground and see if you get erratic movements when its turned hard. I'd look at the mounting tape first. Probably a good idea to replace it anyway after two years especially on a nitro. The servo may be twitching due to pot wear or dirty pot, but that wouldn't show up under high yaw rate.

[LaurenceGough]

That's pretty major... I would test it on the bench, make sure there is no binding by popping off the link from the servo horn, it should be as smooth as butter going to either side of the tail slider when moved by hand.

If it is still that will need to be resolved before moving on.

If it's smooth then put the linkage back on the servo horn and feel the tail slider as you move the servo via your TX. There should be a moderate amount of strength both ways, the tail servos are quite weak overall mind you.

Repeat the tail movement back and forth for a few minutes (4+) to make sure the tail servo does not overheat or otherwise play up.

Check that the belt is not damaged or twisted too many times, or if torque tube that the boom has not come out or is able to come out causing your tail gears to lose mesh.