Twitchy

[Hellraiser7]

I have a KDS 450 and its just developed a tail twitch?
In an hover the tail just wobbles back and forth. can anyone tell me why this happends?
been flying great over the past nothing has been alterd and still standard, I need to learn more!!

[GIXERMAN]

Disconnect linkage and check no binding, is every smooth, nothing loose or worn

[David Drew]

Have a look at the pitch slider.

A friend of mine has one and the inner sleeve that slides on the shaft had come adrift. The inner sleeve is only peened over at the ends and there is not much material at the ends and the peening failed.

Failing that, the servo if standard is not brilliant, nor is the gyro. Repacing both transformed the machine.

[Hellraiser7]

My thoughts were going the servo way! Thanks for the feed back!!

[Hellraiser7]

Have a look at the pitch slider.

A friend of mine has one and the inner sleeve that slides on the shaft had come adrift. The inner sleeve is only peened over at the ends and there is not much material at the ends and the peening failed.

Failing that, the servo if standard is not brilliant, nor is the gyro. Repacing both transformed the machine.

Yes that inner sleeve did come adrift but i super glued it back, the shaft has been greased and workd ok!

[cjcj1949]

You could try lowering the sensitivity on the gyro control. The air has got colder and the main rotor will be developing more thrust and this could be changing the response of your control loop. Your gyro mounting tape may need changing. Things do tend to wear or come loose and it may be that. Any cheap servo will work the tail well enough to prove if the old servo was at fault and the Assan 250 is a very good spare gyro for under £10 from HobbyKing Uk. Even digital servos are cheap like the Corona DS-929MG. Cheap units may not be as reliable, but even the best can fail.

It can also be something that seems to be ok like another servo that has a motor about to fail and is putting lots of noise on the power lines. Our helis are pretty complex and one symptom has many causes. You can try to replicate the fault statically by turning the heli by hand with the motor disconnected. You can also disconnect the gyro and see if the fault disappears, if you can replicate it on the ground.