Tail shudder

[fulcrum2]

Dear fellow Gaui brothers,

can't get my X5 perfect, so I am seeking advise within this community.

The funny thing is, the X5 flies extremely well, the tail has perfect heading hold, no wag at all, stong hold in funnels. Life could be great...

...however, pitch pumps from a flat right side up hover will make the the tail shudder very briefly. It is there on the initial upwards movement and also on the stop (stop the climb after 30 feet or so). A short low amplitue high frequency oscillation. After that, rock solid again.

I use the vbar gov with very mild settings (even below default) and the Gaui LV tail servo. I know, the tail servo is not top of the line, however it does anything else great and I would like to try everything else before considering a replacement.

Tried also tail gain higher lower, no success. Tail blades are KBDD.

Any help is greatly appreciated. Thanks and so long, Stefan

[B.Ewing]

try an extra pushrod support. some members have upgraded the rod to carbon, i havnt found it necessary but its possible your rod is flexing. my kbdd's hold fine too. this one might come down to vbar settings

[blade450]

You might want to play around with the precomp settings of the V-bar.

Sent from my iPad using Tapatalk HD

[x5heli]

I got full vbar and it really picky. Check your tail servo arm from center hole to the arm hole about 14-16mm get servo close to 90degree. Try get 90 from servo to the tail pitch.
As bewings said. If you can change the tail metal pushrods to carbon bc that stock metal pushrods kinda flexi. On the tail precom I got it 28



The pick show how u 90 your x5 if u have manual.

[fulcrum2]

Found the cause. It is the dynamic collective add of the vbar. Reduced this and got rid of the shudder. Thanks to everyone for the help!

[gashead]

Originally Posted by fulcrum2

Found the cause. It is the dynamic collective add of the vbar. Reduced this and got rid of the shudder. Thanks to everyone for the help!

What is the dynamic collective add of the vbar mean?

[psylence519]

I imagine it's the torque pre-compensation. When given a large pitch change, the controller will add a little tail compensation anticipating the changes that will be needed.

[gashead]

Originally Posted by psylence519

I imagine it's the torque pre-compensation. When given a large pitch change, the controller will add a little tail compensation anticipating the changes that will be needed.

So why not just say that? rather than making up new words? lol.

[fulcrum2]

...well because this is how the Parameter is called within the vbar Software

[gashead]

Originally Posted by fulcrum2

...well because this is how the Parameter is called within the vbar Software

I only want to know where this is so if i have this problem in the future i can try this, i have gone through the vbar menu and still cant find where it says that or what its function is, can you tell me where exactly it is?

[fulcrum2]

OK, I see. It is in the gov menu. So the explaination that has been given above is not correct. The tail pitch is not changed, but the throttle.
There are differant "adds" in the gov menu. Dynamic collective add opens the throttle when the pilot moves the pitch gimbal quickly.

Hope this makes it clear.

So long!

[gashead]

Originally Posted by fulcrum2

OK, I see. It is in the gov menu. So the explaination that has been given above is not correct. The tail pitch is not changed, but the throttle.
There are differant "adds" in the gov menu. Dynamic collective add opens the throttle when the pilot moves the pitch gimbal quickly.

Hope this makes it clear.

So long!

Thx, but thats why i've never heard of it, i always use the Kontronik's governor and never even looked in the vbar one.

[fulcrum2]

This one is solved


read here:

https://www.helifreak.com/showthread.php?t=536736


thanks to all for your help and have a great one!