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Re: Gaui X5 Head Wobble

Posted: Sun 22. Feb 2015 22:03:55
by ZeXx86
Good job, it seems you are found the problem!

I believe it will be much better now.

Thanks for sharing your findings.

Re: Gaui X5 Head Wobble

Posted: Mon 23. Feb 2015 18:39:25
by johncclayton
I still have aileron shakes, and will still need to recheck things again. Will report again tonight if I find the time.

Re: Gaui X5 Head Wobble

Posted: Fri 27. Mar 2015 15:48:28
by johncclayton
Greetings

I had lots of work + needed to wait for parts to arrive.

I've now replaced the blade grips as well as the thrust bearings (again). I've hovered again with this setup (head dampers @ 95) and there's still vibration in the head on the aileron axis.

I then switched to head dampers with 75 hardness, the head wobbles are perhaps ever so slightly less - but still not solid as a rock by any means. Hard aileron inputs result in severe head vibration.

I created a video so you can see what I mean. Next I'm thinking of zip-tieing the Spirit FBL to the main body, after that perhaps something in the tail??

http://youtu.be/LNaHuB_2yR4

Re: Gaui X5 Head Wobble

Posted: Fri 27. Mar 2015 17:05:18
by Madmatt986
Hello john,

I am sorry to read the troubles you are having. Just for encouragement, I have an X5 that flew perfectly out of the box using the Logo 500 defaults. It will fly beautifully once you figure this out.

Did you replace the feathering shaft in the head and/or main shaft? I actually had a feathering shaft that was slightly bent from the factory (maybe thats why there are always sold in pairs).

Also, what servos are you using. I have Savox SC-1257's with the linkage mounted 18mm from servo arm center.

-Matt

Re: Gaui X5 Head Wobble

Posted: Fri 27. Mar 2015 17:37:57
by ZeXx86
Video helped a lot.

This behavior can also occur with too high Cyclic Feed Forward, but can be eliminated by more things in the mechanics and the settings as well. Especially length of your servo horns are important there - each FBL works with various length differently.

What is your CFF value?

Re: Gaui X5 Head Wobble

Posted: Fri 27. Mar 2015 18:09:10
by johncclayton
5, I have also tried 6 and 8 to see what happens. What value do you suggest?

Re: Gaui X5 Head Wobble

Posted: Fri 27. Mar 2015 18:18:43
by ZeXx86
Try values of 3 or 4.

Is Geometry 6° parameter configured precisely?

If so, decreasing may fix the problem even with high CFF. Flight Style parameter can induce difference too, but just rather marginal and is not used to fix problem like this.

Re: Gaui X5 Head Wobble

Posted: Sat 28. Mar 2015 0:47:55
by johncclayton
I'll give 3/4 a shot and let you know. The flight style is at default (4) and the 6 deg is set to 75 - that's the value I had to use to get 6 deg to show correctly.

Cheers
--
John

Re: Gaui X5 Head Wobble

Posted: Sat 28. Mar 2015 0:49:00
by johncclayton
Speaking of servo horn length, is shorter going to potentially result in less shake?

Re: Gaui X5 Head Wobble

Posted: Sun 29. Mar 2015 9:41:11
by johncclayton
also - here's the latest vibe analysis with main and tail blades attached:

https://www.evernote.com/l/AAc3LfQwvlNH ... KM3RGAaA6c