Greetings to everyone!

I am setting up a Spirit for the first time on an X5. My previous experience has been with Bav. Demon 3SX units.

I started with a main gain of 55% but sharp aileron inputs (with 20% expo on tx) produced terrible head wobbles. I reduced it all the way down to 25 head gain, but it's still not gone.

At this point I figured I'd ask for advice because most of the guides say that head gain is around 50-60% (depending on heli).

Any tips on where I should check or start looking?

Thanks.

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John Clayton

Hello,

are you using stock double sided tape? The unit should be mounted very hard.

To reduce wobble effect on both Aileron/Elevator axes you can decrease Cyclic Feed Forward (Advanced Tab), with default settings it should work fine.
For Elevator bouncing you can increase Elevator Filter to 3-4, higher values should help.

What Rotation Rate do you configured for Cyclic (Sensor Tab)?
Is Geometry 6° parameter configured precisely?

Are you using flybarless blades?

It should work very well with 60 - 70% Cyclic Gain with this helicopter size.

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Spirit System developer

I was using Scotch 411 Medium, outdoor mounting tape - has worked brilliantly on everything so far. I just switched the FBL to the tape included in the kit, and the wobbles are no different.

Rotation Rate is: 8

Geometry at 6 degrees has a value of 75. I am using the blades that came with the kit, yup - FBL style blades. This machine has been flown for about 140 flights so far using Bavarian Demon without any problems (except of course that I can't get elevator wobble to go away - which is why I'm trying Spirit).

Thanks for the speedy reply.
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john

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John Clayton

Great,

you can also reduce this issue with harder head dampeners. It can help a lot in some cases.

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Spirit System developer

I already switched to 95 hardness, completely new head dampers.

Is the geometry at 75 ok? I was worried this was too low - as it starts out > 100...

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Thanks.

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John Clayton

Yes, it is OK, but if you can put ball linkages closer to servos, it may help and possibly reduce wobble as well.

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Spirit System developer

you mean move the ball link closer to the center of the servo? you DONT mean shorten the servo linkages I hope - as that would put all the head geometry off...

Cheers for the help by the way
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john

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John Clayton

Yes, closer to the center of the servo.

This will change your aileron/elevator limits (cyclic ring), collective pitch and geometry 6°.

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Spirit System developer

Hi!

Today I tried your suggestion moving the ball links one step closer to the servo center, then I re-tuned the helis head + spirit settings to ensure I still have 12 degrees, that it's level and that cyclic movement isn't uneven etc.

Using the SOKO tool I was able to confirm a completely level head at top/mid and lower collective stick.

One thing i noticed is that I've *also* got about 12 degrees of aileron and elevator pitch. I was thinking it should be around 10 degrees - will this matter?

When I ran the heli today I still have bad head oscillations. Once they start they do not stop but they don't get worse either. The look like a violent aileron oscillation that's running at about 8 wobbles per second.

I'm open for any other suggestions. Things I've tried now:
- replaced mounting tape
- brand new very hard dampers
- rechecked setup (at least I'm getting faster at it now - yay!)
- moved ball links one hole closer to the center of the servo on all 3 cyclics
- checked my servo us and mhz - they are correct (333 Mhz) - the X5 uses the same servos that are in the X7 (GS-503/4)

The only thing that makes a difference is putting the main gain down to about 20.

Regarding the firmware link you posted in another thread:
- What else has changed in the firmware please?
- can I flash backwards in case there is no change?

Cheers.
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John Clayton

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John Clayton

Thanks for detailed info.

From first description I have assumed that it was different problem.

Now I think that the best solution is to flash the firmware. This should help.
You can flash different firmware anytime.

The problem is caused by very strange, high amplitude, low frequency noise. Spirit is able to react so fast to this so it is visible.

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Spirit System developer