Cyclic wobbles

[Gman]

Ok folks, i thought my last mod had fixed my problem but it hadn't (only reduced it a little)
I have been watching John Claytons thread in the hopes i may be able to fully fix my problem.
Here's what i have done apart from my previous mods or adjustments.
The dubro balancers are very good but the vibe analyser is even better. I used a laptop and USB extension cable and a large empty shed (no wind) to balanced all the blades at the problem RPM. The helicopter was not flown while attached and not tied down, just left running on it rubber skid nuts with a small amount of negative pitch (almost none) and one finger on throttle hold. I did the tail blades first without the main blades attached and once perfect I did the mains. I used small amounts of clear tape for the balancing.
The result now is a very well balanced helicopter, in fact I have never flown one this smooth before and the result..........no change.
Ok not to be beaten, i installed shorter servo arms (Align 500) 16mm centre to hole instead of Gaui stock 18mm, the result.........no change.
After all this I went back to the software and have managed to fix my problem so that I can fly at all the RPM's that I couldn't before without any cyclic wobble at all........gyro sensor to 20. Yep 20, not sure if this is a good idea but so far with light winds only it is flying well, no wobbles at all and quite stable.
What do you guys think, am I dicing with disaster or is it just not as stable or 'crisp' as it could be?

[ZeXx86]

Hello,

thanks for the update.

It should fly fine even with 20% cyclic gain, but could be not so precise. On the other hand it may be better for hard 3D and smack.
I recommend to set Cyclic Gain to approx. 50% and try to decrease Geometry 6° value. It should cause similar effect, but precision could be better.

[Gman]

Thank you for your fast reply.

At the start I had a reasonably low 6 degree value of I think around 90? I have been trying to increase that by using shorter servo arms and swash balls to reduce mechanical gain and im now up to 140 with geometry. Should I go back to the lower number mechanics? I had the wobbles worse then, or do you mean reduce the geometry number without any mechanical change?

[ZeXx86]

Value of 140 is good. I thought that you can reduce the value without any mechanical changes.

[Gman]

Thanks,

I'll try that tomorrow and see how it goes, how low would you recommend trying?

ps. The new Spirit I just received I put on my 450 and its going fantastic, love it!
I just wish the X5 would co-operate

[ZeXx86]

You can go to value 100 from 140 without any problem.

Thanks!

[Gman]

Hello,

I tried using 50% on the cyclic gain and a value of 100 on the geometry and that does work quite well (is there a downside to runninig it like this?).
The heli' is a little more stable but otherwise reacts as normal as far as I can tell.
I still had some occasional wobbles so I went back to my original settings except I have found increasing the gain to 25 was still wobble free but not above that value.
I have attached my settings and also a freeze from the vibe analyser (running with all blades attached) with the hopes that may help either me or others sort this X5 thing out.

Thank you.

[ZeXx86]

Hello,

vibration analysis seems to be perfect if it looks similarly in all axes. So we can rule out vibration problem.

You can try to lower Geometry 6° even more. But either solution with 20% gain should work too.

[agh321]

Hi just put my red fbl unit on my Trex 550l dominator and ime getting a wobble on the skids in the hover at 1800 rpm

No problems with the heli on the beast X at any head speed

1700 to 1900 slight wobble 2000 and over no wobble

I want 1800 in normal to hover and gently fly round but I've got the wobble problem

Things I've allready done to try to get rid Is fit 70* dampers 80* and 90* fit new spindle
Fit new main shaft tried differant blades and new main shaft bearings , adjusted the cyclic
Gain from 60* to 20* and it's still there

Any help will be great

[Gman]

Hi,
If it is a wobble and not a vibration induce shake (got a vibe analysis?) what type of mounting tape did you use? I have found the soft foam tape not to work very well, the grey 3M stuff works excellent.
Also,what geometry 6' (tuning) value do you have?