Spirit System

My Mostro was flying good on the Spirit. Still had a little tweaking to do with a slight elevator bounce but otherwise great.

6 weeks ago I had a crash (let a guy buddy box and he left his throttle at -100 when I gave him control so it went smash into the ground ). I've since been chasing an issue I haven't been able to resolve. I think I'm passed a hardware issue and now wondering if maybe it is a setting.

I have low vibes and everything appears to be smooth. I tried a friend's head assembly (grips, head, dfc links) from his un-flown mostro and it exhibited the same issue. I've replaced all tail grip bearings and new hub and shaft, main shaft and the bearings in main grips.

I know it isn't the FBL unit because I switched it out with another Spirit I have and it acted the same way.

Only thing I haven't fully ruled out is a bad elevator servo. On the bench it acts perfectly normal and it handles load in all positions smoothly. But I bring it up because it makes more of a hum in idle then I remember.

The issue:
On hard collective, the heli will shake violently on the elevator axis and then stabilize. This will happen slightly on giving quick positive and can be extremely violent if hard stopping. One time it even started flipping uncontrollably a couple revolutions (strictly on the elevator axis and didn't rotate on aileron). before I gained control back. Needless to say, since that day I've been more cautious and only try small collective.

So if everything hardware related seems fine, it's making me think maybe it is my FBL settings. I was tinkering with it after the crash. And at first it wasn't so bad and I was able to do aileron tictocs without issue. I started tinkering to make the ele bounce go away. I then started finding other vibes in the heli and replacing bearings and shafts for good measure, etc. After each replacement, the ele shakes only become worse.

Question
So my question is, I assume cyclic feed forward and elevator filter are the settings to focus on in the Spirit to deal with violent shake on hard collective moves on the elevator axis.

But would a bad setting cause the heli to flip uncontrollably? This obviously has me concerned and cautious about testing it.

Zeks already answered in another forum. In case anyone was looking here and he doesn't have to cross post

Hi,

I guess it is servo issue (probably elevator servo)
There is no parameter that can do such thing in the unit.

If you are doing pitch pumps on the ground and your cyclic is perfectly level, then most probably it is not related with settings at all.
You can only increase Elevator Filter to minimize elevator bouncing, but it is not solution of the problem.

Servo may stop working when it is warm.

I recommend to not fly at all as the helicopter can crash at any moment.

To be sure, you can send your settings so I can review it.
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