Spirit System
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What am I looking for . . . . or at
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Author:  bdfox1 [ Tue 24. Mar 2015 5:24:04 ]
Post subject:  What am I looking for . . . . or at
I have gone through most all of the setup steps and everything seems to be responding as expected so no real setup issues.

I decided to run through the analyzer and see what it would tell me. This is a Chaos 600 ESP, 880 KV motor, 16/170 gearing, 1550 head speed, 6s power. Sitting on a short short pile carpet, inside, no winds, etc.

All three graphs are very close to the same. What I don't understand is the relationship of the graph data to RPM so that I can close in on where I should look. The little bar graph on the screen never went over 50 on any axis but it was generally always in the 40s somewhere.

My guess is that the big spike is not a good thing but I am not sure where to look first. I can tear the whole thing apart (and will do it if that is the answer but I think teh graphs are telling me something and I simply don't know what I am looking at.

I have looked through this entire section of the forum and can't see anything that gives any better idea of what I should be looking for. Ditto on HF.

Some clue as to the direction to head will be appreciated.

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Author:  bdfox1 [ Tue 24. Mar 2015 6:34:44 ]
Post subject:  Re: What am I looking for . . . . or at
I have answered some of my question(s) myself. I figured there was something fundamentally wrong with my layout. I tied the wiring down tighter/closer to the gyro so it couldn't shake, oiled all the main bearings (although I had done that a week ago when I had it apart) and checked my gear lashes (OK).

Back on the carpet and really not much difference. Maybe a touch less but not a significant difference.

So I started to touch things while it was spinning and found that as soon as I put my finger on the gyro body itself the spikes all went down some. So I changed out the mounting tape for some that has almost no give in it at all and presto, a huge difference. Still in the same places but drastically lower and the green bar graph cycled between 9 and 10 on all three axis.

I'm not as bent out of shape now but would still like to know more about how to correlate the spikes to the appropriate areas.

But I'll go to bed now and not have a night of dreams about what could be wrong.

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Author:  MarkT [ Tue 24. Mar 2015 11:08:07 ]
Post subject:  Re: What am I looking for . . . . or at
bdfox1 wrote:
I have looked through this entire section of the forum and can't see anything that gives any better idea of what I should be looking for. Ditto on HF.

Some clue as to the direction to head will be appreciated.


The graph is showing Hz so multiply by 60 to get the RPM figure then use the gearing ratio of the heli to identify the likely sources.

You'll probably find that the first spike around 30Hz is your rotor head (actually anything from the main gear upwards), the much larger spike around 120Hz is probably the tail, higher still you may have a little motor imbalance as well.
Author:  bdfox1 [ Tue 24. Mar 2015 17:15:04 ]
Post subject:  Re: What am I looking for . . . . or at
Thanks Mark, that's the clue I was looking for.

I was pretty happy to get them all down lower but now I will do some searching to find the reason for the ones I have anyway. It is a brand new head on a brand new Align main shaft but I can at least do some balance checking. The motor might be a giggle to chase down but you never know.

Thanks again.
Author:  ZeXx86 [ Tue 24. Mar 2015 18:14:08 ]
Post subject:  Re: What am I looking for . . . . or at
Hello,

it seems that vibration is somewhere in the rudder mechanics.
Spike is at approx. 110-120Hz (7000RPM) which (in case that your head speed is approx. 1600RPM) is really rudder issue.
You can start that you will unmount rotating parts graudally from the rudder. If spikes will be lower, then you are very near or you have found the problem.

All in all, the unit has to be mounted as hard as possible so it can't wobble to any side.
Author:  bdfox1 [ Thu 26. Mar 2015 7:04:06 ]
Post subject:  Re: What am I looking for . . . . or at
Exactly where the problem was once I went looking. For whatever reason, the front end of the tail boom was not fully seating (by about a cm) so the TT end wasn't fully engaged in the umbrella gear (maybe even at both ends at one time) so it could move around a bit and undoubtedly the cause. Got that all fixed up and the spike went down to a very small bump. It has been that way for a long time and the thing flew very nicely in its flybarred form. Now that it is FBL with a Spirit it should just be magic.

Now that I know the factor to use this will be a a tool that I use more frequently just to keep an eye on everything.
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