vibration issue?

[Gregheli]

HI
I'm using the sk720 on a new heli. The vibration score is reaching 10.
since I'm not sure how to read the log correctly, can someone take a look?


heli
TSA700n
sk720
new os105 hz

see attached file

thanks

[A VIKING]

EDIT: I just sat up and paid attention to what you were flying, maybe one of the nitro guys can chime in and help out.
But still....

Certainly not bad.
I don't see anything there that would get you a vibe score of 10 in the SK, maybe a score of 2 or 3 but not 10, I don't know where the 10 came from.

Could you tell me your main rotor head speed and tail?
Most of your higher vibration levels are the fore and aft variety, everything else looks good.

Were you flying when these logs were taken or on the bench with no blades?

It would be helpful to fly a single smooth hover flight, no pitch pumps or jacking it around.
That way we can see the true vibrations from your model and not be looking at vibrations created by rotor wake and gusty winds.

[Gregheli]

Think I'm running 1950 head speed. It flies great so I don't understand why it's says high of vibration of 10.I need it below 6 so I can use the GPS2.

It was flown around a bit then I checked the readings .Either way flying it hard or soft it needs to be below 6.

[A VIKING]

So when you go into the SK and look at View then select Voltage, RPM and Vibe Score the vibe score shows a 10?

With a score of 10 you should also be seeing an alternating Red/Green light from the SK after the flight. Is it Red/Green or just Green?

Anything below a vibe score of 6 or 7 will show only a steady green light after a flight.

The only reason I am asking is I don't see any vibe on the log that would trip the high vibe warning, let alone show a 10 as a vibe score.

[dogbreath]

SK720 black or blue? Just for more detail, tell us where & how it's mounted...i.e. pad type, with or w/o metal plate etc.

I agree with the above responses, to me the 10 seems a lot higher than what we saw. Dan

[Gregheli]

Sk 720 black. It's mounted with pad, plate and m3 tape under the FBL. I always have a steady green After a flight. When I looked into the software for the highest vibration it tells me 9 or 10. Even shows when it set for playback mode. How high does the vibration show in the log?

Maybe something faulty with the FBL unit?

I'll try connecting the GPS2 see what it does.

[A VIKING]

In playback mode do you get the Text warning "High Vibration Level" over and over when playing back the flight?

[Xrayted]

Originally Posted by Gregheli

Sk 720 black. It's mounted with pad, plate and m3 tape under the FBL. I always have a steady green After a flight. When I looked into the software for the highest vibration it tells me 9 or 10. Even shows when it set for playback mode. How high does the vibration show in the log?

Maybe something faulty with the FBL unit?

I'll try connecting the GPS2 see what it does.

A "10" peak on the vibe scale is not the same thing as a 10 vibe score. This is what everyone is trying to tell you. You are looking in the wrong place for your actual score, as this is not found in the vibe log or playback. Those are just transient peaks and are not sustained vibe values the unit sees for the entire flight.

You need to connect the unit up and look for the "View" dropdown link in the upper left corner of the software, then look for the "Voltage. RPM and Vibe score link to see the actual score. That is what determines if your vibes are suitable for GPS or not.

You would be getting a constant red/green high vibration error flashing on the unit after every flight and within the software when you connected up, and your self level would be disabled for every flight if you really had a 10 overall score. All helis create higher transient peaks from time to time in flight when loaded up, and this is normal.

The fact that you dont see this LED error says that you overall vibe score is fine and within the limits

[Gregheli]

I think on a previous comment I said I looked up the vibe score on the software. It said 9 and 10.
Vibration warning comes on during playback. I'll take another look at it.
Thanks for your help guys..

[A VIKING]

No worries Greg!
We will help out as much as we can. Looking at your vibe log is a first for me. I only fly electrics so I don't know what signature the nitro motors usually produce on the vibe graph.

Looks like you have several runs on the log you posted. The last run looks to have the best sustained vibration levels and the easiest to understand.

In that log you have two distinct vibration signatures (see the image I posted of your file).
You have one sustained peak of an average of around 3.74 at an RPM of 4860 and another sustained peak of 2.08 at an RPM of 9660.



You can also see I have eliminated the "Overall" vibe signature line and only have the fore and aft, lateral and up and down vibe lines showing on the graph.

So now looking at your vibe graph you can see the amplitude (severity) of the vibration and its direction, which in your case is "fore and aft" of the three possibilities.

Not knowing what the RPMs of your dynamic components are, I can only guess that the second peak at 9660RPM is your engine. If this were true, I would think that would be a sweet running piston engine.
...or maybe it's your tail rotor? I wish I knew your RPMs.

With the first vibe at 4860RPM, I can't even guess what that would be.
You say you "think" you are running 1950RPM on the main rotor so this vibration does not match that frequency. It could be a multiple of the main rotor RPM but without knowing the RPMs of everything spinning on your model, its difficult to say.

Bottom line...it's not that bad. Could it be better, maybe, depends if we can figure out what that first peak is and if we could make it better.

Because we are seeing both vibrations with a tendency to vibrate in a "fore and aft" direction, I would say that one of those two frequencies or RPM's is the real offender and the other frequency or RPM is being influenced by the other. Another words if you were to figure out how to correct one of the vibrations you would probably see a reduction of the other as well.

But...again...I don't see it as being too bad and its your decision if you would want too pursue it. Working vibrations tends to be a "rabbit hole".
You can waste a lot of time trying to make it perfect when your improvement is only minor.
I do put that much time into my SK vibe charts, but that is a big part of the entertainment for me. I'm sick that way.

All of what I see tells me your TSA 700n is good to fly.
Before you commit to trying the GPS I would take the model out and fly it as hard as you would expect to.
Look at the SK LED after the flight to see it still glows green only, then check your vibe logs to see you don't have any large sustained peaks above 6.
Your vibe score should reflect what you have seen with the LED and vibe chart.
The vibe chart in your post should be recording maybe a 2 in the Vibe Score.
I have noticed with my SK units sometimes the vibe score that I see is not current and it takes a few flights to get a true score so maybe that's what you are seeing.

Anyway hope some of this helps...good luck and let us know how it's going.

...one more thing about the vibe logs.
They are a great tool for determining the health of your model.
Get a good hover vibe chart and keep it. That way you have a base line for the "new" model vibrations you have and can use that vibe chart later to compare the vibrations you have after many flights.
Its a good indicator of the health of the model and you can get an advanced warning something is wearing out or failing.

[Gregheli]

Long as the GPS works, I'm ok with the current setup. I'll looking into some of The things you mentioned .

You guys are awsome! Support that all off you give is one of the reasons I still have Skookum in all 5 of my helicopters.

Cheers!

[A VIKING]

No worries...
One last tip for you in looking at your SK vibe charts.
When first opening a vibe log look at the top number along the left side of the chart.
That number reflects the peak vibration level for that particular flight.
It is not the average but the peak in vibration level.

You show a "peak" vibration number on your vibe graph of 5.4, I have had models with issues that had a peak number of 30! They would have a vibration score of 10 or 15.

What I am telling you is if you don't see a "peak" vibration number on the left hand side of the graph substantially higher than 6, you probably don't have a sustained average vibration level of 6 or higher which would kill your GPS.

So look at the LED indicator after every flight, especially if you don't look at your vibe logs often, its there to protect you and your model from disaster.

"Green" light...GO.
Green/Red...NO.

[Xrayted]

Originally Posted by Gregheli

Long as the GPS works, I'm ok with the current setup. I'll looking into some of The things you mentioned .

You guys are awsome! Support that all off you give is one of the reasons I still have Skookum in all 5 of my helicopters.

Cheers!

Yes, those vibes shown in the log post above are not bad at all and in no way give a score of 9-10. I would be surprised if the score was even 2-3 max or lower with what Im seeing there. As A VIKING said, the peak values seen in the logs themselves are not your vibe score, neither are the real time numbers shown in the playback logs. They all contribute to an overall average score that is found elsewhere, and that is the value you are looking for.

Just connect up the unit to your PC and check the View/vibe Score dropdown link within the setup software itself, not in the data viewer where you look at the logs themselves. Your post still isnt clear to me where you are looking to get this 10 value you keep speaking of which would catastrophic to the model if real

The playback files will also throw momentary warnings when the peaks go over certain threshold, and once again these transient peaks are normal depending on what the model is doing at the moment and the aero forces that are induced. These are not sustained values the entire flight. You cannot use the playback logs to determine an overall vibe score any more than the peak values shown in the vibe logs, so just look for the actual score where it is in the SK setup software itself

[Gregheli]

I now understand your explanation about the vibe log. Thanks,

[winnetou]

Originally Posted by A VIKING

So when you go into the SK and look at View then select Voltage, RPM and Vibe Score the vibe score shows a 10?

With a score of 10 you should also be seeing an alternating Red/Green light from the SK after the flight. Is it Red/Green or just Green?

Anything below a vibe score of 6 or 7 will show only a steady green light after a flight.

The only reason I am asking is I don't see any vibe on the log that would trip the high vibe warning, let alone show a 10 as a vibe score.

Hi

I have a vibe score of 6, but on the logfile no spikes are even higher than 0.3. After landing ex-led flashes green/red.
system is SK720 Black with GPS2 and LZR

any ideas? thanks for helping

[Xrayted]

Originally Posted by winnetou

Hi

I have a vibe score of 6, but on the logfile no spikes are even higher than 0.3. After landing ex-led flashes green/red.
system is SK720 Black with GPS2 and LZR

any ideas? thanks for helping

Either your log file is corrupted or something isnt loading correctly. There is no such things as sustained in flight vibes no more than 0.3. That is lower than the basic noise floor would be.

Are you sure you are scrolling over to where the actual flight values are and not just looking at the area where you may have powered up the model before takeoff, or more likely you are looking at a bench log by mistake, as the unit will create a log every time you power up for any reason

The easiest thing to do is post up one the vibe log you are referencing and let one of the guys here take a look in their software.

[winnetou]

Hi

Thnx for getting back so quickly. Unfortunately I am brand new to this forum and I am not allowed to put attachments. Can I mail it? It is less than 1Mb;

kind regards

[Xrayted]

Originally Posted by winnetou

Hi

Thnx for getting back so quickly. Unfortunately I am brand new to this forum and I am not allowed to put attachments. Can I mail it? It is less than 1Mb;

kind regards

I no longer have the software to evaluate the log as I have moved onto other units now, but maybe one of the guys here that does is willing to take it by email if you cant post it here

[A VIKING]

Originally Posted by winnetou

Hi

I have a vibe score of 6, but on the logfile no spikes are even higher than 0.3. After landing ex-led flashes green/red.
system is SK720 Black with GPS2 and LZR

any ideas? thanks for helping

Were you able to scroll across the vibe chart as Xrated suggested to view your entire vibe signature?

Once you open the vibe log look for the scroll bar at the bottom of the page and drag it to the right to see the in flight vibe data.

You could have a lot of vibe charts in the Skookum from just plugging in the unit without flight, if so, select them all and delete them or make sure you selected the log number that was taken with an actual flight.