Neo Evo and extreme vibration level

Hi,

Just assembled my 700 - Tron 7.0. Heli has option with adjustable fbl tray. I've tighen fbl tray hard as possible, but have etreme vibration level warinin during 3d flight.

Bank1 - 1600 rpms - vibration ok, just raised sometimes
Bank2 - 1800 rpms - vibration ok, raised time to time, may be some xtreme vibration warning
Bank3 - 2100 rpms - constantly extreme vibration level in the log.

Is extreme vibration level is normal situataion for 3d flight on 700 class heli?

Vibration during flight based on vibro analysis app max: 3800

Flight video and log data below:
https://youtu.be/P4DDl9WBJxs

23.04.2023 13:32:20 Info;Bank 3 Loaded
23.04.2023 13:32:52 Good;Motorswitch Motor On
23.04.2023 13:33:12 Error;Extreme Vibration Level
23.04.2023 13:33:22 Error;Extreme Vibration Level
23.04.2023 13:33:32 Error;Extreme Vibration Level
23.04.2023 13:33:42 Error;Extreme Vibration Level
23.04.2023 13:33:52 Error;Extreme Vibration Level
23.04.2023 13:34:02 Warn;High Vibration Level
23.04.2023 13:34:13 Error;Extreme Vibration Level
23.04.2023 13:34:23 Error;Extreme Vibration Level
23.04.2023 13:34:33 Error;Extreme Vibration Level
23.04.2023 13:34:43 Error;Extreme Vibration Level
23.04.2023 13:34:53 Error;Extreme Vibration Level
23.04.2023 13:35:03 Error;Extreme Vibration Level
23.04.2023 13:35:13 Error;Extreme Vibration Level
23.04.2023 13:35:23 Warn;High Vibration Level
23.04.2023 13:35:33 Error;Extreme Vibration Level
23.04.2023 13:35:44 Error;Extreme Vibration Level
23.04.2023 13:35:53 Error;Extreme Vibration Level
23.04.2023 13:36:03 Error;Extreme Vibration Level
23.04.2023 13:36:14 Warn;High Vibration Level

Hi,

well, it depends. In a hover, you should not have vibration entries.
When doing 3D, particularly on stiff carbon-aluminum chassis, vibration entries are usual.

If you get these entries, you could try a softer pad (2 mm instead of 1.2 mm), or a different pad (Kyosho Zeal or similar), or un-tighten your adjustable fbl tray (SAB went from carbon to aluminum to a different position to finally a dampened fbl tray, to try and de-tune the vibration and resonance from the model (particularly gearbox) from the sensitive electronics/sensors.

Harder is not always better, this also goes for rotor head dampening :-/

Kind regards

Eddi

Born to fly ...
forced to work.

Eddi E. aus G. schrieb:
-------------------------------------------------------

> Harder is not always better, this also goes for
> rotor head dampening :-/
>
> Kind regards
>
> Eddi


Hi Eddie,
Thanks for the tips. Just purchsed DD VBar EVO Aluminum Upgrade Case + Dampers. Will back after testing in flight:

https://shop.mikadousa.com/DD-VBar-EVO-Aluminum-Upgrade-Case-Dampers_p_3090.html

Hi,

Is it enough safty to activate rescue mode during flight with extreme vibrations?

Hi,

there is no 'yes' or 'no' answer to this.

Log file vibration entries are measured with the gyros.

You can see extreme vibration from 3D maneuvering, or from other rather harmless frequencies and amplitudes.
They won't cause troubles with Rescue.
And then, you can have next to no vibration entries, but frequencies and amplitudes which dangerously interfere the accelerometers.
And they will cause Rescue to lose the orientation, eventually.

Still, extreme vibration entries are a good tell-tale, that something is afoot, on the model.

In the end, Vibration Analysis Pro on Touch and EVO is the only good indicator, where you can see the load (and G-Forces) for each individual sensor (and accelerometer).

More basic, fly, do the thing you do, and check the Rescue Status display frequently. If it re-centers when you come back into a hover, or land, when the model is (almost) upright, all is well. If it points 'somewhere' or if up is down, Rescue will go 'somewhere' or ... down.

There's a video from Marius Müller, back in the day, where he rescued frequently, during a hard 3D flight, on a 700 XXtreme.
I have no logs for this, but I'm pretty sure this one had extreme vibration in it from top to bottom.
Still, it's a design with a proper rotor head dampening, main and tail, and a gear design which runs comparatively smooth, even under highest loads.

Search "Marius Müller - Mikado Logo 700 - VBar Neo - Rescue function" in youtube, I won't link it, because we don't want yt to interfere with your privacy if you don't actually want to.

Kind regards

Eddi

Born to fly ...
forced to work.

Eddi E. aus G. schrieb:
-------------------------------------------------------

> Search "Marius Müller - Mikado Logo 700 - VBar
> Neo - Rescue function" in youtube
> Kind regards
>
> Eddi

Thanks Eddie, I've just watched the video. Unfortantly i have no same hi 3d skills as Marius but will try to test rescue. Pro bundle on my radio, but is there critical values limits (digits) for gyros, that would be great not exceed?

Hi,

well, there are two accelerometers in the NEO, one is good for up to 16 G (EVO: 32 G) load (more precise, also used for calibration), the other for 200 G (less precise).
What we have to measure and filter out are +/– 1 G with decimals, earth's gravity, and all the time.

So if the values exceed 16/32 G frequently, you are already beyond the IMU sensor's specs, and running on the 200 G sensor.
Even worse, if the vibration is asymmetric, not like a sinus curve but with shifted center or clipped peaks (even beyond the 200 G measuring range).

On some models, we have seen 160+ Gs, and without much in the way of hard 3D flying :-/
That's as if you were trying to hear a whisper (+/– 1 G), in a crowd attending a Metallica concert.

_If_ the rescue subsystem does not get valid data, it will dead-reckon, using all the sensor data it has. It's like flying in the fog, in the dark, it has to rely on the instruments. If the artificial horizon shifts or tilts or flips, because the sensor data are not accurate (because of too much vibration), the rescue subsystem has no way of telling up from down, left from right.

If you do tests, do them at high altitude—always more than four seconds high, this is the timeout, in case something goes wrong.
You can always try and oversteer, but that would at least be beyond _my_ skills.
And even then' there's some risk ...

If you try at beer bottle height ... there's no room for any kind of error, human or electronic.

Kind regards

Eddi

Born to fly ...
forced to work.

Solved.

Solution #1
Improper trust beaing assembly in the main rotor head. As result increased vibration during fligh. Fixed with new trust bearings and proper assembling.

Solution #2
Using DD metal case with dampener (https://shop.mikadousa.com/DD-VBar-EVO-Aluminum-Upgrade-Case-Dampers_p_3090.html). Mounted with stock Mikado double tape 1.2mm of tickness.

Log before:
23.04.2023 13:32:20 Info;Bank 3 Loaded
23.04.2023 13:32:52 Good;Motorswitch Motor On
23.04.2023 13:33:12 Error;Extreme Vibration Level
23.04.2023 13:33:22 Error;Extreme Vibration Level
23.04.2023 13:33:32 Error;Extreme Vibration Level
23.04.2023 13:33:42 Error;Extreme Vibration Level
23.04.2023 13:33:52 Error;Extreme Vibration Level
23.04.2023 13:34:02 Warn;High Vibration Level
23.04.2023 13:34:13 Error;Extreme Vibration Level
23.04.2023 13:34:23 Error;Extreme Vibration Level
23.04.2023 13:34:33 Error;Extreme Vibration Level
23.04.2023 13:34:43 Error;Extreme Vibration Level
23.04.2023 13:34:53 Error;Extreme Vibration Level
23.04.2023 13:35:03 Error;Extreme Vibration Level
23.04.2023 13:35:13 Error;Extreme Vibration Level
23.04.2023 13:35:23 Warn;High Vibration Level
23.04.2023 13:35:33 Error;Extreme Vibration Level
23.04.2023 13:35:44 Error;Extreme Vibration Level
23.04.2023 13:35:53 Error;Extreme Vibration Level
23.04.2023 13:36:03 Error;Extreme Vibration Level
23.04.2023 13:36:14 Warn;High Vibration Level


Log after fix:
12.08.2023 19:42:46 Info;Bank 3 Loaded
12.08.2023 19:42:51 Error;Extreme Vibration Level
12.08.2023 19:43:01 Warn;High Vibration Level
12.08.2023 19:43:11 Info;Raised Vibration Level
12.08.2023 19:43:21 Error;Extreme Vibration Level
12.08.2023 19:43:31 Error;Extreme Vibration Level
12.08.2023 19:43:41 Info;Raised Vibration Level
12.08.2023 19:43:51 Error;Extreme Vibration Level
12.08.2023 19:44:01 Warn;High Vibration Level
12.08.2023 19:44:11 Warn;High Vibration Level
12.08.2023 19:44:21 Warn;High Vibration Level
12.08.2023 19:44:32 Warn;High Vibration Level
12.08.2023 19:44:42 Warn;High Vibration Level
12.08.2023 19:44:52 Info;Raised Vibration Level
12.08.2023 19:45:02 Warn;High Vibration Level
12.08.2023 19:45:12 Warn;High Vibration Level
12.08.2023 19:45:22 Error;Extreme Vibration Level
12.08.2023 19:45:32 Info;Raised Vibration Level
12.08.2023 19:45:42 Warn;High Vibration Level
12.08.2023 19:45:52 Warn;High Vibration Level
12.08.2023 19:46:03 Warn;High Vibration Level
12.08.2023 19:46:13 Warn;High Vibration Level
12.08.2023 19:46:23 Info;Raised Vibration Level
12.08.2023 19:46:33 Info;Raised Vibration Level

Hi,

good! Thank you for your feedback!

And maybe even better than the aluminum case (or in combination) would be the hot glue fix for VBar EVO.

The dampening effect on the sensors was repeatedly in a range of 2/3 with regard to the original value.

—Eddi

Born to fly ...
forced to work.

Eddi E. aus G. schrieb:
-------------------------------------------------------
> Hi,
>
> good! Thank you for your feedback!
>
> And maybe even better than the aluminum case (or
> in combination) would be the hot glue fix for VBar
> EVO.


Thanks Eddie. I will try it, my original case in perfect condition. But currently just really happy because my main problem has been solved, just want to fly now )

I've up servo freq for cyclic servos from 144 Hz to 333 Hz and extreme vibation warnings are back once again:

Tested with two helis:
Heli #1
Tron 7.0, 2100 rpms, Xpret KD1 cyclic servos

Heli #2
Nik7E, 2200 rpms, MKS X8 cyclic servos

144 Hz: 0-2 extreme vibration warnings
200 Hz: 3-5 extreme vibration warnings
333 Hz: up to 11+ extreme vibration warnings



2 mal bearbeitet. Zuletzt am 27.08.2023 19:01 von Jock_rst.

Then - this helis seem not to be fit for the set up servo frequency. There is a dependency between the internal filtering and the servo frequency which assumes that 144hz is one of the "uncritical" frequencies. Less time to calculate (more HZ) will result in higher filter frequency as we do "one shot" always.

Just keep it then at 144 Hz.

https://www.vstabi.info/en/framerates

regards (EN) / Gruss (DE)

Rainer Vetter

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