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[SOLVED] Limits for Vibrations
https://www.spirit-system.com/phpBB3/viewtopic.php?f=20&t=1557		 Page 1 of 1
Author:  scvflyer [ Mon 25. Jul 2016 21:00:27 ]
Post subject:  [SOLVED] Limits for Vibrations
Hi Service team ,
I did my vbrations analyze and got following results - would you like to check it out and give me a feedback.
Test has be done without tail blades and without holder for tail blades - just tail gear and tail shaft (all brand new).
Some words about file names - first letter defines axis , following number RPM main blades , rest some words about test scenario .
By the way what would happen if vibrations are to hight during flight - will spirit system stop working ? Would i see shut down process at log file ? And final - are there ideas to bring log data to telemetrie bus - like HOTT ?
Thanks in advance br Siggi

Attachments:
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Z2150_20160725_neuesHohneHRBH.png [ 32 KiB | Viewed 1627 times ]
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X2150_20160725_neuesHohneHRBH.png [ 31.53 KiB | Viewed 1627 times ]
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Y2150_20160725_neuesHohneHRBH.png [ 50.01 KiB | Viewed 1627 times ]
Author:  Gtamas [ Mon 25. Jul 2016 22:38:53 ]
Post subject:  Re: Limits for Vibrations
How the hell can a heli produce 90+ vibration without blades, , and even without blade holder?

What kind of machine is this? What is the setup?
Author:  scvflyer [ Mon 25. Jul 2016 23:30:59 ]
Post subject:  Re: Limits for Vibrations
Hi - it's TREX 600.
and displayed information, which isn't visible at the image, says raised vibrations for z axis
Author:  ZeXx86 [ Tue 26. Jul 2016 7:59:36 ]
Post subject:  Re: Limits for Vibrations
Hi,

the vibrations are comming from the tail mechanics.

It looks like bent tail shaft of torque tube. It does not look like bearing issue as the spikes are very narrow, at specific frequency.
So first I recommend to examine tail shaft and possibly to replace it. Then I guess it will be much better.

Vibration data are already transmitted to Jeti transmitter via telemetry (at least value). But the upcoming update will add some feature that will solve it for all.
Author:  Adrian [ Tue 26. Jul 2016 12:52:37 ]
Post subject:  Re: Limits for Vibrations
Tomas, please use rpm instead of Hz on upcomming release if possiple. I'm realy bad by muliply by 60 in my head. ;-)
Author:  scvflyer [ Tue 26. Jul 2016 21:06:39 ]
Post subject:  Re: Limits for Vibrations
Hi tail shaft and bearings are already replaced. I will try to add an extra bearing at drive shaft (from front gear to back gear).
Hope it will help.
Some additional information
- normnal test - helicopter is placed at two woolen blanket
- if I lift up helicopter by hand the needle will be reduced round about 50%

thanks and br Siggi
Author:  Adrian [ Wed 27. Jul 2016 7:06:23 ]
Post subject:  Re: Limits for Vibrations
Siggi, try to unmount everything rotating and than add in sequance doing vib analysis. Tube bearings need to be placed at exact defined spot, not at any Harmonics like 1/2 1/3, 1/4, as wave would build up. Also check different head speeds +/- 100 rpm as you might hit system resonance frequencey. Gruss Adrian
Author:  scvflyer [ Fri 12. Aug 2016 23:02:51 ]
Post subject:  Re: Limits for Vibrations
Hi , to give you a feedback.
it's fixed by using a second ball-bearing at torqoue tube - like desoigned at 700er TREX
thanks and br Siggi :D
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