Today's Message Index:
----------------------
1. 05:38 AM - AW: Re: 912 with low RPM--- new vibration problem (Gtblu)
2. 12:31 PM - Re: AW: Re: 912 with low RPM--- new vibration problem (Les Goldner)
3. 03:22 PM - AW: Re: 912 with low RPM--- new vibration problem (Gtblu)
4. 03:22 PM - AW: Re: 912 with low RPM--- new vibration problem (Gtblu)
5. 04:19 PM - AW: Re: 912 with low RPM--- new vibration problem (Roger Lee)
6. 06:45 PM - AW: Re: 912 with low RPM--- new vibration problem (Gtblu)
Message 1
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| Subject: | Re: AW: Re: 912 with low RPM--- new vibration problem |
Hi Les, I had a vibration in 912 uls which turned out to be sprag clutch circlip
coming undone (or breaking) and going through the sprag clutch gears. In my
search for the vibration also found slipper clutch had been incorrectly installed,
which can also be responsible for vibration. There are three disk springs
that must oppose each other, mine were installed in the same plane. Eventually
with the sprag clutch, the engine would not start.
How bad is the vibration? The effect I was getting was enough to shake my legs
on the seat.
Has anyone tried using neoprene mounts instead of rubber mounts? I suspect that
they would be too hard for shock absorbtion.
This is a just released report of an accident in Australia with a 912uls installed. http://www.atsb.gov.au/publications/investigation_reports/2007/AAIR/aair200700054.aspx
--------
Slepcev Storch
912 uls 731 hours
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=169977#169977
Message 2
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| Subject: | Re: AW: Re: 912 with low RPM--- new vibration problem |
Thanks for the info Slepcev,
I'll let the mechanic who is coming on Wednesday know about this but my
vibration is not as bad as yours was. It just doesn't hum like should and
it's a little annoying.
How many hours was on the engine when you discovered the problem? (My engine
has only 20 hours TT).
Les
> -----Original Message-----
> From: owner-rotaxengines-list-server@matronics.com
> [mailto:owner-rotaxengines-list-server@matronics.com] On
> Behalf Of Gtblu
> Sent: Saturday, March 15, 2008 5:34 AM
> To: rotaxengines-list@matronics.com
> Subject: RotaxEngines-List: AW: Re: 912 with low RPM--- new
> vibration problem
>
>
> Hi Les, I had a vibration in 912 uls which turned out to be
> sprag clutch circlip coming undone (or breaking) and going
> through the sprag clutch gears. In my search for the
> vibration also found slipper clutch had been incorrectly
> installed, which can also be responsible for vibration. There
> are three disk springs that must oppose each other, mine were
> installed in the same plane. Eventually with the sprag
> clutch, the engine would not start.
>
> How bad is the vibration? The effect I was getting was enough
> to shake my legs on the seat.
>
> Has anyone tried using neoprene mounts instead of rubber
> mounts? I suspect that they would be too hard for shock absorbtion.
>
> This is a just released report of an accident in Australia
> with a 912uls installed.
> http://www.atsb.gov.au/publications/investigation_reports/2007
> /AAIR/aair200700054.aspx
>
> --------
> Slepcev Storch
> 912 uls 731 hours
>
>
>
>
> Read this topic online here:
>
> http://forums.matronics.com/viewtopic.php?p=169977#169977
>
>
>
>
>
>
>
> Photoshare, and much much more:
>
>
Message 3
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| Subject: | Re: AW: Re: 912 with low RPM--- new vibration problem |
Hi Les,
Hours were about 600. However, there has always been a vibration, an annoying feeling
its not running sweetly, between 4400 and 5100 revs that has just recently
increased to 5300 revs. I have pretty well followed your path trying to track
it down, but without a balance have become stuck on that. I suspect my prop,
and will try and change it for someone elses soon.
I took three photos from a stationary camera of each blade in the same position
then outlined each blade and superimposed them. I don't know if this is a valid
way of checking, but it shows one blade is certainly not on track and surprisingly
for a lot of its length. Checking the tips for track is not enough perhaps.
What is strange, if that is what the problem is, is that at 5400 revs it runs
so sweetly. If the prop was the problem is that possible?
The only other clue I have is that checking the mags will give a rough patch very
briefly as the revs drop, which I think could be in the float of the bearings
of the gearbox. This engine was completely opened up when the sprag clutch
broke, 100 hours ago.
Basically, I "share your pain" It is bloody frustrating trying to track this down
as there are so many variables, and it is potentially an engine destroyer.
I wait for your summing up on Wednesday with baited breath.
regards
Gtblu
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=170073#170073
Message 4
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| Subject: | Re: AW: Re: 912 with low RPM--- new vibration problem |
Hi Les,
Hours were about 600. However, there has always been a vibration, an annoying feeling
its not running sweetly, between 4400 and 5100 revs that has just recently
increased to 5300 revs. I have pretty well followed your path trying to track
it down, but without a balance have become stuck on that. I suspect my prop,
and will try and change it for someone elses soon.
I took three photos from a stationary camera of each blade in the same position
then outlined each blade and superimposed them. I don't know if this is a valid
way of checking, but it shows one blade is certainly not on track and surprisingly
for a lot of its length. Checking the tips for track is not enough perhaps.
What is strange, if that is what the problem is, is that at 5400 revs it runs
so sweetly. If the prop was the problem is that possible?
The only other clue I have is that checking the mags will give a rough patch very
briefly as the revs drop, which I think could be in the float of the bearings
of the gearbox. This engine was completely opened up when the sprag clutch
broke, 100 hours ago.
Basically, I "share your pain" It is bloody frustrating trying to track this down
as there are so many variables, and it is potentially an engine destroyer.
I wait for your summing up on Wednesday with baited breath.
regards
Gtblu
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=170074#170074
Message 5
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| Subject: | Re: AW: Re: 912 with low RPM--- new vibration problem |
Hi GTBLU,
Typically the vibration and the range of rpm with that vibration is what you feel
if you have a bad pneumatic carb balance. Even if you have done it in the last
25 hrs. do it again. I believe that will help. Don't forget the mechanical
balance first and be precise with both.
--------
Roger Lee
Tucson, Az.
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=170080#170080
Message 6
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| Subject: | Re: AW: Re: 912 with low RPM--- new vibration problem |
Cheers Roger. I keep doing them, but I take your point. Be precise!
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=170103#170103
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