Today's Message Index:
----------------------
1. 05:14 AM - Gearbox Bearing limits at the Flange (italianjon)
2. 07:17 AM - Re: Gearbox Bearing limits at the Flange (Roger Lee)
3. 10:07 AM - Re: Gearbox Bearing limits at the Flange (Jim Roberts)
4. 11:43 AM - Re: Gearbox Bearing limits at the Flange (italianjon)
5. 12:58 PM - Rotax 912 oil analysis (Paul Kuntz)
6. 02:07 PM - Re: Re: Gearbox Bearing limits at the Flange (Lyle Peterson)
7. 04:21 PM - Re: Gearbox Bearing limits at the Flange (Roger Lee)
Message 1
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| Subject: | Gearbox Bearing limits at the Flange |
Hi all,
I checked the manual (Heavy Maintenance) but can't find information on the specific
bearing.
If I pull/push the propeller there is a small amount of play between propeller
gearbox shaft and the gearbox housing.
Also if I lift the propeller vertically there is a small amount of play, it is
repeatable in all radial directions. It's not the gear play in the propeller rotation
plane - I'm not that silly :)
Obviously the shaft passes a bearing at the front of the gearbox, so there should
be some play, but I can't find what the limit should be. I have a low frequency
vibration in flight and am trying to find the source.
Cheers
Jon
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=467628#467628
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| Subject: | Re: Gearbox Bearing limits at the Flange |
Hi Jon,
Is it a 912 ULS 100 HP or a 912UL 80 HP? About what year is the engine? (These
two questions tell me if it has an overload clutch) How many hours on the gearbox?
Any strikes? Oil type and change intervals?
The straight answer to your question is no the box should have none of those. You
may have a tiny bit of backlash if moving the prop in its rotational plane,
but very little. No side to side play.
The gearbox needs servicing and most likely the bearing and oils eal need replacement.
It will get shimmed at the same time and most likely new bellville washers.
--------
Roger Lee
Tucson, Az.
Rotax Instructor & Rotax IRC
Light Sport Repairman
Home 520-574-1080 TRY HOME FIRST
Cell 520-349-7056
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=467631#467631
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| Subject: | Re: Gearbox Bearing limits at the Flange |
Worn clutch dogs, just had the gearbox rebuilt and it cured the vibration on
throttle back.
Jim
-----Original Message-----
From: italianjon
Sent: Sunday, March 26, 2017 7:12 AM
Subject: RotaxEngines-List: Gearbox Bearing limits at the Flange
<jon.catilli@gmail.com>
Hi all,
I checked the manual (Heavy Maintenance) but can't find information on the
specific bearing.
If I pull/push the propeller there is a small amount of play between
propeller gearbox shaft and the gearbox housing.
Also if I lift the propeller vertically there is a small amount of play, it
is repeatable in all radial directions. It's not the gear play in the
propeller rotation plane - I'm not that silly :)
Obviously the shaft passes a bearing at the front of the gearbox, so there
should be some play, but I can't find what the limit should be. I have a low
frequency vibration in flight and am trying to find the source.
Cheers
Jon
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=467628#467628
Message 4
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| Subject: | Re: Gearbox Bearing limits at the Flange |
Hi both,
Thanks for the info. I went back out to the plane in the afternoon and tried to
be a bit more specific on the amount of play.
I am not fully convinced that there is the previously mentioned up/down/left/right
play. I can't be sure whether I am slightly rotating the propeller as I do
the test, and therefore I can't be sure is if what I feel is actually just the
play in the gears on through the rotation axis.
But, Roger to answer your questions: It's the 80Hp, with 1090 hours on it, the
engine is from 1995, and it does have the overload clutch fitted in the gearbox.
No strikes, and Aeroshell Sport plus 4, changed annually or 50 hours. Normally
run on Mogas, but has had Avgas.
Returning to the play, I can be sure that there is forward/backward play. It's
not easy to measure, so I have to guess at about 0.2 to 0.3 mm.
Also, what I was trying to do today, was install a Warpdrive Propeller, in place
of my Arplast PV50. The reason is that I have a low frequency vibration that
you can feel in flight, at the rudder pedals and if you place your hand on the
fuselage, and I wanted to fly with another propeller to check if it remains,
and therefore indicates the propeller... but for love nor money, I can not dynamically
balance a brand new warpdrive, I get 0.3 to 0.4 IPS whatever I try to
do...
The Arplast is balanced better, but there is a large mass difference between the
propellers, and this is leading me to think that the source of the vibration
is somewhere else and not directly the propeller. Just that the extra mass of
the Arplast helps somehow...
I think I'll get the gearbox looked at, but any ideas with the extra info above?
Best
Jon
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=467643#467643
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| Subject: | Rotax 912 oil analysis |
People,
I'd be interested in your thoughts on oil analysis trends for my Rotax 912
UL. The engine has been operating for four years, with 410 Hobbs hours to
date. The aircraft is a Pipistrel Sinus motorglider with a Pipistrel
controllable pitch and feathering propeller. Most of the time I use
ethanol-free mogas, but avgas on occasion. I have been changing oil and
filter at roughly 50 hour intervals, and began sending oil samples in for
analysis at 285 hours. I'm using AeroShell Sport Plus 4 oil and Rotax oil
filters. I'm using Aviation Laboratories (AvLab) for this service.
The iron content values are of some concern. AvLab reports metal content
in parts per million, with values for my engine accompanied by what they
say are average values for the same engine model with similar operating
hours. For my engine, the iron content over the 125 hours since I began
sending in samples has risen from 51 to 76 to 117 ppm, versus average iron
values for this engine model of 21 to 27 ppm. I always check the magnetic
plug and the oil filter element at each oil change, and have never detected
any metal on either the magnetic plug or in the filter element.
The other metal components AvLab measures (copper, nickel, chromium,
aluminum, lead, silicon and tin) are either below or only somewhat elevated
from their corresponding average values. The elevated values are for
nickel, silicon and chromium, although they are well below the five times
above average value for iron in the latest sample.
What are your thoughts? Should I be concerned?
Regards,
Paul Kuntz
Message 6
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| Subject: | Re: Gearbox Bearing limits at the Flange |
Jon,
I think you really need to beg, borrow or buy a dial indicator. Using
that you will get a definitive indication of the real play both radially
and axial in the gear box. Get a dial indicator and a mount of some
sort. Magnetic mounts are handy but there may not be any steel near
enough to use one. You may have to remove a bolt and put some sort of
bracket under the bolt. The mount has to be stable so the flexing of it
doesn't give false readings.
Harbor Freight has both indicators and mounts. Northern Tool may have
them too if you want to spend more money. You could go to a machine
tool supply and get a Starrett if you want to spend some real money.
Lyle
On 3/26/2017 1:41 PM, italianjon wrote:
>
> Hi both,
>
> Thanks for the info. I went back out to the plane in the afternoon and tried
to be a bit more specific on the amount of play.
>
> I am not fully convinced that there is the previously mentioned up/down/left/right
play. I can't be sure whether I am slightly rotating the propeller as I
do the test, and therefore I can't be sure is if what I feel is actually just
the play in the gears on through the rotation axis.
>
> But, Roger to answer your questions: It's the 80Hp, with 1090 hours on it, the
engine is from 1995, and it does have the overload clutch fitted in the gearbox.
No strikes, and Aeroshell Sport plus 4, changed annually or 50 hours. Normally
run on Mogas, but has had Avgas.
>
> Returning to the play, I can be sure that there is forward/backward play. It's
not easy to measure, so I have to guess at about 0.2 to 0.3 mm.
>
> Also, what I was trying to do today, was install a Warpdrive Propeller, in place
of my Arplast PV50. The reason is that I have a low frequency vibration that
you can feel in flight, at the rudder pedals and if you place your hand on
the fuselage, and I wanted to fly with another propeller to check if it remains,
and therefore indicates the propeller... but for love nor money, I can not
dynamically balance a brand new warpdrive, I get 0.3 to 0.4 IPS whatever I try
to do...
>
> The Arplast is balanced better, but there is a large mass difference between
the propellers, and this is leading me to think that the source of the vibration
is somewhere else and not directly the propeller. Just that the extra mass
of the Arplast helps somehow...
>
> I think I'll get the gearbox looked at, but any ideas with the extra info above?
>
> Best
>
> Jon
>
>
> Read this topic online here:
>
> http://forums.matronics.com/viewtopic.php?p=467643#467643
>
>
Message 7
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| Subject: | Re: Gearbox Bearing limits at the Flange |
There should be no fore or aft push/pull play. Just a tad of backlash play when
you rotate it back and forth. That part is normal.
If it has that many hours on the engine it is overdue for a gearbox inspection,
new bellville washers and shims. You should also have the bearing replaced. That
part isn't expensive.
Warp Drive props shouldn't be over 68" long and never have nickeled leading edges.
Most planes when flying have a little vibration in the frame. A 2 blade has
a different vibration over a 3 blade. A 2 blade has a wider vibration frequency
and the 3 blade is finer. Some people can feel this and some not. Vibration
can absolutely be caused by a worn gearbox.
--------
Roger Lee
Tucson, Az.
Rotax Instructor & Rotax IRC
Light Sport Repairman
Home 520-574-1080 TRY HOME FIRST
Cell 520-349-7056
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=467654#467654
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