Today's Message Index:
----------------------
1. 06:32 AM - Re: Prop seal replacement and subsequent vibration (flir47)
2. 06:44 AM - Re: Prop seal replacement and subsequent vibration (Scooter)
3. 07:53 AM - Re: Re: Prop seal replacement and subsequent vibration (Walter Lannon)
4. 08:17 AM - Re: Re: Prop seal replacement and subsequent vibration (Jim Bernier)
5. 09:19 AM - Re: Prop seal replacement and subsequent vibration (Scooter)
6. 09:34 AM - Re: Prop seal replacement and subsequent vibration (flir47)
7. 10:16 AM - Re: Re: Prop seal replacement and subsequent vibration (A. Dennis Savarese)
8. 02:49 PM - Re: Re: Prop seal replacement and subsequent vibration (Bitterlich, Mark G CIV Det Cherry Point, MALS-14 64E)
9. 03:00 PM - Re: Re: Prop seal replacement and subsequent vibration (Walter Lannon)
10. 05:34 PM - Re: Re: Prop seal replacement and subsequent vibration (Walter Lannon)
Message 1
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| Subject: | Re: Prop seal replacement and subsequent vibration |
--> Yak-List message posted by: "flir47" <me262pilot@comcast.net>
Scooter,
Did you try Denniss suggestion of the tape first?? Also make the check for the
bent tube. You took some time here to make some rather interesting calculations.
Why not do some more checks before just tearing the hub down??? A hub should
not need an overhaul after a simple seal change. If you need some pics of what
to look for let me know. My prop did the same exact thing and was a bent tube.
Also if you think Im FOS.... fly it from the back seat and feel the growling
drone of the resonance. It will be less from the front.
--------
It's not a real world war untill France surenders!
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=60172#60172
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| Subject: | Re: Prop seal replacement and subsequent vibration |
--> Yak-List message posted by: "Scooter" <yakk52@verizon.net>
Thanks. I am going to pull the blades and regrease/inspect but leave the hub rebuild
for a last option. I've checked the tube pretty thoroughly and it doesn't
appear to be bent or leaking. Does a bent tube cause an imbalance or does
it somehow disrupt oil flow to the dome?
I'm still at a loss to explain why the vibration would suddenly occur after replacing
the two seals in the dome. Ideally I'd like to know what caused it before
trying to fix it by rebalancing the blade. As for flying the aircraft from
the back seat - i can't imagine anyone would fly this aircraft with this amount
of vibration.
flir47 wrote:
> Scooter,
>
> Did you try Denniss suggestion of the tape first?? Also make the check for the
bent tube. You took some time here to make some rather interesting calculations.
Why not do some more checks before just tearing the hub down??? A hub should
not need an overhaul after a simple seal change. If you need some pics of
what to look for let me know. My prop did the same exact thing and was a bent
tube. Also if you think Im FOS.... fly it from the back seat and feel the growling
drone of the resonance. It will be less from the front.
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=60174#60174
Message 3
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| Subject: | Re: Prop seal replacement and subsequent vibration |
--> Yak-List message posted by: "Walter Lannon" <wlannon@cablerocket.com>
Someone has probably suggested this already but just in case!!!!!! Have you
checked the blade angles to see if one blade has moved in the clamp?
There is no way that replacing the pitch change seals could result in the
vibration you describe. The problem is somewhere else. If the blade angles
are OK the next thing I would suggest is a measurement of piston
displacement to check for a bent rod. Good luck
Walt
----- Original Message -----
From: "Scooter" <yakk52@verizon.net>
Sent: Thursday, September 07, 2006 6:43 AM
Subject: Yak-List: Re: Prop seal replacement and subsequent vibration
--> Yak-List message posted by: "Scooter" <yakk52@verizon.net>
Thanks. I am going to pull the blades and regrease/inspect but leave the
hub rebuild for a last option. I've checked the tube pretty thoroughly and
it doesn't appear to be bent or leaking. Does a bent tube cause an
imbalance or does it somehow disrupt oil flow to the dome?
I'm still at a loss to explain why the vibration would suddenly occur after
replacing the two seals in the dome. Ideally I'd like to know what caused
it before trying to fix it by rebalancing the blade. As for flying the
aircraft from the back seat - i can't imagine anyone would fly this aircraft
with this amount of vibration.
flir47 wrote:
> Scooter,
>
> Did you try Dennis?Ts suggestion of the tape first?? Also make the check
> for the bent tube. You took some time here to make some rather interesting
> calculations. Why not do some more checks before just tearing the hub
> down??? A hub should not need an overhaul after a simple seal change. If
> you need some pic?Ts of what to look for let me know. My prop did the
> same exact thing and was a bent tube. Also if you think I?Tm FOS.... fly
> it from the back seat and feel the growling drone of the resonance. It
> will be less from the front.
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=60174#60174
Message 4
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| Subject: | Re: Prop seal replacement and subsequent vibration |
--> Yak-List message posted by: "Jim Bernier" <JBernier@dart.org>
Walt
While we are on the topic of prop hubs, how much grease should be in the hub? And
what weight is best?
Jim B
>>> wlannon@cablerocket.com 9/7/2006 9:50 AM >>>
--> Yak-List message posted by: "Walter Lannon" <wlannon@cablerocket.com>
Someone has probably suggested this already but just in case!!!!!! Have you
checked the blade angles to see if one blade has moved in the clamp?
There is no way that replacing the pitch change seals could result in the
vibration you describe. The problem is somewhere else. If the blade angles
are OK the next thing I would suggest is a measurement of piston
displacement to check for a bent rod. Good luck
Walt
----- Original Message -----
From: "Scooter" <yakk52@verizon.net>
Sent: Thursday, September 07, 2006 6:43 AM
Subject: Yak-List: Re: Prop seal replacement and subsequent vibration
--> Yak-List message posted by: "Scooter" <yakk52@verizon.net>
Thanks. I am going to pull the blades and regrease/inspect but leave the
hub rebuild for a last option. I've checked the tube pretty thoroughly and
it doesn't appear to be bent or leaking. Does a bent tube cause an
imbalance or does it somehow disrupt oil flow to the dome?
I'm still at a loss to explain why the vibration would suddenly occur after
replacing the two seals in the dome. Ideally I'd like to know what caused
it before trying to fix it by rebalancing the blade. As for flying the
aircraft from the back seat - i can't imagine anyone would fly this aircraft
with this amount of vibration.
flir47 wrote:
> Scooter,
>
> Did you try Dennis?Ts suggestion of the tape first?? Also make the check
> for the bent tube. You took some time here to make some rather interesting
> calculations. Why not do some more checks before just tearing the hub
> down??? A hub should not need an overhaul after a simple seal change. If
> you need some pic?Ts of what to look for let me know. My prop did the
> same exact thing and was a bent tube. Also if you think I?Tm FOS.... fly
> it from the back seat and feel the growling drone of the resonance. It
> will be less from the front.
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=60174#60174
Message 5
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| Subject: | Re: Prop seal replacement and subsequent vibration |
--> Yak-List message posted by: "Scooter" <yakk52@verizon.net>
I've read that Aeroshell 22 is good (see www.Yak-52.net).
This is something I found on the net at some point. It's part of a three page
document written by george coy on "overhauling" the prop:
"The blades are removed by removing the cotter key at the nut at the back of the
counterweight / clamp assembly. Loosen the nut / bolt and thus the clamp. Grab
the blade and unscrew it from the hub in the normal thread direction. (rightly
tightly lefty loosey) Repeat for the other blade. You can now see in the hub
and see if you can get away with packing a little grease in at this point,
or if it will need further disassembly. There are three areas that need grease.
The main collar that moves back and forth, this has an internal fiber bearing
that you cannot see. Make sure that there is a good film of grease on the
large diameter polished shaft that the collar slides on. This collar also has
two ( one on each side ) curved cut outs that the blade retainer pin and shoe
bearing ride in. These should also be packed with a little grease. Finally, put
some grease just inside the blade bearing collar ( the part the blade screws
into ) this will work out and hopefully lubricate the blade roller bearings."
[quote="JBernier(at)dart.org"]Walt
While we are on the topic of prop hubs, how much grease should be in the hub? And
what weight is best?
Jim B
> >> wlannon@cablerocket.com 9/7/2006 9:50 AM >>>
>
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=60207#60207
Message 6
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| Subject: | Re: Prop seal replacement and subsequent vibration |
--> Yak-List message posted by: "flir47" <me262pilot@comcast.net>
Scooter,
The piston cocks in the bore of the dome. It is fighting the forces of the prop
and oil pressure. Did you try to work the prop while running it thru the different
power settings?
If so any change???
Mine was bad enough that the sleeve that contacts the piston back was only touching
in one area maybe 30 degrees or soinstead of 360 deg.
Anytime you have something spinning that far out on the end of an axis it will
cause balance issues.
So you have a piston cocked and wobbling around.and also the included weight of
the oil in the dome following shape too.
First eliminate everything you touched then go onto other things like bent rods
etc. The blades should not be out of balance either from just a seal change.
But the old bent tube will cause some funky prop pitch issues. Scrutinize the
dome, piston and tube first. Look for whiteness mars and scoring. A re-balance
may only mask the real issue.
Most of all....take your time and be safe. Good luck!
--------
It's not a real world war untill France surenders!
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=60209#60209
Message 7
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| Subject: | Re: Prop seal replacement and subsequent vibration |
--> Yak-List message posted by: "A. Dennis Savarese" <dsavarese@elmore.rr.com>
Please be aware that Aeroshell has changed their formula for #22. It used
to be thick and pasty. The last batch of #22 that I bought was almost to
the point of being runny. Even body heat would make it runny. It was
horrible and Aeroshell swore they didn't change their formula. I returned
it and bought #5 instead.
Dennis
----- Original Message -----
From: "Scooter" <yakk52@verizon.net>
Sent: Thursday, September 07, 2006 11:18 AM
Subject: Yak-List: Re: Prop seal replacement and subsequent vibration
> --> Yak-List message posted by: "Scooter" <yakk52@verizon.net>
>
> I've read that Aeroshell 22 is good (see www.Yak-52.net).
>
> This is something I found on the net at some point. It's part of a three
> page document written by george coy on "overhauling" the prop:
>
> "The blades are removed by removing the cotter key at the nut at the back
> of the counterweight / clamp assembly. Loosen the nut / bolt and thus the
> clamp. Grab the blade and unscrew it from the hub in the normal thread
> direction. (rightly tightly lefty loosey) Repeat for the other blade. You
> can now see in the hub and see if you can get away with packing a little
> grease in at this point, or if it will need further disassembly. There
> are three areas that need grease. The main collar that moves back and
> forth, this has an internal fiber bearing that you cannot see. Make sure
> that there is a good film of grease on the large diameter polished shaft
> that the collar slides on. This collar also has two ( one on each side )
> curved cut outs that the blade retainer pin and shoe bearing ride in.
> These should also be packed with a little grease. Finally, put some grease
> just inside the blade bearing collar ( the part the blade screws into )
> this will work out and hopefully lubricate t!
> he blade roller bearings."
>
>
> [quote="JBernier(at)dart.org"]Walt
> While we are on the topic of prop hubs, how much grease should be in the
> hub? And what weight is best?
> Jim B
>
>
>> >> wlannon@cablerocket.com 9/7/2006 9:50 AM >>>
>>
>
>
> Read this topic online here:
>
> http://forums.matronics.com/viewtopic.php?p=60207#60207
>
>
>
Message 8
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| Subject: | Re: Prop seal replacement and subsequent vibration |
--> Yak-List message posted by: "Bitterlich, Mark G CIV Det Cherry Point, MALS-14
64E" <mark.bitterlich@navy.mil>
Walter, I agree with all your suggestions and thoughts, but I wanted to offer
one comment via "bent rods". We just had a YAK-52 here locally that had a hyd.
lock that resulted in a bent rod. The aircraft was started, had no vibration
what-so-ever and proceeded to take off and fly. Within 10 minutes of flight,
the rod broke, started slamming around all over the case, and pretty much trashed
the engine. The aircraft flew back to New Bern ... Obviously vibrating very
badly at this point, and landed safely. This might start a debate, but I
submit that a bent rod will not cause this kind of vibration. If a rod is bent
just a tad and is still connected to the piston, that cylinder is just going
to have a stroke that is slightly less than the other 8. It will develop slightly
less compression....not a LOT less, but SLIGHTLY, and it will still fire
and produce energy. At 45% power, and very little load on the engine, I doubt
that even a talented mech could "feel" it. The fact is that the pilot it happened
to here never felt ANYTHING unusual ... Until it failed of course. Of
note is the fact that the bent rod in this engine did not actually bend... It
twisted. Not unusual when you consider that this rod is an I-beam and the forces
involves.
The reason I bring this up is because I have always heard people talking about
bent rods and vibration on M-14's and it never made sense to me, however I never
had experience with it. I can now say from experience that a bent/twisted
rod, damaged so badly that it failed 10 minutes into flight, caused no vibration
on the deck or during take-off that was noticed by the pilot.
Maybe this will start a discussion... If so good, I'd like to hear other peoples
thoughts on the subject.
Mark Bitterlich
N50YK
-----Original Message-----
From: owner-yak-list-server@matronics.com [mailto:owner-yak-list-server@matronics.com] On Behalf Of Walter Lannon
Sent: Thursday, September 07, 2006 10:50
Subject: Re: Yak-List: Re: Prop seal replacement and subsequent vibration
--> Yak-List message posted by: "Walter Lannon"
--> <wlannon@cablerocket.com>
Someone has probably suggested this already but just in case!!!!!! Have you checked
the blade angles to see if one blade has moved in the clamp?
There is no way that replacing the pitch change seals could result in the vibration
you describe. The problem is somewhere else. If the blade angles are OK the
next thing I would suggest is a measurement of piston displacement to check
for a bent rod. Good luck
Walt
----- Original Message -----
From: "Scooter" <yakk52@verizon.net>
Sent: Thursday, September 07, 2006 6:43 AM
Subject: Yak-List: Re: Prop seal replacement and subsequent vibration
--> Yak-List message posted by: "Scooter" <yakk52@verizon.net>
Thanks. I am going to pull the blades and regrease/inspect but leave the
hub rebuild for a last option. I've checked the tube pretty thoroughly and
it doesn't appear to be bent or leaking. Does a bent tube cause an
imbalance or does it somehow disrupt oil flow to the dome?
I'm still at a loss to explain why the vibration would suddenly occur after
replacing the two seals in the dome. Ideally I'd like to know what caused
it before trying to fix it by rebalancing the blade. As for flying the
aircraft from the back seat - i can't imagine anyone would fly this aircraft
with this amount of vibration.
flir47 wrote:
> Scooter,
>
> Did you try Dennis?Ts suggestion of the tape first?? Also make the check
> for the bent tube. You took some time here to make some rather interesting
> calculations. Why not do some more checks before just tearing the hub
> down??? A hub should not need an overhaul after a simple seal change. If
> you need some pic?Ts of what to look for let me know. My prop did the
> same exact thing and was a bent tube. Also if you think I?Tm FOS.... fly
> it from the back seat and feel the growling drone of the resonance. It
> will be less from the front.
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=60174#60174
Message 9
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| Subject: | Re: Prop seal replacement and subsequent vibration |
--> Yak-List message posted by: "Walter Lannon" <wlannon@cablerocket.com>
Jim;
There is only one grease for these props or the equivalent Hamilton Standard
2B20,2D30, 12D40, etc. It is Aeroshell grease 5. Do not use any synthetic
product like Aeroshell Grease 22. As a matter of fact Aeroshell 5 is the
only grease you should use anywhere else on the aircraft.
Do not mix grease brands. If you are changing brands clean out all of the
old grease.
Bear in mind I am an old fart and rather set in my ways but I started in
aviation overhauling propellors 56 years ago. Some years back Shell stopped
making #5 as the MIL Standard was declared obsolete and advised prop.
overhaul facilities to use their new grease #6. That led to numerous
problems and grease 5 was reinstated. It was manufactured for Shell by Royal
Lubricants. Whether that is still the case I don't know. In any event it is
readily available.
As to greasing of the G1 or B530 hub assy. that is basically a shop
function. The critical areas that require grease must be disassembled to
accomplish that. Most critical is the blade bearing assy. including the
micarta (fiber) spacer. There is no way to properly grease these areas
without disassembly.
Cheers
Walt
As to greasing the hub
----- Original Message -----
From: "Jim Bernier" <JBernier@dart.org>
Sent: Thursday, September 07, 2006 8:16 AM
Subject: Re: Yak-List: Re: Prop seal replacement and subsequent vibration
--> Yak-List message posted by: "Jim Bernier" <JBernier@dart.org>
Walt
While we are on the topic of prop hubs, how much grease should be in the
hub? And what weight is best?
Jim B
>>> wlannon@cablerocket.com 9/7/2006 9:50 AM >>>
--> Yak-List message posted by: "Walter Lannon" <wlannon@cablerocket.com>
Someone has probably suggested this already but just in case!!!!!! Have you
checked the blade angles to see if one blade has moved in the clamp?
There is no way that replacing the pitch change seals could result in the
vibration you describe. The problem is somewhere else. If the blade angles
are OK the next thing I would suggest is a measurement of piston
displacement to check for a bent rod. Good luck
Walt
----- Original Message -----
From: "Scooter" <yakk52@verizon.net>
Sent: Thursday, September 07, 2006 6:43 AM
Subject: Yak-List: Re: Prop seal replacement and subsequent vibration
--> Yak-List message posted by: "Scooter" <yakk52@verizon.net>
Thanks. I am going to pull the blades and regrease/inspect but leave the
hub rebuild for a last option. I've checked the tube pretty thoroughly and
it doesn't appear to be bent or leaking. Does a bent tube cause an
imbalance or does it somehow disrupt oil flow to the dome?
I'm still at a loss to explain why the vibration would suddenly occur after
replacing the two seals in the dome. Ideally I'd like to know what caused
it before trying to fix it by rebalancing the blade. As for flying the
aircraft from the back seat - i can't imagine anyone would fly this aircraft
with this amount of vibration.
flir47 wrote:
> Scooter,
>
> Did you try Dennis?Ts suggestion of the tape first?? Also make the check
> for the bent tube. You took some time here to make some rather interesting
> calculations. Why not do some more checks before just tearing the hub
> down??? A hub should not need an overhaul after a simple seal change. If
> you need some pic?Ts of what to look for let me know. My prop did the
> same exact thing and was a bent tube. Also if you think I?Tm FOS.... fly
> it from the back seat and feel the growling drone of the resonance. It
> will be less from the front.
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=60174#60174
Message 10
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| Subject: | Re: Prop seal replacement and subsequent vibration |
--> Yak-List message posted by: "Walter Lannon" <wlannon@cablerocket.com>
Hi Mark;
Never having experienced a damaged link rod from a hydraulic lock I have no
idea what level of vibration would ensue. I would expect that to be a
function of the bending severity.
The only two hyd. lock damaged link rods I have seen were both severely
bent, one almost 90 deg. Whether they were also twisted I don't know, none
was immediately evident.
The force involved would be primarily compression which one would expect to
result in bending since the rod/piston combination has been forced to occupy
a smaller than usual space.
There is a possible method to inspect for compression damage by measuring
the actual piston stroke in each cylinder and comparing that to the
specification standard. The nominal stroke is 130 mm (Huosai, AI14 & M14
engines). Only the master rod cylinder is 130 mm. All link rod pistons have
a slightly longer stroke due to location of the link rod pivot in relation
to the center of the crank journal (all radials). These dimensions are given
in the manuals. A precise measurement would require the manufacture of some
serious tooling but a check for gross damage could be done using the TDC
indicator or a Time-Rite.
Walt
----- Original Message -----
From: "Bitterlich, Mark G CIV Det Cherry Point, MALS-14 64E"
<mark.bitterlich@navy.mil>
Sent: Thursday, September 07, 2006 2:48 PM
Subject: RE: Yak-List: Re: Prop seal replacement and subsequent vibration
--> Yak-List message posted by: "Bitterlich, Mark G CIV Det Cherry Point,
MALS-14 64E" <mark.bitterlich@navy.mil>
Walter, I agree with all your suggestions and thoughts, but I wanted to
offer one comment via "bent rods". We just had a YAK-52 here locally that
had a hyd. lock that resulted in a bent rod. The aircraft was started, had
no vibration what-so-ever and proceeded to take off and fly. Within 10
minutes of flight, the rod broke, started slamming around all over the case,
and pretty much trashed the engine. The aircraft flew back to New Bern ...
Obviously vibrating very badly at this point, and landed safely. This might
start a debate, but I submit that a bent rod will not cause this kind of
vibration. If a rod is bent just a tad and is still connected to the
piston, that cylinder is just going to have a stroke that is slightly less
than the other 8. It will develop slightly less compression....not a LOT
less, but SLIGHTLY, and it will still fire and produce energy. At 45%
power, and very little load on the engine, I doubt that even a talented mech
could "feel" it. The fact is that the pilot it happened to here never felt
ANYTHING unusual ... Until it failed of course. Of note is the fact that
the bent rod in this engine did not actually bend... It twisted. Not
unusual when you consider that this rod is an I-beam and the forces
involves.
The reason I bring this up is because I have always heard people talking
about bent rods and vibration on M-14's and it never made sense to me,
however I never had experience with it. I can now say from experience that
a bent/twisted rod, damaged so badly that it failed 10 minutes into flight,
caused no vibration on the deck or during take-off that was noticed by the
pilot.
Maybe this will start a discussion... If so good, I'd like to hear other
peoples thoughts on the subject.
Mark Bitterlich
N50YK
-----Original Message-----
From: owner-yak-list-server@matronics.com
[mailto:owner-yak-list-server@matronics.com] On Behalf Of Walter Lannon
Sent: Thursday, September 07, 2006 10:50
Subject: Re: Yak-List: Re: Prop seal replacement and subsequent vibration
--> Yak-List message posted by: "Walter Lannon"
--> <wlannon@cablerocket.com>
Someone has probably suggested this already but just in case!!!!!! Have you
checked the blade angles to see if one blade has moved in the clamp?
There is no way that replacing the pitch change seals could result in the
vibration you describe. The problem is somewhere else. If the blade angles
are OK the next thing I would suggest is a measurement of piston
displacement to check for a bent rod. Good luck
Walt
----- Original Message -----
From: "Scooter" <yakk52@verizon.net>
Sent: Thursday, September 07, 2006 6:43 AM
Subject: Yak-List: Re: Prop seal replacement and subsequent vibration
--> Yak-List message posted by: "Scooter" <yakk52@verizon.net>
Thanks. I am going to pull the blades and regrease/inspect but leave the
hub rebuild for a last option. I've checked the tube pretty thoroughly and
it doesn't appear to be bent or leaking. Does a bent tube cause an
imbalance or does it somehow disrupt oil flow to the dome?
I'm still at a loss to explain why the vibration would suddenly occur after
replacing the two seals in the dome. Ideally I'd like to know what caused
it before trying to fix it by rebalancing the blade. As for flying the
aircraft from the back seat - i can't imagine anyone would fly this aircraft
with this amount of vibration.
flir47 wrote:
> Scooter,
>
> Did you try Dennis?Ts suggestion of the tape first?? Also make the check
> for the bent tube. You took some time here to make some rather interesting
> calculations. Why not do some more checks before just tearing the hub
> down??? A hub should not need an overhaul after a simple seal change. If
> you need some pic?Ts of what to look for let me know. My prop did the
> same exact thing and was a bent tube. Also if you think I?Tm FOS.... fly
> it from the back seat and feel the growling drone of the resonance. It
> will be less from the front.
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=60174#60174
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