Today's Message Index:
----------------------
1. 05:07 AM - Engine mount rubbers - YAK-50 (Gordon Price)
2. 05:48 AM - Re: Engine mount rubbers - YAK-50 (Bill Geipel)
3. 09:03 AM - Re: [Non-DoD Source] Engine mount rubbers - YAK-50 (Bitterlich, Mark G CIV NAVAIR, WD)
4. 10:24 AM - Re: [Non-DoD Source] Engine mount rubbers - YAK-50 (Gord Price)
5. 10:50 AM - Re: [Non-DoD Source] Engine mount rubbers - YAK-50 (Frank Stelwagon)
6. 11:33 AM - Re: [Non-DoD Source] Engine mount rubbers - YAK-50 (Bitterlich, Mark G CIV NAVAIR, WD)
7. 11:33 AM - Re: [Non-DoD Source] Engine mount rubbers - YAK-50 (Gordon Price)
8. 12:08 PM - Re: [Non-DoD Source] Engine mount rubbers - YAK-50 (Bitterlich, Mark G CIV NAVAIR, WD)
9. 11:23 PM - Re: [Non-DoD Source] Engine mount rubbers - YAK-50 (That's looking at his note)
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| Subject: | Engine mount rubbers - YAK-50 |
We just installed a zerod M-13PF with Barrett Pistons which dyno'd at 435 HP on
my YAK 50. Performance is much enhanced however we have just found some engine
mount rubbers are being torn up because the metal sleeve is moving and cutting
the rubber. The airplane is being flown under the G limits however during
the air show sequence I am sometimes seeing +8 and -5 G. We never had this
problem with the old 360 HP engine. We have a new set being installed in the
next few days which should yield more information. Does anyone have experience
in this area? Thinking of bonding the sleeve to the rubber to prevent the
sleeve movement. Thanks in advance. Gord
Message 2
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| Subject: | Re: Engine mount rubbers - YAK-50 |
at our age, 8 g is to painful. -5 is worse. My suggestion, stop doing that. Problem
solved.
> On Jul 13, 2017, at 21:04, Gordon Price <gord@thedampub.ca> wrote:
>
>
>
> We just installed a zerod M-13PF with Barrett Pistons which dyno'd at 435 HP
on my YAK 50. Performance is much enhanced however we have just found some engine
mount rubbers are being torn up because the metal sleeve is moving and
cutting the rubber. The airplane is being flown under the G limits however during
the air show sequence I am sometimes seeing +8 and -5 G. We never had this
problem with the old 360 HP engine. We have a new set being installed in
the next few days which should yield more information. Does anyone have experience
in this area? Thinking of bonding the sleeve to the rubber to prevent the
sleeve movement. Thanks in advance. Gord
>
>
>
Message 3
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| Subject: | Engine mount rubbers - YAK-50 |
Typically, the rubber used in these engine mounts deteriorates with age. Personally
what I would try to do under your circumstance is to measure a new one with
a durometer, and then have a mold constructed and replace them with a polyurethane
equivalent.
You did not ask this, and I am sorry for sticking my nose into the topic and changing
the subject somewhat, but I would suggest that you also make sure you have
the Russian recording accelerometer installed in your 50, (or a suitable replacement)
and are keeping track of the cycles. The 50 is indeed rated to +9/-6
assuming all the mods are incorporated. However that was not an unlimited
qualification. Meaning that after so many "cycles" (as documented on the recording
accelerometer), it was a requirement to replace the wings. Considering
most 50's that were flown in unlimited events were usually retired under 100
hours of flight time, it might be worth keeping in mind.
The kind of damage to engine mount rubbers that you are describing is something
commonly seen on Sukhoi's flying Unlimited level aerobatic competition, usually
with engines just like yours and MTV9-260 props, thus I suspect you are approaching
that kind of G loading. That said, the Suke construction otherwise
is much stronger than the 50. Another thing that generates this kind of stress
is gyroscopic maneuvers usually accompanied by prop shaft seal damage.
Good luck.
Mark
-----Original Message-----
From: owner-yak-list-server@matronics.com [mailto:owner-yak-list-server@matronics.com] On Behalf Of Gordon Price
Sent: Thursday, July 13, 2017 8:05 AM
Subject: [Non-DoD Source] Yak-List: Engine mount rubbers - YAK-50
We just installed a zerod M-13PF with Barrett Pistons which dyno'd at 435 HP on
my YAK 50. Performance is much enhanced however we have just found some engine
mount rubbers are being torn up because the metal sleeve is moving and cutting
the rubber. The airplane is being flown under the G limits however during
the air show sequence I am sometimes seeing +8 and -5 G. We never had this
problem with the old 360 HP engine. We have a new set being installed in the
next few days which should yield more information. Does anyone have experience
in this area? Thinking of bonding the sleeve to the rubber to prevent the
sleeve movement. Thanks in advance. Gord
Message 4
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| Subject: | Re: Engine mount rubbers - YAK-50 |
Mark. I asked for help .....not a lecture on a subject that I am well verse
d in nor assumptions that are incorrect
I have solved the problem and I am surprised you did not offer the advice th
at the sleeve does not require bonding....if it is the correct mounting rubb
er.
The rubbers that were supplied and installed by my mechanic do not have the s
leeve bonded. In fact the front rubbers do not even have a sleeve. No wonde
r they were coming apart.
A new 'proper' set is being installed this weekend. I never had this proble
m with the old engine because it had the correct rubber mounts which were so
ld with the engine.
I believe this will solve the problem and I will carry on flying a very aggr
essive and dynamic AIRSHOW routine that is well within the limits of my airp
lane which is constantly being inspected.
It is not the type of flying that most YAK owners engage in however I am qu
ite at ease flying it this way. I first flew Victor Smolin's YAK 50 in 1982
and I was taught the Lomcevak by its inventor Ladislav Bezak in 1980.
331 826 9942. Gord cell Mexico
333 495 5044 Sandy cell Mexico
519 375 6233 Gord cell Canada
519 378 6800 Sandy cell Canada
519 538 2868 House Canada
226 777 4383 Email voice message anywhere
Sent from my iPhone
> On Jul 13, 2017, at 12:00 PM, Bitterlich, Mark G CIV NAVAIR, WD <mark.bitt
erlich@navy.mil> wrote:
>
bitterlich@navy.mil>
>
> Typically, the rubber used in these engine mounts deteriorates with age. P
ersonally what I would try to do under your circumstance is to measure a new
one with a durometer, and then have a mold constructed and replace them wit
h a polyurethane equivalent.
>
> You did not ask this, and I am sorry for sticking my nose into the topic a
nd changing the subject somewhat, but I would suggest that you also make sur
e you have the Russian recording accelerometer installed in your 50, (or a s
uitable replacement) and are keeping track of the cycles. The 50 is indeed r
ated to +9/-6 assuming all the mods are incorporated. However that was not a
n unlimited qualification. Meaning that after so many "cycles" (as document
ed on the recording accelerometer), it was a requirement to replace the wing
s. Considering most 50's that were flown in unlimited events were usually r
etired under 100 hours of flight time, it might be worth keeping in mind.
>
> The kind of damage to engine mount rubbers that you are describing is some
thing commonly seen on Sukhoi's flying Unlimited level aerobatic competitio
n, usually with engines just like yours and MTV9-260 props, thus I suspect y
ou are approaching that kind of G loading. That said, the Suke constructio
n otherwise is much stronger than the 50. Another thing that generates this
kind of stress is gyroscopic maneuvers usually accompanied by prop shaft se
al damage.
>
> Good luck.
>
> Mark
>
>
> -----Original Message-----
> From: owner-yak-list-server@matronics.com [mailto:owner-yak-list-server@ma
tronics.com] On Behalf Of Gordon Price
> Sent: Thursday, July 13, 2017 8:05 AM
> To: yak-list@matronics.com
> Subject: [Non-DoD Source] Yak-List: Engine mount rubbers - YAK-50
>
>
>
> We just installed a zero=99d M-13PF with Barrett Pistons which dyno'
d at 435 HP on my YAK 50. Performance is much enhanced however we have jus
t found some engine mount rubbers are being torn up because the metal sleev
e is moving and cutting the rubber. The airplane is being flown under the G
limits however during the air show sequence I am sometimes seeing +8 and -5
G. We never had this problem with the old 360 HP engine. We have a new s
et being installed in the next few days which should yield more information.
Does anyone have experience in this area? Thinking of bonding the sleeve t
o the rubber to prevent the sleeve movement. Thanks in advance. Gord
>
>
>
>
==========================
=========
==========================
=========
==========================
=========
==========================
=========
==========================
=========
>
>
>
Message 5
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| Subject: | Engine mount rubbers - YAK-50 |
Mark wasn=99t lecturing you! He was telling you what he knows
from experience (lots of it). It might be safer to listen.
From: owner-yak-list-server@matronics.com
[mailto:owner-yak-list-server@matronics.com] On Behalf Of Gord Price
Sent: Thursday, July 13, 2017 10:22 AM
Subject: Re: [Non-DoD Source] Yak-List: Engine mount rubbers - YAK-50
Mark. I asked for help .....not a lecture on a subject that I am well
versed in nor assumptions that are incorrect
I have solved the problem and I am surprised you did not offer the
advice that the sleeve does not require bonding....if it is the correct
mounting rubber.
The rubbers that were supplied and installed by my mechanic do not have
the sleeve bonded. In fact the front rubbers do not even have a sleeve.
No wonder they were coming apart.
A new 'proper' set is being installed this weekend. I never had this
problem with the old engine because it had the correct rubber mounts
which were sold with the engine.
I believe this will solve the problem and I will carry on flying a very
aggressive and dynamic AIRSHOW routine that is well within the limits of
my airplane which is constantly being inspected.
It is not the type of flying that most YAK owners engage in however I
am quite at ease flying it this way. I first flew Victor Smolin's YAK
50 in 1982 and I was taught the Lomcevak by its inventor Ladislav Bezak
in 1980.
331 826 9942 <tel:331%20826%209942> . Gord cell Mexico
333 495 5044 <tel:333%20495%205044> Sandy cell Mexico
519 375 6233 <tel:519%20375%206233> Gord cell Canada
519 378 6800 <tel:519%20378%206800> Sandy cell Canada
519 538 2868 <tel:519%20538%202868> House Canada
226 777 4383 <tel:226%20777%204383> Email voice message anywhere
Sent from my iPhone
On Jul 13, 2017, at 12:00 PM, Bitterlich, Mark G CIV NAVAIR, WD
<mark.bitterlich@navy.mil <mailto:mark.bitterlich@navy.mil> > wrote:
<mark.bitterlich@navy.mil <mailto:mark.bitterlich@navy.mil> >
Typically, the rubber used in these engine mounts deteriorates with age.
Personally what I would try to do under your circumstance is to measure
a new one with a durometer, and then have a mold constructed and replace
them with a polyurethane equivalent.
You did not ask this, and I am sorry for sticking my nose into the topic
and changing the subject somewhat, but I would suggest that you also
make sure you have the Russian recording accelerometer installed in your
50, (or a suitable replacement) and are keeping track of the cycles.
The 50 is indeed rated to +9/-6 assuming all the mods are incorporated.
However that was not an unlimited qualification. Meaning that after so
many "cycles" (as documented on the recording accelerometer), it was a
requirement to replace the wings. Considering most 50's that were
flown in unlimited events were usually retired under 100 hours of flight
time, it might be worth keeping in mind.
The kind of damage to engine mount rubbers that you are describing is
something commonly seen on Sukhoi's flying Unlimited level aerobatic
competition, usually with engines just like yours and MTV9-260 props,
thus I suspect you are approaching that kind of G loading. That said,
the Suke construction otherwise is much stronger than the 50. Another
thing that generates this kind of stress is gyroscopic maneuvers usually
accompanied by prop shaft seal damage.
Good luck.
Mark
-----Original Message-----
From: owner-yak-list-server@matronics.com
<mailto:owner-yak-list-server@matronics.com>
[mailto:owner-yak-list-server@matronics.com] On Behalf Of Gordon Price
Sent: Thursday, July 13, 2017 8:05 AM
Subject: [Non-DoD Source] Yak-List: Engine mount rubbers - YAK-50
<mailto:gord@thedampub.ca> >
We just installed a zero=99d M-13PF with Barrett Pistons which
dyno'd at 435 HP on my YAK 50. Performance is much enhanced however we
have just found some engine mount rubbers are being torn up because the
metal sleeve is moving and cutting the rubber. The airplane is being
flown under the G limits however during the air show sequence I am
sometimes seeing +8 and -5 G. We never had this problem with the old
360 HP engine. We have a new set being installed in the next few days
which should yield more information. Does anyone have experience in
this area? Thinking of bonding the sleeve to the rubber to prevent the
sleeve movement. Thanks in advance. Gord
http://www.matronics.com/Navigator?Yak-List
<========================
== &nb -->
http://forums.ma===================
========; <http://forums.matronics.com> -->
http://wiki.matronics.co=================
=========; <http://wiki.matronics.com> -
List Conbsp; -Matt Dralle, List
Ads.com/contribution">http://www.matronics.com/contribution
Message 6
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| Subject: | Engine mount rubbers - YAK-50 |
Fair enough. Glad that you got the problem fixed. As I said, it is common on
the Sukes. There has been an on-going discussion about replacing them with a
poly/u substitute.
My comments regarding the recording system were done publically not as a lecture,
but as a notification to anyone that decides to push YAK-50's to their design
maximum G loading. I have seen videos of your airshow flying Gordon and applaud
your routine and your aerobatic skills. I did not, and am not discrediting
your skills or intent in any way. That said, I had no way of knowing that
once again someone had installed parts incorrectly into your aircraft. It is
fortunate that you figured that out.
Regarding counting accelerometers and other stress measurement equipment originally
installed in aircraft, the FAA has now written several new Operating Limitations
that address this area specifically, and you will find that if your aircraft
requires a new set of Operating Limitations, that they will include verbiage
that requires the owner to maintain these systems (no removal) and comply
with original design specifications, which in our case means wing replacement
after maximum cycles are reached, regardless of how good your inspections are.
My intent is not to lecture, but to inform. Please think back to your landing
gear actuators.
Best of luck.
Mark
-----Original Message-----
From: owner-yak-list-server@matronics.com [mailto:owner-yak-list-server@matronics.com] On Behalf Of Gord Price
Sent: Thursday, July 13, 2017 1:22 PM
Subject: Re: [Non-DoD Source] Yak-List: Engine mount rubbers - YAK-50
Mark. I asked for help .....not a lecture on a subject that I am well versed in
nor assumptions that are incorrect
I have solved the problem and I am surprised you did not offer the advice that
the sleeve does not require bonding....if it is the correct mounting rubber.
The rubbers that were supplied and installed by my mechanic do not have the sleeve
bonded. In fact the front rubbers do not even have a sleeve. No wonder they
were coming apart.
A new 'proper' set is being installed this weekend. I never had this problem with
the old engine because it had the correct rubber mounts which were sold with
the engine.
I believe this will solve the problem and I will carry on flying a very aggressive
and dynamic AIRSHOW routine that is well within the limits of my airplane
which is constantly being inspected.
It is not the type of flying that most YAK owners engage in however I am quite
at ease flying it this way. I first flew Victor Smolin's YAK 50 in 1982 and
I was taught the Lomcevak by its inventor Ladislav Bezak in 1980.
331 826 9942 <tel:331%20826%209942> . Gord cell Mexico
333 495 5044 <tel:333%20495%205044> Sandy cell Mexico
519 375 6233 <tel:519%20375%206233> Gord cell Canada
519 378 6800 <tel:519%20378%206800> Sandy cell Canada
519 538 2868 <tel:519%20538%202868> House Canada
226 777 4383 <tel:226%20777%204383> Email voice message anywhere Sent from my
iPhone
On Jul 13, 2017, at 12:00 PM, Bitterlich, Mark G CIV NAVAIR, WD <mark.bitterlich@navy.mil>
wrote:
Typically, the rubber used in these engine mounts deteriorates with age. Personally
what I would try to do under your circumstance is to measure a new one
with a durometer, and then have a mold constructed and replace them with a polyurethane
equivalent.
You did not ask this, and I am sorry for sticking my nose into the topic and changing
the subject somewhat, but I would suggest that you also make sure you
have the Russian recording accelerometer installed in your 50, (or a suitable
replacement) and are keeping track of the cycles. The 50 is indeed rated to +9/-6
assuming all the mods are incorporated. However that was not an unlimited
qualification. Meaning that after so many "cycles" (as documented on the recording
accelerometer), it was a requirement to replace the wings. Considering
most 50's that were flown in unlimited events were usually retired under 100
hours of flight time, it might be worth keeping in mind.
The kind of damage to engine mount rubbers that you are describing is something
commonly seen on Sukhoi's flying Unlimited level aerobatic competition, usually
with engines just like yours and MTV9-260 props, thus I suspect you are approaching
that kind of G loading. That said, the Suke construction otherwise
is much stronger than the 50. Another thing that generates this kind of stress
is gyroscopic maneuvers usually accompanied by prop shaft seal damage.
Good luck.
Mark
-----Original Message-----
From: owner-yak-list-server@matronics.com [mailto:owner-yak-list-server@matronics.com] On Behalf Of Gordon Price
Sent: Thursday, July 13, 2017 8:05 AM
To: yak-list@matronics.com
Subject: [Non-DoD Source] Yak-List: Engine mount rubbers - YAK-50
We just installed a zerod M-13PF with Barrett Pistons which dyno'd at 435 HP on
my YAK 50. Performance is much enhanced however we have just found some engine
mount rubbers are being torn up because the metal sleeve is moving and cutting
the rubber. The airplane is being flown under the G limits however during
the air show sequence I am sometimes seeing +8 and -5 G. We never had this
problem with the old 360 HP engine. We have a new set being installed in the
next few days which should yield more information. Does anyone have experience
in this area? Thinking of bonding the sleeve to the rubber to prevent the
sleeve movement. Thanks in advance. Gord
http://www.matronics.com/Navigator?Yak-List
<========================== &nb --> http://forums.ma====================================================; --> <http://forums.matronics.com> http://wiki.matronics.co==========================; - List Conbsp; -Matt Dralle, List Ads.com/contribution">http://www.matronics.com/contribution <http://wiki.matronics.com>
Message 7
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| Subject: | Re: Engine mount rubbers - YAK-50 |
Thanks for the advice Frank however it would be nice on this forum if we
could just stick to the topic at hand.
In this case the topic it is a problem with engine mount
rubbers and the fact that the ones supplied did not have the sleeve
bonded to the rubber.
Has anyone ever experienced this?
> On Jul 13, 2017, at 1:44 PM, Frank Stelwagon
<pfstelwagon@earthlink.net> wrote:
>
> Mark wasn=99t lecturing you! He was telling you what he knows
from experience (lots of it). It might be safer to listen.
>
> From: owner-yak-list-server@matronics.com
<mailto:owner-yak-list-server@matronics.com>
[mailto:owner-yak-list-server@matronics.com
<mailto:owner-yak-list-server@matronics.com>] On Behalf Of Gord Price
> Sent: Thursday, July 13, 2017 10:22 AM
> To: yak-list@matronics.com <mailto:yak-list@matronics.com>
> Subject: Re: [Non-DoD Source] Yak-List: Engine mount rubbers - YAK-50
>
> Mark. I asked for help .....not a lecture on a subject that I am well
versed in nor assumptions that are incorrect
>
> I have solved the problem and I am surprised you did not offer the
advice that the sleeve does not require bonding....if it is the correct
mounting rubber.
>
> The rubbers that were supplied and installed by my mechanic do not
have the sleeve bonded. In fact the front rubbers do not even have a
sleeve. No wonder they were coming apart.
>
> A new 'proper' set is being installed this weekend. I never had this
problem with the old engine because it had the correct rubber mounts
which were sold with the engine.
>
> I believe this will solve the problem and I will carry on flying a
very aggressive and dynamic AIRSHOW routine that is well within the
limits of my airplane which is constantly being inspected.
>
> It is not the type of flying that most YAK owners engage in however I
am quite at ease flying it this way. I first flew Victor Smolin's YAK
50 in 1982 and I was taught the Lomcevak by its inventor Ladislav Bezak
in 1980.
>
> 331 826 9942 <tel:331%20826%209942>. Gord cell Mexico
> 333 495 5044 <tel:333%20495%205044> Sandy cell Mexico
> 519 375 6233 <tel:519%20375%206233> Gord cell Canada
> 519 378 6800 <tel:519%20378%206800> Sandy cell Canada
> 519 538 2868 <tel:519%20538%202868> House Canada
> 226 777 4383 <tel:226%20777%204383> Email voice message anywhere
> Sent from my iPhone
>
> On Jul 13, 2017, at 12:00 PM, Bitterlich, Mark G CIV NAVAIR, WD
<mark.bitterlich@navy.mil <mailto:mark.bitterlich@navy.mil>> wrote:
>
<mark.bitterlich@navy.mil <mailto:mark.bitterlich@navy.mil>>
>>
>> Typically, the rubber used in these engine mounts deteriorates with
age. Personally what I would try to do under your circumstance is to
measure a new one with a durometer, and then have a mold constructed and
replace them with a polyurethane equivalent.
>>
>> You did not ask this, and I am sorry for sticking my nose into the
topic and changing the subject somewhat, but I would suggest that you
also make sure you have the Russian recording accelerometer installed in
your 50, (or a suitable replacement) and are keeping track of the
cycles. The 50 is indeed rated to +9/-6 assuming all the mods are
incorporated. However that was not an unlimited qualification. Meaning
that after so many "cycles" (as documented on the recording
accelerometer), it was a requirement to replace the wings. Considering
most 50's that were flown in unlimited events were usually retired under
100 hours of flight time, it might be worth keeping in mind.
>>
>> The kind of damage to engine mount rubbers that you are describing is
something commonly seen on Sukhoi's flying Unlimited level aerobatic
competition, usually with engines just like yours and MTV9-260 props,
thus I suspect you are approaching that kind of G loading. That said,
the Suke construction otherwise is much stronger than the 50. Another
thing that generates this kind of stress is gyroscopic maneuvers usually
accompanied by prop shaft seal damage.
>>
>> Good luck.
>>
>> Mark
>>
>>
>> -----Original Message-----
>> From: owner-yak-list-server@matronics.com
<mailto:owner-yak-list-server@matronics.com>
[mailto:owner-yak-list-server@matronics.com
<mailto:owner-yak-list-server@matronics.com>] On Behalf Of Gordon Price
>> Sent: Thursday, July 13, 2017 8:05 AM
>> To: yak-list@matronics.com <mailto:yak-list@matronics.com>
>> Subject: [Non-DoD Source] Yak-List: Engine mount rubbers - YAK-50
>>
<mailto:gord@thedampub.ca>>
>>
>>
>> We just installed a zero=99d M-13PF with Barrett Pistons which
dyno'd at 435 HP on my YAK 50. Performance is much enhanced however we
have just found some engine mount rubbers are being torn up because the
metal sleeve is moving and cutting the rubber. The airplane is being
flown under the G limits however during the air show sequence I am
sometimes seeing +8 and -5 G. We never had this problem with the old
360 HP engine. We have a new set being installed in the next few days
which should yield more information. Does anyone have experience in
this area? Thinking of bonding the sleeve to the rubber to prevent the
sleeve movement. Thanks in advance. Gord
>>
>>
>>
>> http://www.matronics.com/Navigator?Yak-List
<http://www.matronics.com/Navigator?Yak-List>
>> <========================
== &nb -->
http://forums.ma====================
=======;=C2--->=C2-
<http://forums.matronics.com/>http://wiki.matronics.co=======
===================;=C2-=C2-=C2-
=C2-=C2-=C2-=C2-=C2-=C2-=C2-=C2-- List
Conbsp;=C2-=C2-=C2-=C2-=C2-=C2-=C2-=C2-=C2-=C2-=C2-=C2
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>>
>>
Message 8
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| Subject: | Engine mount rubbers - YAK-50 |
You said: "we have just found some engine mount rubbers are being torn up because
the metal sleeve is moving and cutting the rubber. The airplane is being
flown under the G limits however during the air show sequence I am sometimes seeing
+8 and -5 G."
You then said: " I have solved the problem and I am surprised you did not offer
the advice that the sleeve does not require bonding....if it is the correct
mounting rubber. "
You then said: " The rubbers that were supplied and installed by my mechanic do
not have the sleeve bonded. In fact the front rubbers do not even have a sleeve.
No wonder they were coming apart."
You then said: "it would be nice on this forum if we could just stick to the topic
at hand."
You then said: " the topic it is a problem with engine mount rubbers and the
fact that the ones supplied did not have the sleeve bonded to the rubber."
Finally you end with: " Has anyone ever experienced this?"
Answer: Why yes. I have.
Mark Bitterlich
-----Original Message-----
From: owner-yak-list-server@matronics.com [mailto:owner-yak-list-server@matronics.com] On Behalf Of Gordon Price
Sent: Thursday, July 13, 2017 2:31 PM
Subject: Re: [Non-DoD Source] Yak-List: Engine mount rubbers - YAK-50
Thanks for the advice Frank however it would be nice on this forum if we could
just stick to the topic at hand.
In this case the topic it is a problem with engine mount rubbers and the fact
that the ones supplied did not have the sleeve bonded to the rubber.
Has anyone ever experienced this?
On Jul 13, 2017, at 1:44 PM, Frank Stelwagon <pfstelwagon@earthlink.net> wrote:
Mark wasnt lecturing you! He was telling you what he knows from experience (lots
of it). It might be safer to listen.
From: owner-yak-list-server@matronics.com [mailto:owner-yak-list-server@matronics.com] On Behalf Of Gord Price
Sent: Thursday, July 13, 2017 10:22 AM
To: yak-list@matronics.com
Subject: Re: [Non-DoD Source] Yak-List: Engine mount rubbers - YAK-50
Mark. I asked for help .....not a lecture on a subject that I am well versed
in nor assumptions that are incorrect
I have solved the problem and I am surprised you did not offer the advice that
the sleeve does not require bonding....if it is the correct mounting rubber.
The rubbers that were supplied and installed by my mechanic do not have the sleeve
bonded. In fact the front rubbers do not even have a sleeve. No wonder they
were coming apart.
A new 'proper' set is being installed this weekend. I never had this problem
with the old engine because it had the correct rubber mounts which were sold with
the engine.
I believe this will solve the problem and I will carry on flying a very aggressive
and dynamic AIRSHOW routine that is well within the limits of my airplane
which is constantly being inspected.
It is not the type of flying that most YAK owners engage in however I am quite
at ease flying it this way. I first flew Victor Smolin's YAK 50 in 1982 and
I was taught the Lomcevak by its inventor Ladislav Bezak in 1980.
331 826 9942 <tel:331%20826%209942> . Gord cell Mexico
333 495 5044 <tel:333%20495%205044> Sandy cell Mexico
519 375 6233 <tel:519%20375%206233> Gord cell Canada
519 378 6800 <tel:519%20378%206800> Sandy cell Canada
519 538 2868 <tel:519%20538%202868> House Canada
226 777 4383 <tel:226%20777%204383> Email voice message anywhere
Sent from my iPhone
On Jul 13, 2017, at 12:00 PM, Bitterlich, Mark G CIV NAVAIR, WD <mark.bitterlich@navy.mil>
wrote:
Typically, the rubber used in these engine mounts deteriorates with age. Personally
what I would try to do under your circumstance is to measure a new one
with a durometer, and then have a mold constructed and replace them with a polyurethane
equivalent.
You did not ask this, and I am sorry for sticking my nose into the topic and
changing the subject somewhat, but I would suggest that you also make sure you
have the Russian recording accelerometer installed in your 50, (or a suitable
replacement) and are keeping track of the cycles. The 50 is indeed rated to
+9/-6 assuming all the mods are incorporated. However that was not an unlimited
qualification. Meaning that after so many "cycles" (as documented on the recording
accelerometer), it was a requirement to replace the wings. Considering
most 50's that were flown in unlimited events were usually retired under 100
hours of flight time, it might be worth keeping in mind.
The kind of damage to engine mount rubbers that you are describing is something
commonly seen on Sukhoi's flying Unlimited level aerobatic competition, usually
with engines just like yours and MTV9-260 props, thus I suspect you are
approaching that kind of G loading. That said, the Suke construction otherwise
is much stronger than the 50. Another thing that generates this kind of stress
is gyroscopic maneuvers usually accompanied by prop shaft seal damage.
Good luck.
Mark
-----Original Message-----
From: owner-yak-list-server@matronics.com [mailto:owner-yak-list-server@matronics.com] On Behalf Of Gordon Price
Sent: Thursday, July 13, 2017 8:05 AM
To: yak-list@matronics.com
Subject: [Non-DoD Source] Yak-List: Engine mount rubbers - YAK-50
We just installed a zerod M-13PF with Barrett Pistons which dyno'd at 435 HP
on my YAK 50. Performance is much enhanced however we have just found some engine
mount rubbers are being torn up because the metal sleeve is moving and
cutting the rubber. The airplane is being flown under the G limits however during
the air show sequence I am sometimes seeing +8 and -5 G. We never had this
problem with the old 360 HP engine. We have a new set being installed in
the next few days which should yield more information. Does anyone have experience
in this area? Thinking of bonding the sleeve to the rubber to prevent the
sleeve movement. Thanks in advance. Gord
http://www.matronics.com/Navigator?Yak-List
<========================== &nb --> http://forums.ma===========================; --> <http://forums.matronics.com/> http://wiki.matronics.co==========================; - List Conbsp; -Matt Dralle, List Ads.com/contribution">http://www.matronics.com/contribution <http://wiki.matronics.com/>
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| Subject: | Engine mount rubbers - YAK-50 |
Firstly I would like to make it clear that we supplied the engine
together with the engine mount rubbers to Gordon Price. But we have used
exactly the same rubbers on around 300 engines that we have supplied to
a wide variety of aircraft, including competition Sukhois and have never
had this problem before. But we will sort it out, and we know from
Gordon that the engine is performing spectacularly well.
But it raises an issue which I think is far more important, and that is
flying a Yak 50 to its design limits of plus 9G and minus 6G. I have
done a lot of research on this topic, and the 50 was unfortunate in that
it was introduced at a time that aerobatics changing from being big
graceful manoeuvres to sharp angles. The Russian team was well funded
and incredibly well motivated, and they were flying them beyond these
limits, and had four fatal accidents to team members. During this period
Yakovlev issued a series of service bulletins to reinforce the last bit
of the aircraft that had broken, culminating in bulletin 79 =93 a
4.5 mm steel plate on top and bottom of the centre section.
But firstly, remember that the Russian pilots were all relatively light;
the aeroplane was flown only with one fuel tank; no generator; air
compressor; a light battery. Then, the TOTAL service life of a team
aircraft was 47 hours. After that it was scrapped. And for any other
aircraft, the total service life was 300 hours, and then it was
scrapped!
I have a serious concern that many pilots today are flying aircraft that
have done far more hours than this; are ignorant of these issues, and
yet feel that they still have a plus 9G aircraft, with a heavy Western
pilot; smoke system; both fuel tanks et cetera!
I prepared a detailed paper some years ago following discussions with
Yakovlev describing the individual failures and then the subsequent
service bulletins. I will send this to anyone who is interested.
Richard Goode Aerobatics
Rhodds Farm
Lyonshall
Hereford
HR5 3LW
Tel: +44 (0) 1544 340120
Fax: +44 (0) 1544 340129
www.russianaeros.com
From: owner-yak-list-server@matronics.com
[mailto:owner-yak-list-server@matronics.com] On Behalf Of Gordon Price
Sent: 13 July 2017 19:31
Subject: Re: [Non-DoD Source] Yak-List: Engine mount rubbers - YAK-50
Thanks for the advice Frank however it would be nice on this forum if we
could just stick to the topic at hand.
In this case the topic it is a problem with engine mount
rubbers and the fact that the ones supplied did not have the sleeve
bonded to the rubber.
Has anyone ever experienced this?
On Jul 13, 2017, at 1:44 PM, Frank Stelwagon <pfstelwagon@earthlink.net
<mailto:pfstelwagon@earthlink.net> > wrote:
Mark wasn=99t lecturing you! He was telling you what he knows
from experience (lots of it). It might be safer to listen.
From: <mailto:owner-yak-list-server@matronics.com>
owner-yak-list-server@matronics.com [
<mailto:owner-yak-list-server@matronics.com>
mailto:owner-yak-list-server@matronics.com] On Behalf Of Gord Price
Sent: Thursday, July 13, 2017 10:22 AM
Subject: Re: [Non-DoD Source] Yak-List: Engine mount rubbers - YAK-50
Mark. I asked for help .....not a lecture on a subject that I am well
versed in nor assumptions that are incorrect
I have solved the problem and I am surprised you did not offer the
advice that the sleeve does not require bonding....if it is the correct
mounting rubber.
The rubbers that were supplied and installed by my mechanic do not have
the sleeve bonded. In fact the front rubbers do not even have a sleeve.
No wonder they were coming apart.
A new 'proper' set is being installed this weekend. I never had this
problem with the old engine because it had the correct rubber mounts
which were sold with the engine.
I believe this will solve the problem and I will carry on flying a very
aggressive and dynamic AIRSHOW routine that is well within the limits of
my airplane which is constantly being inspected.
It is not the type of flying that most YAK owners engage in however I
am quite at ease flying it this way. I first flew Victor Smolin's YAK
50 in 1982 and I was taught the Lomcevak by its inventor Ladislav Bezak
in 1980.
<tel:331%20826%209942> 331 826 9942. Gord cell Mexico
<tel:333%20495%205044> 333 495 5044 Sandy cell Mexico
<tel:519%20375%206233> 519 375 6233 Gord cell Canada
<tel:519%20378%206800> 519 378 6800 Sandy cell Canada
<tel:519%20538%202868> 519 538 2868 House Canada
<tel:226%20777%204383> 226 777 4383 Email voice message anywhere
Sent from my iPhone
On Jul 13, 2017, at 12:00 PM, Bitterlich, Mark G CIV NAVAIR, WD <
<mailto:mark.bitterlich@navy.mil> mark.bitterlich@navy.mil> wrote:
<mailto:mark.bitterlich@navy.mil> mark.bitterlich@navy.mil>
Typically, the rubber used in these engine mounts deteriorates with age.
Personally what I would try to do under your circumstance is to measure
a new one with a durometer, and then have a mold constructed and replace
them with a polyurethane equivalent.
You did not ask this, and I am sorry for sticking my nose into the topic
and changing the subject somewhat, but I would suggest that you also
make sure you have the Russian recording accelerometer installed in your
50, (or a suitable replacement) and are keeping track of the cycles.
The 50 is indeed rated to +9/-6 assuming all the mods are incorporated.
However that was not an unlimited qualification. Meaning that after so
many "cycles" (as documented on the recording accelerometer), it was a
requirement to replace the wings. Considering most 50's that were
flown in unlimited events were usually retired under 100 hours of flight
time, it might be worth keeping in mind.
The kind of damage to engine mount rubbers that you are describing is
something commonly seen on Sukhoi's flying Unlimited level aerobatic
competition, usually with engines just like yours and MTV9-260 props,
thus I suspect you are approaching that kind of G loading. That said,
the Suke construction otherwise is much stronger than the 50. Another
thing that generates this kind of stress is gyroscopic maneuvers usually
accompanied by prop shaft seal damage.
Good luck.
Mark
-----Original Message-----
From: <mailto:owner-yak-list-server@matronics.com>
owner-yak-list-server@matronics.com [
<mailto:owner-yak-list-server@matronics.com>
mailto:owner-yak-list-server@matronics.com] On Behalf Of Gordon Price
Sent: Thursday, July 13, 2017 8:05 AM
Subject: [Non-DoD Source] Yak-List: Engine mount rubbers - YAK-50
<mailto:gord@thedampub.ca> gord@thedampub.ca>
We just installed a zero=99d M-13PF with Barrett Pistons which
dyno'd at 435 HP on my YAK 50. Performance is much enhanced however we
have just found some engine mount rubbers are being torn up because the
metal sleeve is moving and cutting the rubber. The airplane is being
flown under the G limits however during the air show sequence I am
sometimes seeing +8 and -5 G. We never had this problem with the old
360 HP engine. We have a new set being installed in the next few days
which should yield more information. Does anyone have experience in
this area? Thinking of bonding the sleeve to the rubber to prevent the
sleeve movement. Thanks in advance. Gord
<http://www.matronics.com/Navigator?Yak-List>
http://www.matronics.com/Navigator?Yak-List
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