Today's Message Index:
----------------------
1. 04:47 AM - Re: YAK-50 landing gear actuators overhaul time. (Gordon Price)
2. 05:09 AM - Re: YAK-50 landing gear actuators overhaul time. (George S. Coy)
3. 06:13 AM - Re: Sticky valve? (JL2A)
4. 06:35 AM - Re: YAK-50 landing gear actuators overhaul time. (Jan Mevis)
5. 06:39 AM - Re: Re: Sticky valve? (A. Dennis Savarese)
6. 06:47 AM - Re: YAK-50 landing gear actuators overhaul time. (Jan Mevis)
7. 07:34 AM - Re: Sticky valve? (av8ter)
8. 08:01 AM - Re: YAK-50 landing gear actuators overhaul time. (A. Dennis Savarese)
9. 08:39 AM - Re: YAK-50 landing gear actuators overhaul time. (Todd McCutchan)
10. 09:33 AM - Re: YAK-50 landing gear actuators overhaul time. (Bitterlich, Mark G CIV NAVAIR, WD)
11. 09:51 AM - Re: YAK-50 landing gear actuators overhaul time. (Bitterlich, Mark G CIV NAVAIR, WD)
12. 10:30 AM - Re: YAK-50 landing gear actuators overhaul time. (Jan Mevis)
13. 10:31 AM - Re: YAK-50 landing gear actuators overhaul time. (Jan Mevis)
14. 10:34 AM - Re: YAK-50 landing gear actuators overhaul time. (Jan Mevis)
15. 10:39 AM - Yak52 - Prop/Governor problem - help/advice needed (Nigel Willson)
16. 10:50 AM - Re: Yak52 - Prop/Governor problem - help/advice needed (George S. Coy)
17. 11:10 AM - Re: Yak52 - Prop/Governor problem - help/advice needed (Jan Mevis)
18. 11:19 AM - Re: Yak52 - Prop/Governor problem - help/advice needed (Nigel Willson)
19. 11:42 AM - Re: YAK-50 landing gear actuators overhaul time. (Bitterlich, Mark G CIV NAVAIR, WD)
20. 11:43 AM - Re: YAK-50 landing gear actuators overhaul time. (Bitterlich, Mark G CIV NAVAIR, WD)
21. 11:48 AM - Re: Yak52 - Prop/Governor problem - help/advice needed (George Coy)
22. 12:18 PM - Re: YAK-50 landing gear actuators overhaul time. (A. Dennis Savarese)
23. 12:43 PM - Re: YAK-50 landing gear actuators overhaul time. (Jan Mevis)
24. 01:42 PM - Re: YAK-50 landing gear actuators overhaul time. (Bitterlich, Mark G CIV NAVAIR, WD)
25. 02:52 PM - Re: YAK-50 landing gear actuators overhaul time. (Gordon Price)
26. 04:01 PM - Re: YAK-50 landing gear actuators overhaul time. (Todd McCutchan)
Message 1
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| Subject: | Re: YAK-50 landing gear actuators overhaul time. |
Thank you Jan. Very interesting about only 3 emergency extensions. Im wondering
where to look for the damage caused by this. Also, we did not tune the gear
since the actuators were sent back to us the same length as when went sent
them out. Is there something else we should be doing? We had quite a job getting
the right down lock microswitch working properly again. This is SN 01 and
there are 3 different sets of holes for the microswitch. Unfortunately we
could not remove the actuators without removing the downlink micro switches. That
was the worst part..getting them back in.
> On Jul 22, 2015, at 2:07 AM, Jan Mevis <jan.mevis@informavia.be> wrote:
>
>
> Hi Gordon,
>
> I always listen carefully when the gear extends.
> You can hear (or feel) the locking so I don't rely only upon the green
> lights.
> These Yak 50 actuators are one of the issues where the 50 is very
> different compared to the Yak 52.
> IMHO the system has been improved on the 52. The 52 has a separate small
> locking actuator.
> On the 50, the whole actuator moves for locking and unlocking. Tuning this
> is not so easy.
> The original Russian maintenance manual (DOSAAF 1979) says that you may
> only have three complete swings using the emergency bottle.
> After that, a complete overhaul of the landing gear is imperative.
> I had to use it once when the main pressure feed line collapsed (between
> the snot bottle and the cross).
> The full unrestricted blow of the emergency bottle is indeed impressive.
>
>
> BR,
>
> Jan (Yak 50 F-AZUK).
>
Message 2
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| Subject: | YAK-50 landing gear actuators overhaul time. |
Hmmm, So when the emergency gear extension is tested at very annual
condition extension, then it gets rebuilt every third year? I guess most of
us missed that memo.
George
-----Original Message-----
From: owner-yak-list-server@matronics.com
[mailto:owner-yak-list-server@matronics.com] On Behalf Of Gordon Price
Sent: Wednesday, July 22, 2015 7:44 AM
Subject: Re: Yak-List: YAK-50 landing gear actuators overhaul time.
Thank you Jan. Very interesting about only 3 emergency extensions. I'm
wondering where to look for the damage caused by this. Also, we did not
'tune' the gear since the actuators were sent back to us the same length as
when went sent them out. Is there something else we should be doing? We
had quite a job getting the right down lock microswitch working properly
again. This is SN 01 and there are 3 different sets of holes for the
microswitch. Unfortunately we could not remove the actuators without
removing the downlink micro switches. That was the worst part...getting them
back in.
> On Jul 22, 2015, at 2:07 AM, Jan Mevis <jan.mevis@informavia.be> wrote:
>
>
> Hi Gordon,
>
> I always listen carefully when the gear extends.
> You can hear (or feel) the locking so I don't rely only upon the green
> lights.
> These Yak 50 actuators are one of the issues where the 50 is very
> different compared to the Yak 52.
> IMHO the system has been improved on the 52. The 52 has a separate
> small locking actuator.
> On the 50, the whole actuator moves for locking and unlocking. Tuning
> this is not so easy.
> The original Russian maintenance manual (DOSAAF 1979) says that you
> may only have three complete swings using the emergency bottle.
> After that, a complete overhaul of the landing gear is imperative.
> I had to use it once when the main pressure feed line collapsed
> (between the snot bottle and the cross).
> The full unrestricted blow of the emergency bottle is indeed impressive.
>
>
> BR,
>
> Jan (Yak 50 F-AZUK).
>
Message 3
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| Subject: | Re: Sticky valve? |
Thanks Dennis, sounds reasonable. But why only when it's cold? Seems to indicate
to me something is sticky with the cold castor oil? One actuator is new, the
other has been in service for a while and used to drip a bit of oil out one end
- I suspect this one.
I've stared at the schematic for long enough and still can't figure out where the
diverter valves are on the actual aircraft - any hints!?
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=445063#445063
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| Subject: | Re: YAK-50 landing gear actuators overhaul time. |
No, testing is no issue, but with air from the emergency system we don't
let it go the whole way.
I would be very scared doing that with the plane on jacks. The odds are
that it would jump off the jacks.
The one time that I had to use the emergency system in flight, I remember
that it was a very violent experience.
Impossible to not notice it, the gear gets slammed down with so much force
and the whole plane shaked.
The Lithuanian mechanic that services my Yak 50 does check the emergency
system at each annual but he cuts the air supply before it's fully
developped.
Anyway, the Russian DOSAAF manual says that the main gear of the 50 should
be rebuilt after 3 uses of the emergency system.
Not only the actuators, the whole gear.
We sometimes forget that the scheduled lifetime of the Yak 50 was rather
short. The 50 was easily destined to be scrapped after certain mishaps.
Of course we do test the normal system each year and then we do have the
gear retract and extend several times, the whole way.
That's no problem.
We also do check the bottles each year.
BR,
Jan
On 22/07/15 14:05, "George S. Coy" <owner-yak-list-server@matronics.com on
behalf of george.coy@gmail.com> wrote:
>
>Hmmm, So when the emergency gear extension is tested at very annual
>condition extension, then it gets rebuilt every third year? I guess most
>of
>us missed that memo.
>George
>
>-----Original Message-----
>From: owner-yak-list-server@matronics.com
>[mailto:owner-yak-list-server@matronics.com] On Behalf Of Gordon Price
>Sent: Wednesday, July 22, 2015 7:44 AM
>To: yak-list@matronics.com
>Subject: Re: Yak-List: YAK-50 landing gear actuators overhaul time.
>
>
>Thank you Jan. Very interesting about only 3 emergency extensions. I'm
>wondering where to look for the damage caused by this. Also, we did not
>'tune' the gear since the actuators were sent back to us the same length
>as
>when went sent them out. Is there something else we should be doing? We
>had quite a job getting the right down lock microswitch working properly
>again. This is SN 01 and there are 3 different sets of holes for the
>microswitch. Unfortunately we could not remove the actuators without
>removing the downlink micro switches. That was the worst part...getting
>them
>back in.
>
>
>> On Jul 22, 2015, at 2:07 AM, Jan Mevis <jan.mevis@informavia.be> wrote:
>>
>>
>> Hi Gordon,
>>
>> I always listen carefully when the gear extends.
>> You can hear (or feel) the locking so I don't rely only upon the green
>> lights.
>> These Yak 50 actuators are one of the issues where the 50 is very
>> different compared to the Yak 52.
>> IMHO the system has been improved on the 52. The 52 has a separate
>> small locking actuator.
>> On the 50, the whole actuator moves for locking and unlocking. Tuning
>> this is not so easy.
>> The original Russian maintenance manual (DOSAAF 1979) says that you
>> may only have three complete swings using the emergency bottle.
>> After that, a complete overhaul of the landing gear is imperative.
>> I had to use it once when the main pressure feed line collapsed
>> (between the snot bottle and the cross).
>> The full unrestricted blow of the emergency bottle is indeed impressive.
>>
>>
>> BR,
>>
>> Jan (Yak 50 F-AZUK).
>>
>
>
Message 5
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| Subject: | Re: Sticky valve? |
Don't discount the 3rd actuator as being the problem. Regarding the
diverter valves, maybe someone on the list has a photo or two of the
diverter valves they could post to the list. If I remember correctly, if
you follow the air line from the down side of the actuator (that's the
side opposite the chrome shaft that moves in and out of the actuator)
backa bit, it will go into a T. Attached to the other side of the T are
diverter valves.
My suspicion the reason it happens when it's cold is because the seals
inside the actuator cylinders are stiffer and may not be sealing
properly. Once the external temperature goes up, the rubber gets softer
and possibly is allowing the seal to work properly. Perfect indication
of old, dried out rubber seals.
The actuator you said was leaking should be overhauledor replaced before
a more serious situation happens. Like that gear leg not coming down.
If it's been more than 5 years since theactuators and diverter valves
have been overhauled, you're on borrowed time as far as normal gear
operation is concerned.
Dennis
A. Dennis Savarese
334-546-8182 (mobile)
www.yak-52.com
Skype - Yakguy1
On 7/22/2015 8:10 AM, JL2A wrote:
>
> Thanks Dennis, sounds reasonable. But why only when it's cold? Seems to indicate
to me something is sticky with the cold castor oil? One actuator is new, the
other has been in service for a while and used to drip a bit of oil out one
end - I suspect this one.
>
> I've stared at the schematic for long enough and still can't figure out where
the diverter valves are on the actual aircraft - any hints!?
>
>
> Read this topic online here:
>
> http://forums.matronics.com/viewtopic.php?p=445063#445063
>
>
Message 6
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| Subject: | Re: YAK-50 landing gear actuators overhaul time. |
Hi Gordon,
Tuning is not the right expression, sorry (but English is not my native
language).
Re-installing the actuators is demanding: there are small levers that
connect between the actuators and the wing (if I remember well, it has
been some time).
It is possible that on your plane (being SN01 !!!! Waw) it is slightly
different.
I remember that there has to be some specific "play" for these levers
otherwise it could cause a malfunctioning under circumstances.
Bottomline: I have it serviced by a Lithuanian mechanic.
Maybe you should try and find a mechanic that has experience in doing
this?
Next time that you go flying, listen to the gear when it extends, you
should hear or feel it locking.
BR,
Jan
On 22/07/15 13:43, "Gordon Price" <owner-yak-list-server@matronics.com on
behalf of gord@thedampub.ca> wrote:
>
>Thank you Jan. Very interesting about only 3 emergency extensions.
>Im wondering where to look for the damage caused by this. Also, we did
>not tune the gear since the actuators were sent back to us the same
>length as when went sent them out. Is there something else we should be
>doing? We had quite a job getting the right down lock microswitch
>working properly again. This is SN 01 and there are 3 different sets of
>holes for the microswitch. Unfortunately we could not remove the
>actuators without removing the downlink micro switches. That was the
>worst part..getting them back in.
>
>
>> On Jul 22, 2015, at 2:07 AM, Jan Mevis <jan.mevis@informavia.be> wrote:
>>
>>
>> Hi Gordon,
>>
>> I always listen carefully when the gear extends.
>> You can hear (or feel) the locking so I don't rely only upon the green
>> lights.
>> These Yak 50 actuators are one of the issues where the 50 is very
>> different compared to the Yak 52.
>> IMHO the system has been improved on the 52. The 52 has a separate small
>> locking actuator.
>> On the 50, the whole actuator moves for locking and unlocking. Tuning
>>this
>> is not so easy.
>> The original Russian maintenance manual (DOSAAF 1979) says that you may
>> only have three complete swings using the emergency bottle.
>> After that, a complete overhaul of the landing gear is imperative.
>> I had to use it once when the main pressure feed line collapsed (between
>> the snot bottle and the cross).
>> The full unrestricted blow of the emergency bottle is indeed impressive.
>>
>>
>> BR,
>>
>> Jan (Yak 50 F-AZUK).
>>
>
>
Message 7
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| Subject: | Re: Sticky valve? |
I have gone through this issue in the past and I can tell you that the likely culprit
and easiest to troubleshoot first is the rear cockpit handle. Place it
DOWN and see what happens.
Keith
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=445070#445070
Message 8
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| Subject: | Re: YAK-50 landing gear actuators overhaul time. |
re: "I would be very scared doing that with the plane on jacks. The odds
are that it would jump off the jacks."
Not if you use the procedure, which is on my web site.
http://www.yak-52.com/maintena.htm
Try it the next time you have the airplane on jacks. You'll be amazed
at how gently the gear comes down and locks in place using this simple
procedure.
Dennis
A. Dennis Savarese
334-546-8182 (mobile)
www.yak-52.com
Skype - Yakguy1
On 7/22/2015 8:32 AM, Jan Mevis wrote:
>
> No, testing is no issue, but with air from the emergency system we don't
> let it go the whole way.
> I would be very scared doing that with the plane on jacks. The odds are
> that it would jump off the jacks.
> The one time that I had to use the emergency system in flight, I remember
> that it was a very violent experience.
> Impossible to not notice it, the gear gets slammed down with so much force
> and the whole plane shaked.
>
> The Lithuanian mechanic that services my Yak 50 does check the emergency
> system at each annual but he cuts the air supply before it's fully
> developped.
> Anyway, the Russian DOSAAF manual says that the main gear of the 50 should
> be rebuilt after 3 uses of the emergency system.
> Not only the actuators, the whole gear.
>
> We sometimes forget that the scheduled lifetime of the Yak 50 was rather
> short. The 50 was easily destined to be scrapped after certain mishaps.
>
> Of course we do test the normal system each year and then we do have the
> gear retract and extend several times, the whole way.
> That's no problem.
> We also do check the bottles each year.
>
> BR,
>
> Jan
>
>
> On 22/07/15 14:05, "George S. Coy" <owner-yak-list-server@matronics.com on
> behalf of george.coy@gmail.com> wrote:
>
>>
>> Hmmm, So when the emergency gear extension is tested at very annual
>> condition extension, then it gets rebuilt every third year? I guess most
>> of
>> us missed that memo.
>> George
>>
>> -----Original Message-----
>> From: owner-yak-list-server@matronics.com
>> [mailto:owner-yak-list-server@matronics.com] On Behalf Of Gordon Price
>> Sent: Wednesday, July 22, 2015 7:44 AM
>> To: yak-list@matronics.com
>> Subject: Re: Yak-List: YAK-50 landing gear actuators overhaul time.
>>
>>
>> Thank you Jan. Very interesting about only 3 emergency extensions. I'm
>> wondering where to look for the damage caused by this. Also, we did not
>> 'tune' the gear since the actuators were sent back to us the same length
>> as
>> when went sent them out. Is there something else we should be doing? We
>> had quite a job getting the right down lock microswitch working properly
>> again. This is SN 01 and there are 3 different sets of holes for the
>> microswitch. Unfortunately we could not remove the actuators without
>> removing the downlink micro switches. That was the worst part...getting
>> them
>> back in.
>>
>>
>>> On Jul 22, 2015, at 2:07 AM, Jan Mevis <jan.mevis@informavia.be> wrote:
>>>
>>>
>>> Hi Gordon,
>>>
>>> I always listen carefully when the gear extends.
>>> You can hear (or feel) the locking so I don't rely only upon the green
>>> lights.
>>> These Yak 50 actuators are one of the issues where the 50 is very
>>> different compared to the Yak 52.
>>> IMHO the system has been improved on the 52. The 52 has a separate
>>> small locking actuator.
>>> On the 50, the whole actuator moves for locking and unlocking. Tuning
>>> this is not so easy.
>>> The original Russian maintenance manual (DOSAAF 1979) says that you
>>> may only have three complete swings using the emergency bottle.
>>> After that, a complete overhaul of the landing gear is imperative.
>>> I had to use it once when the main pressure feed line collapsed
>>> (between the snot bottle and the cross).
>>> The full unrestricted blow of the emergency bottle is indeed impressive.
>>>
>>>
>>> BR,
>>>
>>> Jan (Yak 50 F-AZUK).
>>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>
>
Message 9
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| Subject: | Re: YAK-50 landing gear actuators overhaul time. |
Jan,
I would love to get a copy of that MX manual.
Please email me directly. The info is below.
Todd McCutchan
T-34A & Yak-50
Cell: (260) 402-1740
E-mail: todd@fastaircraft.com
www.fastaircraft.com
> On Jul 22, 2015, at 9:32 AM, Jan Mevis <jan.mevis@informavia.be> wrote:
>
>
> No, testing is no issue, but with air from the emergency system we don't
> let it go the whole way.
> I would be very scared doing that with the plane on jacks. The odds are
> that it would jump off the jacks.
> The one time that I had to use the emergency system in flight, I remember
> that it was a very violent experience.
> Impossible to not notice it, the gear gets slammed down with so much force
> and the whole plane shaked.
>
> The Lithuanian mechanic that services my Yak 50 does check the emergency
> system at each annual but he cuts the air supply before it's fully
> developped.
> Anyway, the Russian DOSAAF manual says that the main gear of the 50 should
> be rebuilt after 3 uses of the emergency system.
> Not only the actuators, the whole gear.
>
> We sometimes forget that the scheduled lifetime of the Yak 50 was rather
> short. The 50 was easily destined to be scrapped after certain mishaps.
>
> Of course we do test the normal system each year and then we do have the
> gear retract and extend several times, the whole way.
> That's no problem.
> We also do check the bottles each year.
>
> BR,
>
> Jan
>
>
> On 22/07/15 14:05, "George S. Coy" <owner-yak-list-server@matronics.com on
> behalf of george.coy@gmail.com> wrote:
>
>>
>> Hmmm, So when the emergency gear extension is tested at very annual
>> condition extension, then it gets rebuilt every third year? I guess most
>> of
>> us missed that memo.
>> George
>>
>> -----Original Message-----
>> From: owner-yak-list-server@matronics.com
>> [mailto:owner-yak-list-server@matronics.com] On Behalf Of Gordon Price
>> Sent: Wednesday, July 22, 2015 7:44 AM
>> To: yak-list@matronics.com
>> Subject: Re: Yak-List: YAK-50 landing gear actuators overhaul time.
>>
>>
>> Thank you Jan. Very interesting about only 3 emergency extensions. I'm
>> wondering where to look for the damage caused by this. Also, we did not
>> 'tune' the gear since the actuators were sent back to us the same length
>> as
>> when went sent them out. Is there something else we should be doing? We
>> had quite a job getting the right down lock microswitch working properly
>> again. This is SN 01 and there are 3 different sets of holes for the
>> microswitch. Unfortunately we could not remove the actuators without
>> removing the downlink micro switches. That was the worst part...getting
>> them
>> back in.
>>
>>
>>> On Jul 22, 2015, at 2:07 AM, Jan Mevis <jan.mevis@informavia.be> wrote:
>>>
>>>
>>> Hi Gordon,
>>>
>>> I always listen carefully when the gear extends.
>>> You can hear (or feel) the locking so I don't rely only upon the green
>>> lights.
>>> These Yak 50 actuators are one of the issues where the 50 is very
>>> different compared to the Yak 52.
>>> IMHO the system has been improved on the 52. The 52 has a separate
>>> small locking actuator.
>>> On the 50, the whole actuator moves for locking and unlocking. Tuning
>>> this is not so easy.
>>> The original Russian maintenance manual (DOSAAF 1979) says that you
>>> may only have three complete swings using the emergency bottle.
>>> After that, a complete overhaul of the landing gear is imperative.
>>> I had to use it once when the main pressure feed line collapsed
>>> (between the snot bottle and the cross).
>>> The full unrestricted blow of the emergency bottle is indeed impressive.
>>>
>>>
>>> BR,
>>>
>>> Jan (Yak 50 F-AZUK).
>
>
>
>
>
>
Message 10
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| Subject: | YAK-50 landing gear actuators overhaul time. |
Jan,
Comment: I have to politely disagree with you about "feeling the gear come down
and lock". Yes, you can hear it come down. But you sure can NOT hear it lock.
That "thump" you feel is NOT the gear locking. It is the gear actuator
reaching maximum travel and HOPEFULLY the gear moving far enough forward to allow
the down-lock to engage
The simple fact is that the gear lights on the 50 only indicate that the legs have
moved past a certain position. Thus if everything worked correctly the gear
SHOULD have locked. ALWAYS CHECK THE LIGHTS!
The GEAR ACTUATOR on the 50 is what is actually on a mechanism that causes it
to move when air is applied to lower the gear. These are the "levers" you were
thinking about. This movement translates to the UNLOCK mechanism so that the
gear can come off the UP locks and start downward movement.
As for locking DOWN .... you can have the aircraft on jacks, with the gear leg
unlocked and hanging, and no air pressure at all, or even with the actually totally
REMOVED. All you have to do is gently push on the gear leg and the locking
mechanism will engage, and you can actually SEE it if the fiberglass cover
is removed. You can reach in there with a screw driver (flat head) push down
on the locking pin and unlock the DOWNLOCK and it will swing back to just hanging
again.
So the point is, the UP-LOCK only requires the actuator itself to MOVE on concentric
mounting slots which UNLOCKS the UPLOCK, the air pressure than pushes the
gear down far enough to where the gear DOWNLOCK will engage. The actual movement
of the pins and wedge that LOCKS THE GEAR DOWN is actually not a very
loud sound. The "movement" of the whole actuator is only there to unlock the
UPLOCK, after that, the actuator plunger shaft pushes the gear down to final
extension.
Final thought on this. ALWAYS ALWAYS LOOK AT THE LIGHTS! I got into the same
habit Jan did by listening to the THUMP of the gear coming down. And then one
time the gear went THUMP THUMP and the left one was NOT LOCKED and the left
light was seen later to NOT BE ON. So this is not theory, it happened. On
the Conditional, it is best to turn all the air off, then lower the gear (on jacks
obviously), the gear will unlock and not go totally down to lock. Then
with the cover removed over the top of the landing gear strut, gently PUSH on
the gear leg while someone is WATCHING the gear light! You will see and feel
the gear lock down and that is when the light should come on and NOT BEFORE.
If it does, adjust the switch.
Emergency gear extensions have no restrictor in the gear hose. Thus 735 PSI of
air is applied ALL AT ONCE with full flow potential. Not only can it make the
aircraft jump off the jacks, but it also can blow out the chevron seals. The
new chevron seals installed in rebuilt actuators are much better than the originals
that the Russians used, which usually harden and then turn into gel when
someone tells you to inject "stuff" into the air system after it sat for a
few years. Use Dennis's procedure for testing emergency. Then realize too that
you will have to reset the check valves on the bottom of the actuators. Not
hard. See his procedure. I made up my own, but his is better.
Bottom line ... do a careful check on the downlock by hand. Check to make sure
the switches are adjusted properly so they go on when the gear is LOCKED and
not before.
Then listen for the THUMP THUMP, but ALWAYS CHECK THE LIGHTS TOO!
Mark
-----Original Message-----
From: owner-yak-list-server@matronics.com [mailto:owner-yak-list-server@matronics.com] On Behalf Of Jan Mevis
Sent: Wednesday, July 22, 2015 9:45 AM
Subject: Re: Yak-List: YAK-50 landing gear actuators overhaul time.
Hi Gordon,
Tuning is not the right expression, sorry (but English is not my native language).
Re-installing the actuators is demanding: there are small levers that connect between
the actuators and the wing (if I remember well, it has been some time).
It is possible that on your plane (being SN01 !!!! Waw) it is slightly different.
I remember that there has to be some specific "play" for these levers otherwise
it could cause a malfunctioning under circumstances.
Bottomline: I have it serviced by a Lithuanian mechanic.
Maybe you should try and find a mechanic that has experience in doing this?
Next time that you go flying, listen to the gear when it extends, you should hear
or feel it locking.
BR,
Jan
On 22/07/15 13:43, "Gordon Price" <owner-yak-list-server@matronics.com on behalf
of gord@thedampub.ca> wrote:
>
>Thank you Jan. Very interesting about only 3 emergency extensions.
>Im wondering where to look for the damage caused by this. Also, we
>did not tune the gear since the actuators were sent back to us the
>same length as when went sent them out. Is there something else we
>should be doing? We had quite a job getting the right down lock
>microswitch working properly again. This is SN 01 and there are 3
>different sets of holes for the microswitch. Unfortunately we could
>not remove the actuators without removing the downlink micro switches.
>That was the worst part..getting them back in.
>
>
>> On Jul 22, 2015, at 2:07 AM, Jan Mevis <jan.mevis@informavia.be> wrote:
>>
>>
>> Hi Gordon,
>>
>> I always listen carefully when the gear extends.
>> You can hear (or feel) the locking so I don't rely only upon the
>>green lights.
>> These Yak 50 actuators are one of the issues where the 50 is very
>>different compared to the Yak 52.
>> IMHO the system has been improved on the 52. The 52 has a separate
>>small locking actuator.
>> On the 50, the whole actuator moves for locking and unlocking. Tuning
>>this is not so easy.
>> The original Russian maintenance manual (DOSAAF 1979) says that you
>>may only have three complete swings using the emergency bottle.
>> After that, a complete overhaul of the landing gear is imperative.
>> I had to use it once when the main pressure feed line collapsed
>>(between the snot bottle and the cross).
>> The full unrestricted blow of the emergency bottle is indeed impressive.
>>
>>
>> BR,
>>
>> Jan (Yak 50 F-AZUK).
>>
>
>
Message 11
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| Subject: | YAK-50 landing gear actuators overhaul time. |
When you replaced the gear actuators, did anyone tell you about the restrictor
washers that fit into the air line connecting to the up and down side normal hoses?
If they did not, then be aware that they fall out very easily and get lost. Did
you make sure you put them back in exactly as they came out?
The only reason I mention this is because of your comment about the gear coming
down much more violently now.
If you lost those washers with the small holes through them, then your gear will
swing at the same speed it would if emergency air was used and that is a very
bad thing.
I really hope you know what I am talking about here. ..
Next:
If you lower the gear and a light does not come on, put your gear handle in the
middle position. This isolates the landing gear actuators. Then fly around
and wait until main air pressure builds back to 50 ATMOS. Select DOWN on the main
gear handle again and see if the light comes on. If it does not, then use
Emergency Air PROCEDURES. If it still does not come down, close the emergency
air valve, fly around until the pressure builds back up on the emergency bottle
and then TRY EMERGENCY PROCEDURES AGAIN! Note: Yak-50 pressurizes BOTH main
and emergency bottles from the engine compressor, unlike the 52.
People looking at the gear cannot tell if it is really locked when you are flying,
only that it "looks down". It would take a real YAK-50 expert to carefully
see the angle of that gear to even make an educated guess. Chevron seal
failure in the actuators is common. If you were to raise the gear at this point,
what little is left can turn into slush or pieces and then you are looking
at a gear up landing. Bottom line, yes, you should have used the emergency
air procedures (read them carefully). If even THAT fails, having the gear handle
in the middle, close the emergency air bottle valve, fly around and BOTH
bottles will re-pressurize. Try the emergency procedure again! I'd keep doing
that until I almost ran out of gas.
Good job on the "bounce" on the runway. The only reason it worked was that there
was still air in the system pushing on that actuator. With a total chevron
seal failure, it would not have.
Mark
-----Original Message-----
From: owner-yak-list-server@matronics.com [mailto:owner-yak-list-server@matronics.com] On Behalf Of Gordon Price
Sent: Tuesday, July 21, 2015 6:24 PM
Subject: Yak-List: YAK-50 landing gear actuators overhaul time.
It is time to share an adrenaline moment and some good luck in my YAK 50.
As part of my airshow routine I do a final pass with the landing gear down. I
put the gear down below 150 kph. I did not get a green light on the right side.
The light tested OK. I asked the airboss if the gear was down.yes it was.
It was the end of the routine and I had a 10 minute flight back to Owen Sound
airport. Wondering about this, should I leave them, should I retract them,
I decided to retract them. At the airport I put the gear down, got 2 green lights
and landed uneventfully.
We checked the gear visually and the micro switches. That is when we found out
they we wired backwards, but they were working fine. Left means right. I guess
they were facing backwards during installation. A puzzle.
I flew the air show the next day and all was routine. except the weather.
The following week I flew another short demo flight, put the gear down and no right
green light. Since I had good luck last time retracting and extending I
did the same. No green light on the right side again, meaning it was a downlock
problem on the left gear. The light out checked OK. The air pressure was now
just under 3. The emergency system was 5.5. The ground confirmed both gear
were down.
Should I use the emergency system? I thought long and fast since there was not
a lot of fuel available and it was a very busy airport scene. I had sufficient
air pressure to extend the gear with the main system gear. Why then use an alternate
air system? To me, it was a downlock problem. Would the extra pressure
help that? I was not sure. So I decided to try and jar the gear into the
locked position first.
I got the speed back to about 110 kph getting the nose up and angle gear forward,
then bounced the left gear on the runway ready for an immediate go-around.
I heard a snap caught the green light out of the corner of my eye and landed
with 2 green lights. Ground observers confirmed the left wheel moved back about
an inch or two, then snapped forward.
I called Dennis, as I always do when I have a problem, and as usual, he had the
solution. Pull the actuators and send them to Jill at M14P Inc. So we did.
We got the actuators back and finally got them installed. Not an easy job. The
gear swing is certainly a lot more violent now. It was a good thing that we had
one person holding each wing tip down on the jacks during the swing. We havent
bothered to rewire them yet and I have not flown the airplane yet.
I spoke to Jill and the first thing she said was You dodged a bullet.
Apparently, during the initial test, they blew the end off the left actuator with
only 300psi.
I am so glad I did not use the emergency system and ram in all 850 psi. If the
end had blown off in the air what a mess.
Jill put on the last remaining new actuator cap and they are looking for more supply.
So that is my story. Comments criticisms are most welcome. That is the way we
all learn.
I dont have all the answers but I sure had some good luck this time.
And yes we will be removing the actuators in 5 years for another overhaul.
Message 12
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| Subject: | Re: YAK-50 landing gear actuators overhaul time. |
Ok Dennis, but there's a difference between the 50 and the 52.
The 50 is much lighter, and it are the Russian inspectors and mechanics
who advised me NOT to extend the whole gear using the emergency.
Everything I added only applies to the Yak 50.
Jan
On 22/07/15 16:58, "A. Dennis Savarese"
<owner-yak-list-server@matronics.com on behalf of
dsavarese0812@bellsouth.net> wrote:
><dsavarese0812@bellsouth.net>
>
>re: "I would be very scared doing that with the plane on jacks. The odds
>are that it would jump off the jacks."
>
>Not if you use the procedure, which is on my web site.
>
>http://www.yak-52.com/maintena.htm
>
>Try it the next time you have the airplane on jacks. You'll be amazed
>at how gently the gear comes down and locks in place using this simple
>procedure.
>
>Dennis
>
>A. Dennis Savarese
>334-546-8182 (mobile)
>www.yak-52.com
>Skype - Yakguy1
>
>On 7/22/2015 8:32 AM, Jan Mevis wrote:
>>
>> No, testing is no issue, but with air from the emergency system we don't
>> let it go the whole way.
>> I would be very scared doing that with the plane on jacks. The odds are
>> that it would jump off the jacks.
>> The one time that I had to use the emergency system in flight, I
>>remember
>> that it was a very violent experience.
>> Impossible to not notice it, the gear gets slammed down with so much
>>force
>> and the whole plane shaked.
>>
>> The Lithuanian mechanic that services my Yak 50 does check the emergency
>> system at each annual but he cuts the air supply before it's fully
>> developped.
>> Anyway, the Russian DOSAAF manual says that the main gear of the 50
>>should
>> be rebuilt after 3 uses of the emergency system.
>> Not only the actuators, the whole gear.
>>
>> We sometimes forget that the scheduled lifetime of the Yak 50 was rather
>> short. The 50 was easily destined to be scrapped after certain mishaps.
>>
>> Of course we do test the normal system each year and then we do have the
>> gear retract and extend several times, the whole way.
>> That's no problem.
>> We also do check the bottles each year.
>>
>> BR,
>>
>> Jan
>>
>>
>> On 22/07/15 14:05, "George S. Coy" <owner-yak-list-server@matronics.com
>>on
>> behalf of george.coy@gmail.com> wrote:
>>
>>>
>>> Hmmm, So when the emergency gear extension is tested at very annual
>>> condition extension, then it gets rebuilt every third year? I guess
>>>most
>>> of
>>> us missed that memo.
>>> George
>>>
>>> -----Original Message-----
>>> From: owner-yak-list-server@matronics.com
>>> [mailto:owner-yak-list-server@matronics.com] On Behalf Of Gordon Price
>>> Sent: Wednesday, July 22, 2015 7:44 AM
>>> To: yak-list@matronics.com
>>> Subject: Re: Yak-List: YAK-50 landing gear actuators overhaul time.
>>>
>>>
>>> Thank you Jan. Very interesting about only 3 emergency extensions.
>>>I'm
>>> wondering where to look for the damage caused by this. Also, we did
>>>not
>>> 'tune' the gear since the actuators were sent back to us the same
>>>length
>>> as
>>> when went sent them out. Is there something else we should be doing?
>>>We
>>> had quite a job getting the right down lock microswitch working
>>>properly
>>> again. This is SN 01 and there are 3 different sets of holes for the
>>> microswitch. Unfortunately we could not remove the actuators without
>>> removing the downlink micro switches. That was the worst part...getting
>>> them
>>> back in.
>>>
>>>
>>>> On Jul 22, 2015, at 2:07 AM, Jan Mevis <jan.mevis@informavia.be>
>>>>wrote:
>>>>
>>>>
>>>> Hi Gordon,
>>>>
>>>> I always listen carefully when the gear extends.
>>>> You can hear (or feel) the locking so I don't rely only upon the green
>>>> lights.
>>>> These Yak 50 actuators are one of the issues where the 50 is very
>>>> different compared to the Yak 52.
>>>> IMHO the system has been improved on the 52. The 52 has a separate
>>>> small locking actuator.
>>>> On the 50, the whole actuator moves for locking and unlocking. Tuning
>>>> this is not so easy.
>>>> The original Russian maintenance manual (DOSAAF 1979) says that you
>>>> may only have three complete swings using the emergency bottle.
>>>> After that, a complete overhaul of the landing gear is imperative.
>>>> I had to use it once when the main pressure feed line collapsed
>>>> (between the snot bottle and the cross).
>>>> The full unrestricted blow of the emergency bottle is indeed
>>>>impressive.
>>>>
>>>>
>>>> BR,
>>>>
>>>> Jan (Yak 50 F-AZUK).
>>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>
>>
>>
>>
>>
>>
>
>
Message 13
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| Subject: | Re: YAK-50 landing gear actuators overhaul time. |
Hi Todd,
I'll try to make some copies, but it's an old book, so it'll take some time.
Jan
From: <owner-yak-list-server@matronics.com> on behalf of Todd McCutchan
<todd@fastaircraft.com>
Subject: Re: Yak-List: YAK-50 landing gear actuators overhaul time.
Jan,
I would love to get a copy of that MX manual.
Please email me directly. The info is below.
Todd McCutchan
T-34A & Yak-50
Cell: (260) 402-1740
E-mail: todd@fastaircraft.com
www.fastaircraft.com <http://www.fastaircraft.com>
On Jul 22, 2015, at 9:32 AM, Jan Mevis <jan.mevis@informavia.be> wrote:
>
> No, testing is no issue, but with air from the emergency system we don't
> let it go the whole way.
> I would be very scared doing that with the plane on jacks. The odds are
> that it would jump off the jacks.
> The one time that I had to use the emergency system in flight, I remember
> that it was a very violent experience.
> Impossible to not notice it, the gear gets slammed down with so much force
> and the whole plane shaked.
>
> The Lithuanian mechanic that services my Yak 50 does check the emergency
> system at each annual but he cuts the air supply before it's fully
> developped.
> Anyway, the Russian DOSAAF manual says that the main gear of the 50 should
> be rebuilt after 3 uses of the emergency system.
> Not only the actuators, the whole gear.
>
> We sometimes forget that the scheduled lifetime of the Yak 50 was rather
> short. The 50 was easily destined to be scrapped after certain mishaps.
>
> Of course we do test the normal system each year and then we do have the
> gear retract and extend several times, the whole way.
> That's no problem.
> We also do check the bottles each year.
>
> BR,
>
> Jan
>
>
> On 22/07/15 14:05, "George S. Coy" <owner-yak-list-server@matronics.com on
> behalf of george.coy@gmail.com> wrote:
>
>>
>> Hmmm, So when the emergency gear extension is tested at very annual
>> condition extension, then it gets rebuilt every third year? I guess most
>> of
>> us missed that memo.
>> George
>>
>> -----Original Message-----
>> From: owner-yak-list-server@matronics.com
>> [mailto:owner-yak-list-server@matronics.com] On Behalf Of Gordon Price
>> Sent: Wednesday, July 22, 2015 7:44 AM
>> To: yak-list@matronics.com
>> Subject: Re: Yak-List: YAK-50 landing gear actuators overhaul time.
>>
>>
>> Thank you Jan. Very interesting about only 3 emergency extensions. I'm
>> wondering where to look for the damage caused by this. Also, we did not
>> 'tune' the gear since the actuators were sent back to us the same length
>> as
>> when went sent them out. Is there something else we should be doing? We
>> had quite a job getting the right down lock microswitch working properly
>> again. This is SN 01 and there are 3 different sets of holes for the
>> microswitch. Unfortunately we could not remove the actuators without
>> removing the downlink micro switches. That was the worst part...getting
>> them
>> back in.
>>
>>
>>> On Jul 22, 2015, at 2:07 AM, Jan Mevis <jan.mevis@informavia.be> wrote:
>>>
>>>
>>> Hi Gordon,
>>>
>>> I always listen carefully when the gear extends.
>>> You can hear (or feel) the locking so I don't rely only upon the green
>>> lights.
>>> These Yak 50 actuators are one of the issues where the 50 is very
>>> different compared to the Yak 52.
>>> IMHO the system has been improved on the 52. The 52 has a separate
>>> small locking actuator.
>>> On the 50, the whole actuator moves for locking and unlocking. Tuning
>>> this is not so easy.
>>> The original Russian maintenance manual (DOSAAF 1979) says that you
>>> may only have three complete swings using the emergency bottle.
>>> After that, a complete overhaul of the landing gear is imperative.
>>> I had to use it once when the main pressure feed line collapsed
>>> (between the snot bottle and the cross).
>>> The full unrestricted blow of the emergency bottle is indeed impressive.
>>>
>>>
>>> BR,
>>>
>>> Jan (Yak 50 F-AZUK).
>>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
> http://www.matronics.com/Navig===============================================
> ====; - MATRONICS WEB FORUMS -
>
> <=======================================================
>
>
>
Message 14
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| Subject: | Re: YAK-50 landing gear actuators overhaul time. |
Thanks Mark. Of course I always check the lights. I also carefully do the
lamp test before each flight.
I appreciate your correction!
Jan
On 22/07/15 18:29, "Bitterlich, Mark G CIV NAVAIR, WD"
<owner-yak-list-server@matronics.com on behalf of
mark.bitterlich@navy.mil> wrote:
><mark.bitterlich@navy.mil>
>
>Jan,
>
>Comment: I have to politely disagree with you about "feeling the gear
>come down and lock". Yes, you can hear it come down. But you sure can
>NOT hear it lock. That "thump" you feel is NOT the gear locking. It is
>the gear actuator reaching maximum travel and HOPEFULLY the gear moving
>far enough forward to allow the down-lock to engage
>
>The simple fact is that the gear lights on the 50 only indicate that the
>legs have moved past a certain position. Thus if everything worked
>correctly the gear SHOULD have locked. ALWAYS CHECK THE LIGHTS!
>
>The GEAR ACTUATOR on the 50 is what is actually on a mechanism that
>causes it to move when air is applied to lower the gear. These are the
>"levers" you were thinking about. This movement translates to the UNLOCK
>mechanism so that the gear can come off the UP locks and start downward
>movement.
>
>As for locking DOWN .... you can have the aircraft on jacks, with the
>gear leg unlocked and hanging, and no air pressure at all, or even with
>the actually totally REMOVED. All you have to do is gently push on the
>gear leg and the locking mechanism will engage, and you can actually SEE
>it if the fiberglass cover is removed. You can reach in there with a
>screw driver (flat head) push down on the locking pin and unlock the
>DOWNLOCK and it will swing back to just hanging again.
>
>So the point is, the UP-LOCK only requires the actuator itself to MOVE on
>concentric mounting slots which UNLOCKS the UPLOCK, the air pressure than
>pushes the gear down far enough to where the gear DOWNLOCK will engage.
> The actual movement of the pins and wedge that LOCKS THE GEAR DOWN is
>actually not a very loud sound. The "movement" of the whole actuator is
>only there to unlock the UPLOCK, after that, the actuator plunger shaft
>pushes the gear down to final extension.
>
>Final thought on this. ALWAYS ALWAYS LOOK AT THE LIGHTS! I got into
>the same habit Jan did by listening to the THUMP of the gear coming down.
> And then one time the gear went THUMP THUMP and the left one was NOT
>LOCKED and the left light was seen later to NOT BE ON. So this is not
>theory, it happened. On the Conditional, it is best to turn all the air
>off, then lower the gear (on jacks obviously), the gear will unlock and
>not go totally down to lock. Then with the cover removed over the top
>of the landing gear strut, gently PUSH on the gear leg while someone is
>WATCHING the gear light! You will see and feel the gear lock down and
>that is when the light should come on and NOT BEFORE. If it does,
>adjust the switch.
>
>Emergency gear extensions have no restrictor in the gear hose. Thus 735
>PSI of air is applied ALL AT ONCE with full flow potential. Not only can
>it make the aircraft jump off the jacks, but it also can blow out the
>chevron seals. The new chevron seals installed in rebuilt actuators are
>much better than the originals that the Russians used, which usually
>harden and then turn into gel when someone tells you to inject "stuff"
>into the air system after it sat for a few years. Use Dennis's
>procedure for testing emergency. Then realize too that you will have to
>reset the check valves on the bottom of the actuators. Not hard. See
>his procedure. I made up my own, but his is better.
>
>Bottom line ... do a careful check on the downlock by hand. Check to
>make sure the switches are adjusted properly so they go on when the gear
>is LOCKED and not before.
>
>Then listen for the THUMP THUMP, but ALWAYS CHECK THE LIGHTS TOO!
>
>Mark
>
>
>-----Original Message-----
>From: owner-yak-list-server@matronics.com
>[mailto:owner-yak-list-server@matronics.com] On Behalf Of Jan Mevis
>Sent: Wednesday, July 22, 2015 9:45 AM
>To: yak-list@matronics.com
>Subject: Re: Yak-List: YAK-50 landing gear actuators overhaul time.
>
>
>Hi Gordon,
>
>Tuning is not the right expression, sorry (but English is not my native
>language).
>Re-installing the actuators is demanding: there are small levers that
>connect between the actuators and the wing (if I remember well, it has
>been some time).
>It is possible that on your plane (being SN01 !!!! Waw) it is slightly
>different.
>I remember that there has to be some specific "play" for these levers
>otherwise it could cause a malfunctioning under circumstances.
>Bottomline: I have it serviced by a Lithuanian mechanic.
>Maybe you should try and find a mechanic that has experience in doing
>this?
>Next time that you go flying, listen to the gear when it extends, you
>should hear or feel it locking.
>
>BR,
>
>Jan
>
>
>On 22/07/15 13:43, "Gordon Price" <owner-yak-list-server@matronics.com on
>behalf of gord@thedampub.ca> wrote:
>
>>
>>Thank you Jan. Very interesting about only 3 emergency extensions.
>>Im wondering where to look for the damage caused by this. Also, we
>>did not tune the gear since the actuators were sent back to us the
>>same length as when went sent them out. Is there something else we
>>should be doing? We had quite a job getting the right down lock
>>microswitch working properly again. This is SN 01 and there are 3
>>different sets of holes for the microswitch. Unfortunately we could
>>not remove the actuators without removing the downlink micro switches.
>>That was the worst part..getting them back in.
>>
>>
>>> On Jul 22, 2015, at 2:07 AM, Jan Mevis <jan.mevis@informavia.be> wrote:
>>>
>>>
>>> Hi Gordon,
>>>
>>> I always listen carefully when the gear extends.
>>> You can hear (or feel) the locking so I don't rely only upon the
>>>green lights.
>>> These Yak 50 actuators are one of the issues where the 50 is very
>>>different compared to the Yak 52.
>>> IMHO the system has been improved on the 52. The 52 has a separate
>>>small locking actuator.
>>> On the 50, the whole actuator moves for locking and unlocking. Tuning
>>>this is not so easy.
>>> The original Russian maintenance manual (DOSAAF 1979) says that you
>>>may only have three complete swings using the emergency bottle.
>>> After that, a complete overhaul of the landing gear is imperative.
>>> I had to use it once when the main pressure feed line collapsed
>>>(between the snot bottle and the cross).
>>> The full unrestricted blow of the emergency bottle is indeed
>>>impressive.
>>>
>>>
>>> BR,
>>>
>>> Jan (Yak 50 F-AZUK).
>>>
>>
>>
>>
>>
>>
>>
>
>
Message 15
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| Subject: | Yak52 - Prop/Governor problem - help/advice needed |
Asking the fount of all yak knowledge....
Pre-take off checks prop cycle check all fine (70% down to 53% three times).
On take-off, prop went to 110% and stayed there.
Moving the prop lever to full course made no difference to RPM.
Reduced power to bring RPM under control, abbreviated circuit and landed.
Have changed to governor - but appears to still be a problem.
Have had the prop off - and checked blades move freely, and oil is returned when
blades are rotated.
Drive to governor appears to be ok (rotates when prop is turned).
Problem obviously appears to be when the prop is under load.
Can anyone shed any light, experience of happening before?
Clarification of my understanding would also be useful re what does what - i.e.
oil pressure causes fine pitch, weights cause course pitch? In that case, is
it a governor drive problem when under load? IS there a weak link in the drive
system like the compressor?
Any ideas?
Regards,
Nigel Willson
Flying Instructor/Examiner and Display Pilot
_________________________________________________
email: nigel@yakdisplay.com
mobile: (+44) 7809 116676
web:http://yakdisplay.com
Message 16
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| Subject: | Yak52 - Prop/Governor problem - help/advice needed |
check the clamps that secure the cable housing.
-----Original Message-----
From: owner-yak-list-server@matronics.com
[mailto:owner-yak-list-server@matronics.com] On Behalf Of Nigel Willson
Sent: Wednesday, July 22, 2015 1:37 PM
Subject: Yak-List: Yak52 - Prop/Governor problem - help/advice needed
Asking the fount of all yak knowledge....
Pre-take off checks prop cycle check all fine (70% down to 53% three times).
On take-off, prop went to 110% and stayed there.
Moving the prop lever to full course made no difference to RPM.
Reduced power to bring RPM under control, abbreviated circuit and landed.
Have changed to governor - but appears to still be a problem.
Have had the prop off - and checked blades move freely, and oil is returned
when blades are rotated.
Drive to governor appears to be ok (rotates when prop is turned).
Problem obviously appears to be when the prop is under load.
Can anyone shed any light, experience of happening before?
Clarification of my understanding would also be useful re what does what -
i.e. oil pressure causes fine pitch, weights cause course pitch? In that
case, is it a governor drive problem when under load? IS there a weak link
in the drive system like the compressor?
Any ideas?
Regards,
Nigel Willson
Flying Instructor/Examiner and Display Pilot
_________________________________________________
email: nigel@yakdisplay.com
mobile: (+44) 7809 116676
web:http://yakdisplay.com
Message 17
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| Subject: | Re: Yak52 - Prop/Governor problem - help/advice needed |
That's a very good advise George. We had recently some RPM problems on our
Yak 52 because of that.
Jan
On 22/07/15 19:47, "George S. Coy" <owner-yak-list-server@matronics.com on
behalf of george.coy@gmail.com> wrote:
>
>check the clamps that secure the cable housing.
>
>-----Original Message-----
>From: owner-yak-list-server@matronics.com
>[mailto:owner-yak-list-server@matronics.com] On Behalf Of Nigel Willson
>Sent: Wednesday, July 22, 2015 1:37 PM
>To: yak-list@matronics.com
>Subject: Yak-List: Yak52 - Prop/Governor problem - help/advice needed
>
>
>Asking the fount of all yak knowledge....
>
>Pre-take off checks prop cycle check all fine (70% down to 53% three
>times).
>On take-off, prop went to 110% and stayed there.
>Moving the prop lever to full course made no difference to RPM.
>
>Reduced power to bring RPM under control, abbreviated circuit and landed.
>
>Have changed to governor - but appears to still be a problem.
>
>Have had the prop off - and checked blades move freely, and oil is
>returned
>when blades are rotated.
>
>Drive to governor appears to be ok (rotates when prop is turned).
>
>Problem obviously appears to be when the prop is under load.
>
>Can anyone shed any light, experience of happening before?
>
>Clarification of my understanding would also be useful re what does what -
>i.e. oil pressure causes fine pitch, weights cause course pitch? In that
>case, is it a governor drive problem when under load? IS there a weak link
>in the drive system like the compressor?
>
>
>Any ideas?
>
>Regards,
>Nigel Willson
>Flying Instructor/Examiner and Display Pilot
>_________________________________________________
> email: nigel@yakdisplay.com
> mobile: (+44) 7809 116676
> web: http://yakdisplay.com
>
>
Message 18
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| Subject: | Yak52 - Prop/Governor problem - help/advice needed |
Yup, done that. All secure....
Regards,
Nigel Willson
Flying Instructor/Examiner and Display Pilot
_________________________________________________
email: nigel@yakdisplay.com
mobile: (+44) 7809 116676
web:http://yakdisplay.com
-----Original Message-----
From: owner-yak-list-server@matronics.com [mailto:owner-yak-list-server@matronics.com] On Behalf Of George S. Coy
Sent: 22 July 2015 18:48
Subject: RE: Yak-List: Yak52 - Prop/Governor problem - help/advice needed
check the clamps that secure the cable housing.
-----Original Message-----
From: owner-yak-list-server@matronics.com
[mailto:owner-yak-list-server@matronics.com] On Behalf Of Nigel Willson
Sent: Wednesday, July 22, 2015 1:37 PM
Subject: Yak-List: Yak52 - Prop/Governor problem - help/advice needed
Asking the fount of all yak knowledge....
Pre-take off checks prop cycle check all fine (70% down to 53% three times).
On take-off, prop went to 110% and stayed there.
Moving the prop lever to full course made no difference to RPM.
Reduced power to bring RPM under control, abbreviated circuit and landed.
Have changed to governor - but appears to still be a problem.
Have had the prop off - and checked blades move freely, and oil is returned when
blades are rotated.
Drive to governor appears to be ok (rotates when prop is turned).
Problem obviously appears to be when the prop is under load.
Can anyone shed any light, experience of happening before?
Clarification of my understanding would also be useful re what does what - i.e.
oil pressure causes fine pitch, weights cause course pitch? In that case, is
it a governor drive problem when under load? IS there a weak link in the drive
system like the compressor?
Any ideas?
Regards,
Nigel Willson
Flying Instructor/Examiner and Display Pilot _________________________________________________
email: nigel@yakdisplay.com
mobile: (+44) 7809 116676
web:http://yakdisplay.com
Message 19
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| Subject: | YAK-50 landing gear actuators overhaul time. |
Sorry if I misunderstood Jan!
________________________________________
From: owner-yak-list-server@matronics.com [owner-yak-list-server@matronics.com]
on behalf of Jan Mevis [jan.mevis@informavia.be]
Sent: Wednesday, July 22, 2015 1:31 PM
Subject: Re: Yak-List: YAK-50 landing gear actuators overhaul time.
Thanks Mark. Of course I always check the lights. I also carefully do the
lamp test before each flight.
I appreciate your correction!
Jan
On 22/07/15 18:29, "Bitterlich, Mark G CIV NAVAIR, WD"
<owner-yak-list-server@matronics.com on behalf of
mark.bitterlich@navy.mil> wrote:
><mark.bitterlich@navy.mil>
>
>Jan,
>
>Comment: I have to politely disagree with you about "feeling the gear
>come down and lock". Yes, you can hear it come down. But you sure can
>NOT hear it lock. That "thump" you feel is NOT the gear locking. It is
>the gear actuator reaching maximum travel and HOPEFULLY the gear moving
>far enough forward to allow the down-lock to engage
>
>The simple fact is that the gear lights on the 50 only indicate that the
>legs have moved past a certain position. Thus if everything worked
>correctly the gear SHOULD have locked. ALWAYS CHECK THE LIGHTS!
>
>The GEAR ACTUATOR on the 50 is what is actually on a mechanism that
>causes it to move when air is applied to lower the gear. These are the
>"levers" you were thinking about. This movement translates to the UNLOCK
>mechanism so that the gear can come off the UP locks and start downward
>movement.
>
>As for locking DOWN .... you can have the aircraft on jacks, with the
>gear leg unlocked and hanging, and no air pressure at all, or even with
>the actually totally REMOVED. All you have to do is gently push on the
>gear leg and the locking mechanism will engage, and you can actually SEE
>it if the fiberglass cover is removed. You can reach in there with a
>screw driver (flat head) push down on the locking pin and unlock the
>DOWNLOCK and it will swing back to just hanging again.
>
>So the point is, the UP-LOCK only requires the actuator itself to MOVE on
>concentric mounting slots which UNLOCKS the UPLOCK, the air pressure than
>pushes the gear down far enough to where the gear DOWNLOCK will engage.
> The actual movement of the pins and wedge that LOCKS THE GEAR DOWN is
>actually not a very loud sound. The "movement" of the whole actuator is
>only there to unlock the UPLOCK, after that, the actuator plunger shaft
>pushes the gear down to final extension.
>
>Final thought on this. ALWAYS ALWAYS LOOK AT THE LIGHTS! I got into
>the same habit Jan did by listening to the THUMP of the gear coming down.
> And then one time the gear went THUMP THUMP and the left one was NOT
>LOCKED and the left light was seen later to NOT BE ON. So this is not
>theory, it happened. On the Conditional, it is best to turn all the air
>off, then lower the gear (on jacks obviously), the gear will unlock and
>not go totally down to lock. Then with the cover removed over the top
>of the landing gear strut, gently PUSH on the gear leg while someone is
>WATCHING the gear light! You will see and feel the gear lock down and
>that is when the light should come on and NOT BEFORE. If it does,
>adjust the switch.
>
>Emergency gear extensions have no restrictor in the gear hose. Thus 735
>PSI of air is applied ALL AT ONCE with full flow potential. Not only can
>it make the aircraft jump off the jacks, but it also can blow out the
>chevron seals. The new chevron seals installed in rebuilt actuators are
>much better than the originals that the Russians used, which usually
>harden and then turn into gel when someone tells you to inject "stuff"
>into the air system after it sat for a few years. Use Dennis's
>procedure for testing emergency. Then realize too that you will have to
>reset the check valves on the bottom of the actuators. Not hard. See
>his procedure. I made up my own, but his is better.
>
>Bottom line ... do a careful check on the downlock by hand. Check to
>make sure the switches are adjusted properly so they go on when the gear
>is LOCKED and not before.
>
>Then listen for the THUMP THUMP, but ALWAYS CHECK THE LIGHTS TOO!
>
>Mark
>
>
>-----Original Message-----
>From: owner-yak-list-server@matronics.com
>[mailto:owner-yak-list-server@matronics.com] On Behalf Of Jan Mevis
>Sent: Wednesday, July 22, 2015 9:45 AM
>To: yak-list@matronics.com
>Subject: Re: Yak-List: YAK-50 landing gear actuators overhaul time.
>
>
>Hi Gordon,
>
>Tuning is not the right expression, sorry (but English is not my native
>language).
>Re-installing the actuators is demanding: there are small levers that
>connect between the actuators and the wing (if I remember well, it has
>been some time).
>It is possible that on your plane (being SN01 !!!! Waw) it is slightly
>different.
>I remember that there has to be some specific "play" for these levers
>otherwise it could cause a malfunctioning under circumstances.
>Bottomline: I have it serviced by a Lithuanian mechanic.
>Maybe you should try and find a mechanic that has experience in doing
>this?
>Next time that you go flying, listen to the gear when it extends, you
>should hear or feel it locking.
>
>BR,
>
>Jan
>
>
>On 22/07/15 13:43, "Gordon Price" <owner-yak-list-server@matronics.com on
>behalf of gord@thedampub.ca> wrote:
>
>>
>>Thank you Jan. Very interesting about only 3 emergency extensions.
>>Im wondering where to look for the damage caused by this. Also, we
>>did not tune the gear since the actuators were sent back to us the
>>same length as when went sent them out. Is there something else we
>>should be doing? We had quite a job getting the right down lock
>>microswitch working properly again. This is SN 01 and there are 3
>>different sets of holes for the microswitch. Unfortunately we could
>>not remove the actuators without removing the downlink micro switches.
>>That was the worst part..getting them back in.
>>
>>
>>> On Jul 22, 2015, at 2:07 AM, Jan Mevis <jan.mevis@informavia.be> wrote:
>>>
>>>
>>> Hi Gordon,
>>>
>>> I always listen carefully when the gear extends.
>>> You can hear (or feel) the locking so I don't rely only upon the
>>>green lights.
>>> These Yak 50 actuators are one of the issues where the 50 is very
>>>different compared to the Yak 52.
>>> IMHO the system has been improved on the 52. The 52 has a separate
>>>small locking actuator.
>>> On the 50, the whole actuator moves for locking and unlocking. Tuning
>>>this is not so easy.
>>> The original Russian maintenance manual (DOSAAF 1979) says that you
>>>may only have three complete swings using the emergency bottle.
>>> After that, a complete overhaul of the landing gear is imperative.
>>> I had to use it once when the main pressure feed line collapsed
>>>(between the snot bottle and the cross).
>>> The full unrestricted blow of the emergency bottle is indeed
>>>impressive.
>>>
>>>
>>> BR,
>>>
>>> Jan (Yak 50 F-AZUK).
>>>
>>
>>
>>
>>
>>
>>
>
>
Message 20
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| Subject: | YAK-50 landing gear actuators overhaul time. |
Jan, read his procedure.
He understands. :-)
Mark
________________________________________
From: owner-yak-list-server@matronics.com [owner-yak-list-server@matronics.com]
on behalf of Jan Mevis [jan.mevis@informavia.be]
Sent: Wednesday, July 22, 2015 1:27 PM
Subject: Re: Yak-List: YAK-50 landing gear actuators overhaul time.
Ok Dennis, but there's a difference between the 50 and the 52.
The 50 is much lighter, and it are the Russian inspectors and mechanics
who advised me NOT to extend the whole gear using the emergency.
Everything I added only applies to the Yak 50.
Jan
On 22/07/15 16:58, "A. Dennis Savarese"
<owner-yak-list-server@matronics.com on behalf of
dsavarese0812@bellsouth.net> wrote:
><dsavarese0812@bellsouth.net>
>
>re: "I would be very scared doing that with the plane on jacks. The odds
>are that it would jump off the jacks."
>
>Not if you use the procedure, which is on my web site.
>
>http://www.yak-52.com/maintena.htm
>
>Try it the next time you have the airplane on jacks. You'll be amazed
>at how gently the gear comes down and locks in place using this simple
>procedure.
>
>Dennis
>
>A. Dennis Savarese
>334-546-8182 (mobile)
>www.yak-52.com
>Skype - Yakguy1
>
>On 7/22/2015 8:32 AM, Jan Mevis wrote:
>>
>> No, testing is no issue, but with air from the emergency system we don't
>> let it go the whole way.
>> I would be very scared doing that with the plane on jacks. The odds are
>> that it would jump off the jacks.
>> The one time that I had to use the emergency system in flight, I
>>remember
>> that it was a very violent experience.
>> Impossible to not notice it, the gear gets slammed down with so much
>>force
>> and the whole plane shaked.
>>
>> The Lithuanian mechanic that services my Yak 50 does check the emergency
>> system at each annual but he cuts the air supply before it's fully
>> developped.
>> Anyway, the Russian DOSAAF manual says that the main gear of the 50
>>should
>> be rebuilt after 3 uses of the emergency system.
>> Not only the actuators, the whole gear.
>>
>> We sometimes forget that the scheduled lifetime of the Yak 50 was rather
>> short. The 50 was easily destined to be scrapped after certain mishaps.
>>
>> Of course we do test the normal system each year and then we do have the
>> gear retract and extend several times, the whole way.
>> That's no problem.
>> We also do check the bottles each year.
>>
>> BR,
>>
>> Jan
>>
>>
>> On 22/07/15 14:05, "George S. Coy" <owner-yak-list-server@matronics.com
>>on
>> behalf of george.coy@gmail.com> wrote:
>>
>>>
>>> Hmmm, So when the emergency gear extension is tested at very annual
>>> condition extension, then it gets rebuilt every third year? I guess
>>>most
>>> of
>>> us missed that memo.
>>> George
>>>
>>> -----Original Message-----
>>> From: owner-yak-list-server@matronics.com
>>> [mailto:owner-yak-list-server@matronics.com] On Behalf Of Gordon Price
>>> Sent: Wednesday, July 22, 2015 7:44 AM
>>> To: yak-list@matronics.com
>>> Subject: Re: Yak-List: YAK-50 landing gear actuators overhaul time.
>>>
>>>
>>> Thank you Jan. Very interesting about only 3 emergency extensions.
>>>I'm
>>> wondering where to look for the damage caused by this. Also, we did
>>>not
>>> 'tune' the gear since the actuators were sent back to us the same
>>>length
>>> as
>>> when went sent them out. Is there something else we should be doing?
>>>We
>>> had quite a job getting the right down lock microswitch working
>>>properly
>>> again. This is SN 01 and there are 3 different sets of holes for the
>>> microswitch. Unfortunately we could not remove the actuators without
>>> removing the downlink micro switches. That was the worst part...getting
>>> them
>>> back in.
>>>
>>>
>>>> On Jul 22, 2015, at 2:07 AM, Jan Mevis <jan.mevis@informavia.be>
>>>>wrote:
>>>>
>>>>
>>>> Hi Gordon,
>>>>
>>>> I always listen carefully when the gear extends.
>>>> You can hear (or feel) the locking so I don't rely only upon the green
>>>> lights.
>>>> These Yak 50 actuators are one of the issues where the 50 is very
>>>> different compared to the Yak 52.
>>>> IMHO the system has been improved on the 52. The 52 has a separate
>>>> small locking actuator.
>>>> On the 50, the whole actuator moves for locking and unlocking. Tuning
>>>> this is not so easy.
>>>> The original Russian maintenance manual (DOSAAF 1979) says that you
>>>> may only have three complete swings using the emergency bottle.
>>>> After that, a complete overhaul of the landing gear is imperative.
>>>> I had to use it once when the main pressure feed line collapsed
>>>> (between the snot bottle and the cross).
>>>> The full unrestricted blow of the emergency bottle is indeed
>>>>impressive.
>>>>
>>>>
>>>> BR,
>>>>
>>>> Jan (Yak 50 F-AZUK).
>>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>
>>
>>
>>
>>
>>
>
>
Message 21
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|
| Subject: | Re: Yak52 - Prop/Governor problem - help/advice needed |
When we had prop problems we could not figure out, I tapped into the oil
line on the nose case and ran a 1/4 in hose to a pressure gauge and taped
it to the cowl so I could see what was really happening with the oil
pressure during flight. This was years ago when we were messing around with
Hoffman props.
George
On Wed, Jul 22, 2015 at 2:07 PM, Jan Mevis <jan.mevis@informavia.be> wrote:
>
> That's a very good advise George. We had recently some RPM problems on our
> Yak 52 because of that.
>
>
> Jan
>
> On 22/07/15 19:47, "George S. Coy" <owner-yak-list-server@matronics.com on
> behalf of george.coy@gmail.com> wrote:
>
> >
> >check the clamps that secure the cable housing.
> >
> >-----Original Message-----
> >From: owner-yak-list-server@matronics.com
> >[mailto:owner-yak-list-server@matronics.com] On Behalf Of Nigel Willson
> >Sent: Wednesday, July 22, 2015 1:37 PM
> >To: yak-list@matronics.com
> >Subject: Yak-List: Yak52 - Prop/Governor problem - help/advice needed
> >
> >
> >Asking the fount of all yak knowledge....
> >
> >Pre-take off checks prop cycle check all fine (70% down to 53% three
> >times).
> >On take-off, prop went to 110% and stayed there.
> >Moving the prop lever to full course made no difference to RPM.
> >
> >Reduced power to bring RPM under control, abbreviated circuit and landed.
> >
> >Have changed to governor - but appears to still be a problem.
> >
> >Have had the prop off - and checked blades move freely, and oil is
> >returned
> >when blades are rotated.
> >
> >Drive to governor appears to be ok (rotates when prop is turned).
> >
> >Problem obviously appears to be when the prop is under load.
> >
> >Can anyone shed any light, experience of happening before?
> >
> >Clarification of my understanding would also be useful re what does what -
> >i.e. oil pressure causes fine pitch, weights cause course pitch? In that
> >case, is it a governor drive problem when under load? IS there a weak link
> >in the drive system like the compressor?
> >
> >
> >Any ideas?
> >
> >Regards,
> >Nigel Willson
> >Flying Instructor/Examiner and Display Pilot
> >_________________________________________________
> > email: nigel@yakdisplay.com
> > mobile: (+44) 7809 116676
> > web: http://yakdisplay.com
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
>
>
--
George Coy
CAS Ltd.
714 Airport Rd.
Swanton VT 05488
802-868-5633 off
802-363-5782 cell
george.coy@gmail.com
http://coyafct.com/
SKYPE george.coy
Message 22
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|
| Subject: | Re: YAK-50 landing gear actuators overhaul time. |
Jan,Yes, I know the 50 and 52 are different.=C2- BUT the procedure is the
same for both airplanes and the gear will NOT slam down using the emergenc
y system.=C2- Try it.=C2- I think you will be pleasantly surprised.
Dennis=C2-
From: Jan Mevis <jan.mevis@informavia.be>
To: "yak-list@matronics.com" <yak-list@matronics.com>
Sent: Wednesday, July 22, 2015 12:27 PM
Subject: Re: Yak-List: YAK-50 landing gear actuators overhaul time.
Ok Dennis, but there's a difference between the 50 and the 52.
The 50 is much lighter, and it are the Russian inspectors and mechanics
who advised me NOT to extend the whole gear using the emergency.
Everything I added only applies to the Yak 50.
Jan
On 22/07/15 16:58, "A. Dennis Savarese"
<owner-yak-list-server@matronics.com on behalf of
dsavarese0812@bellsouth.net> wrote:
><dsavarese0812@bellsouth.net>
>
>re: "I would be very scared doing that with the plane on jacks. The odds
>are that it would jump off the jacks."
>
>Not if you use the procedure, which is on my web site.
>
>http://www.yak-52.com/maintena.htm
>
>Try it the next time you have the airplane on jacks.=C2- You'll be amaze
d
>at how gently the gear comes down and locks in place using this simple
>procedure.
>
>Dennis
>
>A. Dennis Savarese
>334-546-8182 (mobile)
>www.yak-52.com
>Skype - Yakguy1
>
>On 7/22/2015 8:32 AM, Jan Mevis wrote:
>>
>> No, testing is no issue, but with air from the emergency system we don't
>> let it go the whole way.
>> I would be very scared doing that with the plane on jacks. The odds are
>> that it would jump off the jacks.
>> The one time that I had to use the emergency system in flight, I
>>remember
>> that it was a very violent experience.
>> Impossible to not notice it, the gear gets slammed down with so much
>>force
>> and the whole plane shaked.
>>
>> The Lithuanian mechanic that services my Yak 50 does check the emergency
>> system at each annual but he cuts the air supply before it's fully
>> developped.
>> Anyway, the Russian DOSAAF manual says that the main gear of the 50
>>should
>> be rebuilt after 3 uses of the emergency system.
>> Not only the actuators, the whole gear.
>>
>> We sometimes forget that the scheduled lifetime of the Yak 50 was rather
>> short. The 50 was easily destined to be scrapped after certain mishaps.
>>
>> Of course we do test the normal system each year and then we do have the
>> gear retract and extend several times, the whole way.
>> That's no problem.
>> We also do check the bottles each year.
>>
>> BR,
>>
>> Jan
>>
>>
>> On 22/07/15 14:05, "George S. Coy" <owner-yak-list-server@matronics.com
>>on
>> behalf of george.coy@gmail.com> wrote:
>>
>>>
>>> Hmmm, So when the emergency gear extension is tested at very annual
>>> condition extension, then it gets rebuilt every third year? I guess
>>>most
>>> of
>>> us missed that memo.
>>> George
>>>
>>> -----Original Message-----
>>> From: owner-yak-list-server@matronics.com
>>> [mailto:owner-yak-list-server@matronics.com] On Behalf Of Gordon Price
>>> Sent: Wednesday, July 22, 2015 7:44 AM
>>> To: yak-list@matronics.com
>>> Subject: Re: Yak-List: YAK-50 landing gear actuators overhaul time.
>>>
>>>
>>> Thank you Jan.=C2- Very interesting about only 3=C2- emergency exte
nsions.
>>>I'm
>>> wondering where to look for the damage caused by this.=C2- Also, we d
id
>>>not
>>> 'tune' the gear since the actuators were sent back to us the same
>>>length
>>> as
>>> when went sent them out.=C2- Is there something else we should be doi
ng?
>>>We
>>> had quite a job getting the right down lock microswitch working
>>>properly
>>> again.=C2- This is SN 01 and there are 3 different sets of holes for
the
>>> microswitch.=C2- Unfortunately we could not remove the actuators with
out
>>> removing the downlink micro switches. That was the worst part...getting
>>> them
>>> back in.
>>>
>>>
>>>> On Jul 22, 2015, at 2:07 AM, Jan Mevis <jan.mevis@informavia.be>
>>>>wrote:
>>>>
>>>>
>>>> Hi Gordon,
>>>>
>>>> I always listen carefully when the gear extends.
>>>> You can hear (or feel) the locking so I don't rely only upon the green
>>>> lights.
>>>> These Yak 50 actuators are one of the issues=C2- where the 50 is ver
y
>>>> different compared to the Yak 52.
>>>> IMHO the system has been improved on the 52. The 52 has a separate
>>>> small locking actuator.
>>>> On the 50, the whole actuator moves for locking and unlocking. Tuning
>>>> this is not so easy.
>>>> The original Russian maintenance manual (DOSAAF 1979) says that you
>>>> may only have three complete swings using the emergency bottle.
>>>> After that, a complete overhaul of the landing gear is imperative.
>>>> I had to use it once when the main pressure feed line collapsed
>>>> (between the snot bottle and the cross).
>>>> The full unrestricted blow of the emergency bottle is indeed
>>>>impressive.
>>>>
>>>>
>>>> BR,
>>>>
>>>> Jan (Yak 50 F-AZUK).
>>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>
>>
>>
>>
>>
>>
>
>
S -
-
=C2- =C2- =C2- =C2- =C2- -Matt Dralle, List Admin.
Message 23
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| Subject: | Re: YAK-50 landing gear actuators overhaul time. |
You're correct Dennis, of course one must not let the gear slam down at full
force.
I realize that what I wrote wasn't very precise. That's sometimes a problem
when not writing in your own language. I write better in French.
So instead of helping to clarify things, I did the opposite. I apologize,
that was not what I had in mind.
I try to rephrase:
1.- when operating the gear for lowering the wheels, I always listen to the
"thumb thumb" and then of course, I want to see the lights. Seeing greens
without the noise worries me. Hearing the noise without the green lights
even more.
2.- when I said that the Russians advise to have the whole gear checked
(actuators + legs) that is of course when the full power of the emergency
bottle gets applied, until locking. It is not very probable that that should
happen three times in a lifetime of a Yak 50. But this advise applies ONLY
to the Yak 50.
3.- when the Russian inspector said that you've got to be carefull when
exercising the gear lowering with the emergency, he meant that one must not
try on jacks what would happen in the air.
So bottomline: I use YOUR procedure since many years , including the
emergency-system check :-)
BR,
Jan
From: <owner-yak-list-server@matronics.com> on behalf of "A. Dennis
Savarese" <dsavarese0812@bellsouth.net>
Subject: Re: Yak-List: YAK-50 landing gear actuators overhaul time.
Jan,
Yes, I know the 50 and 52 are different. BUT the procedure is the same for
both airplanes and the gear will NOT slam down using the emergency system.
Try it. I think you will be pleasantly surprised.
Dennis
From: Jan Mevis <jan.mevis@informavia.be>
To: "yak-list@matronics.com" <yak-list@matronics.com>
Sent: Wednesday, July 22, 2015 12:27 PM
Subject: Re: Yak-List: YAK-50 landing gear actuators overhaul time.
Ok Dennis, but there's a difference between the 50 and the 52.
The 50 is much lighter, and it are the Russian inspectors and mechanics
who advised me NOT to extend the whole gear using the emergency.
Everything I added only applies to the Yak 50.
Jan
On 22/07/15 16:58, "A. Dennis Savarese"
<owner-yak-list-server@matronics.com on behalf of
dsavarese0812@bellsouth.net> wrote:
><dsavarese0812@bellsouth.net>
>
>re: "I would be very scared doing that with the plane on jacks. The odds
>are that it would jump off the jacks."
>
>Not if you use the procedure, which is on my web site.
>
>http://www.yak-52.com/maintena.htm
>
>Try it the next time you have the airplane on jacks. You'll be amazed
>at how gently the gear comes down and locks in place using this simple
>procedure.
>
>Dennis
>
>A. Dennis Savarese
>334-546-8182 (mobile)
>www.yak-52.com
>Skype - Yakguy1
>
>On 7/22/2015 8:32 AM, Jan Mevis wrote:
>>
>> No, testing is no issue, but with air from the emergency system we don't
>> let it go the whole way.
>> I would be very scared doing that with the plane on jacks. The odds are
>> that it would jump off the jacks.
>> The one time that I had to use the emergency system in flight, I
>>remember
>> that it was a very violent experience.
>> Impossible to not notice it, the gear gets slammed down with so much
>>force
>> and the whole plane shaked.
>>
>> The Lithuanian mechanic that services my Yak 50 does check the emergency
>> system at each annual but he cuts the air supply before it's fully
>> developped.
>> Anyway, the Russian DOSAAF manual says that the main gear of the 50
>>should
>> be rebuilt after 3 uses of the emergency system.
>> Not only the actuators, the whole gear.
>>
>> We sometimes forget that the scheduled lifetime of the Yak 50 was rather
>> short. The 50 was easily destined to be scrapped after certain mishaps.
>>
>> Of course we do test the normal system each year and then we do have the
>> gear retract and extend several times, the whole way.
>> That's no problem.
>> We also do check the bottles each year.
>>
>> BR,
>>
>> Jan
>>
>>
>> On 22/07/15 14:05, "George S. Coy" <owner-yak-list-server@matronics.com
>>on
>> behalf of george.coy@gmail.com> wrote:
>>
>>>
>>> Hmmm, So when the emergency gear extension is tested at very annual
>>> condition extension, then it gets rebuilt every third year? I guess
>>>most
>>> of
>>> us missed that memo.
>>> George
>>>
>>> -----Original Message-----
>>> From: owner-yak-list-server@matronics.com
>>> [mailto:owner-yak-list-server@matronics.com] On Behalf Of Gordon Price
>>> Sent: Wednesday, July 22, 2015 7:44 AM
>>> To: yak-list@matronics.com
>>> Subject: Re: Yak-List: YAK-50 landing gear actuators overhaul time.
>>>
>>>
>>> Thank you Jan. Very interesting about only 3 emergency extensions.
>>>I'm
>>> wondering where to look for the damage caused by this. Also, we did
>>>not
>>> 'tune' the gear since the actuators were sent back to us the same
>>>length
>>> as
>>> when went sent them out. Is there something else we should be doing?
>>>We
>>> had quite a job getting the right down lock microswitch working
>>>properly
>>> again. This is SN 01 and there are 3 different sets of holes for the
>>> microswitch. Unfortunately we could not remove the actuators without
>>> removing the downlink micro switches. That was the worst part...getting
>>> them
>>> back in.
>>>
>>>
>>>> On Jul 22, 2015, at 2:07 AM, Jan Mevis <jan.mevis@informavia.be>
>>>>wrote:
>>>>
>>>>
>>>> Hi Gordon,
>>>>
>>>> I always listen carefully when the gear extends.
>>>> You can hear (or feel) the locking so I don't rely only upon the green
>>>> lights.
>>>> These Yak 50 actuators are one of the issues where the 50 is very
>>>> different compared to the Yak 52.
>>>> IMHO the system has been improved on the 52. The 52 has a separate
>>>> small locking actuator.
>>>> On the 50, the whole actuator moves for locking and unlocking. Tuning
>>>> this is not so easy.
>>>> The original Russian maintenance manual (DOSAAF 1979) says that you
>>>> may only have three complete swings using the emergency bottle.
>>>> After that, a complete overhaul of the landing gear is imperative.
>>>> I had to use it once when the main pressure feed line collapsed
>>>> (between the snot bottle and the cross).
>>>> The full unrestricted blow of the emergency bottle is indeed
>>>>impressive.
>>>>
>>>>
>>>> BR,
>>>>
>>>> Jan (Yak 50 F-AZUK).
>>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>
>>
>>
>>
>"http://www.matronics.com/Navigator?Yak-List" target="_blank">http://www.
-->
<http://www.matronics.com/contribution>
<http://www.matronics.com/contribution>
<http://www.matronics.com/contribution>
<http://www.matronics.com/contribution>
<http://www.matronics.com/contribution>
http://www.matronics.com/Navigator?Yak-List
Message 24
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| Subject: | YAK-50 landing gear actuators overhaul time. |
As I said Jan, I misunderstood what you were saying as well. I should have known
better. You are very accomplished with your airplane.
Mark
________________________________
From: owner-yak-list-server@matronics.com [owner-yak-list-server@matronics.com]
on behalf of Jan Mevis [jan.mevis@informavia.be]
Sent: Wednesday, July 22, 2015 3:39 PM
Subject: Re: Yak-List: YAK-50 landing gear actuators overhaul time.
You're correct Dennis, of course one must not let the gear slam down at full force.
I realize that what I wrote wasn't very precise. That's sometimes a problem when
not writing in your own language. I write better in French.
So instead of helping to clarify things, I did the opposite. I apologize, that
was not what I had in mind.
I try to rephrase:
1.- when operating the gear for lowering the wheels, I always listen to the "thumb
thumb" and then of course, I want to see the lights. Seeing greens without
the noise worries me. Hearing the noise without the green lights even more.
2.- when I said that the Russians advise to have the whole gear checked (actuators
+ legs) that is of course when the full power of the emergency bottle gets
applied, until locking. It is not very probable that that should happen three
times in a lifetime of a Yak 50. But this advise applies ONLY to the Yak 50.
3.- when the Russian inspector said that you've got to be carefull when exercising
the gear lowering with the emergency, he meant that one must not try on jacks
what would happen in the air.
So bottomline: I use YOUR procedure since many years , including the emergency-system
check :-)
BR,
Jan
From: <owner-yak-list-server@matronics.com<mailto:owner-yak-list-server@matronics.com>> on behalf of "A. Dennis Savarese" <dsavarese0812@bellsouth.net<mailto:dsavarese0812@bellsouth.net>>
Subject: Re: Yak-List: YAK-50 landing gear actuators overhaul time.
Jan,
Yes, I know the 50 and 52 are different. BUT the procedure is the same for both
airplanes and the gear will NOT slam down using the emergency system. Try it.
I think you will be pleasantly surprised.
Dennis
________________________________
From: Jan Mevis <jan.mevis@informavia.be<mailto:jan.mevis@informavia.be>>
Sent: Wednesday, July 22, 2015 12:27 PM
Subject: Re: Yak-List: YAK-50 landing gear actuators overhaul time.
Ok Dennis, but there's a difference between the 50 and the 52.
The 50 is much lighter, and it are the Russian inspectors and mechanics
who advised me NOT to extend the whole gear using the emergency.
Everything I added only applies to the Yak 50.
Jan
On 22/07/15 16:58, "A. Dennis Savarese"
<owner-yak-list-server@matronics.com<mailto:owner-yak-list-server@matronics.com> on behalf of
dsavarese0812@bellsouth.net<mailto:dsavarese0812@bellsouth.net>> wrote:
><dsavarese0812@bellsouth.net<mailto:dsavarese0812@bellsouth.net>>
>
>re: "I would be very scared doing that with the plane on jacks. The odds
>are that it would jump off the jacks."
>
>Not if you use the procedure, which is on my web site.
>
>http://www.yak-52.com/maintena.htm
>
>Try it the next time you have the airplane on jacks. You'll be amazed
>at how gently the gear comes down and locks in place using this simple
>procedure.
>
>Dennis
>
>A. Dennis Savarese
>334-546-8182 (mobile)
>www.yak-52.com
>Skype - Yakguy1
>
>On 7/22/2015 8:32 AM, Jan Mevis wrote:
>>
>> No, testing is no issue, but with air from the emergency system we don't
>> let it go the whole way.
>> I would be very scared doing that with the plane on jacks. The odds are
>> that it would jump off the jacks.
>> The one time that I had to use the emergency system in flight, I
>>remember
>> that it was a very violent experience.
>> Impossible to not notice it, the gear gets slammed down with so much
>>force
>> and the whole plane shaked.
>>
>> The Lithuanian mechanic that services my Yak 50 does check the emergency
>> system at each annual but he cuts the air supply before it's fully
>> developped.
>> Anyway, the Russian DOSAAF manual says that the main gear of the 50
>>should
>> be rebuilt after 3 uses of the emergency system.
>> Not only the actuators, the whole gear.
>>
>> We sometimes forget that the scheduled lifetime of the Yak 50 was rather
>> short. The 50 was easily destined to be scrapped after certain mishaps.
>>
>> Of course we do test the normal system each year and then we do have the
>> gear retract and extend several times, the whole way.
>> That's no problem.
>> We also do check the bottles each year.
>>
>> BR,
>>
>> Jan
>>
>>
>> On 22/07/15 14:05, "George S. Coy" <owner-yak-list-server@matronics.com<mailto:owner-yak-list-server@matronics.com>
>>on
>> behalf of george.coy@gmail.com<mailto:george.coy@gmail.com>> wrote:
>>
>>>
>>> Hmmm, So when the emergency gear extension is tested at very annual
>>> condition extension, then it gets rebuilt every third year? I guess
>>>most
>>> of
>>> us missed that memo.
>>> George
>>>
>>> -----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: Wednesday, July 22, 2015 7:44 AM
>>> To: yak-list@matronics.com<mailto:yak-list@matronics.com>
>>> Subject: Re: Yak-List: YAK-50 landing gear actuators overhaul time.
>>>
>>>
>>> Thank you Jan. Very interesting about only 3 emergency extensions.
>>>I'm
>>> wondering where to look for the damage caused by this. Also, we did
>>>not
>>> 'tune' the gear since the actuators were sent back to us the same
>>>length
>>> as
>>> when went sent them out. Is there something else we should be doing?
>>>We
>>> had quite a job getting the right down lock microswitch working
>>>properly
>>> again. This is SN 01 and there are 3 different sets of holes for the
>>> microswitch. Unfortunately we could not remove the actuators without
>>> removing the downlink micro switches. That was the worst part...getting
>>> them
>>> back in.
>>>
>>>
>>>> On Jul 22, 2015, at 2:07 AM, Jan Mevis <jan.mevis@informavia.be<mailto:jan.mevis@informavia.be>>
>>>>wrote:
>>>>
>>>>
>>>> Hi Gordon,
>>>>
>>>> I always listen carefully when the gear extends.
>>>> You can hear (or feel) the locking so I don't rely only upon the green
>>>> lights.
>>>> These Yak 50 actuators are one of the issues where the 50 is very
>>>> different compared to the Yak 52.
>>>> IMHO the system has been improved on the 52. The 52 has a separate
>>>> small locking actuator.
>>>> On the 50, the whole actuator moves for locking and unlocking. Tuning
>>>> this is not so easy.
>>>> The original Russian maintenance manual (DOSAAF 1979) says that you
>>>> may only have three complete swings using the emergency bottle.
>>>> After that, a complete overhaul of the landing gear is imperative.
>>>> I had to use it once when the main pressure feed line collapsed
>>>> (between the snot bottle and the cross).
>>>> The full unrestricted blow of the emergency bottle is indeed
>>>>impressive.
>>>>
>>>>
>>>> BR,
>>>>
>>>> Jan (Yak 50 F-AZUK).
>>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>
>>
>>
>>
>"http://www.matronics.com/Navigator?Yak-List" target="_blank">http://www.=<UrlBlockedError.aspx> -->
<http://www.matronics.com/contribution>
<http://www.matronics.com/contribution>
<http://www.matronics.com/contribution>
<http://www.matronics.com/contribution>
<http://www.matronics.com/contribution>
new,courier"><http://www.matronics.com/contribution>http://www.matronics.com/Navigator?Yak-List
com
ronics.com/contribution
Message 25
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|
| Subject: | Re: YAK-50 landing gear actuators overhaul time. |
Mark.
Thank you so much for your post. I am learning a lot.
The restrictor washers are still in the lines OK. Nothing fell out. I think the
reason it comes down harder is that basically the actuators were seized. We
could not retract them at all to ship them.
Re: putting the lever in the neutral position and fly around building up pressuregood
to know if there is another event. In this case though I had very little
time since I only had 15 litres left in the tanks and there was a lot of uncontrolled
traffic around the airport.
Based on what you said I dont think I would retract the gear after no green light
again. Now I know why. Thank you.
I am still not sure that, given the problem that I had ( no green light) and the
one I was not aware of at the time ( the end blowing off the actuator at MP4
Inc) that using the emergency system would have been a good idea. If I used
the full pressure of the emergency system and the end blew off the actuator, what
sort of situation would I have been facing? In my mind it would have been
one gear locked down and the other blowing in the wind with no pressure. Am
I wrong?
I am glad we are able to discuss this after the fact and there was no damage.
Luck was on my side.
Best regards
Gord
> On Jul 22, 2015, at 12:48 PM, Bitterlich, Mark G CIV NAVAIR, WD <mark.bitterlich@navy.mil>
wrote:
>
>
> When you replaced the gear actuators, did anyone tell you about the restrictor
washers that fit into the air line connecting to the up and down side normal
hoses?
> If they did not, then be aware that they fall out very easily and get lost.
Did you make sure you put them back in exactly as they came out?
> The only reason I mention this is because of your comment about the gear coming
down much more violently now.
> If you lost those washers with the small holes through them, then your gear will
swing at the same speed it would if emergency air was used and that is a very
bad thing.
>
> I really hope you know what I am talking about here. ..
>
> Next:
>
> If you lower the gear and a light does not come on, put your gear handle in the
middle position. This isolates the landing gear actuators. Then fly around
and wait until main air pressure builds back to 50 ATMOS. Select DOWN on the
main gear handle again and see if the light comes on. If it does not, then
use Emergency Air PROCEDURES. If it still does not come down, close the emergency
air valve, fly around until the pressure builds back up on the emergency
bottle and then TRY EMERGENCY PROCEDURES AGAIN! Note: Yak-50 pressurizes BOTH
main and emergency bottles from the engine compressor, unlike the 52.
>
> People looking at the gear cannot tell if it is really locked when you are flying,
only that it "looks down". It would take a real YAK-50 expert to carefully
see the angle of that gear to even make an educated guess. Chevron seal
failure in the actuators is common. If you were to raise the gear at this point,
what little is left can turn into slush or pieces and then you are looking
at a gear up landing. Bottom line, yes, you should have used the emergency
air procedures (read them carefully). If even THAT fails, having the gear
handle in the middle, close the emergency air bottle valve, fly around and BOTH
bottles will re-pressurize. Try the emergency procedure again! I'd keep doing
that until I almost ran out of gas.
>
> Good job on the "bounce" on the runway. The only reason it worked was that there
was still air in the system pushing on that actuator. With a total chevron
seal failure, it would not have.
>
> Mark
>
Message 26
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|
| Subject: | Re: YAK-50 landing gear actuators overhaul time. |
Thanks Jan.
Once I have it I will scan it and post it online for all Yak 50 guys to have
access. I have been looking for one for 2 yrs.
Todd McCutchan
T-34A & Yak-50
Cell: (260) 402-1740
E-mail: todd@fastaircraft.com
www.fastaircraft.com
> On Jul 22, 2015, at 1:28 PM, Jan Mevis <jan.mevis@informavia.be> wrote:
>
> Hi Todd,
>
> I'll try to make some copies, but it's an old book, so it'll take some tim
e.
>
> Jan
>
> From: <owner-yak-list-server@matronics.com> on behalf of Todd McCutchan <t
odd@fastaircraft.com>
> Date: Wednesday 22 July 2015 17:35
> To: "yak-list@matronics.com" <yak-list@matronics.com>
> Subject: Re: Yak-List: YAK-50 landing gear actuators overhaul time.
>
> Jan,
>
> I would love to get a copy of that MX manual.
>
> Please email me directly. The info is below.
>
> Todd McCutchan
> T-34A & Yak-50
> Cell: (260) 402-1740
> E-mail: todd@fastaircraft.com
> www.fastaircraft.com
>
>
>
>> On Jul 22, 2015, at 9:32 AM, Jan Mevis <jan.mevis@informavia.be> wrote:
>>
>>
>> No, testing is no issue, but with air from the emergency system we don't
>> let it go the whole way.
>> I would be very scared doing that with the plane on jacks. The odds are
>> that it would jump off the jacks.
>> The one time that I had to use the emergency system in flight, I remember
>> that it was a very violent experience.
>> Impossible to not notice it, the gear gets slammed down with so much forc
e
>> and the whole plane shaked.
>>
>> The Lithuanian mechanic that services my Yak 50 does check the emergency
>> system at each annual but he cuts the air supply before it's fully
>> developped.
>> Anyway, the Russian DOSAAF manual says that the main gear of the 50 shoul
d
>> be rebuilt after 3 uses of the emergency system.
>> Not only the actuators, the whole gear.
>>
>> We sometimes forget that the scheduled lifetime of the Yak 50 was rather
>> short. The 50 was easily destined to be scrapped after certain mishaps.
>>
>> Of course we do test the normal system each year and then we do have the
>> gear retract and extend several times, the whole way.
>> That's no problem.
>> We also do check the bottles each year.
>>
>> BR,
>>
>> Jan
>>
>>
>> On 22/07/15 14:05, "George S. Coy" <owner-yak-list-server@matronics.com o
n
>> behalf of george.coy@gmail.com> wrote:
>>
>>>
>>> Hmmm, So when the emergency gear extension is tested at very annual
>>> condition extension, then it gets rebuilt every third year? I guess most
>>> of
>>> us missed that memo.
>>> George
>>>
>>> -----Original Message-----
>>> From: owner-yak-list-server@matronics.com
>>> [mailto:owner-yak-list-server@matronics.com] On Behalf Of Gordon Price
>>> Sent: Wednesday, July 22, 2015 7:44 AM
>>> To: yak-list@matronics.com
>>> Subject: Re: Yak-List: YAK-50 landing gear actuators overhaul time.
>>>
>>>
>>> Thank you Jan. Very interesting about only 3 emergency extensions. I
'm
>>> wondering where to look for the damage caused by this. Also, we did not
>>> 'tune' the gear since the actuators were sent back to us the same length
>>> as
>>> when went sent them out. Is there something else we should be doing? W
e
>>> had quite a job getting the right down lock microswitch working properly
>>> again. This is SN 01 and there are 3 different sets of holes for the
>>> microswitch. Unfortunately we could not remove the actuators without
>>> removing the downlink micro switches. That was the worst part...getting
>>> them
>>> back in.
>>>
>>>
>>>> On Jul 22, 2015, at 2:07 AM, Jan Mevis <jan.mevis@informavia.be> wrote:
>>>>
>>>>
>>>> Hi Gordon,
>>>>
>>>> I always listen carefully when the gear extends.
>>>> You can hear (or feel) the locking so I don't rely only upon the green
>>>> lights.
>>>> These Yak 50 actuators are one of the issues where the 50 is very
>>>> different compared to the Yak 52.
>>>> IMHO the system has been improved on the 52. The 52 has a separate
>>>> small locking actuator.
>>>> On the 50, the whole actuator moves for locking and unlocking. Tuning
>>>> this is not so easy.
>>>> The original Russian maintenance manual (DOSAAF 1979) says that you
>>>> may only have three complete swings using the emergency bottle.
>>>> After that, a complete overhaul of the landing gear is imperative.
>>>> I had to use it once when the main pressure feed line collapsed
>>>> (between the snot bottle and the cross).
>>>> The full unrestricted blow of the emergency bottle is indeed impressive
.
>>>>
>>>>
>>>> BR,
>>>>
>>>> Jan (Yak 50 F-AZUK).
>> http://www.matronics.com/Navig===============
==========================
===========; - MATRONICS WEB FORUMS -
>>
>> <========================
==========================
=====
>
>
> ww.matronics.com/Navigator?Yak-List
> com
> ronics.com/contribution
>
>
>
3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3
D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3
D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3
D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3
D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
>
Message 27
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| Subject: | Re: Sticky valve? |
Thanks guys, I'm tending towards it being an actuator getting worn. I warmed the
suspect one up today and then selected down and there was only a short venting
before it 'sealed'.
Time to put the overhauled one in methinks!
BUT, you never know, av8ter - how could the rear selector cause this? I've only
ever seen the front one in pieces but from what I can see it's all bronze & steel
bits, can't quite visualise how it relates to the symptoms - O ring maybe?
What am I looking for when it is selected down?
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http://forums.matronics.com/viewtopic.php?p=445113#445113
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