Today's Message Index:
----------------------
1. 02:46 AM - Re: Gear uplock piston (Didier Blouzard)
2. 05:05 AM - Re: Gear uplock piston (A. Dennis Savarese)
3. 05:24 AM - Another comment about the UplockRe: Gear uplock piston (A. Dennis Savarese)
4. 06:18 AM - Re: Engine Surge (A. Dennis Savarese)
5. 08:05 AM - Undercarriage problems (Richard Goode)
6. 02:16 PM - Re: Gear uplock piston (Bitterlich, Mark G CIV Det Cherry Point, MALS-14 64E)
7. 02:22 PM - Re: Gear uplock piston (Bitterlich, Mark G CIV Det Cherry Point, MALS-14 64E)
8. 03:30 PM - Re: Yak Radio (Bitterlich, Mark G CIV Det Cherry Point, MALS-14 64E)
9. 05:54 PM - Re: BCAA fly-in Breakfast October 11th. (Nathan_pa)
10. 07:05 PM - Re: Re: BCAA fly-in Breakfast October 11th. (T A LEWIS)
Message 1
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| Subject: | Re: Gear uplock piston |
Thanks to all for your kind comments,
merci beaucoup !!!!!
Dennis, I will follow your recommandations and probably have a thorough
inspection of all actuators done by a DASSAULT specialist. He has all the
specific tools and knowledge.
Just to moderate, on my plane the left uplock was rusted but the right one
was in a good state.
For the liquid to put in the pneumatic system TERMIKAS seems to recommand to
mix 50% ethanol and 50% glycerin (found in any good drugstore) and to inject
this mixture into the pneumatic system as you say.
Regarding the relevance or not of these uplock ...... I question myself. My
hungarian operator has been trained by russian engineers and when he was
aware that I followed the manual regarding the gear handle in neutral
position he told me that this was not the recommandation and I have to keep
the gear handle on retracted or extended all the time.
The only problem is (or might be!!!) the compressor always in charge.
Thanks very much Dennis,
thanks to all
Didier
2009/10/5 A. Dennis Savarese <dsavarese0812@bellsouth.net>
> Didier,
> This is not an unusual problem with Yak's (50's, 52, Yak 18T's) with uplock
> actuators. In fact, it happens more frequently than one might think. The
> problem is poor maintenance of the pneumatic system in years past. As you
> have already found out, when you disassemble the uplock actuator you will
> very likely find rust and corrosion inside. Very likely one or more of the
> C-clips will be rusted or maybe even totally disintegrated. It is highly
> recommended that at every annual inspection at least one uplock actuator be
> removed, disassembled and inspected. Whatever you find in the small uplock
> actuator is representative of what you will find in all the other actuators
> (undercarriage and flap). So if you have an uplock actuator that is not
> functioning and you find corrosion and rust internally in the actuator, you
> can almost count on finding the same thing in your undercarriage and flap
> actuators. Additionally the air start valve is probably full of junk/gunk
> as well.
>
> If the metal parts except the C-clips are in good shape, you can overhaul
> the uplock actuators. I would strongly recommend you do this before you end
> up with an in-flight problem with the undercarriage not coming down. And
> believe me, it WILL happen if you don't take care of it now. Do not use
> grease when reassembling. Use only a light weight oil. Grease may block
> the small holes in the shaft between the main and emergency sections. (The
> steel part that inserts into the brass part). You can pressure test the
> uplock actuator with shop pressure from a standard shop compressor. I would
> recommend you do this on both the main and emergency sides before
> reinstalling in the airplane.
>
> Removing the undercarriage actuators is pretty straight forward. Of course
> you will need to jack the airplane. First remove the end of the actuator
> from the drag link that moves the undercarriage up and down. Then remove
> the bolt and nut at the top of the actuator. I would recommend you take the
> actuators to person who is familiar with disassembling and reassembling the
> actuator because it can be difficult getting the end caps off. Then when
> reassembling it is easy to damage the new seals.
>
> Finally, seriously consider overhauling all of the undercarriage actuators
> and the flap actuator. Better to be safe than sorry.
> Dennis
>
> ----- Original Message -----
> *From:* Didier Blouzard <didier.blouzard@gmail.com>
> *To:* yak-list@matronics.com
> *Sent:* Sunday, October 04, 2009 4:17 PM
> *Subject:* Yak-List: Gear uplock piston
>
> Hello to all,
>
> just to attract your attention on a small problem I had two times on two
> different planes about the small uplock cylinder locking and unlocking the
> gears.
> The gear is locked in the up position by a small hook . When we select the
> gear down position air flows thru the normal circuit to the small uplock
> cylinder that pushes and release the hook. Air goes in the same time into
> the main cylinder to push the gear down and extend it.
> Those last time I had the problem on my Yak18T and on my friend 's Yak52
> just this last week. This small cylinders stopped working locking the gear
> in the retracted position. On my plane, I discovered the problem fortunately
> when my plane was jacked and I was making retractation test (my red
> retracted light did not want to come on and this was the symptom of the
> normal operation piston blocked on the emergency piston. The actuator of the
> light was no more depressed) and without possible anticipation my left gear
> refuses to go down. The hook did not release the gear. The uplock cylinder
> was blocked.
> The same happened to my friend last week on his 52. He landed with the
> emergency system and all was fine.
> What happened was that those little uplock cylinder are made of two piston
> moving one on the other and the movement was completely corroded so it was
> no more moving on normal operation but only in emergency. Inside the
> cylinder I found a lot of corrosion and even old grease blocking the
> cylinder. I had to unmount completely the cylinders, use a hammer to
> separate the two parts of the piston paper sand the corroded parts clean
> completely the interior and apply some Teflon grease.
> I was really surprised how much it was corroded and it seems to me
> important to attract your attention on this problem. These little cylinders
> are very easy to unmont. It takes about one hour to unmont it clean it and
> remount it.
>
> Regarding how annoying it is to land with the gear retracted.....I think it
> is worth checking these uplock cylinders.
>
> If anyone want I can post pictures of the unmonting process.
>
> And if anyone can explain me how difficult it is or how easy it is to make
> the same for the main gear cylinders I will be happy. I think that now I
> will try to check all the cylinders.
>
> Hope that will help
>
> --
> Didier BLOUZARD
> didier.blouzard@gmail.com
> 0624243672
>
> *
>
> href="http://www.matronics.com/Navigator?Yak-List">http://www.matronics.com/Navigator?Yak-List
> href="http://forums.matronics.com">http://forums.matronics.com
> href="http://www.matronics.com/contribution">http://www.matronics.com/c*
>
> *
>
> *
>
>
--
Didier BLOUZARD
didier.blouzard@gmail.com
0624243672
Message 2
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| Subject: | Re: Gear uplock piston |
Regarding the compressor always being "in charge" because you put the
undercarriage selector in neutral - it has no effect on the compressor
whatsoever because the compressor is always charging the system when the
engine in running. Your Hungarian operator is 100% correct.
Another reason I do not subscribe to putting the undercarriage selector
in neutral (with one exception which I will explain shortly) is because
when you put the selector in neutral, the actuators are totally
depressurized. That is the "woosh" sound you hear when the selector is
moved to neutral. If you move the selector to the DOWN position for
landing from NEUTRAL, the undercarriage will slam into the down position
because there is no backpressure on the actuator from the UP side. This
is not good for the undercarriage, or the actuators. The pressure on
the UP side of the actuator acts as a "shock absorber" when the selector
is put in the down position.
The ONLY way moving the selector to neutral is acceptable is if BEFORE
you move the selector to DOWN you first move the selector to the
position the undercarriage is already in. In this case, back to the UP
position. By doing this, you re-pressurize the actuators and then you
can move the selector to the down position. Unless you get into the
habit to do this every time you cycle the undercarriage, leave the
selector in the UP position.
Dennis
----- Original Message -----
From: Didier Blouzard
To: yak-list@matronics.com
Sent: Monday, October 05, 2009 4:31 AM
Subject: Re: Yak-List: Gear uplock piston
Thanks to all for your kind comments,
merci beaucoup !!!!!
Dennis, I will follow your recommandations and probably have a
thorough inspection of all actuators done by a DASSAULT specialist. He
has all the specific tools and knowledge.
Just to moderate, on my plane the left uplock was rusted but the right
one was in a good state.
For the liquid to put in the pneumatic system TERMIKAS seems to
recommand to mix 50% ethanol and 50% glycerin (found in any good
drugstore) and to inject this mixture into the pneumatic system as you
say.
Regarding the relevance or not of these uplock ...... I question
myself. My hungarian operator has been trained by russian engineers and
when he was aware that I followed the manual regarding the gear handle
in neutral position he told me that this was not the recommandation and
I have to keep the gear handle on retracted or extended all the time.
The only problem is (or might be!!!) the compressor always in charge.
Thanks very much Dennis,
thanks to all
Didier
2009/10/5 A. Dennis Savarese <dsavarese0812@bellsouth.net>
Didier,
This is not an unusual problem with Yak's (50's, 52, Yak 18T's) with
uplock actuators. In fact, it happens more frequently than one might
think. The problem is poor maintenance of the pneumatic system in years
past. As you have already found out, when you disassemble the uplock
actuator you will very likely find rust and corrosion inside. Very
likely one or more of the C-clips will be rusted or maybe even totally
disintegrated. It is highly recommended that at every annual inspection
at least one uplock actuator be removed, disassembled and inspected.
Whatever you find in the small uplock actuator is representative of what
you will find in all the other actuators (undercarriage and flap). So
if you have an uplock actuator that is not functioning and you find
corrosion and rust internally in the actuator, you can almost count on
finding the same thing in your undercarriage and flap actuators.
Additionally the air start valve is probably full of junk/gunk as well.
If the metal parts except the C-clips are in good shape, you can
overhaul the uplock actuators. I would strongly recommend you do this
before you end up with an in-flight problem with the undercarriage not
coming down. And believe me, it WILL happen if you don't take care of
it now. Do not use grease when reassembling. Use only a light weight
oil. Grease may block the small holes in the shaft between the main and
emergency sections. (The steel part that inserts into the brass part).
You can pressure test the uplock actuator with shop pressure from a
standard shop compressor. I would recommend you do this on both the
main and emergency sides before reinstalling in the airplane.
Removing the undercarriage actuators is pretty straight forward. Of
course you will need to jack the airplane. First remove the end of the
actuator from the drag link that moves the undercarriage up and down.
Then remove the bolt and nut at the top of the actuator. I would
recommend you take the actuators to person who is familiar with
disassembling and reassembling the actuator because it can be difficult
getting the end caps off. Then when reassembling it is easy to damage
the new seals.
Finally, seriously consider overhauling all of the undercarriage
actuators and the flap actuator. Better to be safe than sorry.
Dennis
----- Original Message -----
From: Didier Blouzard
To: yak-list@matronics.com
Sent: Sunday, October 04, 2009 4:17 PM
Subject: Yak-List: Gear uplock piston
Hello to all,
just to attract your attention on a small problem I had two times
on two different planes about the small uplock cylinder locking and
unlocking the gears.
The gear is locked in the up position by a small hook . When we
select the gear down position air flows thru the normal circuit to the
small uplock cylinder that pushes and release the hook. Air goes in the
same time into the main cylinder to push the gear down and extend it.
Those last time I had the problem on my Yak18T and on my friend 's
Yak52 just this last week. This small cylinders stopped working locking
the gear in the retracted position. On my plane, I discovered the
problem fortunately when my plane was jacked and I was making
retractation test (my red retracted light did not want to come on and
this was the symptom of the normal operation piston blocked on the
emergency piston. The actuator of the light was no more depressed) and
without possible anticipation my left gear refuses to go down. The hook
did not release the gear. The uplock cylinder was blocked.
The same happened to my friend last week on his 52. He landed with
the emergency system and all was fine.
What happened was that those little uplock cylinder are made of
two piston moving one on the other and the movement was completely
corroded so it was no more moving on normal operation but only in
emergency. Inside the cylinder I found a lot of corrosion and even old
grease blocking the cylinder. I had to unmount completely the
cylinders, use a hammer to separate the two parts of the piston paper
sand the corroded parts clean completely the interior and apply some
Teflon grease.
I was really surprised how much it was corroded and it seems to me
important to attract your attention on this problem. These little
cylinders are very easy to unmont. It takes about one hour to unmont it
clean it and remount it.
Regarding how annoying it is to land with the gear retracted.....I
think it is worth checking these uplock cylinders.
If anyone want I can post pictures of the unmonting process.
And if anyone can explain me how difficult it is or how easy it is
to make the same for the main gear cylinders I will be happy. I think
that now I will try to check all the cylinders.
Hope that will help
--
Didier BLOUZARD
didier.blouzard@gmail.com
0624243672
href="http://www.matronics.com/Navigator?Yak-List">http://www.matronics
.com/Navigator?Yak-List
href="http://forums.matronics.com">http://forums.matronics.com
href="http://www.matronics.com/contribution">http://www.matronics.com/c
et="_blank">http://www.matronics.com/Navigator?Yak-List
a href="http://forums.matronics.com/"
target="_blank">http://forums.matronics.com
_blank">http://www.matronics.com/contribution
--
Didier BLOUZARD
didier.blouzard@gmail.com
0624243672
Message 3
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| Subject: | Re: Gear uplock piston |
The uplock is a mechanical latching mechanism that is released by air
pressure moving the pin in the uplock outward which releases the
mechanically latched "parrot hook". If the uplock was not there and you
put the gear selector in neutral, the gear would go limp and drop down
out of the wheel wells. If you lose air pressure in your main system,
the uplocks hold the gear up and locked until you use the emergency
system to blow the gear down, which releases the "parrot hook" the same
way; the uplock pin is moved outward to mechanically release the parrot
hook.
Dennis
----- Original Message -----
From: Didier Blouzard
To: yak-list@matronics.com
Sent: Monday, October 05, 2009 4:31 AM
Subject: Re: Yak-List: Gear uplock piston
Thanks to all for your kind comments,
merci beaucoup !!!!!
Dennis, I will follow your recommandations and probably have a
thorough inspection of all actuators done by a DASSAULT specialist. He
has all the specific tools and knowledge.
Just to moderate, on my plane the left uplock was rusted but the right
one was in a good state.
For the liquid to put in the pneumatic system TERMIKAS seems to
recommand to mix 50% ethanol and 50% glycerin (found in any good
drugstore) and to inject this mixture into the pneumatic system as you
say.
Regarding the relevance or not of these uplock ...... I question
myself. My hungarian operator has been trained by russian engineers and
when he was aware that I followed the manual regarding the gear handle
in neutral position he told me that this was not the recommandation and
I have to keep the gear handle on retracted or extended all the time.
The only problem is (or might be!!!) the compressor always in charge.
Thanks very much Dennis,
thanks to all
Didier
2009/10/5 A. Dennis Savarese <dsavarese0812@bellsouth.net>
Didier,
This is not an unusual problem with Yak's (50's, 52, Yak 18T's) with
uplock actuators. In fact, it happens more frequently than one might
think. The problem is poor maintenance of the pneumatic system in years
past. As you have already found out, when you disassemble the uplock
actuator you will very likely find rust and corrosion inside. Very
likely one or more of the C-clips will be rusted or maybe even totally
disintegrated. It is highly recommended that at every annual inspection
at least one uplock actuator be removed, disassembled and inspected.
Whatever you find in the small uplock actuator is representative of what
you will find in all the other actuators (undercarriage and flap). So
if you have an uplock actuator that is not functioning and you find
corrosion and rust internally in the actuator, you can almost count on
finding the same thing in your undercarriage and flap actuators.
Additionally the air start valve is probably full of junk/gunk as well.
If the metal parts except the C-clips are in good shape, you can
overhaul the uplock actuators. I would strongly recommend you do this
before you end up with an in-flight problem with the undercarriage not
coming down. And believe me, it WILL happen if you don't take care of
it now. Do not use grease when reassembling. Use only a light weight
oil. Grease may block the small holes in the shaft between the main and
emergency sections. (The steel part that inserts into the brass part).
You can pressure test the uplock actuator with shop pressure from a
standard shop compressor. I would recommend you do this on both the
main and emergency sides before reinstalling in the airplane.
Removing the undercarriage actuators is pretty straight forward. Of
course you will need to jack the airplane. First remove the end of the
actuator from the drag link that moves the undercarriage up and down.
Then remove the bolt and nut at the top of the actuator. I would
recommend you take the actuators to person who is familiar with
disassembling and reassembling the actuator because it can be difficult
getting the end caps off. Then when reassembling it is easy to damage
the new seals.
Finally, seriously consider overhauling all of the undercarriage
actuators and the flap actuator. Better to be safe than sorry.
Dennis
----- Original Message -----
From: Didier Blouzard
To: yak-list@matronics.com
Sent: Sunday, October 04, 2009 4:17 PM
Subject: Yak-List: Gear uplock piston
Hello to all,
just to attract your attention on a small problem I had two times
on two different planes about the small uplock cylinder locking and
unlocking the gears.
The gear is locked in the up position by a small hook . When we
select the gear down position air flows thru the normal circuit to the
small uplock cylinder that pushes and release the hook. Air goes in the
same time into the main cylinder to push the gear down and extend it.
Those last time I had the problem on my Yak18T and on my friend 's
Yak52 just this last week. This small cylinders stopped working locking
the gear in the retracted position. On my plane, I discovered the
problem fortunately when my plane was jacked and I was making
retractation test (my red retracted light did not want to come on and
this was the symptom of the normal operation piston blocked on the
emergency piston. The actuator of the light was no more depressed) and
without possible anticipation my left gear refuses to go down. The hook
did not release the gear. The uplock cylinder was blocked.
The same happened to my friend last week on his 52. He landed with
the emergency system and all was fine.
What happened was that those little uplock cylinder are made of
two piston moving one on the other and the movement was completely
corroded so it was no more moving on normal operation but only in
emergency. Inside the cylinder I found a lot of corrosion and even old
grease blocking the cylinder. I had to unmount completely the
cylinders, use a hammer to separate the two parts of the piston paper
sand the corroded parts clean completely the interior and apply some
Teflon grease.
I was really surprised how much it was corroded and it seems to me
important to attract your attention on this problem. These little
cylinders are very easy to unmont. It takes about one hour to unmont it
clean it and remount it.
Regarding how annoying it is to land with the gear retracted.....I
think it is worth checking these uplock cylinders.
If anyone want I can post pictures of the unmonting process.
And if anyone can explain me how difficult it is or how easy it is
to make the same for the main gear cylinders I will be happy. I think
that now I will try to check all the cylinders.
Hope that will help
--
Didier BLOUZARD
didier.blouzard@gmail.com
0624243672
href="http://www.matronics.com/Navigator?Yak-List">http://www.matronics
.com/Navigator?Yak-List
href="http://forums.matronics.com">http://forums.matronics.com
href="http://www.matronics.com/contribution">http://www.matronics.com/c
et="_blank">http://www.matronics.com/Navigator?Yak-List
a href="http://forums.matronics.com/"
target="_blank">http://forums.matronics.com
_blank">http://www.matronics.com/contribution
--
Didier BLOUZARD
didier.blouzard@gmail.com
0624243672
Message 4
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| Subject: | Re: Engine Surge |
Phil,
I seriously doubt it is a mag coil problem. If it is not the prop
governor, then I would suspect a fuel problem. Have you checked all the
fuel screens including the finger screen in the back of the carburetor?
It's the one just above the 90 degree fuel inlet elbow (on a Yak 52); a
22 mm nut. Check this finger screen. Were the hoses, particularly the
fuel hoses, replaced? It is possible there is a "flapper" in one of the
two fuel hoses; the one from the coarse fuel screen to the fuel pump and
the one from the fine fuel screen to the carburetor.
We recently changed a carburetor diaphragm on a Yak 50 with a surging
problem at higher power settings. Although I could not find any cracks
in the diaphragm, the problem went away. Look at the bottom center of
the barometric chamber. There is a small bolt with multiple holes in
it. This is a breather plug for the barometric chamber. I have found
evidence of fuel leakage on the head of this small bolt. It had dark
brown corrosion around it. On one plug there was very slight fuel
drips. This means the plate is loose around the diaphragm and is
leaking fuel into the barometric chamber. If fuel leak out, there can
also be an air leak. So check this as well as this could have easily
been the problem on the Yak 50.
If you decide to change the diaphragm, Mark Jefferies in the UK is
having them made. If I am not mistaken, they are about 75 GBP, plus
shipping of course.
Let me know what you find.
Dennis
----- Original Message -----
From: PSalter@aol.com
To: yak-list@matronics.com
Sent: Sunday, October 04, 2009 6:59 PM
Subject: Yak-List: Engine Surge
Any ideas of what could cause an engine surge at takeoff power which
led to an aborted takeoff. The rpm fluctuated between 85-100%, all run
up checks were normal. The prop gov is new, so gov issues are hopefully
eliminated. Could this be a carb issue, maybe a bad diaphram,
supercharger, or maybe a mag coil? This aircraft had this problem some
time ago and was parked.
All help is appreciated,
Phil
Message 5
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| Subject: | Undercarriage problems |
I agree with Dennis that this is often poor maintenance, but surely the
fundamental reason is that people do not drain the water from the system
EVERY day, or indeed, every flight if it is a long one.
Moisture in the system is the real problem, with out it corrosion will
not even start!
Richard Goode Aerobatics
Rhodds Farm
Lyonshall
Herefordshire
HR5 3LW
United Kingdom
Tel: +44 (0) 1544 340 120
Fax: +44 (0) 1544 340 129
www.russianaeros.com
Message 6
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| Subject: | Gear uplock piston |
Just a note. The YAK-50 does not use UP LOCK actuators. Instead, the
uplock is controlled by a spring and movement of the main gear actuator
itself.
All the corrosion issues are the same as has been reported, but there
are just two main actuators to worry about.
Mark Bitterlich
-----Original Message-----
From: owner-yak-list-server@matronics.com
[mailto:owner-yak-list-server@matronics.com] On Behalf Of
cjpilot710@aol.com
Sent: Sunday, October 04, 2009 16:10
Subject: Re: Yak-List: Gear uplock piston
Guys,
I know these up locks are standard on every Yak and CJ-6 EXCEPT mine.
When I bought my airplane 15 years ago, they were not installed on the
airplane. Somewhere I remember seeing a pneumatic system drawing
without them. I've heard of one other aircraft that didn't have them
either. I now have well over 1,800 hours on my airplane with out them.
I personally think you can get along without them.
Difference? I merely fly around with my gear handle UP, instead going
to OFF. If I put the gear handle to OFF (not down), the air merely
bleeds out of the system though the gear handle, and my gear will drop
out. The same will happen if I happened to lose all my main system air.
One time at a near by airshow, I sheared the pins in the compressor. Of
course the system pressure started slowly dropping. It got pretty (30
atoms) low before I noticed it. I turned off my main air valve. At
about 20 to 25 atoms the gear starts to fall. On the down wind (with
zero pressure on the gage) I put the gear handle from the full UP to the
DOWN position. I noted that all the "Idiot" sticks were showing the
gear nearly down at this point. At this point I opened the main valve,
and heard a satisfying normal "clunk" and 3 green lights. I still had
30 atoms in my system for brakes (min is 10 atoms BTW) and still had my
emergency bottle in reserve.
Now I know the book says to put the gear handle OFF after the gear is
retracted. AND that before extending the gear, one must go from OFF to
UP before going to down. This keeps the gear from slamming down. My
point is that it does not matter if you leave the gear UP. Nothing is
going to happen to the system. There will always be pressure on the up
side of the actuator and that is all. This doesn't do any harm to
seals. Seals are worn out by movement of the piston in the actuators,
not by the air pressure.
Other folks have said that it is easier on the compressor. I say it
makes no difference. The compressor will be putting out the same cubic
whatever's with each stroke . The regulator will dump the excess
pressure when it exceeds the spring's compression set. It would do this
with or without the gear being OFF or UP. BTW if you think by having a
over board dump valve install (some Yak 18Ts) is easier on the
compressor, I find that debatable. The compressor will still chugging
right along with the engine however - - - - the engine will not be
drained of the hp required for the compressor working to build up that
pressure. Hence it would burn a little less fuel (does anyone know how
much?).
At one point I considered putting up locks back on my CJ. Then I
considered the operational differences and that they may in themselves
be a failure point. KISS
Do I recommend taking them off your airplane? No. But for ME - I am
fine without them.
So why do the engineers say "Put the gear handle OFF". I don't know. I
do know that engineers and the FAA use to say "To remove smoke from the
707 cockpit, open up the sextant valve and if it gets worse, open
cockpit windows." (Words to that effect in the emergency check list)
Turns out, that was 100% wrong and 3 friends of mine died at BOS doing
what they were told.
Not that having a gear handle UP or OFF will be as quite as earth
shattering as that, but just the best extreme example I could think of.
BTW (different note) On the B-24 (PW 1830-65 with 14 cylinders) we only
pull though 9 blades. On the B-17 (Wright 1820 with 9 cylinders) we pull
9 blades. On the B-25 its a two man (old men) job to pull the 14
cylinder Wright though 9 blades. I pull my M-14 though 5.
Jim "Pappy" Goolsby
In a message dated 10/4/2009 5:23:53 P.M. Eastern Daylight Time,
didier.blouzard@gmail.com writes:
Hello to all,
just to attract your attention on a small problem I had two
times on two different planes about the small uplock cylinder locking
and unlocking the gears.
The gear is locked in the up position by a small hook . When we
select the gear down position air flows thru the normal circuit to the
small uplock cylinder that pushes and release the hook. Air goes in the
same time into the main cylinder to push the gear down and extend it.
Those last time I had the problem on my Yak18T and on my friend
's Yak52 just this last week. This small cylinders stopped working
locking the gear in the retracted position. On my plane, I discovered
the problem fortunately when my plane was jacked and I was making
retractation test (my red retracted light did not want to come on and
this was the symptom of the normal operation piston blocked on the
emergency piston. The actuator of the light was no more depressed) and
without possible anticipation my left gear refuses to go down. The hook
did not release the gear. The uplock cylinder was blocked.
The same happened to my friend last week on his 52. He landed
with the emergency system and all was fine.
What happened was that those little uplock cylinder are made of
two piston moving one on the other and the movement was completely
corroded so it was no more moving on normal operation but only in
emergency. Inside the cylinder I found a lot of corrosion and even old
grease blocking the cylinder. I had to unmount completely the
cylinders, use a hammer to separate the two parts of the piston paper
sand the corroded parts clean completely the interior and apply some
Teflon grease.
I was really surprised how much it was corroded and it seems to
me important to attract your attention on this problem. These little
cylinders are very easy to unmont. It takes about one hour to unmont it
clean it and remount it.
Regarding how annoying it is to land with the gear
retracted.....I think it is worth checking these uplock cylinders.
If anyone want I can post pictures of the unmonting process.
And if anyone can explain me how difficult it is or how easy it
is to make the same for the main gear cylinders I will be happy. I think
that now I will try to check all the cylinders.
Hope that will help
--
Didier BLOUZARD
didier.blouzard@gmail.com
0624243672
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| Subject: | Gear uplock piston |
There is one more occasion when it is actually smart to move the
actuator level to neutral and this is if you have a bad bad air leak.
It is entirely possible to have a leak in your landing gear system where
it only leaks when the landing gear is selected UP or selected DOWN.
If that happens, you can end up bleeding out your whole air bottle and
not have normal air available for landing.
I had this happen on a YAK-50 that I was ferrying out to California. In
that case, the leak only happened with the gear in the DOWN position.
Keep in mind that the landing gear on a YAK-50 does NOT work the same
way as the YAK-52, and in the 50, the down and lock system is fully
mechanical. If the gear is down and locked, it does not require air
pressure to KEEP it down and locked. The 52 uses actuator locking balls
I think (Dennis? Anyone?) but the 50 has a stand alone mechanism.
Anyway, it is possible to lower the gear... Put the handle back to
neutral, then allow the air to pump back up, and actually LAND with the
actuator in neutral. My leak was so bad, I had to do this, or I would
have had no brakes on landing. Of course, if you could, the better move
would be to select DOWN right before you landed.
Point being, putting the landing gear handle in neutral can ISOLATE a
bad leak and allow you to regain full air pressure.
Mark Bitterlich
-----Original Message-----
From: owner-yak-list-server@matronics.com
[mailto:owner-yak-list-server@matronics.com] On Behalf Of A. Dennis
Savarese
Sent: Monday, October 05, 2009 5:03
Subject: Re: Yak-List: Gear uplock piston
Regarding the compressor always being "in charge" because you put the
undercarriage selector in neutral - it has no effect on the compressor
whatsoever because the compressor is always charging the system when the
engine in running. Your Hungarian operator is 100% correct.
Another reason I do not subscribe to putting the undercarriage selector
in neutral (with one exception which I will explain shortly) is because
when you put the selector in neutral, the actuators are totally
depressurized. That is the "woosh" sound you hear when the selector is
moved to neutral. If you move the selector to the DOWN position for
landing from NEUTRAL, the undercarriage will slam into the down position
because there is no backpressure on the actuator from the UP side. This
is not good for the undercarriage, or the actuators. The pressure on
the UP side of the actuator acts as a "shock absorber" when the selector
is put in the down position.
The ONLY way moving the selector to neutral is acceptable is if BEFORE
you move the selector to DOWN you first move the selector to the
position the undercarriage is already in. In this case, back to the UP
position. By doing this, you re-pressurize the actuators and then you
can move the selector to the down position. Unless you get into the
habit to do this every time you cycle the undercarriage, leave the
selector in the UP position.
Dennis
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I see. Well, I would honestly have to see the whole circuit diagram of
what was put in there and exactly how. Right now I am working blind,
and remotely. Just is not going to work that way. Not a good answer,
but honest.
Yes, it could be impedance. MAYBE, but I doubt it. The person should
have taken the headset audio that formerly came right into your headset
and fed it into the new SPA-400. If he went and took it directly off
the radio, that could be it. Seriously, without knowing what he did,
how he did it, where he hooked in, then it's hard to know WHAT might be
going on.
Also you did not answer my other questions. What about SIDE TONE ???
Can you hear yourself when you TRANSMIT? Do you hear both radios at
once by any chance?
Here's the thing..... The SPA-400 was meant to be connected to ONE radio
and not TWO radios. That means that the person had to design something
DIFFERENT to make that work.
There are three connections that must be made to both radios.
Headset audio. This is normally a signal wire and a ground.
Microphone audio. This is also normally a signal wire (that is
shielded) and a ground. The shield is normally the ground and it is
grounded at BOTH ENDS.
PTT or Push to Talk. This is ONE wire that goes to the radio. You
GROUND that wire and the radio transmits.
Now, how did he handle the HEADSET AUDIO? It is entirely feasible that
he connected them both together... That is he connected the headset
audio wire from BOTH radios together and is only switching the PTT and
the MIKE WIRE. Did he do that? If he did, that is probably your
problem.
This is why I said there is normally a relay. You say you have ONE
SWITCH. Yes, of course. But what does that switch actually DO? It
PROBABLY controls a RELAY.
The relay must switch the connections for MICROPHONE AUDIO, HEADSET
AUDIO, and PTT going to the SPA-400, and all three things must be
switched back and forth between radios.
It is ALSO possible, that the shield for the headset audio for the
Russian radio is supposed to run straight to the headset and not go to
aircraft GROUND. I am not sure, because I do not use your radio in my
YAK-50. I do not own a YAK-52. I have repaired your type of radio, but
have not done the kind of thing you have attempted.
This is normally why you use an AUDIO PANEL. An AUDIO PANEL keeps all
these connections apart and is meant to do what you are attempting to
do. In your case, your technician DESIGNED something to do it, and ...
His design, whatever it is, is not working correctly.
Without knowing what was there to begin with, how it worked when it did
work, and what he has done, EXACTLY, there is simply no way I can fix
this for you.
My GUESS? My GUESS is that he has not referenced headset audio to
ground. In other words, he has hooked up the Russian headset audio wire
as called for, through a switch, or relay, or somehow or another. But,
he did nothing with the SHIELD wire that originally came from the radio.
And thus there is no ground reference for the headset audio. This would
cause it to be extremely weak.
Find the original wiring that came out of the YAK-52 and went to your
headset. Disconnect it from whatever he has done and hook it BACK to a
headset! If you can then hear everything just fine, you are well on
your way to fixing it. In a case like that, you fix it by using a 1:1
audio transformer. You connect one side of the transformer to the
headset audio wire from the radio and the RETURN wire to the radio. The
other side of the transformer you connect one wire to pin 3 of your
SPA-400 (receive audio) and the other side to aircraft GROUND.
It's a guess, but a logical one.
Mark
-----Original Message-----
From: owner-yak-list-server@matronics.com
[mailto:owner-yak-list-server@matronics.com] On Behalf Of Didier
Blouzard
Sent: Sunday, October 04, 2009 13:49
Subject: Re: Yak-List: Yak Radio
Hello Mark,
it is in fact a simple switch that's select the russian and western
radio. Both radios gos through an SPA400. The western radio works fine
but with the vibrations I have to push it back in place from time to
time.
This week I checked both radios. I have been told that everybody receive
much better with the russian radio selected. My main problem is that it
is barely audible.
I wonder if it can be a problem of impedance adaptation? Any hintts
regarding a
Regarding my hungarian avionic tech I am afraid that he can't solve the
problem neither can the french because they don't know the russian
system. So I am alone !!!
Regarding the problem of Mark, I had a similar problem. This problem
came from my antenna's cable which was very poorly connected to the
antenna (just over the pilots head, in the roof) and the frame of the
plane act as a faraday cage. Try to use a safety radio from inside the
yak it is impossible (I had to set an antenna under the plane and a
cable coming thrue the When I changed the connection and reconnected to
the antenna my radio worked fine.
Hope that will help.
Didier
2009/10/3 Bitterlich, Mark G CIV Det Cherry Point, MALS-14 64E
<mark.bitterlich@navy.mil>
Cherry Point, MALS-14 64E" <mark.bitterlich@navy.mil>
Hello Didier.
First, did the technician add an audio panel, or did he just
switch things with relays? I suspect relays. This is not something
that can be troubleshot remotely, but there are some things you can try.
Do you have side-tone? When you transmit, can you hear yourself talk
perfectly, or is it very weak.
If it is weak, or not there, then you simply have a receive
audio line not connected correctly.
This problem is something that can be fixed, but a person needs
to be there with the proper test equipment to do it.
Possibly someone else has some quick suggestions dealing with
the audio interface panel that is located on the radio rack, but nothing
really simple comes to mind. It is going to require some testing. Your
avionics tech should be called back into action I am afraid.
Mark Bitterlich
________________________________
From: owner-yak-list-server@matronics.com on behalf of Didier
Blouzard
Sent: Fri 10/2/2009 4:12 PM
To: yak-list@matronics.com
Subject: Yak-List: Yak Radio
Hello to all,
I have a question regarding my radio.
I have installed both US and russian radio in my plane
(overhauled Baklan 5).
My operator set a switch to change between the US and the
russian radio and changed the headset plugs to western plugs in order to
use regular headset.
My problem is the following.
On the US radio, no problems : Emission's fine and reception's
fine also.
On the russian radio, emission seems to be perfect (better than
with the US radio) but when it comes to listening I can't hear anything.
A sound that's so faint that it is not understandable.
I was wondering if some of you had the same problem and of your
knowledge is there a solution.
Thanks to all and good day
Didier
Yak18T HA-JAC
Paris - FRANCE
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Didier BLOUZARD
didier.blouzard@gmail.com
0624243672
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| Subject: | Re: BCAA fly-in Breakfast October 11th. |
The fly-in is this Sunday. Might be a few yaks there. If anyone is interested
see the above post.
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=266709#266709
Message 10
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| Subject: | Re: BCAA fly-in Breakfast October 11th. |
who, when, where ,what ,why , what time ?
----- Original Message ----
From: Nathan_pa <warhawknm@yahoo.com>
Sent: Monday, October 5, 2009 8:53:37 PM
Subject: Yak-List: Re: BCAA fly-in Breakfast October 11th.
The fly-in is this Sunday. Might be a few yaks there. If anyone is interested see
the above post.
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=266709#266709
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