Today's Message Index:
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1. 04:57 AM - Re: Air System (cjpilot710@aol.com)
2. 10:12 AM - Re: YAK 50- for sale!!!! (Jetj01@aol.com)
Message 1
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In a message dated 5/25/2007 11:49:02 P.M. Eastern Daylight Time,
viperdoc@mindspring.com writes:
In the 14 years now (and 1,500 hours) that I've own my CJ, I think I've come
to know my air system. Early on, the salt moist air of Florida was playing
real havoc with my system. Gear and flap handles were a constant source of
leaks, often twice a year. My check valves were balls of corrosion. I
developed a leak in my main air valve and on inspection found that the aluminum
vale seat was badly corroded and the common steel valve, a ball of rust. (Who
thought up that design?). The desiccant dryer/filter would corrode so badly,
that it was real bugger too disassemble each time for service. It finally
developed hole from corroding though the body.
Here is what I did.
I replaced the main air valve with a stainless steel one made up by Bill
Blackwell. I had to grind the valve seat smooth.
I replaced the desiccant dryer/filter with a stainless steel one made by
Doug Sapp.
For a while I used the Russian white desiccant that comes in the engine
storage crates. This worked fine while I still had the aluminum filter. I've
recently gone back to the purple stuff.
I replaced all springs in the check valves and emergency shuttle valves,
with stainless steel springs (ACE has them). Each time I inspect them, I clean
and apply a light coat of marine axle grease.
The actuators seals were replaced years ago by a US seal. I think I've
changed them 3 times since than and than only because I wanted too. About twice
a year or every 50 hours or so, I open the air lines on both ends of each
actuator. I squirt in a little air tool oil into the lines. Reconnect and
safety. I do the same at the first fitting down stream of the dryer/filter.
The
next time I pressurize the system the oil is sprayed into each actuator.
When the gear and flaps are cycled, oil is spread though the entire system.
This is very evident when I see a spray of oil mist from the gear and flap
handles.
At one point I use WD-40. Than I heard it may not be good for aluminum so I
went to air tool oil.
A while back there was some discussion about using diluted Corrosion X in
the system. Now I can tell you that this stuff is a total unknown in air
systems. I don't think anyone can tell us what it will do to seals. Put when
it
comes to airframes, this STUFF WILL GO EVERY WHERE ! It coats every thing
and seeps along and though the tightest of seams. Maybe some one would want to
investigate that.
Though I'd put in my .02 worth. Got to go eat breakfast.
Jim "Pappy" Goolsby
--> Yak-List message posted by: "Roger Kemp" <viperdoc@mindspring.com>
Mark,
I believe on the 52 systems that the Russians put a mixture of alcohol,
gycerine and something else to the air tanks at inspection. This was a
thread a couple of years ago also. I agree with all you have said too. Like
I said in an earlier post, I do add sewing machine oil to the tank and have
not experienced a problem to date.
Now I have all new seals too though when the 52 came over from Lithuania.
The 50 had all its' actuator seals replaced in 2002 by Shakety. So I am
leary of adding machine oil to the tanks on the 50 when I pull them in a
couple of weeks. The Lithuanian seals actually come for the US.
Doc
-----Original Message-----
Subject: RE: Yak-List: Air System
MALS-14 64E" <mark.bitterlich@navy.mil>
Doc,
Rust is "issue A".
Seals crumbling apart is: "Issue B".
There are at least two types of landing gear actuator seals "out there"
for the YAK-50 that I know of alone. The original Russian seal, and a
replacement that is made here in the United States. The actual material
used in each of them is quite different. The American made seal is more
tolerant of oil. The Russian one will harden, yet still work perfectly
for many years without a problem. However, if it has hardened, and you
add oil, it will crumble and break apart like a piece of burnt wood in
your hands. This is not conjecture speaking here, this is experience.
When making broad, across the board suggestions like "adding oil to the
air system is a good thing", one has to be careful. There is nothing in
any Russian manual about adding oil into the air system. This is a case
of owners of these aircraft seeing rust ... Which is a bad thing.... And
then thinking: "Well, I will just add some oil to this problem which
will help solve that old corrosion issue".
Some of the worst corrosion is seen in the actuators, and there is a
reason for this. The actuators are in fact expansion chambers. Think
what happens when you allow compressed air to expand rapidly.
So we come back to the original problem. Corrosion. In the actuators,
you have several choices. On the 50, you can take them apart, blast off
any and all corrosion, and then paint them with the best epoxy polyamide
paint money can buy. Or you can have them made out of stainless steel
(one gent actually did that). The same thing goes for the air bottles.
Another "good idea" is to mount the air bottles upside down. When you
do that, any water that is in there will come right back out when you
release air for brakes or landing gear actuation.
If you can manage to eliminate the water, you can really slow down the
corrosion process "no matter what". The snot valve is one attempt
towards this. Adding a desiccant filter is yet another.
However, if you want to start adding oil into the air system, I would
strongly suggest you find out the exact type of seal in use on your
aircraft, get one in hand, and cover it with some of the oil you intend
on using. Wait a few months and then take another look at that seal.
Bottom line, if you have brand new landing gear and flap actuator seals,
you are a lot safer adding "oil" or whatever...to your air lines. If
you have an OLD Yak aircraft that has not had the seals replaced since
Christ was a Corporal, I would not rush right in and start squirting oil
all over creation.
I "rushed in".... I also then learned how to blow the gear and remove
and replace the seals in those actuators.
Your milage may vary,
Mark
-----Original Message-----
Subject: RE: Yak-List: Air System
Now this might be another place for MMO for sure! In the quest to find
101 uses for MMO, this might be #89.
Seriously, we have been adding 6 oz of machine oil along with removing,
draining, and drying the tanks at annual. Have not seen any rust in the
tanks to date. We generally get about 3 oz of the oil back and a few
droplets of water that is less that a couple of ccs'.
Doc
Mark- My thoughts exactly. Be very careful what you put in the air
system.
David H.
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Message 2
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| Subject: | Re: YAK 50- for sale!!!! |
I'd like to do that, especially find out how much 'throttle down"ing is
needed in my YAK. I cruise at 175-185 mph...
Or come up to F14 any weekend!
Jj
YAK 50
and 2 for sale, 79, 84
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