Today's Message Index:
----------------------
1. 03:40 AM - Re: Air system 'stuff' (Rob Rowe)
2. 07:44 AM - Re: Air system 'stuff' (Bitterlich, Mark G CIV NAVAIR, WD)
3. 07:49 AM - Re: Fw: Parker pop-off in use on my CJ (Bitterlich, Mark G CIV NAVAIR, WD)
4. 07:59 AM - Re: Re: Air system 'stuff' (Bitterlich, Mark G CIV NAVAIR, WD)
5. 09:20 AM - Re: Air system 'stuff' (Rob Rowe)
6. 04:48 PM - Re: Re: Air system 'stuff' (Bitterlich, Mark G CIV NAVAIR, WD)
Message 1
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| Subject: | Re: Air system 'stuff' |
mark.bitterlich(at)navy.m wrote:
> Yes, it should be polarity sensitive even though I have never tested it
> to that effect. We are talking DC here, so if we reverse the polarity,
> the magnetic field will reverse as well. I never realized that the plug
> could be connected both ways. Hmmm.
>
Mark
Beg to differ here, standard solenoids are inherently NOT polarity sensitive.
Yes reversing the polarity does reverse the magnetic field, but the induced polarity
of the soft iron plunger core also reverses - so the direction of force
remains unchanged.
Now if the soft iron core plunger is replaced with a magnetised version then you'll
get a polarised solenoid ... and it will be marked accordingly.
You will also find polarity marked terminals on more modern solenoids/relays too,
designed to work with electronic drivers versus mostly electro-mechanical systems
in Yaks/CJs (where the bus battery effectively absorbs the bulk of any
transient energy generated).
This is not for their basic function, but because they have an integral back-emf
protection diode in parallel with the coil to suppress the (potentially several
hundred volt) negative spike produced as the coil field collapses when the
solenoid is turned off.
Hence the terminal polarity is essential to prevent this protection diode from
being destroyed through continuous reverse bias, rather then a brief spike.
Hope this helps.
Brgds, Rob
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=402546#402546
Message 2
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| Subject: | Air system 'stuff' |
Contact me with personal email if you still have problems.
Problems with building air. Lots already written on that subject as
well. You're on the right track. I replaced the compressor to snot
valve hard line years ago in my 50 (and a friends 52) with a Russian
flexible line. Sukhoi's have them, but darn if I know the part numbers.
Exact fit. At one time I believe Doug Sapp or someone else was making
them? Can't remember. That line cracks and leaks all the time. Also
the banjo fitting on the compressor. Well known "gets dirty and doesn't
work right" item. Be aware it needs crush washers to repair properly.
This is the short version.
Good luck.
Mark
-----Original Message-----
From: owner-yak-list-server@matronics.com
[mailto:owner-yak-list-server@matronics.com] On Behalf Of bill wade
Sent: Tuesday, June 11, 2013 17:16
Subject: Re: Yak-List: Air system 'stuff'
Actually Mark I've been having problem's building air and a friend
cleaned his air starter and reported very good results on higher RPM
when starting so I thought as I'm messing with the air system and I've
read it should be cleaned periodically (first time in 13 years) I would
take a look, falls under if it isn't broke don't fix it! actually it was
very clean. As for the building air seems to be from the pump to the
check valve and still chasing it, looking for a flex hose from the pump
to the snot valve. I will try the bulb thing and check for an open in
solenoid. Thanks Bill Wade
From: "Bitterlich, Mark G CIV NAVAIR, WD" <mark.bitterlich@navy.mil>
Sent: Tuesday, June 11, 2013 11:29 AM
Subject: RE: Yak-List: Air system 'stuff'
<mark.bitterlich@navy.mil>
Yes, it should be polarity sensitive even though I have never tested it
to that effect. We are talking DC here, so if we reverse the polarity,
the magnetic field will reverse as well. I never realized that the plug
could be connected both ways. Hmmm.
Connect an ohm-meter to the two pins on the solenoid and check to at
least see that you do not have an open, meaning make sure coil is not
dead.
Check cockpit volt meter and make sure when you press the start button
that you are not dropping voltage below say ... 20 volts minimum...
actually should stay up around 23 VDC or so, but even 20 volts (when
pushing the start button) should open the valve.
You checked for voltage to one pin on the feed plug, but did you check
the other pin with an ohm-meter and make sure it has a good reading to
ground? If you really want to be sure, connect about a 20 watt (or so)
light bulb across the two pins in the plug and make sure it lights when
you hit start. Realize that when you check for power on a plug like you
just did, it is being checked with zero load (no current flow). So if
you have a ton of resistance in the wire, it will still read the exact
voltage that you want to see. Meaning, voltage drop equals current
times resistance. So if E=IR and you have zero current ... zero times
anything is zero, so you will have no voltage drop. This rarely is a
concern because wires normally just fail open. But once in awhile it
can really bite you in the tail if you are not aware of it.
In any case, putting a light bulb across the two pins on the feed plug
puts a load on the wires. If the bulb lights up bright, you have good
wiring, if it glows dimly, you have high resistance somewhere. Simple.
Did you take it out and clean it because you were already having a
problem? Or just because ..... Usually problems of this nature are not
with the aircraft wiring, but with the device itself. A lot has already
been writing about these things.. you might want to check the archives.
Mark
p.s. Doug Sapp has new ones.
-----Original Message-----
From: owner-yak-list-server@matronics.com
[mailto:owner-yak-list-server@matronics.com] On Behalf Of bill wade
Sent: Tuesday, June 11, 2013 10:51
Subject: Re: Yak-List: Air system 'stuff'
As were talking about air system stuff
Does any one know if the air start valve solenoid is polarity sensitive?
The wire plug connector can be attached both ways. Took it out cleaned
it now it doesn't work I have voltage at the wire when start button is
pushed, valve works when the lever is pushed down? Just ordered new
Batteries.
Bill Wade
From: Mark Davis <markdavis@wbsnet.org>
Sent: Tuesday, June 11, 2013 10:20 AM
Subject: Re: Yak-List: Air system 'stuff'
The good news with a YAK-52 is that if you kill the mags and land flaps
up you likely will do very little damage to the aircraft in a gear up
landing. This of course would depend on a GIB that understands this
concept and actually gives a s#%t at the time!
Mark Davis
N44YK
----- Original Message -----
From: John Nolan <mailto:johnrobertnolan@gmail.com>
To: yak-list@matronics.com
Sent: Tuesday, June 11, 2013 6:55 AM
Subject: Re: Yak-List: Air system 'stuff'
When removing any components from the aft cockpit I would
consider the possibility of pilot incapacitation in the forward cockpit
with a person in the back.
Regards,
John Nolan
On Tue, Jun 11, 2013 at 7:55 AM, A. Dennis Savarese
<dsavarese0812@bellsouth.net> wrote:
<dsavarese0812@bellsouth.net>
Since neither the CJ nor the Yak 52, which have 100%
identical gear and flap selectors for both front and rear cockpits, the
rear cockpit gear and flap selectors are no longer used as was
originally intended; as primary trainers. Therefore gear and flap
selectors in the rear cockpit serve no functional benefit other than to
pass the air pressure through them to the front cockpit. Why not
fabricate a 3 valve and 5 valve bypass 'block' which could replace both
of these "rarely ever used" components and eliminate potential failures
in the pneumatic system?
This is not difficult to do. In fact, I am pretty sure
Jim Goolsby modified his rear gear selector and created a bypass. Thus
he eliminated the potential failure of the unit. I personally
fabricated a bypass configuration for one Yak 52 and completely removed
the rear gear selector. Replacing a rear gear selector in a Yak 52 is
far more difficult than on a CJ because the CJ's gear selector can be
accessed from behind the front seat. In the Yak 52 you need a 10 year
old skinny kid to get under the instrument panel.
If you have never disassembled a rear gear selector
after it has started leaking, you would not believe the rust and junk
that accumulates inside this piece of equipment when it is never used.
And many folks never even test them during the condition inspection. So
they just sit there and corrode over time.
My contention is, if it is not used and can and will
cause pneumatic system problems, why not remove it from the system and
eliminate the potential problem once and for all.
Dennis
A. Dennis Savarese
334-285-6263
334-546-8182 (mobile)
http://www.yak-52.com/
Skype - Yakguy1
On 6/10/2013 4:41 PM, doug sapp wrote:
Mark,
It has been my experience that 75% or more of
the failures of QSF2A valves (3 port valves to you 52 types), and
12-5522-00 (5 port valve) are caused not by moisture/rust but by grit
and or pieces of rusted springs. Years of rusty springs and poor
maintenance has resulted in the majority of the air systems out there
being contaminated to some degree. To combat the base problem we
switched to all stainless steel springs in most all of our valves quite
some time ago. The secondary problem of contaminated pneumatic problems
is harder to solve as flushing the system out is very difficult. We are
experimenting with the installation of a second stainless steel
desiccant filter installed just prior to the rear gear valve, if
successful this should vastly extend the life of these expensive valves.
Best,
Doug
On Mon, Jun 10, 2013 at 12:10 PM, Bitterlich,
Mark G CIV NAVAIR, WD <mark.bitterlich@navy.mil
<mailto:mark.bitterlich@navy.mil <mailto:mark.bitterlich@navy.mil> >>
wrote:
Mark G CIV NAVAIR,
WD" <mark.bitterlich@navy.mil
<mailto:mark.bitterlich@navy.mil <mailto:mark.bitterlich@navy.mil> >>
Thanks for the expert advice Doug. I had
never even considered that.
By the way, there is an air filter of sorts
in the YAK-50. It is
located on the "T" air divider area where
all the check valves are
located (four of them). It appears to be a
circular device with
fittings at both ends and is possibly filled
with something like steel
wool. In any case, whatever was in mine
came all to pieces and junked
up the check valves.
Again: Good advice on a better filter.
Hmmm.
Mark
-----Original Message-----
From: owner-yak-list-server@matronics.com
<mailto:owner-yak-list-server@matronics.com>
<mailto:owner-yak-list-server@matronics.com
<mailto:owner-yak-list-server@matronics.com> >
[mailto: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 doug sapp
Sent: Monday, June 10, 2013 14:44
To: yak-list@matronics.com
<mailto:yak-list@matronics.com>
Subject: Re: Yak-List: Air system 'stuff'
Cory,
Mark is correct in all he said, however the
valve which you have
selected would be somewhat prone to problems
if your upstream air
system
is not 100% free of foreign material, such
as old std steel rusted
spring parts, dirt, grease, etc. These
valves are intended for use in
clean environments, not the somewhat dirtier
systems of the CJ6.
Placing the valve just after a high quality
filter would both extend
it's life and lower the probability of
reoccurring maintenance issues
I'm sure.
Best,
Doug
On Mon, Jun 10, 2013 at 11:12 AM,
Bitterlich, Mark G CIV NAVAIR, WD
<mark.bitterlich@navy.mil
<mailto:mark.bitterlich@navy.mil <mailto:mark.bitterlich@navy.mil> >>
wrote:
"Bitterlich, Mark G CIV
NAVAIR,
WD" <mark.bitterlich@navy.mil
<mailto:mark.bitterlich@navy.mil <mailto:mark.bitterlich@navy.mil> >>
Cory,
Sorry to disagree, but just in the
details. The valves that
you referenced are indeed pop-off valves.
They open to release or
by-pass pressure to keep at a maintained
value, exactly as does the
pressure relief valve that is in there now.
That said, they are
of much
better design and should work much better
than the ones that are in
there now, if you get one rated for the
pressure and flow for our
application.
Taken from the company's web site:
"Although this valve operates very
similar to a relief valve
which is usually designed to release
pressure quickly as soon as
the set
pressure is exceeded , this valve is
designed to relieve pressure more
gradually with changes in flow resulting in
fewer pressure spikes when
the valve opens and closes. This is a
direct-acting valve with an
adjustable spring operating against a piston
subjected to the inlet
pressure of the valve. Increasing the spring
compression will increase
the system or line pressure to be
maintained. Reducing the spring
compression will reduce the system or line
pressure to be
maintained. "
The summation:
"An increase in system pressure
beyond the set point will
cause
the main valve to open and relieve or bypass
the excess pressure."
This is EXACTLY how our present
valves work, but these are
easier to get and maintain.
Mark
p.s. Probably a darn good
replacement.
-----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> >
[mailto: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 Cory Robin
Sent: Sunday, June 09, 2013 10:09
To: yak-list@matronics.com
<mailto:yak-list@matronics.com>
Subject: Re: Yak-List: Air system
'stuff'
I found a source of a back pressure
relief valve. Rather
than
it popping off and reducing the pressure, it
maintains the pressure at
your pre-set value.
I've ordered a couple to test them.
https://straval.com/catlist-back-pressure-regulators/back-pressure-regul
<https://straval.com/catlist-back-pressure-regulators/back-pressure-regu
l>
ator-piston-angle-valve-threaded-bps-05
<https://straval.com/catlist-back-pressure-regulators/back-pressure-regu
l%0Aator-piston-angle-valve-threaded-bps-05
<https://straval.com/catlist-back-pressure-regulators/back-pressure-regu
l%0Aator-piston-angle-valve-threaded-bps-05> >
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Message 3
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| Subject: | Fwd: Parker pop-off in use on my CJ |
The Western made one I mentioned earlier was also from Kevin Kimball I
believe.
-----Original Message-----
From: owner-yak-list-server@matronics.com
[mailto:owner-yak-list-server@matronics.com] On Behalf Of Roger Kemp
M.D.
Sent: Tuesday, June 11, 2013 22:38
Subject: Yak-List: Fwd: Parker pop-off in use on my CJ
--> <viperdoc@mindspring.com>
Sent from my iPad
>>>
>>> Mark,
>>>
>>> I'm using a Parker pressure relief valve on my CJ, which I
obtained from Kevin Kimball. Check with them for prices if you are
interested at some point. My motives in exploring this were: A.
Cleaner engine compartment and; B. Longterm supportability of this
particularly critical item. (I think that supplies of NOS parts will
eventually dry up.); C. Thought it would be an easy installation---and
it was.
>>>
>>> The unit was factory preset and certified to pop off at 750psi---but
is easily adjustable. It also has an outlet port which I connected to
an unused smoke fitting on the left exhaust stack. It is mounted on the
firewall exactly where the original valve was; uses the stock CJ tubing
and fittings; with the pressure inlet and check valves mounted on an AN
cross. As the brass valve is heavier than the original, I drilled
three holes in the firewall and added plate nuts for adel clamps to hold
the valve. That was it for mods.
>>>
>>> This unit has proven to be reliable; stable in pressure maintenance;
and much cleaner in operation due to venting the bypass crud to the
exhaust...rather than dumping it on the firewall.
>>>
>>> I am out of the county and out of memory re: the Parker part #---
but will be back in country late next week. I will be glad to post
photos of my installation on the list should anyone be interested.
>>>
>>> Buddy Moman
>>> Northport, Alabama
>>> N5616N
>>>
>>>
>>>
>>>
>>>
>>> Sent from my iPad
Message 4
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| Subject: | Re: Air system 'stuff' |
Rob said:
> Beg to differ here, standard solenoids are inherently NOT polarity
sensitive.
Rob's dead right. I was dead wrong. Did not think it through, sorry
folks.
> Yes reversing the polarity does reverse the magnetic field, but the
induced polarity of the soft iron plunger core also reverses - so the
direction of force remains unchanged.
Yep, he's right again.
> This is not for their basic function, but because they have an
integral back-emf protection diode in parallel with the coil to suppress
the (potentially several hundred volt) negative spike produced as the
coil field collapses when the solenoid is turned off.
I doubt many on this list are familiar with reverse EMF caused by a
collapsing magnetic field, but you're right yet *AGAIN*.
Anyone reading this needs to take note of just whom I am speaking to:
Rob Rowe [yak-list@robrowe.plus.com]
I've not met too many people that know more than I do about YAK
Electrical systems. This gent is one of them.
Thanks Rob for the (polite) correction. Hey, when you're wrong, you're
wrong... and I was here! :-)
Take care,
Mark
Message 5
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| Subject: | Re: Air system 'stuff' |
Kind words Mark but you're the real hands-on expert, I'm just the theorist!
Reminds us though that the Yak/CJ electrical bus can be a hard place for modern
hi-tech avionics to survive, where your best friends are well maintained batteries
that help absorb electrical noise.
While the hi-tech kit will have transorbs and other protection devices fitted,
they're designed for occasional transients.
If your batteries are in poor shape then you could be subjecting the bus to frequent
transients from a couple of dozen relays & solenoids, let alone the shower
of sparks & carbon pile regulator.
So a small investment in looking after your batteries will help look after your
big investment in sophisticated avionics kit.
Cheers, Rob
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=402558#402558
Message 6
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| Subject: | Re: Air system 'stuff' |
Boy is that the understatement of the year! A lot of folks in the aerobat
ic world put really small mini batteries in the Sukhoi's to save weight. W
orks great! For a little while. Sometimes less than a year. Then becau
se they are constantly over-charged and otherwise "abused", they sag. Of co
urse then they droop. Then they fail to absorb spikes. Then crap starts b
lowing up all over the airplane.
Add an electric smoke pump, and radios and transponders bite the dust.
As I said, you need to listen tot his guy.
Mark
From: Rob Rowe
Sent: Wed 6/12/2013 12:18 PM
Subject: Yak-List: Re: Air system 'stuff'
Kind words Mark but you're the real hands-on expert, I'm just the theorist!
Reminds us though that the Yak/CJ electrical bus can be a hard place for mo
dern hi-tech avionics to survive, where your best friends are well maintain
ed batteries that help absorb electrical noise.
While the hi-tech kit will have transorbs and other protection devices fitt
ed, they're designed for occasional transients.
If your batteries are in poor shape then you could be subjecting the bus to
frequent transients from a couple of dozen relays & solenoids, let alone t
he shower of sparks & carbon pile regulator.
So a small investment in looking after your batteries will help look after
your big investment in sophisticated avionics kit.
Cheers, Rob
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=402558#402558
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