Today's Message Index:
----------------------
1. 08:06 AM - M14P technical data (Mark Jefferies YAK UK)
2. 08:50 AM - Yak-18 (Jim Selby)
3. 12:35 PM - Re: White Paper on Russian Generator System (Bitterlich, Mark G CIV Det Cherry Point, MALS-14 64E)
4. 01:08 PM - Spark Plug wiring conversion (Bitterlich, Mark G CIV Det Cherry Point, MALS-14 64E)
5. 01:21 PM - Re: White Paper on Russian Generator System (Jan Mevis)
6. 01:49 PM - Re: White Paper on Russian Generator System (Bitterlich, Mark G CIV Det Cherry Point, MALS-14 64E)
7. 01:51 PM - Re: M14P technical data (Bitterlich, Mark G CIV Det Cherry Point, MALS-14 64E)
Message 1
| INDEX | Back to Main INDEX |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
| Subject: | M14P technical data |
This file maybe of help to builders wanting to use the M14P engine in home
builds etc..
www.yakuk.com/m14p-tech-data.pdf 750 kb file
Mark Jefferies for YAK <http://www.yakuk.com> UK Ltd
Message 2
| INDEX | Back to Main INDEX |
| PREVIOUS | Skip to PREVIOUS Message |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
Good Morning,
I wanted to share some photos taken over the weekend by Tyson Rininger..
As you will see we had two Yak-18's/CJ-5's and two CJ-6's, of course there
is only one in the photo, sorry Bill.... ; )))) Tyson, as always did a
Fantastic Job and I wanted to say Thank you, I just wish I could've been
there this weekend to enjoy all the Fun.
We ( the Selby's ), are thinking of having another BBQ get together in the
next few months as we did two years ago and wanted to invite as many to join
the fun, I will try and see what Tyson's schedule looks like during that
Month... As soon as I know the date that will work for others I will post it
on the List... Thank you and enjoy the great photos..
Fly Safe
Best Regards
Jr
http://www.tvrphotography.com/gallery/thumbnails.php?album=176
Message 3
| INDEX | Back to Main INDEX |
| PREVIOUS | Skip to PREVIOUS Message |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
| Subject: | White Paper on Russian Generator System |
Jan, you are the second person I have heard from who has had radio noise
that could not be lived with after the conversion to automobile plugs,
and that fact is beginning to make me nervous about that change! As far
as your comments on the change, I have also heard that mag drops are
much less from everyone who has made the change as well. So, there is
obviously a lot of good things going on as well!
If you want to isolate the generator, simply remove the three wires from
the generator itself Jan. It is pretty easy to do... You simply take a
copy off that wraps around the generator near the top. The only warning
there is when you re-install that cover, it is easy to the threads out
of the "bar" that the screws go into. Careful there. Other than that,
you can simply unscrew the wires and and then start it up and listen for
your noise.
The truth is that turning the generator OFF is supposed to kill the
excitation field and should give you the same result as removing the
wires! However, if you want to be REALLY REALLY sure, you can remove
the wires. In fact, an even easier way would be to simply connect a
voltmeter to the generator itself after removing the cover as described
and then with the generator switch OFF, check for voltage with the
engine running. I never did this myself sorry to say. But you SHOULD
get nothing coming out of the generator. If you don't, there is no
sense in removing the wires.
Now... That said, there IS something that will make a TON of noise into
your radio that is easily overlooked. That is the TACH GENERATOR!
That thing is ALIVE all the time. There is no way to switch it OFF. It
is a 3 phase AC generator and it is absolutely ESSENTIAL that the
shielding on this wiring is perfect, and the fact is that the shielding
and other wiring at this plug routinely goes bad due to bad solder and
vibration. You can check whether this is your noise generator very
easily by simply taking the plug OFF of the tach generator on the left
side of your engine. It's a big black thing that screws into the
accessory gear box and is slightly down and to the left of the air start
distributor. It's definitely worth looking into.
Discussing the wires that Dennis's modification uses. These are
actually (as I am sure you are well aware of) wires that are sold for
racing engines. They are basically standard automobile spark plugs
wires, although a few millimeters larger and claim to have a better
conductor that standard carbon impregnated types. The wires that came
stock with our aircraft uses solid strands of wire, and it is hard to
imagine a better conductor than those! However, the rubber covering
these wires is inferior and breaks down and shorts out a lot. Next,
when you run solid core wires like the Russians (and Americans as well
did on Radial Engines) did, you have little antennas hooked to a
powerful generator. Consider that the very first radios in this world
used spark gap generators to create an RF signal and you will get the
idea here. Since that magneto generates high voltage and sparks, there
is wide band RF noise all over the place! To contain this, they built
the shielding and tubing system that they did, which if course was used
on EVERY radial engine out there!
Since that period of time, spark plug wires have gotten better and types
have been built that allow them to be run out in the open and not in
shielded tubes or conduits. This is what Dennis used. However, there
is NO QUESTION that they are going to create more noise than the
original system did, if the original system was properly maintained.
Dennis never did any real scientific checks of what his wiring system
was going to do. In order to check that, he would need specific test
equipment looking at the on-board radios, etc. At the very minimum a
spectrum analyzer so as to note any changes in the RF noise floor. He
didn't do that either. Bottom line, there is going to be more noise
with his system... But you also gain a TERRIFIC advantage over the
original system when ever you need to do any maintenance!
You may be able to adjust the internal setting of the radio's squelch
setting to over-come the noise problem. Some of these radios are
different from another, but I have one at home I can take pictures of
and show you how to adjust the squelch.
As for checking your cabling... Stop right there.
Simply do this: Get behind your radio and disconnect the antenna.
Start the engine and see if the noise is still there. If it IS, then
the noise is coming in via your cabling, and you very well might have
success in eliminating the noise if you use well shielded wire to
provide power from the battery to the radio as you are presently doing
since your switch failed. Be aware that it helps to use shielded wire
for both the positive AND the negative leads of the radio directly to
the battery, but I doubt you will fix your problem by doing that.
As I said, if the noise stays with the antenna disconnected AT THE
RADIO, then ok... But if the noise goes AWAY with the antenna
disconnected, then checking radio wiring is a waste of time.
By the way, to carefully hear and determine the noise that you are
getting ALWAYS run your checks with the squelch switch set to OFF, so
that you can clearly hear the full extent and type of noise that you are
dealing with.
If you go with the B&C system, I would advise AGAINST their very small
PMG generator, and would instead go with their SK35 and outboard voltage
regulator. This system comes with self-contained under/over voltage and
current protection built into the regulator. The SK35 will give you 35
amps of output. I think they also have a 45 or 50 amp version.
The Russian power system is indeed robust, and can be maintained, IF you
can find the spare parts, or repair what breaks yourself. I now have a
spare regulator, over-voltage unit, and can fix the 200D unit. Fixing
the Russian electrical system was a real exercise for me, and working
with Avionics is what I do for a living . Bottom line, if you ever
have a failure, I will be glad to help talk you through fixing it.
Mark
-----Original Message-----
From: owner-yak-list-server@matronics.com
[mailto:owner-yak-list-server@matronics.com] On Behalf Of Jan Mevis
Sent: Tuesday, February 20, 2007 1:47
Subject: RE: Yak-List: White Paper on Russian Generator System
I have a lot of radio noise (rattling noise). I suspected the voltage
regulation but I do have that loud noise also with the engine running
and master and other switches off (the radio is connected with a
separate breaker switch and fuse to the battery since the original radio
switch in the front panel is faulty; when I connect the radio to this
switch, the voltage over the radio drops to 3 volts).
I already did Dennis' plug conversion and I also replaced the high
tension lead of the booster coil. The engine runs perfectly smooth and
seems to have more power! Mag drops on 1 and on 2 at 70 % are small. So
this conversion is a very good thing. I also double checked the plug
wires and connexions, and strapped all the wires very securely so that
they don't move around when going negative. I also double-checked the
positioning of the mag caps, and cleaned them thoroughly with alcohol.
Since the engine runs so well, I hardly doubt the problem comes from the
conversion. But it's enigmatic since I had less noise with the old
Russian harness.
Recently I replaced my faulty ZIABRIK by a BRIZ. I tested this BRIZ on a
test bench before installing. The BRIZ works good when the engine is not
running. When it runs, there's a loud and annoying noise, as if I hear
the contacts of the mags. This only happens when the channel is clear.
When someone sends on the frequency, reception is perfect, and when I
send, they hear me 5 to 5 and in both cases I have almost no background
noise at all. I 'm going to check the cabling of the radio. Is it
possible that there's more EMI radiation of the ignition system since it
works "better" than before ? Perhaps there's a grounding problem ?
Anyway, I am impressed by what you did on your plane, I don't have the
knowledge nor the experience to do these kind of checks. I am
considering the B&C alternator + regulator and crowbar. Nevertheless the
whole Russian system seems to be very well designed and robust. I'd like
to keep the Yak 50 as original as possible, since it's so beautiful and
well designed.
Best regards,
Jan
________________________________
From: owner-yak-list-server@matronics.com
[mailto:owner-yak-list-server@matronics.com] On Behalf Of Yak Pilot
Sent: dinsdag 20 februari 2007 4:11
Subject: RE: Yak-List: White Paper on Russian Generator System
Jan, while this is fresh in my mind, what kind of problems are you
having with your 50?
Mark
Jan Mevis <jan.mevis@informavia.be> wrote:
What a great job, Mark, THANKS A LOT! This will help me solve
the Voltage
Regulation problems in my Yak 50 !
Jan Mevis
RA2005K
-----Original Message-----
From: owner-yak-list-server@matronics.com
[mailto:owner-yak-list-server@matronics.com] On Behalf Of
Bitterlich, Mark G
CIV Det Cherry Point, MALS-14 64E
Sent: woensdag 14 februari 2007 23:15
To: yak-list@matronics.com
Subject: Yak-List: White Paper on Russian Generator System
Cherry Point,
MALS-14 64E"
YAK-50 DC Power Generation and Troubleshooting by Mark
Bitterlich N50YK
Warning: This is a technical explanation of the power
generation,
regulation, and connection to aircraft main's of the typical
Yak-50/52/55 or Sukhoi-26/29/31. It is offered for those that
have at
least a general understanding of electronics. In all cases where
voltage from power supplies or from batteries were connected for
testing, circuit breakers were installed for safety. If anyone
tries to
follow these notes and duplicate my efforts, beware... if you
make
mistakes, or fail to include current limiting devices such as
light
bulbs and circuit breakers/fuses, you could easily cause serious
damage
to aircraft wiring. Ok.. so I had to cover my six. That said,
let's
move on.
I just spent the last few days learning my YAK-50's electrical
power
generation system. Thanks for all of those that sent schematics
of what
you had on hand. Every person contributed towards solving this
puzzle!
THANKS TO EVERYONE! The specifics in some regards focus on the
YAK-50,
although all of the Yak's and Sukhoi's use close to the same
design with
some slight wiring differences here and there. The important
thing is
that in most cases the parts are all identical. Of course this
does not
include "Westernized" designs, such as the 52W, 52TW, etc. Most
of
these have already had B&C (or other) products installed.
Power generation starts with the generator. This is a 3 KW
monster that
is capable of 100 amps output if properly cooled. This same
generator
can operate at 30 amps intermittent duty with no cooling air.
There are 3 wires on the generator, + positive, - negative, and
what the
Russians refer to as "Shunting Input". This input is actually
what
controls the generator output and is normally called "Field
Excitation".
This generator has a very well designed voltage regulation
system using
a carbon pile voltage regulator that controls field voltage
within a +2
/ -2 volt range. Voltage output is also stabilized with a
bucking
transformer known in Russian as "The Stabilizing Transformer".
If you
want to see examples of systems like this, go back to WW-II
designs and
you will see the exact same thing. In other words, this is 60
year old
technology and you need to go back and read about some of the
theory
involved, because like a bucking transformer, you rarely see
these
components in today's designs, but they were very common before
the
discovery of high current voltage regulation transistors.
Basically, most of the system is self starting and self
contained
regulating in a closed loop circuit. As soon as the generator
starts
spinning, it will put out voltage although at idle it will be
much lower
than 28 volts and it will not be connected into the aircraft
mains. As
RPM comes up and voltage rises, it will eventually stabilize at
the
rated voltage set by the carbon pile regulator. So, if you have
any
kind of problem, the first thing you will want to do is to gain
access
to the main generator terminals (you have to remove a cover on
the
generator) and hook a meter to the PLUS and MINUS connectors
with LONG
meter leads so that you can then safely check the voltage when
you start
the engine. If your generator is putting out voltage at idle,
give it a
quick boost to about 60% or so, and you should see your meter
come up to
around 28 voltage (plus or minus a few tenths) and then start
regulating. By "starting to regulate", I mean that the voltage
will stop
increasing as you continue to raise engine RPM If you have NO
output
voltage, shut the engine off, and then when you are eyeballing
the
inside of the generator, slowly move the prop. Does the
generator spin?
If so, then that is a good thing. If NOT, then you have sheared
a shaft,
replace the generator. If it does rotate, start it back up and
run a
test for Field Excitation Voltage. If you have excitation
voltage, then
again it is probably a bad generator. If you have no excitation,
there
are a few other things that could be wrong, such as the carbon
pile
regulator itself, or your over voltage breaker has tripped.
If at any time the generator puts out too much voltage, in the
realm of
31.5 volts or so (+/- 0.5 volt) then a circuit breaker will pop
on the
over/under voltage detection and protection unit. This is a
silver box
with two cannon plugs on it, that is in the nose inspection hole
left
side top in the 50, and somewhere else in the 52. I think it is
in the
forward cockpit underneath the instrument panel on the 52 but
don't
quote me. This unit has a rubber covered breaker button that you
can
reach in and reset if you have had an over-voltage condition. It
is
another thing to check anytime you have a problem, but typically
an
over-voltage trip is not common.
Moving on, the closed loop design has generator output going
first to
the stabilization transformer primary winding, then through that
directly to a component called "The Combined Device" also known
as the
DMR-200D. This component (the DMR-200D) is located in the gray
box
mounted on the firewall, top right side (looking forward) in the
50, and
by the Pilots right foot in the 52. Power goes through a MAIN
CONTACTOR
RELAY inside of the Combined Device ONLY IF CERTAIN CONDITIONS
ARE MET.
Here is where things get tricky.
Going back the Stabilizing Transformer for a minute, (just to
complete
the mental image) main output voltage of the generator goes
through the
primary winding as I already mentioned. This is just a few turns
of
wire, and offers VERY little resistance. Part of the secondary
windings
of this transformer system has outputs going to the voltage
regulator
and the over voltage box. The Voltage Regulator (official name
"R-27")
has outputs that feed back to control the generator excitation
field,
but it also has another output that goes over to the over
voltage box.
If the voltage is normal, the over voltage box feeds this same
voltage
(28 volts) back to pin B on the Combined Device. (Note, it looks
like a
"B" to me, that is the SHAPE of the marking, but it is actually
the
Russian letter "V".) This input voltage to pin B (V in Russian)
turns
on internal relay TKE-210B INSIDE of the Combined Unit. The
nomenclature of this relay means nothing since you can't see or
touch it
without taking the whole thing apart. Just realize that when you
put 28
volts to the connection marked "B" and a ground on the
connection marked
"-" (for minus), an internal relay will close and it will ENABLE
the
rest of the Combined Device. When this first relay closes, it
then
enables yet another system inside of the Combined Device known
as the
Polarization Relay. The "PR" is a special dual winding relay
that will
close only if current flows through the relay coil itself in the
proper
direction. If you try to flow current through this relay
backwards, it
simply won't work, and that is by design. It is SUPPOSED to do
that.
After the Polarization Relay (or PR) is enabled, it has a
circuit that
connects it to both the output main terminal and the input main
terminal. If the PR likes what it sees and closes, it then in
turn
provides power for yet ANOTHER Relay Coil inside of the Combined
Unit,
this one is known as the MAIN POWER CONTACTOR RELAY. This is the
big
boss relay in the whole thing, and when it closes, generator
power then
comes OUT of the Combined Unit and is fed to the aircraft MAIN
BUS BAR.
In other words, the MAIN POWER CONTACTOR actually connects the
large
input terminal to the large output terminal on the Combined
Unit.
What is really tricky to understand about this whole design is
the
Polarization Relay. Consider this: When you turn on the Aircraft
Master, Battery Voltage is fed to the MAIN BUS and as such it
also is
fed right down to the large OUTPUT terminal of the Combined
Unit. At
this point, the OUTPUT of the Combined Unit is not connected to
ANYTHING, because the MAIN CONTACTOR RELAY is still OPEN. Let's
consider our battery voltage to be a normal. As such, there is
about 24
volts on the Combined Units OUTPUT terminal post coming from the
battery
with the Aircraft Master switch turned on.
Now let's start the engine. The generator starts to spin.
Everything
works properly and as your engine speed comes up, so does
generator
voltage. This voltage is now fed to the Combined Unit's INPUT
power
terminal. Assuming 28 volts is fed to terminal "B" ("V" in
Russian)
thus ENABLING the Combined Unit, you will end up with battery
voltage on
one side of the Polarization Relay Coil and Generator Voltage on
the
OTHER side of the Polarization Relay Coil. Once there is a
difference
in voltage between battery voltage and generator voltage of
about 2
volts or so, and the generator voltage is HIGHER than the
battery
voltage, the Polarization Relay will CLOSE and will then in turn
close
the MAIN POWER CONTACTOR. Once the MAIN POWER CONTACTOR is
closed, 28
volts will be fed out terminal "C" which will then in turn close
yet
another relay (external to the Combined Device) and turn OFF the
Generator Light in the cockpit. It also then of course is
feeding
generator power directly to the aircraft main power bus.
Not done yet! There is yet ANOTHER relay coil in the Combined
Device
that is only enabled if the main enabling relay is powered up
through
terminal "B" as mentioned earlier. If terminal B has 28 volts,
then
terminal "6" becomes active (In Russian the "6" is actually the
Russian
letter "B"... confused yet? Easy to do. Just remember that as I
write
this, I refer to how they look to me and how they will look to
YOU!) If
you put a GROUND on this terminal "6" it will close yet another
relay
coil inside of the Combined Device and will REMOVE the generator
feed
voltage from the Polarization Relay thus making it INOPERATIVE!
Remember, if you disable the PR relay, then of course you have
also
disabled the MAIN CONTACTOR Relay, and thus, no voltage from the
generator will ever make it to the main aircraft bus. The ground
on
terminal "6" is usually controlled by the Generator Switch in
the
cockpit. And here is a warning... not all Russian designs work
like
this. From the Sukhoi to the Yak there are major wiring
differences in
how they wire this device, but the general concepts are the
same.
Operationally testing a system like this can be difficult at
best. I
tried a method that worked for me, but is offered with a Caveat
Emptor
warning... buyer beware, your mileage may vary and if you smoke
you
whole aircrafts electrical system, DO NOT blame me.
I disconnected all three leads from the generator. I used a
small 10
watt 28 VDC light bulb connected to the field winding wire to
ground. I
took the main generator PLUS and MINUS wires off of the
generator and
hooked them to a 28 volt variable DC power supply of about 20
amps
capacity. DO NOT LEAVE ANY OF THE AIRCRAFTS WIRES CONNECTED TO
THE
GENERATOR. The Field Winding can either float or have a SMALL 28
volt
DC light bulb hooked from it to ground.
You can now bring up voltage with the variable supply and check
for
voltages at proper locations without having to run the M-14
engine
itself. Initially set the variable supply to about 20 volts.
Look for
this 20 volts from the variable power supply at Combined Device
Input
terminal. (Right side bottom.. the BIG one). Turn on the
Aircraft
Master and look for BATTERY voltage on the OUTPUT terminal (left
side
middle of the Combined Device...the OTHER big one) Look for 20
volts on
terminal "B" and NO GROUND on terminal "6". Increase voltage on
the
variable supply to 28.0 volts even. As you come up on the
voltage, the
MAIN CONTACTOR should close with a loud WHACK. If not, you have
problems with the Combined Device.
Remove the Combined Device and bench check it. Here is how you
go about
doing that.
Some of the internal relays can be checked simply by listening
to them
click. No, this does not check the relay CONTACTS themselves,
but hey,
that comes later. Using a 28 volt source, either battery or
variable
supply, connect negative to the (-) terminal on the Combined
Device.
Connect 28 volts to terminal B. You should hear a relay click.
Disconnect from B. Now connect 28 volts to terminal A..(It looks
sort
of like an A anyway) It is on the right side above the large
INPUT
terminal. You should hear a LOUD relay closing, this is the main
contactor. Remove power from "A". Reapply power to "B"... again
you
hear a relay click. Leaving power applied to B, now hook a
grounded
wire to pin 6. This will close ANOTHER relay and you should be
able to
hear it click. You have now checked every relay coil in the
Combined
Device, other than the Polarization Relay, and the internal
relay
contacts themselves.
Find a 24 volt battery, or hook two 12 volt batteries in series.
Hook
the negative lead of the battery to the negative side of your
variable
power supply. Also connect a wire from this to the MINUS (-)
terminal
on the Combined Device. So all negatives (grounds/earths) are
now
common to each other. Hook the plus lead of the battery to the
OUTPUT
side of the Combined Device (Big terminal left side middle).
Variable power supply is now OFF.
Apply a wire from the 28 volt variable supply output (plus
voltage) to
the MAIN INPUT terminal (bottom right side). Also connect a
jumper from
this terminal to terminal "B". Put some voltmeters here and
there to
monitor whatever you feel like, but most certainly variable
power supply
output voltage. Increase the variable power supply output. When
it
reaches about 2 volts or so MORE than the battery voltage, the
MAIN
CONTACTOR will close, and you will now have connected your
variable
power supply to your test batteries.... and remember, when you
do this,
you have just created a battery charger, and the variable power
supply
will now try to start charging the batteries! If your variable
power
supply is too small, as soon as it starts to try and charge the
batteries through the now closed MAIN CONTACTOR RELAY, the
variable
power supply voltage will DROP. This will trigger the
Polarization
Relay to OPEN, then causing the MAIN CONTACTOR to open as well,
and
battery charging will cease... at which point the variable power
supply
will jump back up in voltage, the polarization relay will close
again
and the whole cycle will repeat. This event happens very fast
and will
make a lot of noise. So... warning... use a variable power
supply that
can handle more than a few amps without voltage drop for this
test. A
regulated supply that is variable as well would be ideal.
Ok, so what if the MAIN CONTACTOR does NOT energize when you
increase
the voltage? More than likely, you have problems with the
Polarization
Relay. This device seems to wear out first, and the word has it
that you
can take this Combined Device apart and adjust these contacts to
fix
this relay. I have not done that yet, but am getting ready to.
The Combined Device is a rather rare animal and sooner or later
is going
to give us all a certain amount of grief. Without a doubt, I
suspect if
we continue to fly these aircraft we are going to have to get
more of
these devices at a reasonable cost, or build our own, or convert
the
whole aircraft power generation system over to American made.
The
latter is probably the best idea over the long run.
So there you have it. The methods for testing this system are my
own
and not adopted from any other manual or article. Use them at
your own
risk. Feel free to copy and distribute this article as you see
fit, but
I would sincerely appreciate it if you left my name on it as the
author.
Addendum:
Every Russian aircraft owner should take a careful look at the
Carbon
Pile Voltage Regulator R-27. Vladimir Yastremski warned me about
this
device, and his warning was dead on accurate. This device is
mounted on
a very very loose shock mount and rocks and rolls all over the
place in
flight. It has wires that screw onto terminals and as the thing
moves,
it can cause a short circuit to certain
Message 4
| INDEX | Back to Main INDEX |
| PREVIOUS | Skip to PREVIOUS Message |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
| Subject: | Spark Plug wiring conversion |
Just one more comment if I may on here.
In re-reading my comments written to Jan, it might have appeared that I
was in some way denigrating Dennis's spark plug and spark plug wire
conversion kit for the M-14 engine. That would be a misunderstanding on
any readers part, because I strongly endorse the change, (have purchased
it myself) and believe that any small amount of noise floor increase
that probably will result, can be easily be taken care of with small
changes to squelch settings in the radio. Many users of Dennis's system
have reported no increase in radio noise at all! Only about 4 that I
have talked to have noticed a change. Of course, this kind of analysis
is not really scientific as I mentioned. To really check this issue
out, it would be necessary to set up test equipment and measure the
sensitivity and noise floor of the installed radio with the antenna
connected and the engine not running, and then again with the engine
running. All other possible sources of noise would also have to be
totally removed to make the test accurate. This is clearly not an easy
thing to do, and the equipment to do it properly costs thousands. That
said, the very best (traditional) way to shield RF type noise is with a
Faraday Shield. This approach consists of solid metal barriers, and
closely woven metal stranding that surrounds any RF noise source. The
original Russian system used this approach, and I believe that without
question it was a superior system for containing ignition noise. It
also was, (and is) the biggest pain in the tail to work on,
troubleshoot, repair, replace, etc., that can be imagined. It also
mandated the use of very expensive spark plugs.
So, my only point was (and is) that there may occasionally be a very
small trade-off between RF noise and the installation of the Taylor
spark plug wires used in the kit. To me, the juice is definitely worth
the squeeze.
Mark Bitterlich
N50YK
-----Original Message-----
From: owner-yak-list-server@matronics.com
[mailto:owner-yak-list-server@matronics.com] On Behalf Of Bitterlich,
Mark G CIV Det Cherry Point, MALS-14 64E
Sent: Tuesday, February 20, 2007 15:34
Subject: RE: Yak-List: White Paper on Russian Generator System
--> Point, MALS-14 64E" <mark.bitterlich@navy.mil>
Jan, you are the second person I have heard from who has had radio noise
that could not be lived with after the conversion to automobile plugs,
and that fact is beginning to make me nervous about that change! As far
as your comments on the change, I have also heard that mag drops are
much less from everyone who has made the change as well. So, there is
obviously a lot of good things going on as well!
If you want to isolate the generator, simply remove the three wires from
the generator itself Jan. It is pretty easy to do... You simply take a
copy off that wraps around the generator near the top. The only warning
there is when you re-install that cover, it is easy to the threads out
of the "bar" that the screws go into. Careful there. Other than that,
you can simply unscrew the wires and and then start it up and listen for
your noise.
The truth is that turning the generator OFF is supposed to kill the
excitation field and should give you the same result as removing the
wires! However, if you want to be REALLY REALLY sure, you can remove
the wires. In fact, an even easier way would be to simply connect a
voltmeter to the generator itself after removing the cover as described
and then with the generator switch OFF, check for voltage with the
engine running. I never did this myself sorry to say. But you SHOULD
get nothing coming out of the generator. If you don't, there is no
sense in removing the wires.
Now... That said, there IS something that will make a TON of noise into
your radio that is easily overlooked. That is the TACH GENERATOR!
That thing is ALIVE all the time. There is no way to switch it OFF. It
is a 3 phase AC generator and it is absolutely ESSENTIAL that the
shielding on this wiring is perfect, and the fact is that the shielding
and other wiring at this plug routinely goes bad due to bad solder and
vibration. You can check whether this is your noise generator very
easily by simply taking the plug OFF of the tach generator on the left
side of your engine. It's a big black thing that screws into the
accessory gear box and is slightly down and to the left of the air start
distributor. It's definitely worth looking into.
Discussing the wires that Dennis's modification uses. These are
actually (as I am sure you are well aware of) wires that are sold for
racing engines. They are basically standard automobile spark plugs
wires, although a few millimeters larger and claim to have a better
conductor that standard carbon impregnated types. The wires that came
stock with our aircraft uses solid strands of wire, and it is hard to
imagine a better conductor than those! However, the rubber covering
these wires is inferior and breaks down and shorts out a lot. Next,
when you run solid core wires like the Russians (and Americans as well
did on Radial Engines) did, you have little antennas hooked to a
powerful generator. Consider that the very first radios in this world
used spark gap generators to create an RF signal and you will get the
idea here. Since that magneto generates high voltage and sparks, there
is wide band RF noise all over the place! To contain this, they built
the shielding and tubing system that they did, which if course was used
on EVERY radial engine out there!
Since that period of time, spark plug wires have gotten better and types
have been built that allow them to be run out in the open and not in
shielded tubes or conduits. This is what Dennis used. However, there
is NO QUESTION that they are going to create more noise than the
original system did, if the original system was properly maintained.
Dennis never did any real scientific checks of what his wiring system
was going to do. In order to check that, he would need specific test
equipment looking at the on-board radios, etc. At the very minimum a
spectrum analyzer so as to note any changes in the RF noise floor. He
didn't do that either. Bottom line, there is going to be more noise
with his system... But you also gain a TERRIFIC advantage over the
original system when ever you need to do any maintenance!
You may be able to adjust the internal setting of the radio's squelch
setting to over-come the noise problem. Some of these radios are
different from another, but I have one at home I can take pictures of
and show you how to adjust the squelch.
As for checking your cabling... Stop right there.
Simply do this: Get behind your radio and disconnect the antenna.
Start the engine and see if the noise is still there. If it IS, then
the noise is coming in via your cabling, and you very well might have
success in eliminating the noise if you use well shielded wire to
provide power from the battery to the radio as you are presently doing
since your switch failed. Be aware that it helps to use shielded wire
for both the positive AND the negative leads of the radio directly to
the battery, but I doubt you will fix your problem by doing that.
As I said, if the noise stays with the antenna disconnected AT THE
RADIO, then ok... But if the noise goes AWAY with the antenna
disconnected, then checking radio wiring is a waste of time.
By the way, to carefully hear and determine the noise that you are
getting ALWAYS run your checks with the squelch switch set to OFF, so
that you can clearly hear the full extent and type of noise that you are
dealing with.
If you go with the B&C system, I would advise AGAINST their very small
PMG generator, and would instead go with their SK35 and outboard voltage
regulator. This system comes with self-contained under/over voltage and
current protection built into the regulator. The SK35 will give you 35
amps of output. I think they also have a 45 or 50 amp version.
The Russian power system is indeed robust, and can be maintained, IF you
can find the spare parts, or repair what breaks yourself. I now have a
spare regulator, over-voltage unit, and can fix the 200D unit. Fixing
the Russian electrical system was a real exercise for me, and working
with Avionics is what I do for a living . Bottom line, if you ever
have a failure, I will be glad to help talk you through fixing it.
Mark
-----Original Message-----
From: owner-yak-list-server@matronics.com
[mailto:owner-yak-list-server@matronics.com] On Behalf Of Jan Mevis
Sent: Tuesday, February 20, 2007 1:47
Subject: RE: Yak-List: White Paper on Russian Generator System
I have a lot of radio noise (rattling noise). I suspected the voltage
regulation but I do have that loud noise also with the engine running
and master and other switches off (the radio is connected with a
separate breaker switch and fuse to the battery since the original radio
switch in the front panel is faulty; when I connect the radio to this
switch, the voltage over the radio drops to 3 volts).
I already did Dennis' plug conversion and I also replaced the high
tension lead of the booster coil. The engine runs perfectly smooth and
seems to have more power! Mag drops on 1 and on 2 at 70 % are small. So
this conversion is a very good thing. I also double checked the plug
wires and connexions, and strapped all the wires very securely so that
they don't move around when going negative. I also double-checked the
positioning of the mag caps, and cleaned them thoroughly with alcohol.
Since the engine runs so well, I hardly doubt the problem comes from the
conversion. But it's enigmatic since I had less noise with the old
Russian harness.
Recently I replaced my faulty ZIABRIK by a BRIZ. I tested this BRIZ on a
test bench before installing. The BRIZ works good when the engine is not
running. When it runs, there's a loud and annoying noise, as if I hear
the contacts of the mags. This only happens when the channel is clear.
When someone sends on the frequency, reception is perfect, and when I
send, they hear me 5 to 5 and in both cases I have almost no background
noise at all. I 'm going to check the cabling of the radio. Is it
possible that there's more EMI radiation of the ignition system since it
works "better" than before ? Perhaps there's a grounding problem ?
Anyway, I am impressed by what you did on your plane, I don't have the
knowledge nor the experience to do these kind of checks. I am
considering the B&C alternator + regulator and crowbar. Nevertheless the
whole Russian system seems to be very well designed and robust. I'd like
to keep the Yak 50 as original as possible, since it's so beautiful and
well designed.
Best regards,
Jan
________________________________
From: owner-yak-list-server@matronics.com
[mailto:owner-yak-list-server@matronics.com] On Behalf Of Yak Pilot
Sent: dinsdag 20 februari 2007 4:11
Subject: RE: Yak-List: White Paper on Russian Generator System
Jan, while this is fresh in my mind, what kind of problems are you
having with your 50?
Mark
Jan Mevis <jan.mevis@informavia.be> wrote:
What a great job, Mark, THANKS A LOT! This will help me solve
the Voltage
Regulation problems in my Yak 50 !
Jan Mevis
RA2005K
-----Original Message-----
From: owner-yak-list-server@matronics.com
[mailto:owner-yak-list-server@matronics.com] On Behalf Of
Bitterlich, Mark G
CIV Det Cherry Point, MALS-14 64E
Sent: woensdag 14 februari 2007 23:15
To: yak-list@matronics.com
Subject: Yak-List: White Paper on Russian Generator System
Cherry Point,
MALS-14 64E"
YAK-50 DC Power Generation and Troubleshooting by Mark
Bitterlich N50YK
Warning: This is a technical explanation of the power
generation,
regulation, and connection to aircraft main's of the typical
Yak-50/52/55 or Sukhoi-26/29/31. It is offered for those that
have at
least a general understanding of electronics. In all cases where
voltage from power supplies or from batteries were connected for
testing, circuit breakers were installed for safety. If anyone
tries to
follow these notes and duplicate my efforts, beware... if you
make
mistakes, or fail to include current limiting devices such as
light
bulbs and circuit breakers/fuses, you could easily cause serious
damage
to aircraft wiring. Ok.. so I had to cover my six. That said,
let's
move on.
I just spent the last few days learning my YAK-50's electrical
power
generation system. Thanks for all of those that sent schematics
of what
you had on hand. Every person contributed towards solving this
puzzle!
THANKS TO EVERYONE! The specifics in some regards focus on the
YAK-50,
although all of the Yak's and Sukhoi's use close to the same
design with
some slight wiring differences here and there. The important
thing is
that in most cases the parts are all identical. Of course this
does not
include "Westernized" designs, such as the 52W, 52TW, etc. Most
of
these have already had B&C (or other) products installed.
Power generation starts with the generator. This is a 3 KW
monster that
is capable of 100 amps output if properly cooled. This same
generator
can operate at 30 amps intermittent duty with no cooling air.
There are 3 wires on the generator, + positive, - negative, and
what the
Russians refer to as "Shunting Input". This input is actually
what
controls the generator output and is normally called "Field
Excitation".
This generator has a very well designed voltage regulation
system using
a carbon pile voltage regulator that controls field voltage
within a +2
/ -2 volt range. Voltage output is also stabilized with a
bucking
transformer known in Russian as "The Stabilizing Transformer".
If you
want to see examples of systems like this, go back to WW-II
designs and
you will see the exact same thing. In other words, this is 60
year old
technology and you need to go back and read about some of the
theory
involved, because like a bucking transformer, you rarely see
these
components in today's designs, but they were very common before
the
discovery of high current voltage regulation transistors.
Basically, most of the system is self starting and self
contained
regulating in a closed loop circuit. As soon as the generator
starts
spinning, it will put out voltage although at idle it will be
much lower
than 28 volts and it will not be connected into the aircraft
mains. As
RPM comes up and voltage rises, it will eventually stabilize at
the
rated voltage set by the carbon pile regulator. So, if you have
any
kind of problem, the first thing you will want to do is to gain
access
to the main generator terminals (you have to remove a cover on
the
generator) and hook a meter to the PLUS and MINUS connectors
with LONG
meter leads so that you can then safely check the voltage when
you start
the engine. If your generator is putting out voltage at idle,
give it a
quick boost to about 60% or so, and you should see your meter
come up to
around 28 voltage (plus or minus a few tenths) and then start
regulating. By "starting to regulate", I mean that the voltage
will stop
increasing as you continue to raise engine RPM If you have NO
output
voltage, shut the engine off, and then when you are eyeballing
the
inside of the generator, slowly move the prop. Does the
generator spin?
If so, then that is a good thing. If NOT, then you have sheared
a shaft,
replace the generator. If it does rotate, start it back up and
run a
test for Field Excitation Voltage. If you have excitation
voltage, then
again it is probably a bad generator. If you have no excitation,
there
are a few other things that could be wrong, such as the carbon
pile
regulator itself, or your over voltage breaker has tripped.
If at any time the generator puts out too much voltage, in the
realm of
31.5 volts or so (+/- 0.5 volt) then a circuit breaker will pop
on the
over/under voltage detection and protection unit. This is a
silver box
with two cannon plugs on it, that is in the nose inspection hole
left
side top in the 50, and somewhere else in the 52. I think it is
in the
forward cockpit underneath the instrument panel on the 52 but
don't
quote me. This unit has a rubber covered breaker button that you
can
reach in and reset if you have had an over-voltage condition. It
is
another thing to check anytime you have a problem, but typically
an
over-voltage trip is not common.
Moving on, the closed loop design has generator output going
first to
the stabilization transformer primary winding, then through that
directly to a component called "The Combined Device" also known
as the
DMR-200D. This component (the DMR-200D) is located in the gray
box
mounted on the firewall, top right side (looking forward) in the
50, and
by the Pilots right foot in the 52. Power goes through a MAIN
CONTACTOR
RELAY inside of the Combined Device ONLY IF CERTAIN CONDITIONS
ARE MET.
Here is where things get tricky.
Going back the Stabilizing Transformer for a minute, (just to
complete
the mental image) main output voltage of the generator goes
through the
primary winding as I already mentioned. This is just a few turns
of
wire, and offers VERY little resistance. Part of the secondary
windings
of this transformer system has outputs going to the voltage
regulator
and the over voltage box. The Voltage Regulator (official name
"R-27")
has outputs that feed back to control the generator excitation
field,
but it also has another output that goes over to the over
voltage box.
If the voltage is normal, the over voltage box feeds this same
voltage
(28 volts) back to pin B on the Combined Device. (Note, it looks
like a
"B" to me, that is the SHAPE of the marking, but it is actually
the
Russian letter "V".) This input voltage to pin B (V in Russian)
turns
on internal relay TKE-210B INSIDE of the Combined Unit. The
nomenclature of this relay means nothing since you can't see or
touch it
without taking the whole thing apart. Just realize that when you
put 28
volts to the connection marked "B" and a ground on the
connection marked
"-" (for minus), an internal relay will close and it will ENABLE
the
rest of the Combined Device. When this first relay closes, it
then
enables yet another system inside of the Combined Device known
as the
Polarization Relay. The "PR" is a special dual winding relay
that will
close only if current flows through the relay coil itself in the
proper
direction. If you try to flow current through this relay
backwards, it
simply won't work, and that is by design. It is SUPPOSED to do
that.
After the Polarization Relay (or PR) is enabled, it has a
circuit that
connects it to both the output main terminal and the input main
terminal. If the PR likes what it sees and closes, it then in
turn
provides power for yet ANOTHER Relay Coil inside of the Combined
Unit,
this one is known as the MAIN POWER CONTACTOR RELAY. This is the
big
boss relay in the whole thing, and when it closes, generator
power then
comes OUT of the Combined Unit and is fed to the aircraft MAIN
BUS BAR.
In other words, the MAIN POWER CONTACTOR actually connects the
large
input terminal to the large output terminal on the Combined
Unit.
What is really tricky to understand about this whole design is
the
Polarization Relay. Consider this: When you turn on the Aircraft
Master, Battery Voltage is fed to the MAIN BUS and as such it
also is
fed right down to the large OUTPUT terminal of the Combined
Unit. At
this point, the OUTPUT of the Combined Unit is not connected to
ANYTHING, because the MAIN CONTACTOR RELAY is still OPEN. Let's
consider our battery voltage to be a normal. As such, there is
about 24
volts on the Combined Units OUTPUT terminal post coming from the
battery
with the Aircraft Master switch turned on.
Now let's start the engine. The generator starts to spin.
Everything
works properly and as your engine speed comes up, so does
generator
voltage. This voltage is now fed to the Combined Unit's INPUT
power
terminal. Assuming 28 volts is fed to terminal "B" ("V" in
Russian)
thus ENABLING the Combined Unit, you will end up with battery
voltage on
one side of the Polarization Relay Coil and Generator Voltage on
the
OTHER side of the Polarization Relay Coil. Once there is a
difference
in voltage between battery voltage and generator voltage of
about 2
volts or so, and the generator voltage is HIGHER than the
battery
voltage, the Polarization Relay will CLOSE and will then in turn
close
the MAIN POWER CONTACTOR. Once the MAIN POWER CONTACTOR is
closed, 28
volts will be fed out terminal "C" which will then in turn close
yet
another relay (external to the Combined Device) and turn OFF the
Generator Light in the cockpit. It also then of course is
feeding
generator power directly to the aircraft main power bus.
Not done yet! There is yet ANOTHER relay coil in the Combined
Device
that is only enabled if the main enabling relay is powered up
through
terminal "B" as mentioned earlier. If terminal B has 28 volts,
then
terminal "6" becomes active (In Russian the "6" is actually the
Russian
letter "B"... confused yet? Easy to do. Just remember that as I
write
this, I refer to how they look to me and how they will look to
YOU!) If
you put a GROUND on this terminal "6" it will close yet another
relay
coil inside of the Combined Device and will REMOVE the generator
feed
voltage from the Polarization Relay thus making it INOPERATIVE!
Remember, if you disable the PR relay, then of course you have
also
disabled the MAIN CONTACTOR Relay, and thus, no voltage from the
generator will ever make it to the main aircraft bus. The ground
on
terminal "6" is usually controlled by the Generator Switch in
the
cockpit. And here is a warning... not all Russian designs work
like
this. From the Sukhoi to the Yak there are major wiring
differences in
how they wire this device, but the general concepts are the
same.
Operationally testing a system like this can be difficult at
best. I
tried a method that worked for me, but is offered with a Caveat
Emptor
warning... buyer beware, your mileage may vary and if you smoke
you
whole aircrafts electrical system, DO NOT blame me.
I disconnected all three leads from the generator. I used a
small 10
watt 28 VDC light bulb connected to the field winding wire to
ground. I
took the main generator PLUS and MINUS wires off of the
generator and
hooked them to a 28 volt variable DC power supply of about 20
amps
capacity. DO NOT LEAVE ANY OF THE AIRCRAFTS WIRES CONNECTED TO
THE
GENERATOR. The Field Winding can either float or have a SMALL 28
volt
DC light bulb hooked from it to ground.
You can now bring up voltage with the variable supply and check
for
voltages at proper locations without having to run the M-14
engine
itself. Initially set the variable supply to about 20 volts.
Look for
this 20 volts from the variable power supply at Combined Device
Input
terminal. (Right side bottom.. the BIG one). Turn on the
Aircraft
Master and look for BATTERY voltage on the OUTPUT terminal (left
side
middle of the Combined Device...the OTHER big one) Look for 20
volts on
terminal "B" and NO GROUND on terminal "6". Increase voltage on
the
variable supply to 28.0 volts even. As you come up on the
voltage, the
MAIN CONTACTOR should close with a loud WHACK. If not, you have
problems with the Combined Device.
Remove the Combined Device and bench check it. Here is how you
go about
doing that.
Some of the internal relays can be checked simply by listening
to them
click. No, this does not check the relay CONTACTS themselves,
but hey,
that comes later. Using a 28 volt source, either battery or
variable
supply, connect negative to the (-) terminal on the Combined
Device.
Connect 28 volts to terminal B. You should hear a relay click.
Disconnect from B. Now connect 28 volts to terminal A..(It looks
sort
of like an A anyway) It is on the right side above the large
INPUT
terminal. You should hear a LOUD relay closing, this is the main
contactor. Remove power from "A". Reapply power to "B"... again
you
hear a relay click. Leaving power applied to B, now hook a
grounded
wire to pin 6. This will close ANOTHER relay and you should be
able to
hear it click. You have now checked every relay coil in the
Combined
Device, other than the Polarization Relay, and the internal
relay
contacts themselves.
Find a 24 volt battery, or hook two 12 volt batteries in series.
Hook
the negative lead of the battery to the negative side of your
variable
power supply. Also connect a wire from this to the MINUS (-)
terminal
on the Combined Device. So all negatives (grounds/earths) are
now
common to each other. Hook the plus lead of the battery to the
OUTPUT
side of the Combined Device (Big terminal left side middle).
Variable power supply is now OFF.
Apply a wire from the 28 volt variable supply output (plus
voltage) to
the MAIN INPUT terminal (bottom right side). Also connect a
jumper from
this terminal to terminal "B". Put some voltmeters here and
there to
monitor whatever you feel like, but most certainly variable
power supply
output voltage. Increase the variable power supply output. When
it
reaches about 2 volts or so MORE than the battery voltage, the
MAIN
CONTACTOR will close, and you will now have connected your
variable
power supply to your test batteries.... and remember, when you
do this,
you have just created a battery charger, and the variable power
supply
will now try to start charging the batteries! If your variable
power
supply is too small, as soon as it starts to try and charge the
batteries through the now closed MAIN CONTACTOR RELAY, the
variable
power supply voltage will DROP. This will trigger the
Polarization
Relay to OPEN, then causing the MAIN CONTACTOR to open as well,
and
battery charging will cease... at which point the variable power
supply
will jump back up in voltage, the polarization relay will close
again
and the whole cycle will repeat. This event happens very fast
and will
make a lot of noise. So... warning... use a variable power
supply that
can handle more than a few amps without voltage drop for this
test. A
regulated supply that is variable as well would be ideal.
Ok, so what if the MAIN CONTACTOR does NOT energize when you
increase
the voltage? More than likely, you have problems with the
Polarization
Relay. This device seems to wear out first, and the word has it
that you
can take this Combined Device apart and adjust these contacts to
fix
this relay. I have not done that yet, but am getting ready to.
The Combined Device is a rather rare animal and sooner or later
is going
to give us all a certain amount of grief. Without a doubt, I
suspect if
we continue to fly these aircraft we are going to have to get
more of
these devices at a reasonable cost, or build our own, or convert
the
whole aircraft power generation system over to American made.
The
latter is probably the best idea over the long run.
So there you have it. The methods for testing this system are my
own
and not adopted from any other manual or article. Use them at
your own
risk. Feel free to copy and distribute this article as you see
fit, but
I would sincerely appreciate it if you left my name on it as the
author.
Addendum:
Every Russian aircraft owner should take a careful look at the
Carbon
Pile Voltage Regulator R-27. Vladimir Yastremski warned me about
this
device, and his warning was dead on accurate. This device is
mounted on
a very very loose shock mount and rocks and rolls all over the
place in
flight. It has wires that screw onto terminals and as the thing
moves,
it can cause a short circuit to certain
Message 5
| INDEX | Back to Main INDEX |
| PREVIOUS | Skip to PREVIOUS Message |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
| Subject: | White Paper on Russian Generator System |
Thanks Mark,
I'll follow your advise and check the antenna cabling, but I also will
verify the different groundings of the radio system(the casing, the
connectors on the left side of the cockpit, and the connectors of the
push-to-talk switch behind the throttle. I'll fix a grounding wire thru all
those ground connectors right up to the battery to make certain that there's
no ground loop. A second thing that I'll try (if this does not solve the
problem) is a noise filter on the DC line to the radio.
Anyway, I am CERTAIN that the silicone plug wires from Dennis' kit are a
very good thing. The engine simply runs better (and only 15 flying hours
before I had installed NEW Russian spark plugs + my mags were serviced in
Nov 2006 by a very good Russian mechanic, Sergei Makarov).
With the old Russian ignition harness I also had some noise but it was less
apparent. The new American cables give a better spark, and thus I suppose
they draw more power from the mags, so the fact there's more EMI radiation
coming from the mag POINTS is feasible.
The wiring of my radio is not perfect. I replaced the original Ziabrik by a
Briz a few months ago, but the Briz cabling was entirely different. I kept
the old Ziabrik cables and did put the new Briz cables alongside. This is
probably far from ideal but as you know, this is not an easy job.
I also will check the Tach generator as you suggested. As a matter of fact
I'll verify all non-plug wires on the engine side of the firewall(I noticed
that my carburettor temperature cable is in a bad shape, for instance).
I'll keep you informed about the test results,
Best regards,
Jan
-----Original Message-----
From: owner-yak-list-server@matronics.com
[mailto:owner-yak-list-server@matronics.com] On Behalf Of Bitterlich, Mark G
CIV Det Cherry Point, MALS-14 64E
Sent: dinsdag 20 februari 2007 21:34
Subject: RE: Yak-List: White Paper on Russian Generator System
MALS-14 64E" <mark.bitterlich@navy.mil>
Jan, you are the second person I have heard from who has had radio noise
that could not be lived with after the conversion to automobile plugs,
and that fact is beginning to make me nervous about that change! As far
as your comments on the change, I have also heard that mag drops are
much less from everyone who has made the change as well. So, there is
obviously a lot of good things going on as well!
If you want to isolate the generator, simply remove the three wires from
the generator itself Jan. It is pretty easy to do... You simply take a
copy off that wraps around the generator near the top. The only warning
there is when you re-install that cover, it is easy to the threads out
of the "bar" that the screws go into. Careful there. Other than that,
you can simply unscrew the wires and and then start it up and listen for
your noise.
The truth is that turning the generator OFF is supposed to kill the
excitation field and should give you the same result as removing the
wires! However, if you want to be REALLY REALLY sure, you can remove
the wires. In fact, an even easier way would be to simply connect a
voltmeter to the generator itself after removing the cover as described
and then with the generator switch OFF, check for voltage with the
engine running. I never did this myself sorry to say. But you SHOULD
get nothing coming out of the generator. If you don't, there is no
sense in removing the wires.
Now... That said, there IS something that will make a TON of noise into
your radio that is easily overlooked. That is the TACH GENERATOR!
That thing is ALIVE all the time. There is no way to switch it OFF. It
is a 3 phase AC generator and it is absolutely ESSENTIAL that the
shielding on this wiring is perfect, and the fact is that the shielding
and other wiring at this plug routinely goes bad due to bad solder and
vibration. You can check whether this is your noise generator very
easily by simply taking the plug OFF of the tach generator on the left
side of your engine. It's a big black thing that screws into the
accessory gear box and is slightly down and to the left of the air start
distributor. It's definitely worth looking into.
Discussing the wires that Dennis's modification uses. These are
actually (as I am sure you are well aware of) wires that are sold for
racing engines. They are basically standard automobile spark plugs
wires, although a few millimeters larger and claim to have a better
conductor that standard carbon impregnated types. The wires that came
stock with our aircraft uses solid strands of wire, and it is hard to
imagine a better conductor than those! However, the rubber covering
these wires is inferior and breaks down and shorts out a lot. Next,
when you run solid core wires like the Russians (and Americans as well
did on Radial Engines) did, you have little antennas hooked to a
powerful generator. Consider that the very first radios in this world
used spark gap generators to create an RF signal and you will get the
idea here. Since that magneto generates high voltage and sparks, there
is wide band RF noise all over the place! To contain this, they built
the shielding and tubing system that they did, which if course was used
on EVERY radial engine out there!
Since that period of time, spark plug wires have gotten better and types
have been built that allow them to be run out in the open and not in
shielded tubes or conduits. This is what Dennis used. However, there
is NO QUESTION that they are going to create more noise than the
original system did, if the original system was properly maintained.
Dennis never did any real scientific checks of what his wiring system
was going to do. In order to check that, he would need specific test
equipment looking at the on-board radios, etc. At the very minimum a
spectrum analyzer so as to note any changes in the RF noise floor. He
didn't do that either. Bottom line, there is going to be more noise
with his system... But you also gain a TERRIFIC advantage over the
original system when ever you need to do any maintenance!
You may be able to adjust the internal setting of the radio's squelch
setting to over-come the noise problem. Some of these radios are
different from another, but I have one at home I can take pictures of
and show you how to adjust the squelch.
As for checking your cabling... Stop right there.
Simply do this: Get behind your radio and disconnect the antenna.
Start the engine and see if the noise is still there. If it IS, then
the noise is coming in via your cabling, and you very well might have
success in eliminating the noise if you use well shielded wire to
provide power from the battery to the radio as you are presently doing
since your switch failed. Be aware that it helps to use shielded wire
for both the positive AND the negative leads of the radio directly to
the battery, but I doubt you will fix your problem by doing that.
As I said, if the noise stays with the antenna disconnected AT THE
RADIO, then ok... But if the noise goes AWAY with the antenna
disconnected, then checking radio wiring is a waste of time.
By the way, to carefully hear and determine the noise that you are
getting ALWAYS run your checks with the squelch switch set to OFF, so
that you can clearly hear the full extent and type of noise that you are
dealing with.
If you go with the B&C system, I would advise AGAINST their very small
PMG generator, and would instead go with their SK35 and outboard voltage
regulator. This system comes with self-contained under/over voltage and
current protection built into the regulator. The SK35 will give you 35
amps of output. I think they also have a 45 or 50 amp version.
The Russian power system is indeed robust, and can be maintained, IF you
can find the spare parts, or repair what breaks yourself. I now have a
spare regulator, over-voltage unit, and can fix the 200D unit. Fixing
the Russian electrical system was a real exercise for me, and working
with Avionics is what I do for a living . Bottom line, if you ever
have a failure, I will be glad to help talk you through fixing it.
Mark
-----Original Message-----
From: owner-yak-list-server@matronics.com
[mailto:owner-yak-list-server@matronics.com] On Behalf Of Jan Mevis
Sent: Tuesday, February 20, 2007 1:47
Subject: RE: Yak-List: White Paper on Russian Generator System
I have a lot of radio noise (rattling noise). I suspected the voltage
regulation but I do have that loud noise also with the engine running
and master and other switches off (the radio is connected with a
separate breaker switch and fuse to the battery since the original radio
switch in the front panel is faulty; when I connect the radio to this
switch, the voltage over the radio drops to 3 volts).
I already did Dennis' plug conversion and I also replaced the high
tension lead of the booster coil. The engine runs perfectly smooth and
seems to have more power! Mag drops on 1 and on 2 at 70 % are small. So
this conversion is a very good thing. I also double checked the plug
wires and connexions, and strapped all the wires very securely so that
they don't move around when going negative. I also double-checked the
positioning of the mag caps, and cleaned them thoroughly with alcohol.
Since the engine runs so well, I hardly doubt the problem comes from the
conversion. But it's enigmatic since I had less noise with the old
Russian harness.
Recently I replaced my faulty ZIABRIK by a BRIZ. I tested this BRIZ on a
test bench before installing. The BRIZ works good when the engine is not
running. When it runs, there's a loud and annoying noise, as if I hear
the contacts of the mags. This only happens when the channel is clear.
When someone sends on the frequency, reception is perfect, and when I
send, they hear me 5 to 5 and in both cases I have almost no background
noise at all. I 'm going to check the cabling of the radio. Is it
possible that there's more EMI radiation of the ignition system since it
works "better" than before ? Perhaps there's a grounding problem ?
Anyway, I am impressed by what you did on your plane, I don't have the
knowledge nor the experience to do these kind of checks. I am
considering the B&C alternator + regulator and crowbar. Nevertheless the
whole Russian system seems to be very well designed and robust. I'd like
to keep the Yak 50 as original as possible, since it's so beautiful and
well designed.
Best regards,
Jan
________________________________
From: owner-yak-list-server@matronics.com
[mailto:owner-yak-list-server@matronics.com] On Behalf Of Yak Pilot
Sent: dinsdag 20 februari 2007 4:11
Subject: RE: Yak-List: White Paper on Russian Generator System
Jan, while this is fresh in my mind, what kind of problems are you
having with your 50?
Mark
Jan Mevis <jan.mevis@informavia.be> wrote:
What a great job, Mark, THANKS A LOT! This will help me solve
the Voltage
Regulation problems in my Yak 50 !
Jan Mevis
RA2005K
-----Original Message-----
From: owner-yak-list-server@matronics.com
[mailto:owner-yak-list-server@matronics.com] On Behalf Of
Bitterlich, Mark G
CIV Det Cherry Point, MALS-14 64E
Sent: woensdag 14 februari 2007 23:15
To: yak-list@matronics.com
Subject: Yak-List: White Paper on Russian Generator System
Cherry Point,
MALS-14 64E"
YAK-50 DC Power Generation and Troubleshooting by Mark
Bitterlich N50YK
Warning: This is a technical explanation of the power
generation,
regulation, and connection to aircraft main's of the typical
Yak-50/52/55 or Sukhoi-26/29/31. It is offered for those that
have at
least a general understanding of electronics. In all cases where
voltage from power supplies or from batteries were connected for
testing, circuit breakers were installed for safety. If anyone
tries to
follow these notes and duplicate my efforts, beware... if you
make
mistakes, or fail to include current limiting devices such as
light
bulbs and circuit breakers/fuses, you could easily cause serious
damage
to aircraft wiring. Ok.. so I had to cover my six. That said,
let's
move on.
I just spent the last few days learning my YAK-50's electrical
power
generation system. Thanks for all of those that sent schematics
of what
you had on hand. Every person contributed towards solving this
puzzle!
THANKS TO EVERYONE! The specifics in some regards focus on the
YAK-50,
although all of the Yak's and Sukhoi's use close to the same
design with
some slight wiring differences here and there. The important
thing is
that in most cases the parts are all identical. Of course this
does not
include "Westernized" designs, such as the 52W, 52TW, etc. Most
of
these have already had B&C (or other) products installed.
Power generation starts with the generator. This is a 3 KW
monster that
is capable of 100 amps output if properly cooled. This same
generator
can operate at 30 amps intermittent duty with no cooling air.
There are 3 wires on the generator, + positive, - negative, and
what the
Russians refer to as "Shunting Input". This input is actually
what
controls the generator output and is normally called "Field
Excitation".
This generator has a very well designed voltage regulation
system using
a carbon pile voltage regulator that controls field voltage
within a +2
/ -2 volt range. Voltage output is also stabilized with a
bucking
transformer known in Russian as "The Stabilizing Transformer".
If you
want to see examples of systems like this, go back to WW-II
designs and
you will see the exact same thing. In other words, this is 60
year old
technology and you need to go back and read about some of the
theory
involved, because like a bucking transformer, you rarely see
these
components in today's designs, but they were very common before
the
discovery of high current voltage regulation transistors.
Basically, most of the system is self starting and self
contained
regulating in a closed loop circuit. As soon as the generator
starts
spinning, it will put out voltage although at idle it will be
much lower
than 28 volts and it will not be connected into the aircraft
mains. As
RPM comes up and voltage rises, it will eventually stabilize at
the
rated voltage set by the carbon pile regulator. So, if you have
any
kind of problem, the first thing you will want to do is to gain
access
to the main generator terminals (you have to remove a cover on
the
generator) and hook a meter to the PLUS and MINUS connectors
with LONG
meter leads so that you can then safely check the voltage when
you start
the engine. If your generator is putting out voltage at idle,
give it a
quick boost to about 60% or so, and you should see your meter
come up to
around 28 voltage (plus or minus a few tenths) and then start
regulating. By "starting to regulate", I mean that the voltage
will stop
increasing as you continue to raise engine RPM If you have NO
output
voltage, shut the engine off, and then when you are eyeballing
the
inside of the generator, slowly move the prop. Does the
generator spin?
If so, then that is a good thing. If NOT, then you have sheared
a shaft,
replace the generator. If it does rotate, start it back up and
run a
test for Field Excitation Voltage. If you have excitation
voltage, then
again it is probably a bad generator. If you have no excitation,
there
are a few other things that could be wrong, such as the carbon
pile
regulator itself, or your over voltage breaker has tripped.
If at any time the generator puts out too much voltage, in the
realm of
31.5 volts or so (+/- 0.5 volt) then a circuit breaker will pop
on the
over/under voltage detection and protection unit. This is a
silver box
with two cannon plugs on it, that is in the nose inspection hole
left
side top in the 50, and somewhere else in the 52. I think it is
in the
forward cockpit underneath the instrument panel on the 52 but
don't
quote me. This unit has a rubber covered breaker button that you
can
reach in and reset if you have had an over-voltage condition. It
is
another thing to check anytime you have a problem, but typically
an
over-voltage trip is not common.
Moving on, the closed loop design has generator output going
first to
the stabilization transformer primary winding, then through that
directly to a component called "The Combined Device" also known
as the
DMR-200D. This component (the DMR-200D) is located in the gray
box
mounted on the firewall, top right side (looking forward) in the
50, and
by the Pilots right foot in the 52. Power goes through a MAIN
CONTACTOR
RELAY inside of the Combined Device ONLY IF CERTAIN CONDITIONS
ARE MET.
Here is where things get tricky.
Going back the Stabilizing Transformer for a minute, (just to
complete
the mental image) main output voltage of the generator goes
through the
primary winding as I already mentioned. This is just a few turns
of
wire, and offers VERY little resistance. Part of the secondary
windings
of this transformer system has outputs going to the voltage
regulator
and the over voltage box. The Voltage Regulator (official name
"R-27")
has outputs that feed back to control the generator excitation
field,
but it also has another output that goes over to the over
voltage box.
If the voltage is normal, the over voltage box feeds this same
voltage
(28 volts) back to pin B on the Combined Device. (Note, it looks
like a
"B" to me, that is the SHAPE of the marking, but it is actually
the
Russian letter "V".) This input voltage to pin B (V in Russian)
turns
on internal relay TKE-210B INSIDE of the Combined Unit. The
nomenclature of this relay means nothing since you can't see or
touch it
without taking the whole thing apart. Just realize that when you
put 28
volts to the connection marked "B" and a ground on the
connection marked
"-" (for minus), an internal relay will close and it will ENABLE
the
rest of the Combined Device. When this first relay closes, it
then
enables yet another system inside of the Combined Device known
as the
Polarization Relay. The "PR" is a special dual winding relay
that will
close only if current flows through the relay coil itself in the
proper
direction. If you try to flow current through this relay
backwards, it
simply won't work, and that is by design. It is SUPPOSED to do
that.
After the Polarization Relay (or PR) is enabled, it has a
circuit that
connects it to both the output main terminal and the input main
terminal. If the PR likes what it sees and closes, it then in
turn
provides power for yet ANOTHER Relay Coil inside of the Combined
Unit,
this one is known as the MAIN POWER CONTACTOR RELAY. This is the
big
boss relay in the whole thing, and when it closes, generator
power then
comes OUT of the Combined Unit and is fed to the aircraft MAIN
BUS BAR.
In other words, the MAIN POWER CONTACTOR actually connects the
large
input terminal to the large output terminal on the Combined
Unit.
What is really tricky to understand about this whole design is
the
Polarization Relay. Consider this: When you turn on the Aircraft
Master, Battery Voltage is fed to the MAIN BUS and as such it
also is
fed right down to the large OUTPUT terminal of the Combined
Unit. At
this point, the OUTPUT of the Combined Unit is not connected to
ANYTHING, because the MAIN CONTACTOR RELAY is still OPEN. Let's
consider our battery voltage to be a normal. As such, there is
about 24
volts on the Combined Units OUTPUT terminal post coming from the
battery
with the Aircraft Master switch turned on.
Now let's start the engine. The generator starts to spin.
Everything
works properly and as your engine speed comes up, so does
generator
voltage. This voltage is now fed to the Combined Unit's INPUT
power
terminal. Assuming 28 volts is fed to terminal "B" ("V" in
Russian)
thus ENABLING the Combined Unit, you will end up with battery
voltage on
one side of the Polarization Relay Coil and Generator Voltage on
the
OTHER side of the Polarization Relay Coil. Once there is a
difference
in voltage between battery voltage and generator voltage of
about 2
volts or so, and the generator voltage is HIGHER than the
battery
voltage, the Polarization Relay will CLOSE and will then in turn
close
the MAIN POWER CONTACTOR. Once the MAIN POWER CONTACTOR is
closed, 28
volts will be fed out terminal "C" which will then in turn close
yet
another relay (external to the Combined Device) and turn OFF the
Generator Light in the cockpit. It also then of course is
feeding
generator power directly to the aircraft main power bus.
Not done yet! There is yet ANOTHER relay coil in the Combined
Device
that is only enabled if the main enabling relay is powered up
through
terminal "B" as mentioned earlier. If terminal B has 28 volts,
then
terminal "6" becomes active (In Russian the "6" is actually the
Russian
letter "B"... confused yet? Easy to do. Just remember that as I
write
this, I refer to how they look to me and how they will look to
YOU!) If
you put a GROUND on this terminal "6" it will close yet another
relay
coil inside of the Combined Device and will REMOVE the generator
feed
voltage from the Polarization Relay thus making it INOPERATIVE!
Remember, if you disable the PR relay, then of course you have
also
disabled the MAIN CONTACTOR Relay, and thus, no voltage from the
generator will ever make it to the main aircraft bus. The ground
on
terminal "6" is usually controlled by the Generator Switch in
the
cockpit. And here is a warning... not all Russian designs work
like
this. From the Sukhoi to the Yak there are major wiring
differences in
how they wire this device, but the general concepts are the
same.
Operationally testing a system like this can be difficult at
best. I
tried a method that worked for me, but is offered with a Caveat
Emptor
warning... buyer beware, your mileage may vary and if you smoke
you
whole aircrafts electrical system, DO NOT blame me.
I disconnected all three leads from the generator. I used a
small 10
watt 28 VDC light bulb connected to the field winding wire to
ground. I
took the main generator PLUS and MINUS wires off of the
generator and
hooked them to a 28 volt variable DC power supply of about 20
amps
capacity. DO NOT LEAVE ANY OF THE AIRCRAFTS WIRES CONNECTED TO
THE
GENERATOR. The Field Winding can either float or have a SMALL 28
volt
DC light bulb hooked from it to ground.
You can now bring up voltage with the variable supply and check
for
voltages at proper locations without having to run the M-14
engine
itself. Initially set the variable supply to about 20 volts.
Look for
this 20 volts from the variable power supply at Combined Device
Input
terminal. (Right side bottom.. the BIG one). Turn on the
Aircraft
Master and look for BATTERY voltage on the OUTPUT terminal (left
side
middle of the Combined Device...the OTHER big one) Look for 20
volts on
terminal "B" and NO GROUND on terminal "6". Increase voltage on
the
variable supply to 28.0 volts even. As you come up on the
voltage, the
MAIN CONTACTOR should close with a loud WHACK. If not, you have
problems with the Combined Device.
Remove the Combined Device and bench check it. Here is how you
go about
doing that.
Some of the internal relays can be checked simply by listening
to them
click. No, this does not check the relay CONTACTS themselves,
but hey,
that comes later. Using a 28 volt source, either battery or
variable
supply, connect negative to the (-) terminal on the Combined
Device.
Connect 28 volts to terminal B. You should hear a relay click.
Disconnect from B. Now connect 28 volts to terminal A..(It looks
sort
of like an A anyway) It is on the right side above the large
INPUT
terminal. You should hear a LOUD relay closing, this is the main
contactor. Remove power from "A". Reapply power to "B"... again
you
hear a relay click. Leaving power applied to B, now hook a
grounded
wire to pin 6. This will close ANOTHER relay and you should be
able to
hear it click. You have now checked every relay coil in the
Combined
Device, other than the Polarization Relay, and the internal
relay
contacts themselves.
Find a 24 volt battery, or hook two 12 volt batteries in series.
Hook
the negative lead of the battery to the negative side of your
variable
power supply. Also connect a wire from this to the MINUS (-)
terminal
on the Combined Device. So all negatives (grounds/earths) are
now
common to each other. Hook the plus lead of the battery to the
OUTPUT
side of the Combined Device (Big terminal left side middle).
Variable power supply is now OFF.
Apply a wire from the 28 volt variable supply output (plus
voltage) to
the MAIN INPUT terminal (bottom right side). Also connect a
jumper from
this terminal to terminal "B". Put some voltmeters here and
there to
monitor whatever you feel like, but most certainly variable
power supply
output voltage. Increase the variable power supply output. When
it
reaches about 2 volts or so MORE than the battery voltage, the
MAIN
CONTACTOR will close, and you will now have connected your
variable
power supply to your test batteries.... and remember, when you
do this,
you have just created a battery charger, and the variable power
supply
will now try to start charging the batteries! If your variable
power
supply is too small, as soon as it starts to try and charge the
batteries through the now closed MAIN CONTACTOR RELAY, the
variable
power supply voltage will DROP. This will trigger the
Polarization
Relay to OPEN, then causing the MAIN CONTACTOR to open as well,
and
battery charging will cease... at which point the variable power
supply
will jump back up in voltage, the polarization relay will close
again
and the whole cycle will repeat. This event happens very fast
and will
make a lot of noise. So... warning... use a variable power
supply that
can handle more than a few amps without voltage drop for this
test. A
regulated supply that is variable as well would be ideal.
Ok, so what if the MAIN CONTACTOR does NOT energize when you
increase
the voltage? More than likely, you have problems with the
Polarization
Relay. This device seems to wear out first, and the word has it
that you
can take this Combined Device apart and adjust these contacts to
fix
this relay. I have not done that yet, but am getting ready to.
The Combined Device is a rather rare animal and sooner or later
is going
to give us all a certain amount of grief. Without a doubt, I
suspect if
we continue to fly these aircraft we are going to have to get
more of
these devices at a reasonable cost, or build our own, or convert
the
whole aircraft power generation system over to American made.
The
latter is probably the best idea over the long run.
So there you have it. The methods for testing this system are my
own
and not adopted from any other manual or article. Use them at
your own
risk. Feel free to copy and distribute this article as you see
fit, but
I would sincerely appreciate it if you left my name on it as the
author.
Addendum:
Every Russian aircraft owner should take a careful look at the
Carbon
Pile Voltage Regulator R-27. Vladimir Yastremski warned me about
this
device, and his warning was dead on accurate. This device is
mounted on
a very very loose shock mount and rocks and rolls all over the
place in
flight. It has wires that screw onto terminals and as the thing
moves,
it can cause a short circuit to certain
Message 6
| INDEX | Back to Main INDEX |
| PREVIOUS | Skip to PREVIOUS Message |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
| Subject: | White Paper on Russian Generator System |
Jan,
Let me repeat one thing if I may. If the noise to your radio goes away
completely when you disconnect the (almost) BNC connector on the back of
the radio that connects the antenna, then there is absolutely no use in
messing with the radios wiring what-so-over. Trust me on this one.
Radio noise can come in via a few different sources. The wires you
speak of, or the antenna, or both. If you disconnect the coax
connection to the radio, AT the radio, and all noise goes away
completely, then all noise is coming in from the antenna itself. Noise
filters will NEVER stop this type of noise. That is because the radio
is actually RECEIVING what it is SUPPOSED to be receiving. I.E. "RF
ENERGY".
As for spark energy.... You mention the spark plug cables. I agree ...
More or less.... But don't forget that the spark plugs now being used
are much MUCH better than anything being used before. Leaps and bounds
better.
If the shielding on the Tach Generator becomes completely disconnected,
the resultant noise can be so strong that it actually causes DAMAGE to
the receiver front end in a Balken-5 (sp) model radio flying in a 52. I
have actually seen that happen and have repaired the damage myself....
So believe me, it's true.
Pulling the antenna connector off the radio will tell the story.
Mark
P.s. There is ONE very REMOTE possibility that can help if all noise
STOPS when you pull off the coax cable connector from the radio, and
that is called "common mode interference". In cases like that, noise
comes down the shield of the coax and gets into the radio THAT way.
This can be eliminated by using torroidal chokes on the exerior of the
coax close to the radio. They look like small donuts, and using the
right ones are important. Regardless, this still presumes that all
noise goes away when you disconnect the antenna coax from the radio.
If that does as I expect it to do, and all noise goes away, then put the
coax back on the radio, and disconnect the connection from the antenna
itself. It the noise is still gone, it is NOT common mode interference,
and you either need to turn up the squelch, or eliminate the noise at
the source.... Not radio wiring.
-----Original Message-----
From: owner-yak-list-server@matronics.com
[mailto:owner-yak-list-server@matronics.com] On Behalf Of Jan Mevis
Sent: Tuesday, February 20, 2007 16:21
Subject: RE: Yak-List: White Paper on Russian Generator System
Thanks Mark,
I'll follow your advise and check the antenna cabling, but I also will
verify the different groundings of the radio system(the casing, the
connectors on the left side of the cockpit, and the connectors of the
push-to-talk switch behind the throttle. I'll fix a grounding wire thru
all those ground connectors right up to the battery to make certain that
there's no ground loop. A second thing that I'll try (if this does not
solve the
problem) is a noise filter on the DC line to the radio.
Anyway, I am CERTAIN that the silicone plug wires from Dennis' kit are a
very good thing. The engine simply runs better (and only 15 flying hours
before I had installed NEW Russian spark plugs + my mags were serviced
in Nov 2006 by a very good Russian mechanic, Sergei Makarov).
With the old Russian ignition harness I also had some noise but it was
less apparent. The new American cables give a better spark, and thus I
suppose they draw more power from the mags, so the fact there's more EMI
radiation coming from the mag POINTS is feasible.
The wiring of my radio is not perfect. I replaced the original Ziabrik
by a Briz a few months ago, but the Briz cabling was entirely different.
I kept the old Ziabrik cables and did put the new Briz cables alongside.
This is probably far from ideal but as you know, this is not an easy
job.
I also will check the Tach generator as you suggested. As a matter of
fact I'll verify all non-plug wires on the engine side of the firewall(I
noticed that my carburettor temperature cable is in a bad shape, for
instance).
I'll keep you informed about the test results,
Best regards,
Jan
-----Original Message-----
From: owner-yak-list-server@matronics.com
[mailto:owner-yak-list-server@matronics.com] On Behalf Of Bitterlich,
Mark G CIV Det Cherry Point, MALS-14 64E
Sent: dinsdag 20 februari 2007 21:34
Subject: RE: Yak-List: White Paper on Russian Generator System
--> Point,
MALS-14 64E" <mark.bitterlich@navy.mil>
Jan, you are the second person I have heard from who has had radio noise
that could not be lived with after the conversion to automobile plugs,
and that fact is beginning to make me nervous about that change! As far
as your comments on the change, I have also heard that mag drops are
much less from everyone who has made the change as well. So, there is
obviously a lot of good things going on as well!
If you want to isolate the generator, simply remove the three wires from
the generator itself Jan. It is pretty easy to do... You simply take a
copy off that wraps around the generator near the top. The only warning
there is when you re-install that cover, it is easy to the threads out
of the "bar" that the screws go into. Careful there. Other than that,
you can simply unscrew the wires and and then start it up and listen for
your noise.
The truth is that turning the generator OFF is supposed to kill the
excitation field and should give you the same result as removing the
wires! However, if you want to be REALLY REALLY sure, you can remove
the wires. In fact, an even easier way would be to simply connect a
voltmeter to the generator itself after removing the cover as described
and then with the generator switch OFF, check for voltage with the
engine running. I never did this myself sorry to say. But you SHOULD
get nothing coming out of the generator. If you don't, there is no
sense in removing the wires.
Now... That said, there IS something that will make a TON of noise into
your radio that is easily overlooked. That is the TACH GENERATOR!
That thing is ALIVE all the time. There is no way to switch it OFF. It
is a 3 phase AC generator and it is absolutely ESSENTIAL that the
shielding on this wiring is perfect, and the fact is that the shielding
and other wiring at this plug routinely goes bad due to bad solder and
vibration. You can check whether this is your noise generator very
easily by simply taking the plug OFF of the tach generator on the left
side of your engine. It's a big black thing that screws into the
accessory gear box and is slightly down and to the left of the air start
distributor. It's definitely worth looking into.
Discussing the wires that Dennis's modification uses. These are
actually (as I am sure you are well aware of) wires that are sold for
racing engines. They are basically standard automobile spark plugs
wires, although a few millimeters larger and claim to have a better
conductor that standard carbon impregnated types. The wires that came
stock with our aircraft uses solid strands of wire, and it is hard to
imagine a better conductor than those! However, the rubber covering
these wires is inferior and breaks down and shorts out a lot. Next,
when you run solid core wires like the Russians (and Americans as well
did on Radial Engines) did, you have little antennas hooked to a
powerful generator. Consider that the very first radios in this world
used spark gap generators to create an RF signal and you will get the
idea here. Since that magneto generates high voltage and sparks, there
is wide band RF noise all over the place! To contain this, they built
the shielding and tubing system that they did, which if course was used
on EVERY radial engine out there!
Since that period of time, spark plug wires have gotten better and types
have been built that allow them to be run out in the open and not in
shielded tubes or conduits. This is what Dennis used. However, there
is NO QUESTION that they are going to create more noise than the
original system did, if the original system was properly maintained.
Dennis never did any real scientific checks of what his wiring system
was going to do. In order to check that, he would need specific test
equipment looking at the on-board radios, etc. At the very minimum a
spectrum analyzer so as to note any changes in the RF noise floor. He
didn't do that either. Bottom line, there is going to be more noise
with his system... But you also gain a TERRIFIC advantage over the
original system when ever you need to do any maintenance!
You may be able to adjust the internal setting of the radio's squelch
setting to over-come the noise problem. Some of these radios are
different from another, but I have one at home I can take pictures of
and show you how to adjust the squelch.
As for checking your cabling... Stop right there.
Simply do this: Get behind your radio and disconnect the antenna.
Start the engine and see if the noise is still there. If it IS, then
the noise is coming in via your cabling, and you very well might have
success in eliminating the noise if you use well shielded wire to
provide power from the battery to the radio as you are presently doing
since your switch failed. Be aware that it helps to use shielded wire
for both the positive AND the negative leads of the radio directly to
the battery, but I doubt you will fix your problem by doing that.
As I said, if the noise stays with the antenna disconnected AT THE
RADIO, then ok... But if the noise goes AWAY with the antenna
disconnected, then checking radio wiring is a waste of time.
By the way, to carefully hear and determine the noise that you are
getting ALWAYS run your checks with the squelch switch set to OFF, so
that you can clearly hear the full extent and type of noise that you are
dealing with.
If you go with the B&C system, I would advise AGAINST their very small
PMG generator, and would instead go with their SK35 and outboard voltage
regulator. This system comes with self-contained under/over voltage and
current protection built into the regulator. The SK35 will give you 35
amps of output. I think they also have a 45 or 50 amp version.
The Russian power system is indeed robust, and can be maintained, IF you
can find the spare parts, or repair what breaks yourself. I now have a
spare regulator, over-voltage unit, and can fix the 200D unit. Fixing
the Russian electrical system was a real exercise for me, and working
with Avionics is what I do for a living . Bottom line, if you ever
have a failure, I will be glad to help talk you through fixing it.
Mark
-----Original Message-----
From: owner-yak-list-server@matronics.com
[mailto:owner-yak-list-server@matronics.com] On Behalf Of Jan Mevis
Sent: Tuesday, February 20, 2007 1:47
Subject: RE: Yak-List: White Paper on Russian Generator System
I have a lot of radio noise (rattling noise). I suspected the voltage
regulation but I do have that loud noise also with the engine running
and master and other switches off (the radio is connected with a
separate breaker switch and fuse to the battery since the original radio
switch in the front panel is faulty; when I connect the radio to this
switch, the voltage over the radio drops to 3 volts).
I already did Dennis' plug conversion and I also replaced the high
tension lead of the booster coil. The engine runs perfectly smooth and
seems to have more power! Mag drops on 1 and on 2 at 70 % are small. So
this conversion is a very good thing. I also double checked the plug
wires and connexions, and strapped all the wires very securely so that
they don't move around when going negative. I also double-checked the
positioning of the mag caps, and cleaned them thoroughly with alcohol.
Since the engine runs so well, I hardly doubt the problem comes from the
conversion. But it's enigmatic since I had less noise with the old
Russian harness.
Recently I replaced my faulty ZIABRIK by a BRIZ. I tested this BRIZ on a
test bench before installing. The BRIZ works good when the engine is not
running. When it runs, there's a loud and annoying noise, as if I hear
the contacts of the mags. This only happens when the channel is clear.
When someone sends on the frequency, reception is perfect, and when I
send, they hear me 5 to 5 and in both cases I have almost no background
noise at all. I 'm going to check the cabling of the radio. Is it
possible that there's more EMI radiation of the ignition system since it
works "better" than before ? Perhaps there's a grounding problem ?
Anyway, I am impressed by what you did on your plane, I don't have the
knowledge nor the experience to do these kind of checks. I am
considering the B&C alternator + regulator and crowbar. Nevertheless the
whole Russian system seems to be very well designed and robust. I'd like
to keep the Yak 50 as original as possible, since it's so beautiful and
well designed.
Best regards,
Jan
________________________________
From: owner-yak-list-server@matronics.com
[mailto:owner-yak-list-server@matronics.com] On Behalf Of Yak Pilot
Sent: dinsdag 20 februari 2007 4:11
Subject: RE: Yak-List: White Paper on Russian Generator System
Jan, while this is fresh in my mind, what kind of problems are you
having with your 50?
Mark
Jan Mevis <jan.mevis@informavia.be> wrote:
What a great job, Mark, THANKS A LOT! This will help me solve
the Voltage
Regulation problems in my Yak 50 !
Jan Mevis
RA2005K
-----Original Message-----
From: owner-yak-list-server@matronics.com
[mailto:owner-yak-list-server@matronics.com] On Behalf Of
Bitterlich, Mark G
CIV Det Cherry Point, MALS-14 64E
Sent: woensdag 14 februari 2007 23:15
To: yak-list@matronics.com
Subject: Yak-List: White Paper on Russian Generator System
Cherry Point,
MALS-14 64E"
YAK-50 DC Power Generation and Troubleshooting by Mark
Bitterlich N50YK
Warning: This is a technical explanation of the power
generation,
regulation, and connection to aircraft main's of the typical
Yak-50/52/55 or Sukhoi-26/29/31. It is offered for those that
have at
least a general understanding of electronics. In all cases where
voltage from power supplies or from batteries were connected for
testing, circuit breakers were installed for safety. If anyone
tries to
follow these notes and duplicate my efforts, beware... if you
make
mistakes, or fail to include current limiting devices such as
light
bulbs and circuit breakers/fuses, you could easily cause serious
damage
to aircraft wiring. Ok.. so I had to cover my six. That said,
let's
move on.
I just spent the last few days learning my YAK-50's electrical
power
generation system. Thanks for all of those that sent schematics
of what
you had on hand. Every person contributed towards solving this
puzzle!
THANKS TO EVERYONE! The specifics in some regards focus on the
YAK-50,
although all of the Yak's and Sukhoi's use close to the same
design with
some slight wiring differences here and there. The important
thing is
that in most cases the parts are all identical. Of course this
does not
include "Westernized" designs, such as the 52W, 52TW, etc. Most
of
these have already had B&C (or other) products installed.
Power generation starts with the generator. This is a 3 KW
monster that
is capable of 100 amps output if properly cooled. This same
generator
can operate at 30 amps intermittent duty with no cooling air.
There are 3 wires on the generator, + positive, - negative, and
what the
Russians refer to as "Shunting Input". This input is actually
what
controls the generator output and is normally called "Field
Excitation".
This generator has a very well designed voltage regulation
system using
a carbon pile voltage regulator that controls field voltage
within a +2
/ -2 volt range. Voltage output is also stabilized with a
bucking
transformer known in Russian as "The Stabilizing Transformer".
If you
want to see examples of systems like this, go back to WW-II
designs and
you will see the exact same thing. In other words, this is 60
year old
technology and you need to go back and read about some of the
theory
involved, because like a bucking transformer, you rarely see
these
components in today's designs, but they were very common before
the
discovery of high current voltage regulation transistors.
Basically, most of the system is self starting and self
contained
regulating in a closed loop circuit. As soon as the generator
starts
spinning, it will put out voltage although at idle it will be
much lower
than 28 volts and it will not be connected into the aircraft
mains. As
RPM comes up and voltage rises, it will eventually stabilize at
the
rated voltage set by the carbon pile regulator. So, if you have
any
kind of problem, the first thing you will want to do is to gain
access
to the main generator terminals (you have to remove a cover on
the
generator) and hook a meter to the PLUS and MINUS connectors
with LONG
meter leads so that you can then safely check the voltage when
you start
the engine. If your generator is putting out voltage at idle,
give it a
quick boost to about 60% or so, and you should see your meter
come up to
around 28 voltage (plus or minus a few tenths) and then start
regulating. By "starting to regulate", I mean that the voltage
will stop
increasing as you continue to raise engine RPM If you have NO
output
voltage, shut the engine off, and then when you are eyeballing
the
inside of the generator, slowly move the prop. Does the
generator spin?
If so, then that is a good thing. If NOT, then you have sheared
a shaft,
replace the generator. If it does rotate, start it back up and
run a
test for Field Excitation Voltage. If you have excitation
voltage, then
again it is probably a bad generator. If you have no excitation,
there
are a few other things that could be wrong, such as the carbon
pile
regulator itself, or your over voltage breaker has tripped.
If at any time the generator puts out too much voltage, in the
realm of
31.5 volts or so (+/- 0.5 volt) then a circuit breaker will pop
on the
over/under voltage detection and protection unit. This is a
silver box
with two cannon plugs on it, that is in the nose inspection hole
left
side top in the 50, and somewhere else in the 52. I think it is
in the
forward cockpit underneath the instrument panel on the 52 but
don't
quote me. This unit has a rubber covered breaker button that you
can
reach in and reset if you have had an over-voltage condition. It
is
another thing to check anytime you have a problem, but typically
an
over-voltage trip is not common.
Moving on, the closed loop design has generator output going
first to
the stabilization transformer primary winding, then through that
directly to a component called "The Combined Device" also known
as the
DMR-200D. This component (the DMR-200D) is located in the gray
box
mounted on the firewall, top right side (looking forward) in the
50, and
by the Pilots right foot in the 52. Power goes through a MAIN
CONTACTOR
RELAY inside of the Combined Device ONLY IF CERTAIN CONDITIONS
ARE MET.
Here is where things get tricky.
Going back the Stabilizing Transformer for a minute, (just to
complete
the mental image) main output voltage of the generator goes
through the
primary winding as I already mentioned. This is just a few turns
of
wire, and offers VERY little resistance. Part of the secondary
windings
of this transformer system has outputs going to the voltage
regulator
and the over voltage box. The Voltage Regulator (official name
"R-27")
has outputs that feed back to control the generator excitation
field,
but it also has another output that goes over to the over
voltage box.
If the voltage is normal, the over voltage box feeds this same
voltage
(28 volts) back to pin B on the Combined Device. (Note, it looks
like a
"B" to me, that is the SHAPE of the marking, but it is actually
the
Russian letter "V".) This input voltage to pin B (V in Russian)
turns
on internal relay TKE-210B INSIDE of the Combined Unit. The
nomenclature of this relay means nothing since you can't see or
touch it
without taking the whole thing apart. Just realize that when you
put 28
volts to the connection marked "B" and a ground on the
connection marked
"-" (for minus), an internal relay will close and it will ENABLE
the
rest of the Combined Device. When this first relay closes, it
then
enables yet another system inside of the Combined Device known
as the
Polarization Relay. The "PR" is a special dual winding relay
that will
close only if current flows through the relay coil itself in the
proper
direction. If you try to flow current through this relay
backwards, it
simply won't work, and that is by design. It is SUPPOSED to do
that.
After the Polarization Relay (or PR) is enabled, it has a
circuit that
connects it to both the output main terminal and the input main
terminal. If the PR likes what it sees and closes, it then in
turn
provides power for yet ANOTHER Relay Coil inside of the Combined
Unit,
this one is known as the MAIN POWER CONTACTOR RELAY. This is the
big
boss relay in the whole thing, and when it closes, generator
power then
comes OUT of the Combined Unit and is fed to the aircraft MAIN
BUS BAR.
In other words, the MAIN POWER CONTACTOR actually connects the
large
input terminal to the large output terminal on the Combined
Unit.
What is really tricky to understand about this whole design is
the
Polarization Relay. Consider this: When you turn on the Aircraft
Master, Battery Voltage is fed to the MAIN BUS and as such it
also is
fed right down to the large OUTPUT terminal of the Combined
Unit. At
this point, the OUTPUT of the Combined Unit is not connected to
ANYTHING, because the MAIN CONTACTOR RELAY is still OPEN. Let's
consider our battery voltage to be a normal. As such, there is
about 24
volts on the Combined Units OUTPUT terminal post coming from the
battery
with the Aircraft Master switch turned on.
Now let's start the engine. The generator starts to spin.
Everything
works properly and as your engine speed comes up, so does
generator
voltage. This voltage is now fed to the Combined Unit's INPUT
power
terminal. Assuming 28 volts is fed to terminal "B" ("V" in
Russian)
thus ENABLING the Combined Unit, you will end up with battery
voltage on
one side of the Polarization Relay Coil and Generator Voltage on
the
OTHER side of the Polarization Relay Coil. Once there is a
difference
in voltage between battery voltage and generator voltage of
about 2
volts or so, and the generator voltage is HIGHER than the
battery
voltage, the Polarization Relay will CLOSE and will then in turn
close
the MAIN POWER CONTACTOR. Once the MAIN POWER CONTACTOR is
closed, 28
volts will be fed out terminal "C" which will then in turn close
yet
another relay (external to the Combined Device) and turn OFF the
Generator Light in the cockpit. It also then of course is
feeding
generator power directly to the aircraft main power bus.
Not done yet! There is yet ANOTHER relay coil in the Combined
Device
that is only enabled if the main enabling relay is powered up
through
terminal "B" as mentioned earlier. If terminal B has 28 volts,
then
terminal "6" becomes active (In Russian the "6" is actually the
Russian
letter "B"... confused yet? Easy to do. Just remember that as I
write
this, I refer to how they look to me and how they will look to
YOU!) If
you put a GROUND on this terminal "6" it will close yet another
relay
coil inside of the Combined Device and will REMOVE the generator
feed
voltage from the Polarization Relay thus making it INOPERATIVE!
Remember, if you disable the PR relay, then of course you have
also
disabled the MAIN CONTACTOR Relay, and thus, no voltage from the
generator will ever make it to the main aircraft bus. The ground
on
terminal "6" is usually controlled by the Generator Switch in
the
cockpit. And here is a warning... not all Russian designs work
like
this. From the Sukhoi to the Yak there are major wiring
differences in
how they wire this device, but the general concepts are the
same.
Operationally testing a system like this can be difficult at
best. I
tried a method that worked for me, but is offered with a Caveat
Emptor
warning... buyer beware, your mileage may vary and if you smoke
you
whole aircrafts electrical system, DO NOT blame me.
I disconnected all three leads from the generator. I used a
small 10
watt 28 VDC light bulb connected to the field winding wire to
ground. I
took the main generator PLUS and MINUS wires off of the
generator and
hooked them to a 28 volt variable DC power supply of about 20
amps
capacity. DO NOT LEAVE ANY OF THE AIRCRAFTS WIRES CONNECTED TO
THE
GENERATOR. The Field Winding can either float or have a SMALL 28
volt
DC light bulb hooked from it to ground.
You can now bring up voltage with the variable supply and check
for
voltages at proper locations without having to run the M-14
engine
itself. Initially set the variable supply to about 20 volts.
Look for
this 20 volts from the variable power supply at Combined Device
Input
terminal. (Right side bottom.. the BIG one). Turn on the
Aircraft
Master and look for BATTERY voltage on the OUTPUT terminal (left
side
middle of the Combined Device...the OTHER big one) Look for 20
volts on
terminal "B" and NO GROUND on terminal "6". Increase voltage on
the
variable supply to 28.0 volts even. As you come up on the
voltage, the
MAIN CONTACTOR should close with a loud WHACK. If not, you have
problems with the Combined Device.
Remove the Combined Device and bench check it. Here is how you
go about
doing that.
Some of the internal relays can be checked simply by listening
to them
click. No, this does not check the relay CONTACTS themselves,
but hey,
that comes later. Using a 28 volt source, either battery or
variable
supply, connect negative to the (-) terminal on the Combined
Device.
Connect 28 volts to terminal B. You should hear a relay click.
Disconnect from B. Now connect 28 volts to terminal A..(It looks
sort
of like an A anyway) It is on the right side above the large
INPUT
terminal. You should hear a LOUD relay closing, this is the main
contactor. Remove power from "A". Reapply power to "B"... again
you
hear a relay click. Leaving power applied to B, now hook a
grounded
wire to pin 6. This will close ANOTHER relay and you should be
able to
hear it click. You have now checked every relay coil in the
Combined
Device, other than the Polarization Relay, and the internal
relay
contacts themselves.
Find a 24 volt battery, or hook two 12 volt batteries in series.
Hook
the negative lead of the battery to the negative side of your
variable
power supply. Also connect a wire from this to the MINUS (-)
terminal
on the Combined Device. So all negatives (grounds/earths) are
now
common to each other. Hook the plus lead of the battery to the
OUTPUT
side of the Combined Device (Big terminal left side middle).
Variable power supply is now OFF.
Apply a wire from the 28 volt variable supply output (plus
voltage) to
the MAIN INPUT terminal (bottom right side). Also connect a
jumper from
this terminal to terminal "B". Put some voltmeters here and
there to
monitor whatever you feel like, but most certainly variable
power supply
output voltage. Increase the variable power supply output. When
it
reaches about 2 volts or so MORE than the battery voltage, the
MAIN
CONTACTOR will close, and you will now have connected your
variable
power supply to your test batteries.... and remember, when you
do this,
you have just created a battery charger, and the variable power
supply
will now try to start charging the batteries! If your variable
power
supply is too small, as soon as it starts to try and charge the
batteries through the now closed MAIN CONTACTOR RELAY, the
variable
power supply voltage will DROP. This will trigger the
Polarization
Relay to OPEN, then causing the MAIN CONTACTOR to open as well,
and
battery charging will cease... at which point the variable power
supply
will jump back up in voltage, the polarization relay will close
again
and the whole cycle will repeat. This event happens very fast
and will
make a lot of noise. So... warning... use a variable power
supply that
can handle more than a few amps without voltage drop for this
test. A
regulated supply that is variable as well would be ideal.
Ok, so what if the MAIN CONTACTOR does NOT energize when you
increase
the voltage? More than likely, you have problems with the
Polarization
Relay. This device seems to wear out first, and the word has it
that you
can take this Combined Device apart and adjust these contacts to
fix
this relay. I have not done that yet, but am getting ready to.
The Combined Device is a rather rare animal and sooner or later
is going
to give us all a certain amount of grief. Without a doubt, I
suspect if
we continue to fly these aircraft we are going to have to get
more of
these devices at a reasonable cost, or build our own, or convert
the
whole aircraft power generation system over to American made.
The
latter is probably the best idea over the long run.
So there you have it. The methods for testing this system are my
own
and not adopted from any other manual or article. Use them at
your own
risk. Feel free to copy and distribute this article as you see
fit, but
I would sincerely appreciate it if you left my name on it as the
author.
Addendum:
Every Russian aircraft owner should take a careful look at the
Carbon
Pile Voltage Regulator R-27. Vladimir Yastremski warned me about
this
device, and his warning was dead on accurate. This device is
mounted on
a very very loose shock mount and rocks and rolls all over the
place in
flight. It has wires that screw onto terminals and as the thing
moves,
it can cause a short circuit to certain
Message 7
| INDEX | Back to Main INDEX |
| PREVIOUS | Skip to PREVIOUS Message |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
| Subject: | M14P technical data |
Thanks Mark.
Mgb N50YK
-----Original Message-----
From: owner-yak-list-server@matronics.com
[mailto:owner-yak-list-server@matronics.com] On Behalf Of Mark Jefferies
YAK UK
Sent: Tuesday, February 20, 2007 11:04
Subject: Yak-List: M14P technical data
This file maybe of help to builders wanting to use the M14P engine in
home builds etc..
www.yakuk.com/m14p-tech-data.pdf 750 kb file
Mark Jefferies for YAK <http://www.yakuk.com> UK Ltd
Other Matronics Email List Services
These Email List Services are sponsored solely by Matronics and through the generous Contributions of its members.
-- Please support this service by making your Contribution today! --
|