Today's Message Index:
----------------------
1. 07:48 AM - JL-7/Yak-152K History (Cpayne)
2. 08:03 AM - Re: RF interference (A Dennis Savarese)
3. 09:10 AM - Re: JL-7/Yak-152K History (George Coy)
4. 10:55 AM - l-7 (Joe Howse)
5. 11:14 AM - FW: JL-7/Yak-152K History (George Coy)
6. 01:35 PM - Re: RF interference (Yak Pilot)
7. 11:52 PM - Re: l-7 (Richard Goode)
Message 1
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| Subject: | JL-7/Yak-152K History |
Military bloggers have tracked this development for several years. The JL-7 is
the production version of the prototype L-7/Yak-152K. This trainer will be built
on production lines in both China and Russia, the differences will be avionics
suites. Since the time the CJ-6 was made available to the western market,
PLAAF planners have been looking for a replacement that fit the budget. After
evaluating the Yak-152, some changes were proposed and the Yak-152K was the result.
A 50/50 partnership between Russia's Irkut (Yakovlev) and HongDu was formed.
Design and development came from the Russian side while HongDu built the
prototype L-7/152K.
The plan is to certify the base version with both FAA and JAA in order to market
the product internationally. A 10,000 hr/30 year airframe limit has been initially
set with hopes of manufacturing up to 3000 over the product's life cycle.
Low procurement and operating cost and a rugged airframe will be part of the
hard sell to airforces.
The M-14X will power initial versions. The M-14X is the flat flanged version of
the M-14P in order to fit a 3-blade "MT" type prop. Weight will be about 2950lbs
gross with a 1000km range. Climb performance is reported be about the same
as the Yak-52 but cruise is reported be quite a bit higher, up to 360kph. (seems
too high to me) All versions will use a "glass" cockpit and some variants
will include a basic targeting system although this trainer will not have any
combat capability.
Of interest to Red Star owners is that a lightweight 0/0 ejection (extraction?)
system is employed as well the M-14 engine rather than turboprop power used everywhere
else in the military world. I hope this bodes well for our long-term
engine parts issues. Voronezh will be the Russian engine supplier.
Regarding development history, the Yak-52 was morphed into the -52M aka -56 and
-54M. Next was the -152 and now the Yak-152K/L-7. Note that the Yak-54 is mid-wing
while the JL-7/152K are low wing. I'm not sure what happened to the Sukhoi
entry into the competition but the Yak was said to have met the specs better.
($$$ anyone?) Chinese marketing has slapped the name "Baby Eagle" on the JL-7
so I would expect to see it offered to the Western market in the future.
Doug, do you have any insight into all this??
Craig Payne
Message 2
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| Subject: | Re: RF interference |
Scott,
The back of the mag switch is in a metal "can". At the rear of the
"can" the braided shield of the P leads is affixed to the "can", thus
grounding it. FWIW, assuming the mag switch is wired correctly and
looking at the front of the mag switch, the #1 position is the left mag,
looking at the engine from the cockpit. When the mag switch is in the
#1 position, #2 mag P lead is grounded and vice versa when the switch is
in the #2 position.
Dennis
On 12/18/2010 9:43 PM, Scott Poehlmann wrote:
>
> Hi Mark,
>
> Of course this all makes sense, and you are right. Fortunately I have
> such a source readily available... the ATIS on the field at ELP is 11
> NM away--straight LOS through a mountain. Under good circumstances it
> is just audible on my field (when the Mexican cell phones are playing
> tricks, it isn't audible at all, but that's another story...), so I
> can use that for the test you propose. I don't have access to a signal
> generator, nor do I have any interest in trying to mess with it beyond
> that which is required to obtain good communication in both directions.
>
> I am just happy it is something straightforward and not in the power
> system. I was not looking forward to that job. Frankly, shielding the
> wires from the mag switch to the tach should be easy (it's all behind
> the panel with a total run of less than 2 feet). Now the question
> which end to ground, and to what? Do you know if the housing of the
> mag switch will tolerate being grounded (perhaps it already IS
> grounded?) or does it need to "float"?
>
> Thanks,
>
> Scott
>
>
> On 12-18-2010 17:31, Yak Pilot wrote:
>> --> Yak-List message posted by: Yak Pilot<yakplt@yahoo.com>
>>
>> Scott, without going into a long discussion on how radios work, the
>> simple fact is that you can not determine how much interference you
>> are getting simply by plugging in the headset and listening for
>> noise. Without using test equipment it is sometimes hard to quantify.
>>
>> However, there are some simple tests that allow the human ear to
>> determine if you are being impacted by it or not.
>>
>> The most simple test is to tune the radio to a really weak signal
>> that is just barely readable, and then start the engine and see how
>> the noise impacts the reception of that signal. That can be hard to
>> do at the airport where most RF sources are right there on the
>> field. This test will only work if you can tune into a signal that
>> is already right on the threshold of detection. If you can do that
>> now, great. If not, you need a sig-gen and somebody who knows how to
>> use it.
>>
>> Failing that, go fly and tune your radio into some ASOS or ATIS
>> transmission a long way aways and listen to them. Then turn off the
>> mags and see how much the signal improves. If it does, then you need
>> to attack your shielding more vigorously. If turning the engine off
>> with the mag switch does not impact your weak received signal at all,
>> then you have done as much as you can to shield P leads. Crude but
>> it will work..
>>
>> Mark Bitterlich
>>
>>
>> --- On Sat, 12/18/10, Scott Poehlmann<scott-p@texas.net> wrote:
>>
>>> From: Scott Poehlmann<scott-p@texas.net>
>>> Subject: Re: Yak-List: RF interference
>>> To: yak-list@matronics.com
>>> Date: Saturday, December 18, 2010, 5:37 PM
>>> --> Yak-List message posted by:
>>> Scott Poehlmann<scott-p@texas.net>
>>>
>>> Ahh.
>>>
>>> Perhaps I should shield the wires to the tach, too. The interference
>>> really does go away to essentially nothing (ok, I get an
>>> occasional
>>> "pop" or two, but NOTHING like before) when running on just
>>> Mag 1 now,
>>> so if I can accomplish the same thing with Mag 2, then I am
>>> happy.
>>>
>>> Will look into the shielding on those wires after fixing
>>> P-lead on Mag
>>> 2, and report back.
>>>
>>> Scott
>>>
>>> On 12-18-2010 13:46, Yak Pilot wrote:
>>>> --> Yak-List message posted by: Yak
>>> Pilot<yakplt@yahoo.com>
>>>>
>>>> Hmmm!
>>>>
>>>> I need to add one step to my troubleshooting
>>> procedures Scott:
>>>> Step Three: Have you added a digital tach that
>>> takes it's input off the P Leads. If so, that is very
>>> high potential for noise addition to your aircraft.
>>>> I actually thought of mentioning that, but since you
>>> did not bring it up in your initial email, I guessed
>>> (incorrectly) that you had not modified anything since you
>>> put in the new spark plugs and wire kit.
>>>> To answer your question: When pulling the Tach
>>> Drive, most of the folks I know have had a plate made that
>>> bolts on with the four corner bolts to the plate and there
>>> you go. You make it yourself. You need to be
>>> very very careful here, because if you remove the wrong
>>> "plate" you also will expose the gearing for the tach drive
>>> that also is part of the air distributor drive. What I
>>> am saying here is that if you pull the wrong plates and
>>> stuff in an attempt to put a new cover plate over the tach
>>> drive, you can easily disturb the gearing inside, which will
>>> in turn through your air start distributor out of adjustment
>>> and then you are DEEP KIMSHEE! Re-timing the airstart
>>> distributor is NOT EASY regardless of what anyone might tell
>>> you otherwise. So Scott, be very very careful of what
>>> you take apart in that area. Without photo's it is
>>> hard for me to describe what to take off and what not to
>>> take off. Talk to Dennis about that for details.
>>>> Somehow I just managed to send this message when my
>>> fingers slipped on the keyboard oops so here is the
>>> end of the message, sorry.
>>>> Going back to your noise on your radios. I hate
>>> to tell you this Scott, but those new digital tachs that
>>> attach to your P leads are a real source of radio
>>> noise. This is the forth time I have had a person who
>>> installed that tach start talking about radio noise. I
>>> also have personal experience with that thing myself.
>>>> Given that your Tach Generator is now removed from the
>>> aircraft, and you have installed the Digital Tach that used
>>> your P leads for a input, I am 99.999% sure that your new
>>> radio noise is from the P leads. Yes, you should
>>> repair the shields down at the MAGs and that will
>>> help. But you also are going to have to go back to the
>>> wires that have been attached behind the mag switch and make
>>> darn sure that shielded wires were used there as well. Just leaving
>>> a tiny bit of exposed wire (I.E. Where there is
>>> no shielding on the P leads) will allow that to act as an
>>> antenna and RADIATE NOISE all over the aircraft.
>>>> In one aircraft I worked on (a Sukhoi 26) I had to
>>> replace all of that wiring to the digital tach, and then...
>>> get ready for this.. I had to make an actual BOX out of
>>> aluminum and enclose the whole tach inside that box (a
>>> Faraday Shield per se) and ground all that.
>>>> So that is the downside of using that kind of Tach, I
>>> am sorry to have to say. Its a GREAT TACH, and I
>>> love the way it works, but since it uses the P leads, you
>>> have to really pay attention to your shielding. There
>>> is usually no filter that can eliminate this kind of
>>> noise. Spark noise is very broad spectrum and if you
>>> are anywhere in the near field from this noise, youre
>>> pretty much screwed.
>>>> One trick that SOMETIMES helps: Take a handheld
>>> VHF radio, remove the antenna and stick a paperclip into the
>>> center conductor of the antenna jack. Hook headphones
>>> to the handheld radio. Now start the aircraft and use
>>> the radio as a test wand and run it around the wiring
>>> to try and find the source. This is not easy and takes
>>> some effort.
>>>> Bottom line: Your noise is coming from your P
>>> leads and new tach. Good luck. Merry Christmas.
>>>> Mark Bitterlich
>>>>
>>>>
>>>> --- On Fri, 12/17/10, Scott Poehlmann<scott-p@texas.net>
>>> wrote:
>>>>> From: Scott Poehlmann<scott-p@texas.net>
>>>>> Subject: Re: Yak-List: RF interference
>>>>> To: yak-list@matronics.com
>>>>> Date: Friday, December 17, 2010, 9:03 PM
>>>>> --> Yak-List message posted by:
>>>>> Scott Poehlmann<scott-p@texas.net>
>>>>>
>>>>> Thanks Mark,
>>>>>
>>>>> I knew that you would have a great, step by step
>>> method.
>>>>> Went out to the hangar today: looks like the
>>> P-leads are
>>>>> the
>>>>> culprit--BOTH have the shielding detached from
>>> the
>>>>> connector and about 1
>>>>> cm of unshielded lead "hanging in the breeze".
>>> I'll spend
>>>>> some time
>>>>> tomorrow AM soldering the shielding to the
>>> connector (it
>>>>> appears that
>>>>> this has been done before and that the solder
>>> joints have
>>>>> failed...),
>>>>> and will advise if this doesn't fix the problem.
>>>>>
>>>>> Now for the next question: any ideas where to find
>>> a cover
>>>>> for the tach
>>>>> generator drive? I am running a Horizon digital
>>> tach (which
>>>>> takes its
>>>>> data from the mag--in fact it is wired into the
>>> back of the
>>>>> mag
>>>>> switch...), and I have no tach generator, just a
>>> big open
>>>>> fitting with a
>>>>> drive (and seal) at the bottom... Threaded on the
>>> outside,
>>>>> of course.
>>>>>
>>>>> Thanks again, and to everyone else who provided
>>>>> information. This list
>>>>> is a tremendous asset to the continued operation
>>> of these
>>>>> airplanes.
>>>>>
>>>>> Scott
>>>>>
>>>>> On 12-17-2010 10:15, Yak Pilot wrote:
>>>>>> --> Yak-List message
>>> posted by: Yak
>>>>> Pilot<yakplt@yahoo.com>
>>>>>> Do the following:
>>>>>>
>>>>>> Remove the plug from the Tach Gen and tie it
>>> back. Run
>>>>> the aircraft. Does the noise go away?
>>> Then it is
>>>>> indeed your Tach Gen and it is most likely
>>> shielding at the
>>>>> Tach Generator plug itself. Be careful
>>> taking this
>>>>> plug apart as it is common for the soldering on
>>> these wires
>>>>> to break.
>>>>>> If the noise does not go away, fly the
>>> airplane.
>>>>> Over the airport come to complete idle and then
>>> shut the
>>>>> mags off. Both mags, turn them off.
>>>>>> You're now a glider.
>>>>>>
>>>>>> Did the noise go away? If it did, then
>>> you have
>>>>> a MAG noise problem. The mag noise filters
>>> will help,
>>>>> but before you go to that effort, look at the P
>>> leak plugs
>>>>> that go into the side of the mags. It is
>>> very common
>>>>> for people to twist these plugs off during some
>>> kind of
>>>>> maint. action and in the process twist the shield
>>> right off
>>>>> the plug as well. If the P Lead is
>>> unshielded you will
>>>>> have one huge amount of noise.
>>>>>> If the noise is still there even when you
>>> have
>>>>> performed these steps (whcih is highly unlikely)
>>> then you've
>>>>> got some other device radiating energy in the
>>>>> aircraft. Start turning everything that you
>>> can off to
>>>>> try and identify it.
>>>>>> Suggestions have been made to see if it is
>>> coming in
>>>>> via the antenna or the power wiring. I have
>>> posted
>>>>> these suggestions before, but it is something you
>>> do at the
>>>>> end of troubleshooting and not the
>>> beginning. It is
>>>>> much easier to identify the noise source and
>>> eliminate it
>>>>> where it is coming from. If you can't
>>> identify the
>>>>> noise and you are lucky enough to have it coming
>>> in via the
>>>>> power wires (again this is rare), a choke on the
>>> input power
>>>>> wiring can help eliminate the noise. This
>>> can be as
>>>>> simple as a snap on torroid, or an expensive
>>> (purchased)
>>>>> filter, that is usually some sort of "Pi L brute
>>> force"
>>>>> filter consisting of two caps and an inductor.
>>>>> Usually, snap on torroids are just as effective
>>> and much
>>>>> cheaper. Again though, noise coming in via
>>> the power
>>>>> wiring is rare. It usually is coming in via
>>> the
>>>>> antenna, and that means you MUST eliminate the
>>> noise at it's
>>>>> source.
>>>>>> The tests described above will usually nail
>>> the
>>>>> problem in short order.
>>>>>> Mark Bitterlich
>>>>>>
>>>>>> p.s. The reason I recommend shutting the
>>> mags
>>>>> off at idle in flight versus doing it on the
>>> ground is
>>>>> because the engine keeps wind-milling even with
>>> the mags
>>>>> off, and you can leave them off much longer while
>>> you are
>>>>> listening for radio noise and seeing if it goes
>>> away.
>>>>> Shutting the engine off with the mags and the
>>> engine
>>>>> windmilling with it at idle will not hurt
>>> anything, although
>>>>> the engine will cool off really fast, so when you
>>> turn the
>>>>> mags back on and the engine once again is
>>> actually
>>>>> "running", don't just cob the power to 100%.
>>> Bring it
>>>>> in slowly. Common sense applies.
>>>>>> --- On Thu, 12/16/10, Roger Kemp M.D.<viperdoc@mindspring.com>
>>>>> wrote:
>>>>>>> From: Roger Kemp M.D.<viperdoc@mindspring.com>
>>>>>>> Subject: RE: Yak-List: RF interference
>>>>>>> To: yak-list@matronics.com
>>>>>>> Date: Thursday, December 16, 2010, 1:35
>>> PM
>>>>>>> --> Yak-List message
>>> posted by:
>>>>>>> "Roger Kemp M.D."<viperdoc@mindspring.com>
>>>>>>>
>>>>>>> Check the shielding on your Tac Generator.
>>> That is
>>>>> the most
>>>>>>> likely source
>>>>>>> for RPM related noise.
>>>>>>> Doc
>>>>>>>
>>>>>>> -----Original Message-----
>>>>>>> From: owner-yak-list-server@matronics.com
>>>>>>> [mailto:owner-yak-list-server@matronics.com]
>>>>>>> On Behalf Of Scott Poehlmann
>>>>>>> Sent: Thursday, December 16, 2010 5:07 AM
>>>>>>> To: yak-list@matronics.com
>>>>>>> Subject: Yak-List: RF interference
>>>>>>>
>>>>>>> --> Yak-List message
>>> posted by: Scott
>>>>> Poehlmann<scott-p@texas.net>
>>>>>>> Hi All,
>>>>>>>
>>>>>>> I am aware this has been discussed before,
>>> but as
>>>>> the
>>>>>>> problem now
>>>>>>> effects my own airplane, I have am a bit
>>> more
>>>>> attentive...
>>>>>>> I have a Yak 55M with an auto-plug
>>> conversion.
>>>>> The
>>>>>>> conversion has been
>>>>>>> in place for about 3 years now (roughly
>>> 400
>>>>> hours). I am
>>>>>>> now getting RF
>>>>>>> interference picked up in the Briz radio
>>> from the
>>>>> mags/plug
>>>>>>> wires. At
>>>>>>> least I assume that is the source, as it
>>> is RPM
>>>>> dependent.
>>>>>>> It has been
>>>>>>> present since installation, but has been
>>> gradually
>>>>> getting
>>>>>>> worse over
>>>>>>> the past year or so. I assume that there
>>> is a
>>>>> shielding
>>>>>>> issue either at
>>>>>>> the mag connection or along the wires
>>> somewhere.
>>>>> My
>>>>>>> question to you is
>>>>>>> where should I start to look at trouble
>>> shooting
>>>>> this
>>>>>>> issue, and how do
>>>>>>> I go about fixing it (shy of completely
>>> replacing
>>>>> the plug
>>>>>>> wires, which
>>>>>>> I'd prefer not to do... But will do if
>>> need
>>>>> be...)?
>>>>>>> Any thoughts you might have on the matter
>>> would
>>>>> be
>>>>>>> appreciated.
>>>>>>>
>>>>>>> Thanks,
>>>>>>>
>>>>>>> Scott Poehlmann
>>>>>>> Yak 55M N155YK
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>> Lists This Month --
>>>>>>> Some AWESOME FREE Gifts!)
>>>>>>> Raiser. Click on
>>>>>>> out more about
>>>>>>> Gifts provided
>>>>>>> www.aeroelectric.com
>>>>>>> www.buildersbooks.com
>>>>>>> www.homebuilthelp.com
>>>>>>>
>>>>> -Matt
>>>>>>> Dralle, List Admin.
>>>>>>> Forum -
>>>>>>> FAQ,
>>>>>>> - MATRONICS
>>> WEB FORUMS -
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>> Lists This Month --
>>>>> Some AWESOME FREE Gifts!)
>>>>> Raiser. Click on
>>>>> out more about
>>>>> Gifts provided
>>>>> www.aeroelectric.com
>>>>> www.buildersbooks.com
>>>>> www.homebuilthelp.com
>>>>>
>>> -Matt
>>>>> Dralle, List Admin.
>>>>> Forum -
>>>>> FAQ,
>>>>> - MATRONICS WEB FORUMS -
>>>>>
>>>>>
>>>>>
>>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>
>>>
>>>
>>> Lists This Month --
>>> Some AWESOME FREE Gifts!)
>>> Raiser. Click on
>>> out more about
>>> Gifts provided
>>> www.aeroelectric.com
>>> www.buildersbooks.com
>>> www.homebuilthelp.com
>>> -Matt
>>> Dralle, List Admin.
>>> Forum -
>>> FAQ,
>>> - MATRONICS WEB FORUMS -
>>>
>>>
>>>
>>>
>>
>>
>>
>>
>>
>>
>>
>
>
Message 3
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| Subject: | JL-7/Yak-152K History |
Craig,
I have been in contact with the chief designer of the light aircraft
division of the Yakovlev design bureau for many years. Craig is correct
about the design history. The brochure I published was given to me at
the Moscow air show two years ago.
It is my understanding that Voronezh was not able to supply engines.
In fact they ended up using new old stock and overhauled engines for the
last 50 Yak18T aircraft. There are serious questions as to Voronezh
factory ability to ever produce engines in the future. The M14
production there was only a very small part of their business even in
the old days in soviet times.
The Chinese bought 5 engines from the Motorstar Romanian factory as
they were the only ones able to supply New production engines. Motorstar
engineers are in China now to assist in the initial start and testing of
the aircraft. It is hoped that the Chinese will start production jointly
with the Romanian factory. There are still some "RIGHTS" to the design
issues that have to be resolved.
Interesting question about Sukhoi design bureau. It is my understanding
that the light aircraft design division was pretty much disbanded due to
lack of government support.
Some of the younger modern designers were subsequently employed by a
private firm. They have designed a light jet aircraft for a possible
military trainer and for a personal jet. It is an advanced composite two
place design. I am working with them sometimes on some issues. I have
attached a picture of the aircraft. They are looking to form a joint
venture here in the U.S. to manufacture and market the aircraft.
George Coy
Message 4
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I wonder why the Chinese did not use their own 400 HP H6K engine, I had
one of the few examples they built along with a 3 blade propeller.
It was a very smooth engine that adapted to the CJ6 easily.
Joe Howse
Message 5
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| Subject: | JL-7/Yak-152K History |
Craig,
I have been in contact with the chief designer of the light aircraft
division of the Yakovlev design bureau for many years. Craig is correct
about the design history. The brochure I published was given to me at
the Moscow air show two years ago.
It is my understanding that Voronezh was not able to supply engines.
In fact they ended up using new old stock and overhauled engines for the
last 50 Yak18T aircraft. There are serious questions as to Voronezh
factory ability to ever produce engines in the future. The M14
production there was only a very small part of their business even in
the old days in soviet times.
The Chinese bought 5 engines from the Motorstar Romanian factory as
they were the only ones able to supply New production engines. Motorstar
engineers are in China now to assist in the initial start and testing of
the aircraft. It is hoped that the Chinese will start production jointly
with the Romanian factory. There are still some "RIGHTS" to the design
issues that have to be resolved.
Interesting question about Sukhoi design bureau. It is my understanding
that the light aircraft design division was pretty much disbanded due to
lack of government support.
Some of the younger modern designers were subsequently employed by a
private firm. They have designed a light jet aircraft for a possible
military trainer and for a personal jet. It is an advanced composite two
place design. I am working with them sometimes on some issues. I have
attached a picture of the aircraft. They are looking to form a joint
venture here in the U.S. to manufacture and market the aircraft.
George Coy
Message 6
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| Subject: | Re: RF interference |
Good question.
Normally it is OK to ground both ends of the shield unless you are worried about
"shield conduction". This is a case where the shield that is grounded at both
ends in an aircraft becomes a better conductor of electricity than the frame
of the aircraft itself. Some folks refer to this as a "ground loop".
If you are worried about it, just ground one end. But honestly, I doubt if you
would have a problem grounding BOTH ends.
I really am not sure about the mag switch itself, but it should be already grounded.
Just using shielded wire on the P leads and grounding the shield at each
end should go miles and miles towards reducing noise.
Mark Bitterlich
--- On Sat, 12/18/10, Scott Poehlmann <scott-p@texas.net> wrote:
> From: Scott Poehlmann <scott-p@texas.net>
> Subject: Re: Yak-List: RF interference
> To: yak-list@matronics.com
> Date: Saturday, December 18, 2010, 10:43 PM
> Scott Poehlmann <scott-p@texas.net>
>
> Hi Mark,
>
> Of course this all makes sense, and you are right.
> Fortunately I have
> such a source readily available... the ATIS on the field at
> ELP is 11 NM
> away--straight LOS through a mountain. Under good
> circumstances it is
> just audible on my field (when the Mexican cell phones are
> playing
> tricks, it isn't audible at all, but that's another
> story...), so I can
> use that for the test you propose. I don't have access to a
> signal
> generator, nor do I have any interest in trying to mess
> with it beyond
> that which is required to obtain good communication in both
> directions.
>
> I am just happy it is something straightforward and not in
> the power
> system. I was not looking forward to that job. Frankly,
> shielding the
> wires from the mag switch to the tach should be easy (it's
> all behind
> the panel with a total run of less than 2 feet). Now the
> question which
> end to ground, and to what? Do you know if the housing of
> the mag switch
> will tolerate being grounded (perhaps it already IS
> grounded?) or does
> it need to "float"?
>
> Thanks,
>
> Scott
>
>
>
> On 12-18-2010 17:31, Yak Pilot wrote:
> Pilot<yakplt@yahoo.com>
> >
> > Scott, without going into a long discussion on how
> radios work, the simple fact is that you can not determine
> how much interference you are getting simply by plugging in
> the headset and listening for noise. Without using
> test equipment it is sometimes hard to quantify.
> >
> > However, there are some simple tests that allow the
> human ear to determine if you are being impacted by it or
> not.
> >
> > The most simple test is to tune the radio to a really
> weak signal that is just barely readable, and then start the
> engine and see how the noise impacts the reception of that
> signal. That can be hard to do at the airport where
> most RF sources are right there on the field. This
> test will only work if you can tune into a signal that is
> already right on the threshold of detection. If you
> can do that now, great. If not, you need a sig-gen and
> somebody who knows how to use it.
> >
> > Failing that, go fly and tune your radio into some
> ASOS or ATIS transmission a long way aways and listen to
> them. Then turn off the mags and see how much the
> signal improves. If it does, then you need to attack
> your shielding more vigorously. If turning the engine
> off with the mag switch does not impact your weak received
> signal at all, then you have done as much as you can to
> shield P leads. Crude but it will work..
> >
> > Mark Bitterlich
> >
> >
> > --- On Sat, 12/18/10, Scott Poehlmann<scott-p@texas.net>
> wrote:
> >
> >> From: Scott Poehlmann<scott-p@texas.net>
> >> Subject: Re: Yak-List: RF interference
> >> To: yak-list@matronics.com
> >> Date: Saturday, December 18, 2010, 5:37 PM
> >> Scott Poehlmann<scott-p@texas.net>
> >>
> >> Ahh.
> >>
> >> Perhaps I should shield the wires to the tach,
> too.
> >> The interference
> >> really does go away to essentially nothing (ok, I
> get an
> >> occasional
> >> "pop" or two, but NOTHING like before) when
> running on just
> >> Mag 1 now,
> >> so if I can accomplish the same thing with Mag 2,
> then I am
> >> happy.
> >>
> >> Will look into the shielding on those wires after
> fixing
> >> P-lead on Mag
> >> 2, and report back.
> >>
> >> Scott
> >>
> >> On 12-18-2010 13:46, Yak Pilot wrote:
> >>> -->Yak-List message
> posted by: Yak
> >> Pilot<yakplt@yahoo.com>
> >>>
> >>> Hmmm!
> >>>
> >>> I need to add one step to my troubleshooting
> >> procedures Scott:
> >>> Step Three: Have you added a digital
> tach that
> >> takes it's input off the P Leads. If so,
> that is very
> >> high potential for noise addition to your
> aircraft.
> >>> I actually thought of mentioning that, but
> since you
> >> did not bring it up in your initial email, I
> guessed
> >> (incorrectly) that you had not modified anything
> since you
> >> put in the new spark plugs and wire kit.
> >>> To answer your question: When pulling
> the Tach
> >> Drive, most of the folks I know have had a plate
> made that
> >> bolts on with the four corner bolts to the plate
> and there
> >> you go. You make it yourself. You need
> to be
> >> very very careful here, because if you remove the
> wrong
> >> "plate" you also will expose the gearing for the
> tach drive
> >> that also is part of the air distributor
> drive. What I
> >> am saying here is that if you pull the wrong
> plates and
> >> stuff in an attempt to put a new cover plate over
> the tach
> >> drive, you can easily disturb the gearing inside,
> which will
> >> in turn through your air start distributor out of
> adjustment
> >> and then you are DEEP KIMSHEE! Re-timing the
> airstart
> >> distributor is NOT EASY regardless of what anyone
> might tell
> >> you otherwise. So Scott, be very very
> careful of what
> >> you take apart in that area. Without photo's
> it is
> >> hard for me to describe what to take off and what
> not to
> >> take off. Talk to Dennis about that for
> details.
> >>> Somehow I just managed to send this message
> when my
> >> fingers slipped on the keyboard oops so here
> is the
> >> end of the message, sorry.
> >>> Going back to your noise on your radios.
> I hate
> >> to tell you this Scott, but those new digital
> tachs that
> >> attach to your P leads are a real source of radio
> >> noise. This is the forth time I have had a
> person who
> >> installed that tach start talking about radio
> noise. I
> >> also have personal experience with that thing
> myself.
> >>> Given that your Tach Generator is now removed
> from the
> >> aircraft, and you have installed the Digital Tach
> that used
> >> your P leads for a input, I am 99.999% sure that
> your new
> >> radio noise is from the P leads. Yes, you
> should
> >> repair the shields down at the MAGs and that
> will
> >> help. But you also are going to have to go
> back to the
> >> wires that have been attached behind the mag
> switch and make
> >> darn sure that shielded wires were used there as
> well.
> >> Just leaving a tiny bit of exposed wire (I.E.
> Where there is
> >> no shielding on the P leads) will allow that to
> act as an
> >> antenna and RADIATE NOISE all over the aircraft.
> >>> In one aircraft I worked on (a Sukhoi 26) I
> had to
> >> replace all of that wiring to the digital tach,
> and then...
> >> get ready for this.. I had to make an actual
> BOX out of
> >> aluminum and enclose the whole tach inside that
> box (a
> >> Faraday Shield per se) and ground all that.
> >>> So that is the downside of using that kind of
> Tach, I
> >> am sorry to have to say. Its a GREAT
> TACH, and I
> >> love the way it works, but since it uses the P
> leads, you
> >> have to really pay attention to your
> shielding. There
> >> is usually no filter that can eliminate this kind
> of
> >> noise. Spark noise is very broad spectrum
> and if you
> >> are anywhere in the near field from this noise,
> youre
> >> pretty much screwed.
> >>> One trick that SOMETIMES helps: Take a
> handheld
> >> VHF radio, remove the antenna and stick a
> paperclip into the
> >> center conductor of the antenna jack. Hook
> headphones
> >> to the handheld radio. Now start the
> aircraft and use
> >> the radio as a test wand and run it around
> the wiring
> >> to try and find the source. This is not easy
> and takes
> >> some effort.
> >>> Bottom line: Your noise is coming from
> your P
> >> leads and new tach. Good luck. Merry
> Christmas.
> >>> Mark Bitterlich
> >>>
> >>>
> >>> --- On Fri, 12/17/10, Scott Poehlmann<scott-p@texas.net>
> >> wrote:
> >>>> From: Scott Poehlmann<scott-p@texas.net>
> >>>> Subject: Re: Yak-List: RF interference
> >>>> To: yak-list@matronics.com
> >>>> Date: Friday, December 17, 2010, 9:03 PM
> >>>> -->Yak-List message
> posted by:
> >>>> Scott Poehlmann<scott-p@texas.net>
> >>>>
> >>>> Thanks Mark,
> >>>>
> >>>> I knew that you would have a great, step
> by step
> >> method.
> >>>> Went out to the hangar today: looks like
> the
> >> P-leads are
> >>>> the
> >>>> culprit--BOTH have the shielding detached
> from
> >> the
> >>>> connector and about 1
> >>>> cm of unshielded lead "hanging in the
> breeze".
> >> I'll spend
> >>>> some time
> >>>> tomorrow AM soldering the shielding to
> the
> >> connector (it
> >>>> appears that
> >>>> this has been done before and that the
> solder
> >> joints have
> >>>> failed...),
> >>>> and will advise if this doesn't fix the
> problem.
> >>>>
> >>>> Now for the next question: any ideas where
> to find
> >> a cover
> >>>> for the tach
> >>>> generator drive? I am running a Horizon
> digital
> >> tach (which
> >>>> takes its
> >>>> data from the mag--in fact it is wired
> into the
> >> back of the
> >>>> mag
> >>>> switch...), and I have no tach generator,
> just a
> >> big open
> >>>> fitting with a
> >>>> drive (and seal) at the bottom... Threaded
> on the
> >> outside,
> >>>> of course.
> >>>>
> >>>> Thanks again, and to everyone else who
> provided
> >>>> information. This list
> >>>> is a tremendous asset to the continued
> operation
> >> of these
> >>>> airplanes.
> >>>>
> >>>> Scott
> >>>>
> >>>> On 12-17-2010 10:15, Yak Pilot wrote:
> >>>>> --> Yak-List message
> >> posted by: Yak
> >>>> Pilot<yakplt@yahoo.com>
> >>>>> Do the following:
> >>>>>
> >>>>> Remove the plug from the Tach Gen and
> tie it
> >> back. Run
> >>>> the aircraft. Does the noise go
> away?
> >> Then it is
> >>>> indeed your Tach Gen and it is most
> likely
> >> shielding at the
> >>>> Tach Generator plug itself. Be
> careful
> >> taking this
> >>>> plug apart as it is common for the
> soldering on
> >> these wires
> >>>> to break.
> >>>>> If the noise does not go away, fly
> the
> >> airplane.
> >>>> Over the airport come to complete idle and
> then
> >> shut the
> >>>> mags off. Both mags, turn them off.
> >>>>> You're now a glider.
> >>>>>
> >>>>> Did the noise go away? If it
> did, then
> >> you have
> >>>> a MAG noise problem. The mag noise
> filters
> >> will help,
> >>>> but before you go to that effort, look at
> the P
> >> leak plugs
> >>>> that go into the side of the mags.
> It is
> >> very common
> >>>> for people to twist these plugs off during
> some
> >> kind of
> >>>> maint. action and in the process twist the
> shield
> >> right off
> >>>> the plug as well. If the P Lead is
> >> unshielded you will
> >>>> have one huge amount of noise.
> >>>>> If the noise is still there even when
> you
> >> have
> >>>> performed these steps (whcih is highly
> unlikely)
> >> then you've
> >>>> got some other device radiating energy in
> the
> >>>> aircraft. Start turning everything
> that you
> >> can off to
> >>>> try and identify it.
> >>>>> Suggestions have been made to see if
> it is
> >> coming in
> >>>> via the antenna or the power wiring.
> I have
> >> posted
> >>>> these suggestions before, but it is
> something you
> >> do at the
> >>>> end of troubleshooting and not the
> >> beginning. It is
> >>>> much easier to identify the noise source
> and
> >> eliminate it
> >>>> where it is coming from. If you
> can't
> >> identify the
> >>>> noise and you are lucky enough to have it
> coming
> >> in via the
> >>>> power wires (again this is rare), a choke
> on the
> >> input power
> >>>> wiring can help eliminate the noise.
> This
> >> can be as
> >>>> simple as a snap on torroid, or an
> expensive
> >> (purchased)
> >>>> filter, that is usually some sort of "Pi L
> brute
> >> force"
> >>>> filter consisting of two caps and an
> inductor.
> >>>> Usually, snap on torroids are just as
> effective
> >> and much
> >>>> cheaper. Again though, noise coming
> in via
> >> the power
> >>>> wiring is rare. It usually is coming
> in via
> >> the
> >>>> antenna, and that means you MUST eliminate
> the
> >> noise at it's
> >>>> source.
> >>>>> The tests described above will usually
> nail
> >> the
> >>>> problem in short order.
> >>>>> Mark Bitterlich
> >>>>>
> >>>>> p.s. The reason I recommend
> shutting the
> >> mags
> >>>> off at idle in flight versus doing it on
> the
> >> ground is
> >>>> because the engine keeps wind-milling even
> with
> >> the mags
> >>>> off, and you can leave them off much
> longer while
> >> you are
> >>>> listening for radio noise and seeing if it
> goes
> >> away.
> >>>> Shutting the engine off with the mags and
> the
> >> engine
> >>>> windmilling with it at idle will not hurt
> >> anything, although
> >>>> the engine will cool off really fast, so
> when you
> >> turn the
> >>>> mags back on and the engine once again is
> >> actually
> >>>> "running", don't just cob the power to
> 100%.
> >> Bring it
> >>>> in slowly. Common sense applies.
> >>>>> --- On Thu, 12/16/10, Roger Kemp
> M.D.<viperdoc@mindspring.com>
> >>>> wrote:
> >>>>>> From: Roger Kemp M.D.<viperdoc@mindspring.com>
> >>>>>> Subject: RE: Yak-List: RF
> interference
> >>>>>> To: yak-list@matronics.com
> >>>>>> Date: Thursday, December 16, 2010,
> 1:35
> >> PM
> >>>>>> --> Yak-List
> message
> >> posted by:
> >>>>>> "Roger Kemp M.D."<viperdoc@mindspring.com>
> >>>>>>
> >>>>>> Check the shielding on your Tac
> Generator.
> >> That is
> >>>> the most
> >>>>>> likely source
> >>>>>> for RPM related noise.
> >>>>>> Doc
> >>>>>>
> >>>>>> -----Original Message-----
> >>>>>> From: owner-yak-list-server@matronics.com
> >>>>>> [mailto:owner-yak-list-server@matronics.com]
> >>>>>> On Behalf Of Scott Poehlmann
> >>>>>> Sent: Thursday, December 16, 2010
> 5:07 AM
> >>>>>> To: yak-list@matronics.com
> >>>>>> Subject: Yak-List: RF
> interference
> >>>>>>
> >>>>>> --> Yak-List
> message
> >> posted by: Scott
> >>>> Poehlmann<scott-p@texas.net>
> >>>>>> Hi All,
> >>>>>>
> >>>>>> I am aware this has been discussed
> before,
> >> but as
> >>>> the
> >>>>>> problem now
> >>>>>> effects my own airplane, I have am
> a bit
> >> more
> >>>> attentive...
> >>>>>> I have a Yak 55M with an
> auto-plug
> >> conversion.
> >>>> The
> >>>>>> conversion has been
> >>>>>> in place for about 3 years now
> (roughly
> >> 400
> >>>> hours). I am
> >>>>>> now getting RF
> >>>>>> interference picked up in the Briz
> radio
> >> from the
> >>>> mags/plug
> >>>>>> wires. At
> >>>>>> least I assume that is the source,
> as it
> >> is RPM
> >>>> dependent.
> >>>>>> It has been
> >>>>>> present since installation, but
> has been
> >> gradually
> >>>> getting
> >>>>>> worse over
> >>>>>> the past year or so. I assume that
> there
> >> is a
> >>>> shielding
> >>>>>> issue either at
> >>>>>> the mag connection or along the
> wires
> >> somewhere.
> >>>> My
> >>>>>> question to you is
> >>>>>> where should I start to look at
> trouble
> >> shooting
> >>>> this
> >>>>>> issue, and how do
> >>>>>> I go about fixing it (shy of
> completely
> >> replacing
> >>>> the plug
> >>>>>> wires, which
> >>>>>> I'd prefer not to do... But will
> do if
> >> need
> >>>> be...)?
> >>>>>> Any thoughts you might have on the
> matter
> >> would
> >>>> be
> >>>>>> appreciated.
> >>>>>>
> >>>>>> Thanks,
> >>>>>>
> >>>>>> Scott Poehlmann
> >>>>>> Yak 55M N155YK
> >>>>>>
> >>>>>>
> >>>>>>
> >>>>>>
> >>>>>>
> >>>>>>
> >>>>>>
> >>>>>> Lists This Month --
> >>>>>> Some AWESOME FREE Gifts!)
> >>>>>> Raiser. Click on
> >>>>>> out more about
> >>>>>> Gifts provided
> >>>>>> www.aeroelectric.com
> >>>>>> www.buildersbooks.com
> >>>>>> www.homebuilthelp.com
> >>>>>>
> >>>> -Matt
> >>>>>> Dralle, List Admin.
> >>>>>> Forum -
> >>>>>> FAQ,
> >>>>>>
> - MATRONICS
> >> WEB FORUMS -
> >>>>>>
> >>>>>>
> >>>>>>
> >>>>>
> >>>>>
> >>>>>
> >>>>>
> >>>>>
> >>>> Lists This Month --
> >>>> Some AWESOME FREE Gifts!)
> >>>> Raiser. Click on
> >>>> out more about
> >>>> Gifts provided
> >>>> www.aeroelectric.com
> >>>> www.buildersbooks.com
> >>>> www.homebuilthelp.com
> >>>>
> >> -Matt
> >>>> Dralle, List Admin.
> >>>> Forum -
> >>>> FAQ,
> >>>> - MATRONICS
> WEB FORUMS -
> >>>>
> >>>>
> >>>>
> >>>>
> >>>
> >>>
> >>>
> >>>
> >>>
> >>>
> >>
> >>
> >>
> >> Lists This Month --
> >> Some AWESOME FREE Gifts!)
> >> Raiser. Click on
> >> out more about
> >> Gifts provided
> >> www.aeroelectric.com
> >> www.buildersbooks.com
> >> www.homebuilthelp.com
> >>
> -Matt
> >> Dralle, List Admin.
> >> Forum -
> >> FAQ,
> >> - MATRONICS WEB FORUMS -
> >>
> >>
> >>
> >>
> >
> >
> >
> >
> >
> >
> >
>
>
> Lists This Month --
> Some AWESOME FREE Gifts!)
> Raiser. Click on
> out more about
> Gifts provided
> www.aeroelectric.com
> www.buildersbooks.com
> www.homebuilthelp.com
> -Matt
> Dralle, List Admin.
> Forum -
> FAQ,
> - MATRONICS WEB FORUMS -
>
>
>
>
Message 7
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Is it definitely 400HP?
Do you know what changes they made?
Vedenyeev made a huge number of changes going from the AI14 [260HP],on
which the Chineese engine [285 HP] is based to the M14P [360 HP].
Richard
Richard Goode Aerobatics
Rhodds Farm
Lyonshall
Hereford
HR5 3LW
United Kingdom
Tel: +44 (0) 1544 340120
Fax: +44 (0) 1544 340129
www.russianaeros.com
----- Original Message -----
From: Joe Howse
To: Yak-List@Matronics.Com
Sent: Sunday, December 19, 2010 6:51 PM
Subject: Yak-List: l-7
I wonder why the Chinese did not use their own 400 HP H6K engine, I
had one of the few examples they built along with a 3 blade propeller.
It was a very smooth engine that adapted to the CJ6 easily.
Joe Howse
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