Today's Message Index:
----------------------
1. 08:17 AM - Re: Re: Engine roughness, as in stops. starts. stops. starts. (Bitterlich, Mark G CIV NAVAIR, WD)
2. 09:42 AM - Re: Re: Engine roughness, as in stops. starts. stops. starts. (Walter Lannon)
3. 11:46 AM - Re: Re: Engine roughness, as in stops. starts. stops. starts. (Bitterlich, Mark G CIV NAVAIR, WD)
4. 05:37 PM - Re: Re: Engine roughness, as in stops. starts. stops. starts. (Roger Kemp)
5. 08:41 PM - Re: Re: Engine roughness, as in stops. starts. stops. starts. (Jan Mevis)
6. 08:55 PM - Re: Re: Engine roughness, as in stops. starts. stops. starts. (Frank Stelwagon)
7. 09:14 PM - Re: Re: Engine roughness, as in stops. starts. stops. starts. (Jan Mevis)
Message 1
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| Subject: | Re: Engine roughness, as in stops. starts. stops. starts. |
Jan,
I never considered a corona in action. Just for the sake of discussion, I'll
mention that I measured the heat rise in a MSD Blaster II coil using an infra-red
gun and it is significant (and it is also oil filled), which is kind of why
I started wondering if it really is just engine heat that is involved. No
doubt heat is contributory, but while it might be an insignificant point, I question
whether it is all engine heat and not just self-induced, or maybe a combination
of both.
So I am trying to get my mind around this. Without creating an actual arc, the
corona should rob energy from the coil correct? Not to mention if there is
moist air...... there should be the formation of nitric acid, although since the
premise is that there is such a small amount of air and water available, that
might not be much ... but never-the-less there should be a chemical reaction
that also would be contributory to insulation loss.
Another thought is that the high voltage potential necessary for a corona to form
would not be present throughout the whole coil but instead only near a certain
percentage near the end where the voltage becomes "high enough" voltage to
create corona loss.
The problem I have with this explanation is understanding why it would make the
engine run rough, cough, lug, etc., with the opposite mag operating properly?
I can see where it could cause the engine to run rough or misfire on that one
mag, but how would it do it with both operating?
Mark
-----Original Message-----
From: owner-yak-list-server@matronics.com [mailto:owner-yak-list-server@matronics.com] On Behalf Of Jan Mevis
Sent: Wednesday, June 03, 2015 1:06 AM
Subject: Re: Yak-List: Re: Engine roughness, as in stops. starts. stops. starts.
Hi Mark, Walt,
What I think that happens, is corona discharge in the coil.
Typically these coils start malfunctioning after 20, 30 minutes, when the heat
of the engine is well diffused into the coil.
Corona discharge is caused by imperfections in the insulation of the coil.
The original Russian (and I suppose the same for the Chinese) coils were made manually
(in labour camps !) and layer after layer of winding, insulation resins
are applied.
These resins are diluted with solvents for better applicance. And that's where
it goes wrong after some years.
The solvents evaporate and create tiny tunnels in the coil where moist air can
get trapped.
Then at higher temperature, you get discharging but not a real electrical breakdown.
So once the coil cools down again, everything is normal again and subsequent testing
on the ground reveals no problem anymore.
The difficult issue in this theory is that we don't have an exact picture of how
it exactly happens.
I'd like to SEE it happen, but I don't have the money to investigate that.
Of course you can get other problems such as a failing capacitor.
This capacitor is only two tiny sheets of metal wrapped around with the same insulation
material applied in between.
The capacitance is rather low and if you measure it between different coils, it
varies substantially.
Modern ways of making coils first use high vacuum procedures to evacuate all the
air.
Then high-quality insulation products are applied under high pressure.
Since the wire of the secondary is so thin, it's an art to warrant the insulation
product being well applied everywhere. That's why making a new coil is expensive.
In order to achieve a perfect insulation, you don't re-use the bakelite flanges,
but modern transformer cardboard that gets well penetrated with insulation product.
Only my 2 cents,
Jan
On 02/06/15 22:16, "Bitterlich, Mark G CIV NAVAIR, WD"
<mark.bitterlich@navy.mil> wrote:
><mark.bitterlich@navy.mil>
>
>Walt > I have been trying to get my head around this theory of a
>"massive discharge" etc. but have been too busy of late to sit down and think
it
>through. So far it just doesn't compute.
>
>I concur. There is no failure mode that can occur that would increase
>the intensity of the firing pulse above what it was designed to provide.
>
>Walt > I have had only one coil failure in forty years of playing with
>radial engines. That was in a Harvard with Bosch mags. That mag simply
>quit
>working, not intermittent, no bangs or whatever just simply and
>permanently dead.
>
>The interesting thing about the original Russian coil designs is that
>the condenser is actually integral and internal to the coil itself.
>Rather unusual. Since coils get hot, this also means the trapped heat
>is applied to the condenser as well. The common discussion theme
>regarding the topic under discussion (which is: Engine roughness, as in stops.
>starts. stops. starts.) is that it is related to "engine heat".
>Actually, I believe that is not quite accurate. I personally believe
>the problem is related to HEAT IN THE COIL, which is not necessarily
>synonymous with engine heat. In addition, since the coil assembly is
>internal to the mag, there is no easy way to get rid of that heat and
>it becomes cumulative.
>
>If that premise is accurate, then emphasis might be placed on what
>external factors increase heat in the coil since regardless of whether
>we are talking coil windings, or condenser malfunction, heat is the enemy.
>Kind of an "AHA" moment. Things such as spark plug gap, what spark
>plug wires are used, point dwell (!!), etc., all would impact coil heat.
>
>Best to you Walt,
>
>Mark
>
>
>
>----Original Message-----
>From: owner-yak-list-server@matronics.com
>[mailto:owner-yak-list-server@matronics.com] On Behalf Of Walter Lannon
>Sent: Monday, June 01, 2015 10:31 PM
>To: yak-list@matronics.com
>Subject: Re: Yak-List: Re: Engine roughness, as in stops. starts. stops.
>starts.
>
>
>Mark;
>
>I have been trying to get my head around this theory of a "massive
>discharge" etc. but have been too busy of late to sit down and think it
>through. So far it just doesn't compute.
>I have had only one coil failure in forty years of playing with radial
>engines. That was in a Harvard with Bosch mags. That mag simply quit
>working, not intermittent, no bangs or whatever just simply and
>permanently dead.
>Right now dead tired and another full day tomorrow.
>
>Cheers;
>Walt
>
>
>-----Original Message-----
>From: Bitterlich, Mark G CIV NAVAIR, WD
>Sent: Monday, June 01, 2015 8:00 AM
>To: yak-list@matronics.com
>Subject: RE: Yak-List: Re: Engine roughness, as in stops. starts. stops.
>starts.
>
><mark.bitterlich@navy.mil>
>
>
>Well.. Doc, I think there might have been a misunderstanding somewhere
>along the line. This is not a reasonable explanation.
>
>
>-----Original Message-----
>From: owner-yak-list-server@matronics.com
>[mailto:owner-yak-list-server@matronics.com] On Behalf Of Roger Kemp
>Sent: Sunday, May 31, 2015 12:48 PM
>To: yak-list@matronics.com
>Subject: Re: Yak-List: Re: Engine roughness, as in stops. starts. stops.
>starts.
>
>
>As explained by the Lithuanian engineers the massive discharge with the
>heat induced break down of the capacitor in the coil results in arcing
>in the distributor cap so that discharge flows / jumps to the next
>cylinder in line on the intake stroke. With the intake valve open when
>that aberrant discharge arrives the spark will consume the supercharger
>contents. The backfire is most likely through the carb when the charge
>is consumed.
>The pilots of the aircraft in formation with me said they saw a sudden
>belch of black smoke from under the chin of my bird. I felt the
>hesitation as well as saw the momentary hesitation of the prop slowing.
>Then the engine picked back up like nothing occurred. Have had that
>happen twice since owning my 52. Did an airborne mag check the second
>time with the engine quitting on selection of the #1 mag. In both cases
>changing the mag coils resolved the problem.
>Litaurus and Termikus are the bearers of that tidbit of info. Made
>sense to me then and now.
>Doc
>
>Sent from my iPad
>
>> On May 31, 2015, at 3:38 AM, JL2A <info@flyingwarbirds.com.au> wrote:
>>
>>
>> I'm with Egon, getting an engine anywhere near 200C on the ground is
>>very hard on them, let alone 250C. Without the proper cooling airflow
>>wrapping around the cylinders they are getting unevenly hot, with
>>hotspots that may exceed the temperature of where the thermocouple is
>>placed.
>>
>> I've got to ask - what are we talking about lighting the whole
>> supercharger 'charge' on fire?
>>
>> Do they mean the spark is so advanced it lights off way early and the
>> flame front travels backwards through the induction system? Is this
>> even physically at anything above starting RPM?
>>
>>
>>
>>
>> Read this topic online here:
>>
>> http://forums.matronics.com/viewtopic.php?p=442829#442829
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>
>
Message 2
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|
| Subject: | Re: Engine roughness, as in stops. starts. stops. starts. |
Mark and Jan;
Many thanks for your expertise in this area. I begin to understand why
this mag. coil assy. is so prone to failure as compared other manufacturers
products.
Also realize my knowledge in this area is primitive at best and will rely on
both of you to solve the mystery.
Best:
Walt
-----Original Message-----
From: Bitterlich, Mark G CIV NAVAIR, WD
Sent: Wednesday, June 03, 2015 8:16 AM
Subject: RE: Yak-List: Re: Engine roughness, as in stops. starts. stops.
starts.
<mark.bitterlich@navy.mil>
Jan,
I never considered a corona in action. Just for the sake of discussion,
I'll mention that I measured the heat rise in a MSD Blaster II coil using an
infra-red gun and it is significant (and it is also oil filled), which is
kind of why I started wondering if it really is just engine heat that is
involved. No doubt heat is contributory, but while it might be an
insignificant point, I question whether it is all engine heat and not just
self-induced, or maybe a combination of both.
So I am trying to get my mind around this. Without creating an actual arc,
the corona should rob energy from the coil correct? Not to mention if
there is moist air...... there should be the formation of nitric acid,
although since the premise is that there is such a small amount of air and
water available, that might not be much ... but never-the-less there should
be a chemical reaction that also would be contributory to insulation loss.
Another thought is that the high voltage potential necessary for a corona to
form would not be present throughout the whole coil but instead only near a
certain percentage near the end where the voltage becomes "high enough"
voltage to create corona loss.
The problem I have with this explanation is understanding why it would make
the engine run rough, cough, lug, etc., with the opposite mag operating
properly? I can see where it could cause the engine to run rough or
misfire on that one mag, but how would it do it with both operating?
Mark
-----Original Message-----
From: owner-yak-list-server@matronics.com
[mailto:owner-yak-list-server@matronics.com] On Behalf Of Jan Mevis
Sent: Wednesday, June 03, 2015 1:06 AM
Subject: Re: Yak-List: Re: Engine roughness, as in stops. starts. stops.
starts.
Hi Mark, Walt,
What I think that happens, is corona discharge in the coil.
Typically these coils start malfunctioning after 20, 30 minutes, when the
heat of the engine is well diffused into the coil.
Corona discharge is caused by imperfections in the insulation of the coil.
The original Russian (and I suppose the same for the Chinese) coils were
made manually (in labour camps !) and layer after layer of winding,
insulation resins are applied.
These resins are diluted with solvents for better applicance. And that's
where it goes wrong after some years.
The solvents evaporate and create tiny tunnels in the coil where moist air
can get trapped.
Then at higher temperature, you get discharging but not a real electrical
breakdown.
So once the coil cools down again, everything is normal again and subsequent
testing on the ground reveals no problem anymore.
The difficult issue in this theory is that we don't have an exact picture of
how it exactly happens.
I'd like to SEE it happen, but I don't have the money to investigate that.
Of course you can get other problems such as a failing capacitor.
This capacitor is only two tiny sheets of metal wrapped around with the same
insulation material applied in between.
The capacitance is rather low and if you measure it between different coils,
it varies substantially.
Modern ways of making coils first use high vacuum procedures to evacuate all
the air.
Then high-quality insulation products are applied under high pressure.
Since the wire of the secondary is so thin, it's an art to warrant the
insulation product being well applied everywhere. That's why making a new
coil is expensive.
In order to achieve a perfect insulation, you don't re-use the bakelite
flanges, but modern transformer cardboard that gets well penetrated with
insulation product.
Only my 2 cents,
Jan
On 02/06/15 22:16, "Bitterlich, Mark G CIV NAVAIR, WD"
<mark.bitterlich@navy.mil> wrote:
><mark.bitterlich@navy.mil>
>
>Walt > I have been trying to get my head around this theory of a
>"massive discharge" etc. but have been too busy of late to sit down and
>think it
>through. So far it just doesn't compute.
>
>I concur. There is no failure mode that can occur that would increase
>the intensity of the firing pulse above what it was designed to provide.
>
>Walt > I have had only one coil failure in forty years of playing with
>radial engines. That was in a Harvard with Bosch mags. That mag simply
>quit
>working, not intermittent, no bangs or whatever just simply and
>permanently dead.
>
>The interesting thing about the original Russian coil designs is that
>the condenser is actually integral and internal to the coil itself.
>Rather unusual. Since coils get hot, this also means the trapped heat
>is applied to the condenser as well. The common discussion theme
>regarding the topic under discussion (which is: Engine roughness, as in
>stops.
>starts. stops. starts.) is that it is related to "engine heat".
>Actually, I believe that is not quite accurate. I personally believe
>the problem is related to HEAT IN THE COIL, which is not necessarily
>synonymous with engine heat. In addition, since the coil assembly is
>internal to the mag, there is no easy way to get rid of that heat and
>it becomes cumulative.
>
>If that premise is accurate, then emphasis might be placed on what
>external factors increase heat in the coil since regardless of whether
>we are talking coil windings, or condenser malfunction, heat is the enemy.
>Kind of an "AHA" moment. Things such as spark plug gap, what spark
>plug wires are used, point dwell (!!), etc., all would impact coil heat.
>
>Best to you Walt,
>
>Mark
>
>
>----Original Message-----
>From: owner-yak-list-server@matronics.com
>[mailto:owner-yak-list-server@matronics.com] On Behalf Of Walter Lannon
>Sent: Monday, June 01, 2015 10:31 PM
>To: yak-list@matronics.com
>Subject: Re: Yak-List: Re: Engine roughness, as in stops. starts. stops.
>starts.
>
>
>Mark;
>
>I have been trying to get my head around this theory of a "massive
>discharge" etc. but have been too busy of late to sit down and think it
>through. So far it just doesn't compute.
>I have had only one coil failure in forty years of playing with radial
>engines. That was in a Harvard with Bosch mags. That mag simply quit
>working, not intermittent, no bangs or whatever just simply and
>permanently dead.
>Right now dead tired and another full day tomorrow.
>
>Cheers;
>Walt
>
>
>-----Original Message-----
>From: Bitterlich, Mark G CIV NAVAIR, WD
>Sent: Monday, June 01, 2015 8:00 AM
>To: yak-list@matronics.com
>Subject: RE: Yak-List: Re: Engine roughness, as in stops. starts. stops.
>starts.
>
><mark.bitterlich@navy.mil>
>
>
>Well.. Doc, I think there might have been a misunderstanding somewhere
>along the line. This is not a reasonable explanation.
>
>
>-----Original Message-----
>From: owner-yak-list-server@matronics.com
>[mailto:owner-yak-list-server@matronics.com] On Behalf Of Roger Kemp
>Sent: Sunday, May 31, 2015 12:48 PM
>To: yak-list@matronics.com
>Subject: Re: Yak-List: Re: Engine roughness, as in stops. starts. stops.
>starts.
>
>
>As explained by the Lithuanian engineers the massive discharge with the
>heat induced break down of the capacitor in the coil results in arcing
>in the distributor cap so that discharge flows / jumps to the next
>cylinder in line on the intake stroke. With the intake valve open when
>that aberrant discharge arrives the spark will consume the supercharger
>contents. The backfire is most likely through the carb when the charge
>is consumed.
>The pilots of the aircraft in formation with me said they saw a sudden
>belch of black smoke from under the chin of my bird. I felt the
>hesitation as well as saw the momentary hesitation of the prop slowing.
>Then the engine picked back up like nothing occurred. Have had that
>happen twice since owning my 52. Did an airborne mag check the second
>time with the engine quitting on selection of the #1 mag. In both cases
>changing the mag coils resolved the problem.
>Litaurus and Termikus are the bearers of that tidbit of info. Made
>sense to me then and now.
>Doc
>
>Sent from my iPad
>
>> On May 31, 2015, at 3:38 AM, JL2A <info@flyingwarbirds.com.au> wrote:
>>
>>
>> I'm with Egon, getting an engine anywhere near 200C on the ground is
>>very hard on them, let alone 250C. Without the proper cooling airflow
>>wrapping around the cylinders they are getting unevenly hot, with
>>hotspots that may exceed the temperature of where the thermocouple is
>>placed.
>>
>> I've got to ask - what are we talking about lighting the whole
>> supercharger 'charge' on fire?
>>
>> Do they mean the spark is so advanced it lights off way early and the
>> flame front travels backwards through the induction system? Is this
>> even physically at anything above starting RPM?
>>
>>
>>
>>
>> Read this topic online here:
>>
>> http://forums.matronics.com/viewtopic.php?p=442829#442829
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>
>
Message 3
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| Subject: | Re: Engine roughness, as in stops. starts. stops. starts. |
I honestly don't think that is going to happen conclusively Walt.
Thanks,
Mark
-----Original Message-----
From: owner-yak-list-server@matronics.com [mailto:owner-yak-list-server@matronics.com] On Behalf Of Walter Lannon
Sent: Wednesday, June 03, 2015 12:42 PM
Subject: Re: Yak-List: Re: Engine roughness, as in stops. starts. stops. starts.
Mark and Jan;
Many thanks for your expertise in this area. I begin to understand why
this mag. coil assy. is so prone to failure as compared other manufacturers products.
Also realize my knowledge in this area is primitive at best and will rely on both
of you to solve the mystery.
Best:
Walt
-----Original Message-----
From: Bitterlich, Mark G CIV NAVAIR, WD
Sent: Wednesday, June 03, 2015 8:16 AM
Subject: RE: Yak-List: Re: Engine roughness, as in stops. starts. stops.
starts.
<mark.bitterlich@navy.mil>
Jan,
I never considered a corona in action. Just for the sake of discussion,
I'll mention that I measured the heat rise in a MSD Blaster II coil using an infra-red
gun and it is significant (and it is also oil filled), which is kind of
why I started wondering if it really is just engine heat that is
involved. No doubt heat is contributory, but while it might be an
insignificant point, I question whether it is all engine heat and not just self-induced,
or maybe a combination of both.
So I am trying to get my mind around this. Without creating an actual arc,
the corona should rob energy from the coil correct? Not to mention if
there is moist air...... there should be the formation of nitric acid, although
since the premise is that there is such a small amount of air and water available,
that might not be much ... but never-the-less there should be a chemical
reaction that also would be contributory to insulation loss.
Another thought is that the high voltage potential necessary for a corona to form
would not be present throughout the whole coil but instead only near a certain
percentage near the end where the voltage becomes "high enough"
voltage to create corona loss.
The problem I have with this explanation is understanding why it would make the
engine run rough, cough, lug, etc., with the opposite mag operating
properly? I can see where it could cause the engine to run rough or
misfire on that one mag, but how would it do it with both operating?
Mark
-----Original Message-----
From: owner-yak-list-server@matronics.com
[mailto:owner-yak-list-server@matronics.com] On Behalf Of Jan Mevis
Sent: Wednesday, June 03, 2015 1:06 AM
Subject: Re: Yak-List: Re: Engine roughness, as in stops. starts. stops.
starts.
Hi Mark, Walt,
What I think that happens, is corona discharge in the coil.
Typically these coils start malfunctioning after 20, 30 minutes, when the heat
of the engine is well diffused into the coil.
Corona discharge is caused by imperfections in the insulation of the coil.
The original Russian (and I suppose the same for the Chinese) coils were made manually
(in labour camps !) and layer after layer of winding, insulation resins
are applied.
These resins are diluted with solvents for better applicance. And that's where
it goes wrong after some years.
The solvents evaporate and create tiny tunnels in the coil where moist air can
get trapped.
Then at higher temperature, you get discharging but not a real electrical breakdown.
So once the coil cools down again, everything is normal again and subsequent testing
on the ground reveals no problem anymore.
The difficult issue in this theory is that we don't have an exact picture of how
it exactly happens.
I'd like to SEE it happen, but I don't have the money to investigate that.
Of course you can get other problems such as a failing capacitor.
This capacitor is only two tiny sheets of metal wrapped around with the same insulation
material applied in between.
The capacitance is rather low and if you measure it between different coils, it
varies substantially.
Modern ways of making coils first use high vacuum procedures to evacuate all the
air.
Then high-quality insulation products are applied under high pressure.
Since the wire of the secondary is so thin, it's an art to warrant the insulation
product being well applied everywhere. That's why making a new coil is expensive.
In order to achieve a perfect insulation, you don't re-use the bakelite flanges,
but modern transformer cardboard that gets well penetrated with insulation product.
Only my 2 cents,
Jan
On 02/06/15 22:16, "Bitterlich, Mark G CIV NAVAIR, WD"
<mark.bitterlich@navy.mil> wrote:
><mark.bitterlich@navy.mil>
>
>Walt > I have been trying to get my head around this theory of a
>"massive discharge" etc. but have been too busy of late to sit down and
>think it
>through. So far it just doesn't compute.
>
>I concur. There is no failure mode that can occur that would increase
>the intensity of the firing pulse above what it was designed to provide.
>
>Walt > I have had only one coil failure in forty years of playing with
>radial engines. That was in a Harvard with Bosch mags. That mag simply
>quit
>working, not intermittent, no bangs or whatever just simply and
>permanently dead.
>
>The interesting thing about the original Russian coil designs is that
>the condenser is actually integral and internal to the coil itself.
>Rather unusual. Since coils get hot, this also means the trapped heat
>is applied to the condenser as well. The common discussion theme
>regarding the topic under discussion (which is: Engine roughness, as
>in stops.
>starts. stops. starts.) is that it is related to "engine heat".
>Actually, I believe that is not quite accurate. I personally believe
>the problem is related to HEAT IN THE COIL, which is not necessarily
>synonymous with engine heat. In addition, since the coil assembly is
>internal to the mag, there is no easy way to get rid of that heat and
>it becomes cumulative.
>
>If that premise is accurate, then emphasis might be placed on what
>external factors increase heat in the coil since regardless of whether
>we are talking coil windings, or condenser malfunction, heat is the enemy.
>Kind of an "AHA" moment. Things such as spark plug gap, what spark
>plug wires are used, point dwell (!!), etc., all would impact coil heat.
>
>Best to you Walt,
>
>Mark
>
>
>----Original Message-----
>From: owner-yak-list-server@matronics.com
>[mailto:owner-yak-list-server@matronics.com] On Behalf Of Walter Lannon
>Sent: Monday, June 01, 2015 10:31 PM
>To: yak-list@matronics.com
>Subject: Re: Yak-List: Re: Engine roughness, as in stops. starts. stops.
>starts.
>
>
>Mark;
>
>I have been trying to get my head around this theory of a "massive
>discharge" etc. but have been too busy of late to sit down and think it
>through. So far it just doesn't compute.
>I have had only one coil failure in forty years of playing with radial
>engines. That was in a Harvard with Bosch mags. That mag simply quit
>working, not intermittent, no bangs or whatever just simply and
>permanently dead.
>Right now dead tired and another full day tomorrow.
>
>Cheers;
>Walt
>
>
>-----Original Message-----
>From: Bitterlich, Mark G CIV NAVAIR, WD
>Sent: Monday, June 01, 2015 8:00 AM
>To: yak-list@matronics.com
>Subject: RE: Yak-List: Re: Engine roughness, as in stops. starts. stops.
>starts.
>
><mark.bitterlich@navy.mil>
>
>
>Well.. Doc, I think there might have been a misunderstanding somewhere
>along the line. This is not a reasonable explanation.
>
>
>-----Original Message-----
>From: owner-yak-list-server@matronics.com
>[mailto:owner-yak-list-server@matronics.com] On Behalf Of Roger Kemp
>Sent: Sunday, May 31, 2015 12:48 PM
>To: yak-list@matronics.com
>Subject: Re: Yak-List: Re: Engine roughness, as in stops. starts. stops.
>starts.
>
>
>As explained by the Lithuanian engineers the massive discharge with the
>heat induced break down of the capacitor in the coil results in arcing
>in the distributor cap so that discharge flows / jumps to the next
>cylinder in line on the intake stroke. With the intake valve open when
>that aberrant discharge arrives the spark will consume the supercharger
>contents. The backfire is most likely through the carb when the charge
>is consumed.
>The pilots of the aircraft in formation with me said they saw a sudden
>belch of black smoke from under the chin of my bird. I felt the
>hesitation as well as saw the momentary hesitation of the prop slowing.
>Then the engine picked back up like nothing occurred. Have had that
>happen twice since owning my 52. Did an airborne mag check the second
>time with the engine quitting on selection of the #1 mag. In both cases
>changing the mag coils resolved the problem.
>Litaurus and Termikus are the bearers of that tidbit of info. Made
>sense to me then and now.
>Doc
>
>Sent from my iPad
>
>> On May 31, 2015, at 3:38 AM, JL2A <info@flyingwarbirds.com.au> wrote:
>>
>>
>> I'm with Egon, getting an engine anywhere near 200C on the ground is
>>very hard on them, let alone 250C. Without the proper cooling airflow
>>wrapping around the cylinders they are getting unevenly hot, with
>>hotspots that may exceed the temperature of where the thermocouple is
>>placed.
>>
>> I've got to ask - what are we talking about lighting the whole
>> supercharger 'charge' on fire?
>>
>> Do they mean the spark is so advanced it lights off way early and the
>> flame front travels backwards through the induction system? Is this
>> even physically at anything above starting RPM?
>>
>>
>>
>>
>> Read this topic online here:
>>
>> http://forums.matronics.com/viewtopic.php?p=442829#442829
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>
>
Message 4
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| Subject: | Re: Engine roughness, as in stops. starts. stops. starts. |
Okay, can the spear be removed now? In layman's terms the aged coil broke down
under chronic heat load from who knows why and puked a high voltage discharge
that resulted in a misfire somewhere in the bowels of the engine that consumed
enough fuel charge to make the engine stop for a heartbeat puking black smoke
out of somewhere under the chin of the engine cowl resulting in sucking of the
seat pack up mine and Mongooses collective asses before the prop resumed making
thrusties and we aborted the flight landing at the nearest paved Terra firma!
For those that have never had the experience...it is fucking impressive! Not
quit as impressive as a main bearing failure in a GE 100 though. Luckily that
came on engine start. Shut that puppy down and we handed the keys back to chief
and stepped to the spare.
Anyway as I said in my one liner early in this diatribe of a thread...change the
fucking coil or both coils...it will fix the problem and you will sleep better
knowing your little magnetos are again making voltage for your spark plugs
in the normal firing order so you can break the bonds of Terra firma and look
down on all the poor schmucks stuck on the interstates trudging along never knowing
the pleasures of dancing with the wind and cloud chasing !
Nuf said.
Doc
Sent from my iPad
> On Jun 3, 2015, at 10:16 AM, Bitterlich, Mark G CIV NAVAIR, WD <mark.bitterlich@navy.mil>
wrote:
>
>
> Jan,
>
> I never considered a corona in action. Just for the sake of discussion, I'll
mention that I measured the heat rise in a MSD Blaster II coil using an infra-red
gun and it is significant (and it is also oil filled), which is kind of
why I started wondering if it really is just engine heat that is involved. No
doubt heat is contributory, but while it might be an insignificant point, I
question whether it is all engine heat and not just self-induced, or maybe a
combination of both.
>
> So I am trying to get my mind around this. Without creating an actual arc, the
corona should rob energy from the coil correct? Not to mention if there is
moist air...... there should be the formation of nitric acid, although since
the premise is that there is such a small amount of air and water available,
that might not be much ... but never-the-less there should be a chemical reaction
that also would be contributory to insulation loss.
>
> Another thought is that the high voltage potential necessary for a corona to
form would not be present throughout the whole coil but instead only near a certain
percentage near the end where the voltage becomes "high enough" voltage
to create corona loss.
>
> The problem I have with this explanation is understanding why it would make the
engine run rough, cough, lug, etc., with the opposite mag operating properly?
I can see where it could cause the engine to run rough or misfire on that
one mag, but how would it do it with both operating?
>
> Mark
>
>
>
>
> -----Original Message-----
> From: owner-yak-list-server@matronics.com [mailto:owner-yak-list-server@matronics.com] On Behalf Of Jan Mevis
> Sent: Wednesday, June 03, 2015 1:06 AM
> To: yak-list@matronics.com
> Subject: Re: Yak-List: Re: Engine roughness, as in stops. starts. stops. starts.
>
>
> Hi Mark, Walt,
>
> What I think that happens, is corona discharge in the coil.
> Typically these coils start malfunctioning after 20, 30 minutes, when the heat
of the engine is well diffused into the coil.
> Corona discharge is caused by imperfections in the insulation of the coil.
>
> The original Russian (and I suppose the same for the Chinese) coils were made
manually (in labour camps !) and layer after layer of winding, insulation resins
are applied.
> These resins are diluted with solvents for better applicance. And that's where
it goes wrong after some years.
>
> The solvents evaporate and create tiny tunnels in the coil where moist air can
get trapped.
> Then at higher temperature, you get discharging but not a real electrical breakdown.
>
> So once the coil cools down again, everything is normal again and subsequent
testing on the ground reveals no problem anymore.
>
> The difficult issue in this theory is that we don't have an exact picture of
how it exactly happens.
> I'd like to SEE it happen, but I don't have the money to investigate that.
>
> Of course you can get other problems such as a failing capacitor.
> This capacitor is only two tiny sheets of metal wrapped around with the same
insulation material applied in between.
> The capacitance is rather low and if you measure it between different coils,
it varies substantially.
>
> Modern ways of making coils first use high vacuum procedures to evacuate all
the air.
>
> Then high-quality insulation products are applied under high pressure.
>
> Since the wire of the secondary is so thin, it's an art to warrant the insulation
product being well applied everywhere. That's why making a new coil is expensive.
>
> In order to achieve a perfect insulation, you don't re-use the bakelite flanges,
but modern transformer cardboard that gets well penetrated with insulation
product.
>
>
> Only my 2 cents,
>
> Jan
>
>
>
> On 02/06/15 22:16, "Bitterlich, Mark G CIV NAVAIR, WD"
> <mark.bitterlich@navy.mil> wrote:
>
>> <mark.bitterlich@navy.mil>
>>
>> Walt > I have been trying to get my head around this theory of a
>> "massive discharge" etc. but have been too busy of late to sit down and think
it
>> through. So far it just doesn't compute.
>>
>> I concur. There is no failure mode that can occur that would increase
>> the intensity of the firing pulse above what it was designed to provide.
>>
>> Walt > I have had only one coil failure in forty years of playing with
>> radial engines. That was in a Harvard with Bosch mags. That mag simply
>> quit
>> working, not intermittent, no bangs or whatever just simply and
>> permanently dead.
>>
>> The interesting thing about the original Russian coil designs is that
>> the condenser is actually integral and internal to the coil itself.
>> Rather unusual. Since coils get hot, this also means the trapped heat
>> is applied to the condenser as well. The common discussion theme
>> regarding the topic under discussion (which is: Engine roughness, as in stops.
>> starts. stops. starts.) is that it is related to "engine heat".
>> Actually, I believe that is not quite accurate. I personally believe
>> the problem is related to HEAT IN THE COIL, which is not necessarily
>> synonymous with engine heat. In addition, since the coil assembly is
>> internal to the mag, there is no easy way to get rid of that heat and
>> it becomes cumulative.
>>
>> If that premise is accurate, then emphasis might be placed on what
>> external factors increase heat in the coil since regardless of whether
>> we are talking coil windings, or condenser malfunction, heat is the enemy.
>> Kind of an "AHA" moment. Things such as spark plug gap, what spark
>> plug wires are used, point dwell (!!), etc., all would impact coil heat.
>>
>> Best to you Walt,
>>
>> Mark
>>
>>
>>
>>
>> ----Original Message-----
>> From: owner-yak-list-server@matronics.com
>> [mailto:owner-yak-list-server@matronics.com] On Behalf Of Walter Lannon
>> Sent: Monday, June 01, 2015 10:31 PM
>> To: yak-list@matronics.com
>> Subject: Re: Yak-List: Re: Engine roughness, as in stops. starts. stops.
>> starts.
>>
>>
>> Mark;
>>
>> I have been trying to get my head around this theory of a "massive
>> discharge" etc. but have been too busy of late to sit down and think it
>> through. So far it just doesn't compute.
>> I have had only one coil failure in forty years of playing with radial
>> engines. That was in a Harvard with Bosch mags. That mag simply quit
>> working, not intermittent, no bangs or whatever just simply and
>> permanently dead.
>> Right now dead tired and another full day tomorrow.
>>
>> Cheers;
>> Walt
>>
>>
>> -----Original Message-----
>> From: Bitterlich, Mark G CIV NAVAIR, WD
>> Sent: Monday, June 01, 2015 8:00 AM
>> To: yak-list@matronics.com
>> Subject: RE: Yak-List: Re: Engine roughness, as in stops. starts. stops.
>> starts.
>>
>> <mark.bitterlich@navy.mil>
>>
>>
>> Well.. Doc, I think there might have been a misunderstanding somewhere
>> along the line. This is not a reasonable explanation.
>>
>>
>>
>> -----Original Message-----
>> From: owner-yak-list-server@matronics.com
>> [mailto:owner-yak-list-server@matronics.com] On Behalf Of Roger Kemp
>> Sent: Sunday, May 31, 2015 12:48 PM
>> To: yak-list@matronics.com
>> Subject: Re: Yak-List: Re: Engine roughness, as in stops. starts. stops.
>> starts.
>>
>>
>> As explained by the Lithuanian engineers the massive discharge with the
>> heat induced break down of the capacitor in the coil results in arcing
>> in the distributor cap so that discharge flows / jumps to the next
>> cylinder in line on the intake stroke. With the intake valve open when
>> that aberrant discharge arrives the spark will consume the supercharger
>> contents. The backfire is most likely through the carb when the charge
>> is consumed.
>> The pilots of the aircraft in formation with me said they saw a sudden
>> belch of black smoke from under the chin of my bird. I felt the
>> hesitation as well as saw the momentary hesitation of the prop slowing.
>> Then the engine picked back up like nothing occurred. Have had that
>> happen twice since owning my 52. Did an airborne mag check the second
>> time with the engine quitting on selection of the #1 mag. In both cases
>> changing the mag coils resolved the problem.
>> Litaurus and Termikus are the bearers of that tidbit of info. Made
>> sense to me then and now.
>> Doc
>>
>> Sent from my iPad
>>
>>> On May 31, 2015, at 3:38 AM, JL2A <info@flyingwarbirds.com.au> wrote:
>>>
>>>
>>> I'm with Egon, getting an engine anywhere near 200C on the ground is
>>> very hard on them, let alone 250C. Without the proper cooling airflow
>>> wrapping around the cylinders they are getting unevenly hot, with
>>> hotspots that may exceed the temperature of where the thermocouple is
>>> placed.
>>>
>>> I've got to ask - what are we talking about lighting the whole
>>> supercharger 'charge' on fire?
>>>
>>> Do they mean the spark is so advanced it lights off way early and the
>>> flame front travels backwards through the induction system? Is this
>>> even physically at anything above starting RPM?
>>>
>>>
>>>
>>>
>>> Read this topic online here:
>>>
>>> http://forums.matronics.com/viewtopic.php?p=442829#442829
>
>
>
>
>
>
>
>
>
>
>
>
Message 5
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| LIST | Reply to LIST Regarding this Message |
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|
| Subject: | Re: Engine roughness, as in stops. starts. stops. |
starts.
Doc,
I thought that this list was aimed at discussing Yak / Nanchang / engine
matters, and this thread is about one of the misteries of these aircraft.
This coil behaviour is particular and has to be a consequence of the way
it is designed. Nobody really knows what happens.
So we all have to try and dig up as much information as we can and
fortunately there are some very knowledgeable people on this list who want
to share what they know.
And I am certainly not one of those very knowledgeable people.
It is near to impossible to get detailed descriptions from the
manufacturers.
Because it didn't work like that back in the USSR. Technical documentation
was State Secret, almost always.
Planes were delivered via DOSAAF to flying clubs without any real manuals.
Mechanics learned the trade from other mechanics.
If a local mechanic needed some specific information from the
manufacturer, the only way was to do a request via DOSAAF.
Last time when I was in Russia, I asked about some tech doc, and the
answer was astonishing: you have to ask DOSAAF!
Apparently that organisation still exists: a few old guys and girls in a
dusty office waiting for their pension.
Anyway, simply replacing parts without exactly knowing what's wrong, makes
me feel uneasy.
BR,
Jan
On 04/06/15 02:35, "Roger Kemp" <f16viperdoc@me.com> wrote:
>
>Okay, can the spear be removed now? In layman's terms the aged coil broke
>down under chronic heat load from who knows why and puked a high voltage
>discharge that resulted in a misfire somewhere in the bowels of the
>engine that consumed enough fuel charge to make the engine stop for a
>heartbeat puking black smoke out of somewhere under the chin of the
>engine cowl resulting in sucking of the seat pack up mine and Mongooses
>collective asses before the prop resumed making thrusties and we aborted
>the flight landing at the nearest paved Terra firma! For those that have
>never had the experience...it is fucking impressive! Not quit as
>impressive as a main bearing failure in a GE 100 though. Luckily that
>came on engine start. Shut that puppy down and we handed the keys back to
>chief and stepped to the spare.
>Anyway as I said in my one liner early in this diatribe of a
>thread...change the fucking coil or both coils...it will fix the problem
>and you will sleep better knowing your little magnetos are again making
>voltage for your spark plugs in the normal firing order so you can break
>the bonds of Terra firma and look down on all the poor schmucks stuck on
>the interstates trudging along never knowing the pleasures of dancing
>with the wind and cloud chasing !
>Nuf said.
>Doc
>
>Sent from my iPad
>
>> On Jun 3, 2015, at 10:16 AM, Bitterlich, Mark G CIV NAVAIR, WD
>><mark.bitterlich@navy.mil> wrote:
>>
>><mark.bitterlich@navy.mil>
>>
>> Jan,
>>
>> I never considered a corona in action. Just for the sake of
>>discussion, I'll mention that I measured the heat rise in a MSD Blaster
>>II coil using an infra-red gun and it is significant (and it is also oil
>>filled), which is kind of why I started wondering if it really is just
>>engine heat that is involved. No doubt heat is contributory, but while
>>it might be an insignificant point, I question whether it is all engine
>>heat and not just self-induced, or maybe a combination of both.
>>
>> So I am trying to get my mind around this. Without creating an actual
>>arc, the corona should rob energy from the coil correct? Not to
>>mention if there is moist air...... there should be the formation of
>>nitric acid, although since the premise is that there is such a small
>>amount of air and water available, that might not be much ... but
>>never-the-less there should be a chemical reaction that also would be
>>contributory to insulation loss.
>>
>> Another thought is that the high voltage potential necessary for a
>>corona to form would not be present throughout the whole coil but
>>instead only near a certain percentage near the end where the voltage
>>becomes "high enough" voltage to create corona loss.
>>
>> The problem I have with this explanation is understanding why it would
>>make the engine run rough, cough, lug, etc., with the opposite mag
>>operating properly? I can see where it could cause the engine to run
>>rough or misfire on that one mag, but how would it do it with both
>>operating?
>>
>> Mark
>>
>>
>>
>>
>> -----Original Message-----
>> From: owner-yak-list-server@matronics.com
>>[mailto:owner-yak-list-server@matronics.com] On Behalf Of Jan Mevis
>> Sent: Wednesday, June 03, 2015 1:06 AM
>> To: yak-list@matronics.com
>> Subject: Re: Yak-List: Re: Engine roughness, as in stops. starts.
>>stops. starts.
>>
>>
>> Hi Mark, Walt,
>>
>> What I think that happens, is corona discharge in the coil.
>> Typically these coils start malfunctioning after 20, 30 minutes, when
>>the heat of the engine is well diffused into the coil.
>> Corona discharge is caused by imperfections in the insulation of the
>>coil.
>>
>> The original Russian (and I suppose the same for the Chinese) coils
>>were made manually (in labour camps !) and layer after layer of winding,
>>insulation resins are applied.
>> These resins are diluted with solvents for better applicance. And
>>that's where it goes wrong after some years.
>>
>> The solvents evaporate and create tiny tunnels in the coil where moist
>>air can get trapped.
>> Then at higher temperature, you get discharging but not a real
>>electrical breakdown.
>>
>> So once the coil cools down again, everything is normal again and
>>subsequent testing on the ground reveals no problem anymore.
>>
>> The difficult issue in this theory is that we don't have an exact
>>picture of how it exactly happens.
>> I'd like to SEE it happen, but I don't have the money to investigate
>>that.
>>
>> Of course you can get other problems such as a failing capacitor.
>> This capacitor is only two tiny sheets of metal wrapped around with the
>>same insulation material applied in between.
>> The capacitance is rather low and if you measure it between different
>>coils, it varies substantially.
>>
>> Modern ways of making coils first use high vacuum procedures to
>>evacuate all the air.
>>
>> Then high-quality insulation products are applied under high pressure.
>>
>> Since the wire of the secondary is so thin, it's an art to warrant the
>>insulation product being well applied everywhere. That's why making a
>>new coil is expensive.
>>
>> In order to achieve a perfect insulation, you don't re-use the bakelite
>>flanges, but modern transformer cardboard that gets well penetrated with
>>insulation product.
>>
>>
>> Only my 2 cents,
>>
>> Jan
>>
>>
>>
>> On 02/06/15 22:16, "Bitterlich, Mark G CIV NAVAIR, WD"
>> <mark.bitterlich@navy.mil> wrote:
>>
>>> <mark.bitterlich@navy.mil>
>>>
>>> Walt > I have been trying to get my head around this theory of a
>>> "massive discharge" etc. but have been too busy of late to sit down
>>>and think it
>>> through. So far it just doesn't compute.
>>>
>>> I concur. There is no failure mode that can occur that would increase
>>> the intensity of the firing pulse above what it was designed to
>>>provide.
>>>
>>> Walt > I have had only one coil failure in forty years of playing with
>>> radial engines. That was in a Harvard with Bosch mags. That mag
>>>simply
>>> quit
>>> working, not intermittent, no bangs or whatever just simply and
>>> permanently dead.
>>>
>>> The interesting thing about the original Russian coil designs is that
>>> the condenser is actually integral and internal to the coil itself.
>>> Rather unusual. Since coils get hot, this also means the trapped heat
>>> is applied to the condenser as well. The common discussion theme
>>> regarding the topic under discussion (which is: Engine roughness, as
>>>in stops.
>>> starts. stops. starts.) is that it is related to "engine heat".
>>> Actually, I believe that is not quite accurate. I personally believe
>>> the problem is related to HEAT IN THE COIL, which is not necessarily
>>> synonymous with engine heat. In addition, since the coil assembly is
>>> internal to the mag, there is no easy way to get rid of that heat and
>>> it becomes cumulative.
>>>
>>> If that premise is accurate, then emphasis might be placed on what
>>> external factors increase heat in the coil since regardless of whether
>>> we are talking coil windings, or condenser malfunction, heat is the
>>>enemy.
>>> Kind of an "AHA" moment. Things such as spark plug gap, what spark
>>> plug wires are used, point dwell (!!), etc., all would impact coil
>>>heat.
>>>
>>> Best to you Walt,
>>>
>>> Mark
>>>
>>>
>>>
>>>
>>> ----Original Message-----
>>> From: owner-yak-list-server@matronics.com
>>> [mailto:owner-yak-list-server@matronics.com] On Behalf Of Walter Lannon
>>> Sent: Monday, June 01, 2015 10:31 PM
>>> To: yak-list@matronics.com
>>> Subject: Re: Yak-List: Re: Engine roughness, as in stops. starts.
>>>stops.
>>> starts.
>>>
>>>
>>> Mark;
>>>
>>> I have been trying to get my head around this theory of a "massive
>>> discharge" etc. but have been too busy of late to sit down and think it
>>> through. So far it just doesn't compute.
>>> I have had only one coil failure in forty years of playing with radial
>>> engines. That was in a Harvard with Bosch mags. That mag simply quit
>>> working, not intermittent, no bangs or whatever just simply and
>>> permanently dead.
>>> Right now dead tired and another full day tomorrow.
>>>
>>> Cheers;
>>> Walt
>>>
>>>
>>> -----Original Message-----
>>> From: Bitterlich, Mark G CIV NAVAIR, WD
>>> Sent: Monday, June 01, 2015 8:00 AM
>>> To: yak-list@matronics.com
>>> Subject: RE: Yak-List: Re: Engine roughness, as in stops. starts.
>>>stops.
>>> starts.
>>>
>>> <mark.bitterlich@navy.mil>
>>>
>>>
>>> Well.. Doc, I think there might have been a misunderstanding somewhere
>>> along the line. This is not a reasonable explanation.
>>>
>>>
>>>
>>> -----Original Message-----
>>> From: owner-yak-list-server@matronics.com
>>> [mailto:owner-yak-list-server@matronics.com] On Behalf Of Roger Kemp
>>> Sent: Sunday, May 31, 2015 12:48 PM
>>> To: yak-list@matronics.com
>>> Subject: Re: Yak-List: Re: Engine roughness, as in stops. starts.
>>>stops.
>>> starts.
>>>
>>>
>>> As explained by the Lithuanian engineers the massive discharge with
>>>the
>>> heat induced break down of the capacitor in the coil results in arcing
>>> in the distributor cap so that discharge flows / jumps to the next
>>> cylinder in line on the intake stroke. With the intake valve open when
>>> that aberrant discharge arrives the spark will consume the
>>>supercharger
>>> contents. The backfire is most likely through the carb when the charge
>>> is consumed.
>>> The pilots of the aircraft in formation with me said they saw a
>>>sudden
>>> belch of black smoke from under the chin of my bird. I felt the
>>> hesitation as well as saw the momentary hesitation of the prop slowing.
>>> Then the engine picked back up like nothing occurred. Have had that
>>> happen twice since owning my 52. Did an airborne mag check the second
>>> time with the engine quitting on selection of the #1 mag. In both
>>>cases
>>> changing the mag coils resolved the problem.
>>> Litaurus and Termikus are the bearers of that tidbit of info. Made
>>> sense to me then and now.
>>> Doc
>>>
>>> Sent from my iPad
>>>
>>>> On May 31, 2015, at 3:38 AM, JL2A <info@flyingwarbirds.com.au> wrote:
>>>>
>>>>
>>>> I'm with Egon, getting an engine anywhere near 200C on the ground is
>>>>
>>>> very hard on them, let alone 250C. Without the proper cooling
>>>>airflow
>>>> wrapping around the cylinders they are getting unevenly hot, with
>>>> hotspots that may exceed the temperature of where the thermocouple is
>>>> placed.
>>>>
>>>> I've got to ask - what are we talking about lighting the whole
>>>> supercharger 'charge' on fire?
>>>>
>>>> Do they mean the spark is so advanced it lights off way early and the
>>>> flame front travels backwards through the induction system? Is this
>>>> even physically at anything above starting RPM?
>>>>
>>>>
>>>>
>>>>
>>>> Read this topic online here:
>>>>
>>>> http://forums.matronics.com/viewtopic.php?p=442829#442829
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>
>
Message 6
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|
| Subject: | Re: Engine roughness, as in stops. starts. stops. |
starts.
As an aside, in racing for years the magneto of choice was the Vertex which
had the coil internal. When Mallory came out with their magnetos they used
an external coil. Eventually Vertex went to the external coil. The MSD
magnetos used in top fuel racing use external coils and they are extremely
high output. Just for what it is worth.
Frank
----- Original Message -----
From: "Jan Mevis" <jan.mevis@informavia.be>
Sent: Wednesday, June 03, 2015 8:40 PM
Subject: Re: Yak-List: Re: Engine roughness, as in stops. starts. stops.
starts.
>
> Doc,
>
>
> I thought that this list was aimed at discussing Yak / Nanchang / engine
> matters, and this thread is about one of the misteries of these aircraft.
>
> This coil behaviour is particular and has to be a consequence of the way
> it is designed. Nobody really knows what happens.
>
> So we all have to try and dig up as much information as we can and
> fortunately there are some very knowledgeable people on this list who want
> to share what they know.
>
> And I am certainly not one of those very knowledgeable people.
>
> It is near to impossible to get detailed descriptions from the
> manufacturers.
>
> Because it didn't work like that back in the USSR. Technical documentation
> was State Secret, almost always.
>
> Planes were delivered via DOSAAF to flying clubs without any real manuals.
> Mechanics learned the trade from other mechanics.
>
> If a local mechanic needed some specific information from the
> manufacturer, the only way was to do a request via DOSAAF.
>
> Last time when I was in Russia, I asked about some tech doc, and the
> answer was astonishing: you have to ask DOSAAF!
>
> Apparently that organisation still exists: a few old guys and girls in a
> dusty office waiting for their pension.
>
> Anyway, simply replacing parts without exactly knowing what's wrong, makes
> me feel uneasy.
>
>
> BR,
>
> Jan
>
> On 04/06/15 02:35, "Roger Kemp" <f16viperdoc@me.com> wrote:
>
>>
>>Okay, can the spear be removed now? In layman's terms the aged coil broke
>>down under chronic heat load from who knows why and puked a high voltage
>>discharge that resulted in a misfire somewhere in the bowels of the
>>engine that consumed enough fuel charge to make the engine stop for a
>>heartbeat puking black smoke out of somewhere under the chin of the
>>engine cowl resulting in sucking of the seat pack up mine and Mongooses
>>collective asses before the prop resumed making thrusties and we aborted
>>the flight landing at the nearest paved Terra firma! For those that have
>>never had the experience...it is fucking impressive! Not quit as
>>impressive as a main bearing failure in a GE 100 though. Luckily that
>>came on engine start. Shut that puppy down and we handed the keys back to
>>chief and stepped to the spare.
>>Anyway as I said in my one liner early in this diatribe of a
>>thread...change the fucking coil or both coils...it will fix the problem
>>and you will sleep better knowing your little magnetos are again making
>>voltage for your spark plugs in the normal firing order so you can break
>>the bonds of Terra firma and look down on all the poor schmucks stuck on
>>the interstates trudging along never knowing the pleasures of dancing
>>with the wind and cloud chasing !
>>Nuf said.
>>Doc
>>
>>Sent from my iPad
>>
>>> On Jun 3, 2015, at 10:16 AM, Bitterlich, Mark G CIV NAVAIR, WD
>>><mark.bitterlich@navy.mil> wrote:
>>>
>>><mark.bitterlich@navy.mil>
>>>
>>> Jan,
>>>
>>> I never considered a corona in action. Just for the sake of
>>>discussion, I'll mention that I measured the heat rise in a MSD Blaster
>>>II coil using an infra-red gun and it is significant (and it is also oil
>>>filled), which is kind of why I started wondering if it really is just
>>>engine heat that is involved. No doubt heat is contributory, but while
>>>it might be an insignificant point, I question whether it is all engine
>>>heat and not just self-induced, or maybe a combination of both.
>>>
>>> So I am trying to get my mind around this. Without creating an actual
>>>arc, the corona should rob energy from the coil correct? Not to
>>>mention if there is moist air...... there should be the formation of
>>>nitric acid, although since the premise is that there is such a small
>>>amount of air and water available, that might not be much ... but
>>>never-the-less there should be a chemical reaction that also would be
>>>contributory to insulation loss.
>>>
>>> Another thought is that the high voltage potential necessary for a
>>>corona to form would not be present throughout the whole coil but
>>>instead only near a certain percentage near the end where the voltage
>>>becomes "high enough" voltage to create corona loss.
>>>
>>> The problem I have with this explanation is understanding why it would
>>>make the engine run rough, cough, lug, etc., with the opposite mag
>>>operating properly? I can see where it could cause the engine to run
>>>rough or misfire on that one mag, but how would it do it with both
>>>operating?
>>>
>>> Mark
>>>
>>>
>>>
>>>
>>> -----Original Message-----
>>> From: owner-yak-list-server@matronics.com
>>>[mailto:owner-yak-list-server@matronics.com] On Behalf Of Jan Mevis
>>> Sent: Wednesday, June 03, 2015 1:06 AM
>>> To: yak-list@matronics.com
>>> Subject: Re: Yak-List: Re: Engine roughness, as in stops. starts.
>>>stops. starts.
>>>
>>>
>>> Hi Mark, Walt,
>>>
>>> What I think that happens, is corona discharge in the coil.
>>> Typically these coils start malfunctioning after 20, 30 minutes, when
>>>the heat of the engine is well diffused into the coil.
>>> Corona discharge is caused by imperfections in the insulation of the
>>>coil.
>>>
>>> The original Russian (and I suppose the same for the Chinese) coils
>>>were made manually (in labour camps !) and layer after layer of winding,
>>>insulation resins are applied.
>>> These resins are diluted with solvents for better applicance. And
>>>that's where it goes wrong after some years.
>>>
>>> The solvents evaporate and create tiny tunnels in the coil where moist
>>>air can get trapped.
>>> Then at higher temperature, you get discharging but not a real
>>>electrical breakdown.
>>>
>>> So once the coil cools down again, everything is normal again and
>>>subsequent testing on the ground reveals no problem anymore.
>>>
>>> The difficult issue in this theory is that we don't have an exact
>>>picture of how it exactly happens.
>>> I'd like to SEE it happen, but I don't have the money to investigate
>>>that.
>>>
>>> Of course you can get other problems such as a failing capacitor.
>>> This capacitor is only two tiny sheets of metal wrapped around with the
>>>same insulation material applied in between.
>>> The capacitance is rather low and if you measure it between different
>>>coils, it varies substantially.
>>>
>>> Modern ways of making coils first use high vacuum procedures to
>>>evacuate all the air.
>>>
>>> Then high-quality insulation products are applied under high pressure.
>>>
>>> Since the wire of the secondary is so thin, it's an art to warrant the
>>>insulation product being well applied everywhere. That's why making a
>>>new coil is expensive.
>>>
>>> In order to achieve a perfect insulation, you don't re-use the bakelite
>>>flanges, but modern transformer cardboard that gets well penetrated with
>>>insulation product.
>>>
>>>
>>> Only my 2 cents,
>>>
>>> Jan
>>>
>>>
>>>
>>> On 02/06/15 22:16, "Bitterlich, Mark G CIV NAVAIR, WD"
>>> <mark.bitterlich@navy.mil> wrote:
>>>
>>>> <mark.bitterlich@navy.mil>
>>>>
>>>> Walt > I have been trying to get my head around this theory of a
>>>> "massive discharge" etc. but have been too busy of late to sit down
>>>>and think it
>>>> through. So far it just doesn't compute.
>>>>
>>>> I concur. There is no failure mode that can occur that would increase
>>>> the intensity of the firing pulse above what it was designed to
>>>>provide.
>>>>
>>>> Walt > I have had only one coil failure in forty years of playing with
>>>> radial engines. That was in a Harvard with Bosch mags. That mag
>>>>simply
>>>> quit
>>>> working, not intermittent, no bangs or whatever just simply and
>>>> permanently dead.
>>>>
>>>> The interesting thing about the original Russian coil designs is that
>>>> the condenser is actually integral and internal to the coil itself.
>>>> Rather unusual. Since coils get hot, this also means the trapped heat
>>>> is applied to the condenser as well. The common discussion theme
>>>> regarding the topic under discussion (which is: Engine roughness, as
>>>>in stops.
>>>> starts. stops. starts.) is that it is related to "engine heat".
>>>> Actually, I believe that is not quite accurate. I personally believe
>>>> the problem is related to HEAT IN THE COIL, which is not necessarily
>>>> synonymous with engine heat. In addition, since the coil assembly is
>>>> internal to the mag, there is no easy way to get rid of that heat and
>>>> it becomes cumulative.
>>>>
>>>> If that premise is accurate, then emphasis might be placed on what
>>>> external factors increase heat in the coil since regardless of whether
>>>> we are talking coil windings, or condenser malfunction, heat is the
>>>>enemy.
>>>> Kind of an "AHA" moment. Things such as spark plug gap, what spark
>>>> plug wires are used, point dwell (!!), etc., all would impact coil
>>>>heat.
>>>>
>>>> Best to you Walt,
>>>>
>>>> Mark
>>>>
>>>>
>>>>
>>>>
>>>> ----Original Message-----
>>>> From: owner-yak-list-server@matronics.com
>>>> [mailto:owner-yak-list-server@matronics.com] On Behalf Of Walter Lannon
>>>> Sent: Monday, June 01, 2015 10:31 PM
>>>> To: yak-list@matronics.com
>>>> Subject: Re: Yak-List: Re: Engine roughness, as in stops. starts.
>>>>stops.
>>>> starts.
>>>>
>>>>
>>>> Mark;
>>>>
>>>> I have been trying to get my head around this theory of a "massive
>>>> discharge" etc. but have been too busy of late to sit down and think it
>>>> through. So far it just doesn't compute.
>>>> I have had only one coil failure in forty years of playing with radial
>>>> engines. That was in a Harvard with Bosch mags. That mag simply quit
>>>> working, not intermittent, no bangs or whatever just simply and
>>>> permanently dead.
>>>> Right now dead tired and another full day tomorrow.
>>>>
>>>> Cheers;
>>>> Walt
>>>>
>>>>
>>>> -----Original Message-----
>>>> From: Bitterlich, Mark G CIV NAVAIR, WD
>>>> Sent: Monday, June 01, 2015 8:00 AM
>>>> To: yak-list@matronics.com
>>>> Subject: RE: Yak-List: Re: Engine roughness, as in stops. starts.
>>>>stops.
>>>> starts.
>>>>
>>>> <mark.bitterlich@navy.mil>
>>>>
>>>>
>>>> Well.. Doc, I think there might have been a misunderstanding somewhere
>>>> along the line. This is not a reasonable explanation.
>>>>
>>>>
>>>>
>>>> -----Original Message-----
>>>> From: owner-yak-list-server@matronics.com
>>>> [mailto:owner-yak-list-server@matronics.com] On Behalf Of Roger Kemp
>>>> Sent: Sunday, May 31, 2015 12:48 PM
>>>> To: yak-list@matronics.com
>>>> Subject: Re: Yak-List: Re: Engine roughness, as in stops. starts.
>>>>stops.
>>>> starts.
>>>>
>>>>
>>>> As explained by the Lithuanian engineers the massive discharge with
>>>>the
>>>> heat induced break down of the capacitor in the coil results in arcing
>>>> in the distributor cap so that discharge flows / jumps to the next
>>>> cylinder in line on the intake stroke. With the intake valve open when
>>>> that aberrant discharge arrives the spark will consume the
>>>>supercharger
>>>> contents. The backfire is most likely through the carb when the charge
>>>> is consumed.
>>>> The pilots of the aircraft in formation with me said they saw a
>>>>sudden
>>>> belch of black smoke from under the chin of my bird. I felt the
>>>> hesitation as well as saw the momentary hesitation of the prop slowing.
>>>> Then the engine picked back up like nothing occurred. Have had that
>>>> happen twice since owning my 52. Did an airborne mag check the second
>>>> time with the engine quitting on selection of the #1 mag. In both
>>>>cases
>>>> changing the mag coils resolved the problem.
>>>> Litaurus and Termikus are the bearers of that tidbit of info. Made
>>>> sense to me then and now.
>>>> Doc
>>>>
>>>> Sent from my iPad
>>>>
>>>>> On May 31, 2015, at 3:38 AM, JL2A <info@flyingwarbirds.com.au> wrote:
>>>>>
>>>>>
>>>>> I'm with Egon, getting an engine anywhere near 200C on the ground is
>>>>>
>>>>> very hard on them, let alone 250C. Without the proper cooling
>>>>>airflow
>>>>> wrapping around the cylinders they are getting unevenly hot, with
>>>>> hotspots that may exceed the temperature of where the thermocouple is
>>>>> placed.
>>>>>
>>>>> I've got to ask - what are we talking about lighting the whole
>>>>> supercharger 'charge' on fire?
>>>>>
>>>>> Do they mean the spark is so advanced it lights off way early and the
>>>>> flame front travels backwards through the induction system? Is this
>>>>> even physically at anything above starting RPM?
>>>>>
>>>>>
>>>>>
>>>>>
>>>>> Read this topic online here:
>>>>>
>>>>> http://forums.matronics.com/viewtopic.php?p=442829#442829
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>
>>
>>
>>
>>
>
>
>
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| Subject: | Re: Engine roughness, as in stops. starts. stops. |
starts.
Thanks Frank,
I have an MSD-ignition in stead of the right mag on my Yak 50. (Mark
Bitterlich's idea).
Since then, I measure substantially higher CHT on all cylinders so better
combustion.
On the primary the blaster coil gets several HUNDREDS of volts from the
electronics.
But also it draws at least 10 amp from the electrical installation (I
busted a 10 amp B&C + regulator).
A few years ago, I tried this as an alternative for the failing coils.
It works very well, but the installation is not so easy.
For instance you do need powerful and aviation-quality 24 to 12 DC-DC
converter.
Jan
On 04/06/15 05:53, "Frank Stelwagon" <pfstelwagon@earthlink.net> wrote:
><pfstelwagon@earthlink.net>
>
>As an aside, in racing for years the magneto of choice was the Vertex
>which
>had the coil internal. When Mallory came out with their magnetos they
>used
>an external coil. Eventually Vertex went to the external coil. The MSD
>magnetos used in top fuel racing use external coils and they are
>extremely
>high output. Just for what it is worth.
>
>Frank
>----- Original Message -----
>From: "Jan Mevis" <jan.mevis@informavia.be>
>To: <yak-list@matronics.com>
>Sent: Wednesday, June 03, 2015 8:40 PM
>Subject: Re: Yak-List: Re: Engine roughness, as in stops. starts. stops.
>starts.
>
>
>>
>> Doc,
>>
>>
>> I thought that this list was aimed at discussing Yak / Nanchang / engine
>> matters, and this thread is about one of the misteries of these
>>aircraft.
>>
>> This coil behaviour is particular and has to be a consequence of the way
>> it is designed. Nobody really knows what happens.
>>
>> So we all have to try and dig up as much information as we can and
>> fortunately there are some very knowledgeable people on this list who
>>want
>> to share what they know.
>>
>> And I am certainly not one of those very knowledgeable people.
>>
>> It is near to impossible to get detailed descriptions from the
>> manufacturers.
>>
>> Because it didn't work like that back in the USSR. Technical
>>documentation
>> was State Secret, almost always.
>>
>> Planes were delivered via DOSAAF to flying clubs without any real
>>manuals.
>> Mechanics learned the trade from other mechanics.
>>
>> If a local mechanic needed some specific information from the
>> manufacturer, the only way was to do a request via DOSAAF.
>>
>> Last time when I was in Russia, I asked about some tech doc, and the
>> answer was astonishing: you have to ask DOSAAF!
>>
>> Apparently that organisation still exists: a few old guys and girls in a
>> dusty office waiting for their pension.
>>
>> Anyway, simply replacing parts without exactly knowing what's wrong,
>>makes
>> me feel uneasy.
>>
>>
>> BR,
>>
>> Jan
>>
>> On 04/06/15 02:35, "Roger Kemp" <f16viperdoc@me.com> wrote:
>>
>>>
>>>Okay, can the spear be removed now? In layman's terms the aged coil
>>>broke
>>>down under chronic heat load from who knows why and puked a high voltage
>>>discharge that resulted in a misfire somewhere in the bowels of the
>>>engine that consumed enough fuel charge to make the engine stop for a
>>>heartbeat puking black smoke out of somewhere under the chin of the
>>>engine cowl resulting in sucking of the seat pack up mine and Mongooses
>>>collective asses before the prop resumed making thrusties and we aborted
>>>the flight landing at the nearest paved Terra firma! For those that have
>>>never had the experience...it is fucking impressive! Not quit as
>>>impressive as a main bearing failure in a GE 100 though. Luckily that
>>>came on engine start. Shut that puppy down and we handed the keys back
>>>to
>>>chief and stepped to the spare.
>>>Anyway as I said in my one liner early in this diatribe of a
>>>thread...change the fucking coil or both coils...it will fix the problem
>>>and you will sleep better knowing your little magnetos are again making
>>>voltage for your spark plugs in the normal firing order so you can break
>>>the bonds of Terra firma and look down on all the poor schmucks stuck on
>>>the interstates trudging along never knowing the pleasures of dancing
>>>with the wind and cloud chasing !
>>>Nuf said.
>>>Doc
>>>
>>>Sent from my iPad
>>>
>>>> On Jun 3, 2015, at 10:16 AM, Bitterlich, Mark G CIV NAVAIR, WD
>>>><mark.bitterlich@navy.mil> wrote:
>>>>
>>>><mark.bitterlich@navy.mil>
>>>>
>>>> Jan,
>>>>
>>>> I never considered a corona in action. Just for the sake of
>>>>discussion, I'll mention that I measured the heat rise in a MSD Blaster
>>>>II coil using an infra-red gun and it is significant (and it is also
>>>>oil
>>>>filled), which is kind of why I started wondering if it really is just
>>>>engine heat that is involved. No doubt heat is contributory, but
>>>>while
>>>>it might be an insignificant point, I question whether it is all engine
>>>>heat and not just self-induced, or maybe a combination of both.
>>>>
>>>> So I am trying to get my mind around this. Without creating an actual
>>>>arc, the corona should rob energy from the coil correct? Not to
>>>>mention if there is moist air...... there should be the formation of
>>>>nitric acid, although since the premise is that there is such a small
>>>>amount of air and water available, that might not be much ... but
>>>>never-the-less there should be a chemical reaction that also would be
>>>>contributory to insulation loss.
>>>>
>>>> Another thought is that the high voltage potential necessary for a
>>>>corona to form would not be present throughout the whole coil but
>>>>instead only near a certain percentage near the end where the voltage
>>>>becomes "high enough" voltage to create corona loss.
>>>>
>>>> The problem I have with this explanation is understanding why it would
>>>>make the engine run rough, cough, lug, etc., with the opposite mag
>>>>operating properly? I can see where it could cause the engine to run
>>>>rough or misfire on that one mag, but how would it do it with both
>>>>operating?
>>>>
>>>> Mark
>>>>
>>>>
>>>>
>>>>
>>>> -----Original Message-----
>>>> From: owner-yak-list-server@matronics.com
>>>>[mailto:owner-yak-list-server@matronics.com] On Behalf Of Jan Mevis
>>>> Sent: Wednesday, June 03, 2015 1:06 AM
>>>> To: yak-list@matronics.com
>>>> Subject: Re: Yak-List: Re: Engine roughness, as in stops. starts.
>>>>stops. starts.
>>>>
>>>>
>>>> Hi Mark, Walt,
>>>>
>>>> What I think that happens, is corona discharge in the coil.
>>>> Typically these coils start malfunctioning after 20, 30 minutes, when
>>>>the heat of the engine is well diffused into the coil.
>>>> Corona discharge is caused by imperfections in the insulation of the
>>>>coil.
>>>>
>>>> The original Russian (and I suppose the same for the Chinese) coils
>>>>were made manually (in labour camps !) and layer after layer of
>>>>winding,
>>>>insulation resins are applied.
>>>> These resins are diluted with solvents for better applicance. And
>>>>that's where it goes wrong after some years.
>>>>
>>>> The solvents evaporate and create tiny tunnels in the coil where moist
>>>>air can get trapped.
>>>> Then at higher temperature, you get discharging but not a real
>>>>electrical breakdown.
>>>>
>>>> So once the coil cools down again, everything is normal again and
>>>>subsequent testing on the ground reveals no problem anymore.
>>>>
>>>> The difficult issue in this theory is that we don't have an exact
>>>>picture of how it exactly happens.
>>>> I'd like to SEE it happen, but I don't have the money to investigate
>>>>that.
>>>>
>>>> Of course you can get other problems such as a failing capacitor.
>>>> This capacitor is only two tiny sheets of metal wrapped around with
>>>>the
>>>>same insulation material applied in between.
>>>> The capacitance is rather low and if you measure it between different
>>>>coils, it varies substantially.
>>>>
>>>> Modern ways of making coils first use high vacuum procedures to
>>>>evacuate all the air.
>>>>
>>>> Then high-quality insulation products are applied under high pressure.
>>>>
>>>> Since the wire of the secondary is so thin, it's an art to warrant the
>>>>insulation product being well applied everywhere. That's why making a
>>>>new coil is expensive.
>>>>
>>>> In order to achieve a perfect insulation, you don't re-use the
>>>>bakelite
>>>>flanges, but modern transformer cardboard that gets well penetrated
>>>>with
>>>>insulation product.
>>>>
>>>>
>>>> Only my 2 cents,
>>>>
>>>> Jan
>>>>
>>>>
>>>>
>>>> On 02/06/15 22:16, "Bitterlich, Mark G CIV NAVAIR, WD"
>>>> <mark.bitterlich@navy.mil> wrote:
>>>>
>>>>> <mark.bitterlich@navy.mil>
>>>>>
>>>>> Walt > I have been trying to get my head around this theory of a
>>>>> "massive discharge" etc. but have been too busy of late to sit down
>>>>>and think it
>>>>> through. So far it just doesn't compute.
>>>>>
>>>>> I concur. There is no failure mode that can occur that would
>>>>>increase
>>>>> the intensity of the firing pulse above what it was designed to
>>>>>provide.
>>>>>
>>>>> Walt > I have had only one coil failure in forty years of playing
>>>>>with
>>>>> radial engines. That was in a Harvard with Bosch mags. That mag
>>>>>simply
>>>>> quit
>>>>> working, not intermittent, no bangs or whatever just simply and
>>>>> permanently dead.
>>>>>
>>>>> The interesting thing about the original Russian coil designs is that
>>>>> the condenser is actually integral and internal to the coil itself.
>>>>> Rather unusual. Since coils get hot, this also means the trapped
>>>>>heat
>>>>> is applied to the condenser as well. The common discussion theme
>>>>> regarding the topic under discussion (which is: Engine roughness, as
>>>>>in stops.
>>>>> starts. stops. starts.) is that it is related to "engine heat".
>>>>> Actually, I believe that is not quite accurate. I personally believe
>>>>> the problem is related to HEAT IN THE COIL, which is not necessarily
>>>>> synonymous with engine heat. In addition, since the coil assembly is
>>>>> internal to the mag, there is no easy way to get rid of that heat and
>>>>> it becomes cumulative.
>>>>>
>>>>> If that premise is accurate, then emphasis might be placed on what
>>>>> external factors increase heat in the coil since regardless of
>>>>>whether
>>>>> we are talking coil windings, or condenser malfunction, heat is the
>>>>>enemy.
>>>>> Kind of an "AHA" moment. Things such as spark plug gap, what spark
>>>>> plug wires are used, point dwell (!!), etc., all would impact coil
>>>>>heat.
>>>>>
>>>>> Best to you Walt,
>>>>>
>>>>> Mark
>>>>>
>>>>>
>>>>>
>>>>>
>>>>> ----Original Message-----
>>>>> From: owner-yak-list-server@matronics.com
>>>>> [mailto:owner-yak-list-server@matronics.com] On Behalf Of Walter
>>>>>Lannon
>>>>> Sent: Monday, June 01, 2015 10:31 PM
>>>>> To: yak-list@matronics.com
>>>>> Subject: Re: Yak-List: Re: Engine roughness, as in stops. starts.
>>>>>stops.
>>>>> starts.
>>>>>
>>>>>
>>>>> Mark;
>>>>>
>>>>> I have been trying to get my head around this theory of a "massive
>>>>> discharge" etc. but have been too busy of late to sit down and think
>>>>>it
>>>>> through. So far it just doesn't compute.
>>>>> I have had only one coil failure in forty years of playing with
>>>>>radial
>>>>> engines. That was in a Harvard with Bosch mags. That mag simply
>>>>>quit
>>>>> working, not intermittent, no bangs or whatever just simply and
>>>>> permanently dead.
>>>>> Right now dead tired and another full day tomorrow.
>>>>>
>>>>> Cheers;
>>>>> Walt
>>>>>
>>>>>
>>>>> -----Original Message-----
>>>>> From: Bitterlich, Mark G CIV NAVAIR, WD
>>>>> Sent: Monday, June 01, 2015 8:00 AM
>>>>> To: yak-list@matronics.com
>>>>> Subject: RE: Yak-List: Re: Engine roughness, as in stops. starts.
>>>>>stops.
>>>>> starts.
>>>>>
>>>>> <mark.bitterlich@navy.mil>
>>>>>
>>>>>
>>>>> Well.. Doc, I think there might have been a misunderstanding
>>>>>somewhere
>>>>> along the line. This is not a reasonable explanation.
>>>>>
>>>>>
>>>>>
>>>>> -----Original Message-----
>>>>> From: owner-yak-list-server@matronics.com
>>>>> [mailto:owner-yak-list-server@matronics.com] On Behalf Of Roger Kemp
>>>>> Sent: Sunday, May 31, 2015 12:48 PM
>>>>> To: yak-list@matronics.com
>>>>> Subject: Re: Yak-List: Re: Engine roughness, as in stops. starts.
>>>>>stops.
>>>>> starts.
>>>>>
>>>>>
>>>>> As explained by the Lithuanian engineers the massive discharge with
>>>>>the
>>>>> heat induced break down of the capacitor in the coil results in
>>>>>arcing
>>>>> in the distributor cap so that discharge flows / jumps to the next
>>>>> cylinder in line on the intake stroke. With the intake valve open
>>>>>when
>>>>> that aberrant discharge arrives the spark will consume the
>>>>>supercharger
>>>>> contents. The backfire is most likely through the carb when the
>>>>>charge
>>>>> is consumed.
>>>>> The pilots of the aircraft in formation with me said they saw a
>>>>>sudden
>>>>> belch of black smoke from under the chin of my bird. I felt the
>>>>> hesitation as well as saw the momentary hesitation of the prop
>>>>>slowing.
>>>>> Then the engine picked back up like nothing occurred. Have had that
>>>>> happen twice since owning my 52. Did an airborne mag check the second
>>>>> time with the engine quitting on selection of the #1 mag. In both
>>>>>cases
>>>>> changing the mag coils resolved the problem.
>>>>> Litaurus and Termikus are the bearers of that tidbit of info. Made
>>>>> sense to me then and now.
>>>>> Doc
>>>>>
>>>>> Sent from my iPad
>>>>>
>>>>>> On May 31, 2015, at 3:38 AM, JL2A <info@flyingwarbirds.com.au>
>>>>>>wrote:
>>>>>>
>>>>>>
>>>>>> I'm with Egon, getting an engine anywhere near 200C on the ground
>>>>>>is
>>>>>>
>>>>>> very hard on them, let alone 250C. Without the proper cooling
>>>>>>airflow
>>>>>> wrapping around the cylinders they are getting unevenly hot, with
>>>>>> hotspots that may exceed the temperature of where the thermocouple
>>>>>>is
>>>>>> placed.
>>>>>>
>>>>>> I've got to ask - what are we talking about lighting the whole
>>>>>> supercharger 'charge' on fire?
>>>>>>
>>>>>> Do they mean the spark is so advanced it lights off way early and
>>>>>>the
>>>>>> flame front travels backwards through the induction system? Is this
>>>>>> even physically at anything above starting RPM?
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>> Read this topic online here:
>>>>>>
>>>>>> http://forums.matronics.com/viewtopic.php?p=442829#442829
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>
>>>
>>>
>>>
>>>
>>
>>
>>
>>
>>
>>
>>
>>
>
>
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