Today's Message Index:
----------------------
1. 03:58 AM - M14P misfiring (Bruce Thomas)
2. 04:27 AM - Re: M14P misfiring (A. Dennis Savarese)
3. 03:52 PM - Re: M14P misfiring (Roger Kemp)
4. 04:21 PM - Re: M14P misfiring (A. Dennis Savarese)
5. 04:36 PM - Misfiring (Roger Kemp)
6. 07:28 PM - MiG-21 Heads Up Display (Tim Gagnon)
Message 1
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Hi All,
I have a problem that I will tell you about in the hope that somebody
can throw some light on it.
Last Wednesday Garry Mitchell of Australian Air ferry and myself took
off from White Waltham Airfield In the UK in my newly acquired Yak 18T.
We were bound for Genoa Italy as the first leg of a long trip which was
to end in Melbourne Australia.
After 30 minutes flying we cleared English airspace and were handed to
Paris control and were given clearance to climb to 8000 ft. from 2500ft
over the English channel, shortly after passing through 3500ft the motor
at climb power,82%, the engine gave one cough as if power was completely
turned off then instantly back on.
This concerned us, but it continued to run well and smoothly, Ok as
smoothly as a M14P can , then about one minute later all hell broke
loose; It began coughing and popping and loosing power. The fuel and oil
pressure gauges were oscillating to zero then almost instantly back to
full pressure again ( I don't know if this was a cause or an effect )
however it continued to run albeit without much power, Garry tried
various minor adjustments without being too adventurous as we were over
water at this stage and didn't want to kill what power we had.
.
We declared an emergency and London control vectored us back towards
Shoreham airfield at Brighton, about 12 miles back, luckily we made it
having lost about 2500ft.
As we dropped the gear and flap then went to full fine pitch prior to
landing, the banging and backfiring stopped and we were able to land
normally, the motor ran well during taxi and also ran cleanly at 65% for
30 sec, at shut down.
We rang Russian engineering at White Waltham and ran the symptoms past
Genna and Atur
and they thought it was magnetos, and bought two new units to Shoreham
next morning and fitted them. Did comprehensive run up checks and
pronounced it cured,
Alex Berry , the previous owner, then flew her back to White Waltham,
without incident, to be dissembled and packed into a container to be
shipped to Australia as both Garry and I at this point decided that we
didn't have the confidence to attempt another 12000 mile trip again.
On reflection we are inclined to think that it was fuel starvation,
rather than magneto's that caused the problem, and will disassemble the
entire fuel supply system when it gets here.
This is where I am looking for assistance, has anybody out there had a
similar occurrence,
or has any suggestions on what it may be and how to cure it once and for
all.
One other point, I fitted an ignition harness from Dennis prior to the
flight and the engine checks
at the 100 hourly indicated smoother running, however this is not the
cause as it has done the same thing previously, but was put down to
carby icing, a reason that I accepted at the time but which I now do not
believe. Incidentally at the time it was CAVOC and 30o C so icing was
impossible on this day as it was on the previous occasion. I have since
found out that the last time it was 24o C and fine.
Sorry about the long winded explanation, but it has me stumped and I
hope some of the vast knowledge available on this list will point me in
the right direction to avoid repitition when she arrives home.
Kind Regards Bruce Thomas
Message 2
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| Subject: | Re: M14P misfiring |
Bruce,
I have seen this problem several times before. When it happens, it
typically happens somewhere between the initial 20 and 35 minutes of
flight. It has always been a bad coil breaking down in one of the mags.
The symptom is an engine "cough" which feels like a complete engine
shutdown for a half second or so. It DOES get your attention. You will
have fly the airplane over your airfield for 20 - 40 minutes hoping the
engine cough will show up again. When it does, switch to one mag then
the other. Whichever mag coil has failed will definitely be
discernable. Remove the suspected mag and replace the coil. Bench
testing the coil will show the coil as normal. But do not use this coil
again because under heat and load, it will fail again.
To access the front mag hold-down nut, (a real pain to get to) purchase
an inexpensive 14 mm combination (box end/open end) wrench. Heat the
wrench shaft with an acetylene torch and put a bend in the shaft of
approximately 120 degrees. Use the box end wrench to loosen and tighten
the front hold down nut. That is the easiest way to access the front
nut. If you put 3 vertical marks between the base of the mag and the
accessory case using a Sharpie pen or similar marking device, you should
be able to remove and replace the mag by lining up the 3 marks and not
have to retime the magneto.
Dennis
----- Original Message -----
From: Bruce Thomas
To: yak-list@matronics.com
Sent: Saturday, July 29, 2006 10:50 PM
Subject: Yak-List: M14P misfiring
Hi All,
I have a problem that I will tell you about in the hope that somebody
can throw some light on it.
Last Wednesday Garry Mitchell of Australian Air ferry and myself took
off from White Waltham Airfield In the UK in my newly acquired Yak 18T.
We were bound for Genoa Italy as the first leg of a long trip which
was to end in Melbourne Australia.
After 30 minutes flying we cleared English airspace and were handed to
Paris control and were given clearance to climb to 8000 ft. from 2500ft
over the English channel, shortly after passing through 3500ft the motor
at climb power,82%, the engine gave one cough as if power was completely
turned off then instantly back on.
This concerned us, but it continued to run well and smoothly, Ok as
smoothly as a M14P can , then about one minute later all hell broke
loose; It began coughing and popping and loosing power. The fuel and oil
pressure gauges were oscillating to zero then almost instantly back to
full pressure again ( I don't know if this was a cause or an effect )
however it continued to run albeit without much power, Garry tried
various minor adjustments without being too adventurous as we were over
water at this stage and didn't want to kill what power we had.
.
We declared an emergency and London control vectored us back towards
Shoreham airfield at Brighton, about 12 miles back, luckily we made it
having lost about 2500ft.
As we dropped the gear and flap then went to full fine pitch prior to
landing, the banging and backfiring stopped and we were able to land
normally, the motor ran well during taxi and also ran cleanly at 65% for
30 sec, at shut down.
We rang Russian engineering at White Waltham and ran the symptoms past
Genna and Atur
and they thought it was magnetos, and bought two new units to Shoreham
next morning and fitted them. Did comprehensive run up checks and
pronounced it cured,
Alex Berry , the previous owner, then flew her back to White Waltham,
without incident, to be dissembled and packed into a container to be
shipped to Australia as both Garry and I at this point decided that we
didn't have the confidence to attempt another 12000 mile trip again.
On reflection we are inclined to think that it was fuel starvation,
rather than magneto's that caused the problem, and will disassemble the
entire fuel supply system when it gets here.
This is where I am looking for assistance, has anybody out there had a
similar occurrence,
or has any suggestions on what it may be and how to cure it once and
for all.
One other point, I fitted an ignition harness from Dennis prior to the
flight and the engine checks
at the 100 hourly indicated smoother running, however this is not the
cause as it has done the same thing previously, but was put down to
carby icing, a reason that I accepted at the time but which I now do not
believe. Incidentally at the time it was CAVOC and 30o C so icing was
impossible on this day as it was on the previous occasion. I have since
found out that the last time it was 24o C and fine.
Sorry about the long winded explanation, but it has me stumped and I
hope some of the vast knowledge available on this list will point me in
the right direction to avoid repitition when she arrives home.
Kind Regards Bruce Thomas
Message 3
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| Subject: | Re: M14P misfiring |
Bruce,
Did you say you bought two new mags and it continued to misfire. The incidents
Dennis speaks were indeed a bad coil. I happened on my YAK-50. The loss of engine
power comes a sphinter tightening silence for a heartbeat. The reason for
the loss of power is pressumed to be a misfire that is like a backfire that consumes
all the aeosolized fuel in the intakes and supercharger. After it does
this, then it begins to run correctly again. If the flight continues for about
10-15 min, then it starts to run rough and only jockying the throttle will give
enough power to land. When it cools down, then it will run normally for about
20 minutes then the process starts all over again,
An airborne mag check will identify the offending mag. As Dennis says, it takes
changing out the coils to fix this particular problem. That was the way my engine
misfires went. This does not sound completely like a mag problem though,
unless you got M9 F mags with an advancing dwell (found on the 52 W and TW). If
you have the standard M-14, then the centrifigal advancing magnetos will be
next to impossible to get tuned. You will have uneventful runups but will find
yourself riding a bucking bronco after coming up to 100% and generally passing
about 1500 feet. By retarding the power, the engine runs more normally much
like a fuel flow problem. Been there, got the T shirt and do not want another!
The reason I ended up with the wrong mag, was that the case had had the embosing
sanded off.
Just to confuse a little more.
Sorry, hope all works out. Keep us informed.
Doc
----- Original Message -----
Sent: 7/29/2006 6:35:32 AM
Bruce,
I have seen this problem several times before. When it happens, it typically happens
somewhere between the initial 20 and 35 minutes of flight. It has always
been a bad coil breaking down in one of the mags. The symptom is an engine
"cough" which feels like a complete engine shutdown for a half second or so.
It DOES get your attention. You will have fly the airplane over your airfield
for 20 - 40 minutes hoping the engine cough will show up again. When it does,
switch to one mag then the other. Whichever mag coil has failed will definitely
be discernable. Remove the suspected mag and replace the coil. Bench testing
the coil will show the coil as normal. But do not use this coil again
because under heat and load, it will fail again.
To access the front mag hold-down nut, (a real pain to get to) purchase an inexpensive
14 mm combination (box end/open end) wrench. Heat the wrench shaft with
an acetylene torch and put a bend in the shaft of approximately 120 degrees.
Use the box end wrench to loosen and tighten the front hold down nut. That
is the easiest way to access the front nut. If you put 3 vertical marks between
the base of the mag and the accessory case using a Sharpie pen or similar
marking device, you should be able to remove and replace the mag by lining up
the 3 marks and not have to retime the magneto.
Dennis
----- Original Message -----
Sent: Saturday, July 29, 2006 10:50 PM
Hi All,
I have a problem that I will tell you about in the hope that somebody can throw
some light on it.
Last Wednesday Garry Mitchell of Australian Air ferry and myself took off from
White Waltham Airfield In the UK in my newly acquired Yak 18T.
We were bound for Genoa Italy as the first leg of a long trip which was to end
in Melbourne Australia.
After 30 minutes flying we cleared English airspace and were handed to Paris control
and were given clearance to climb to 8000 ft. from 2500ft over the English
channel, shortly after passing through 3500ft the motor at climb power,82%,
the engine gave one cough as if power was completely turned off then instantly
back on.
This concerned us, but it continued to run well and smoothly, Ok as smoothly as
a M14P can , then about one minute later all hell broke loose; It began coughing
and popping and loosing power. The fuel and oil pressure gauges were oscillating
to zero then almost instantly back to full pressure again ( I don't know
if this was a cause or an effect ) however it continued to run albeit without
much power, Garry tried various minor adjustments without being too adventurous
as we were over water at this stage and didn't want to kill what power we
had.
.
We declared an emergency and London control vectored us back towards Shoreham airfield
at Brighton, about 12 miles back, luckily we made it having lost about
2500ft.
As we dropped the gear and flap then went to full fine pitch prior to landing,
the banging and backfiring stopped and we were able to land normally, the motor
ran well during taxi and also ran cleanly at 65% for 30 sec, at shut down.
We rang Russian engineering at White Waltham and ran the symptoms past Genna and
Atur
and they thought it was magnetos, and bought two new units to Shoreham next morning
and fitted them. Did comprehensive run up checks and pronounced it cured,
Alex Berry , the previous owner, then flew her back to White Waltham, without incident,
to be dissembled and packed into a container to be shipped to Australia
as both Garry and I at this point decided that we didn't have the confidence
to attempt another 12000 mile trip again.
On reflection we are inclined to think that it was fuel starvation, rather than
magneto's that caused the problem, and will disassemble the entire fuel supply
system when it gets here.
This is where I am looking for assistance, has anybody out there had a similar
occurrence,
or has any suggestions on what it may be and how to cure it once and for all.
One other point, I fitted an ignition harness from Dennis prior to the flight and
the engine checks
at the 100 hourly indicated smoother running, however this is not the cause as
it has done the same thing previously, but was put down to carby icing, a reason
that I accepted at the time but which I now do not believe. Incidentally at
the time it was CAVOC and 30o C so icing was impossible on this day as it was
on the previous occasion. I have since found out that the last time it was 24o
C and fine.
Sorry about the long winded explanation, but it has me stumped and I hope some
of the vast knowledge available on this list will point me in the right direction
to avoid repitition when she arrives home.
Kind Regards Bruce Thomas
Message 4
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| Subject: | Re: M14P misfiring |
When Bruce said "the engine gave one cough as if power was completely
turned off then instantly back on", I was fairly certain it's the mag
coil and it doesn't matter if it's a pair of M9F mags or a pair of M9-35
mags.
What Doc is talking about is his airplane had the same symptom. We
replaced one of the mags (the one we suspected to be bad) with one we
received from across the pond that had just come out of overhaul. The
data plate on the mag was clearly marked as an M9F. So we timed it as
an M9F. The damn engine simply would not run on the ground without
misfiring. We replaced wires, plugs, cap, points, but no change in the
problem. Then I just happen to notice that under the cover on the boss
of the mag was stamped a "36", just like on a centrifugal advance mag
like the M9-35 used on the Romanian 400 HP engines. Humm I said to
myself, I wonder if this mag's data plate was removed and replaced with
an M9F marked data plate. After careful examination of the area around
the data plate, one could see circular grinder marks in the area around
where the data plate was affixed. We replaced this same mag with a
known good M9F mag and bingo, problem solved.
Why is this a problem? Mixing one centrifugal mag (M9-35) which is
suppose to be timed at 5 degrees AFTER TDC with an M9F mag which is
timed at 15 degrees BEFORE TDC just ain't going to work when the mag
switch is in the 1+2 position.
But Doc's original problem was exactly as Bruce described. As Doc
said. It really does get your attention.
Dennis
----- Original Message -----
From: Roger Kemp
To: yak-list@matronics.com
Sent: Saturday, July 29, 2006 5:49 PM
Subject: Re: Yak-List: M14P misfiring
Bruce,
Did you say you bought two new mags and it continued to misfire. The
incidents Dennis speaks were indeed a bad coil. I happened on my YAK-50.
The loss of engine power comes a sphinter tightening silence for a
heartbeat. The reason for the loss of power is pressumed to be a
misfire that is like a backfire that consumes all the aeosolized fuel in
the intakes and supercharger. After it does this, then it begins to run
correctly again. If the flight continues for about 10-15 min, then it
starts to run rough and only jockying the throttle will give enough
power to land. When it cools down, then it will run normally for about
20 minutes then the process starts all over again,
An airborne mag check will identify the offending mag. As Dennis says,
it takes changing out the coils to fix this particular problem. That was
the way my engine misfires went. This does not sound completely like a
mag problem though, unless you got M9 F mags with an advancing dwell
(found on the 52 W and TW). If you have the standard M-14, then the
centrifigal advancing magnetos will be next to impossible to get tuned.
You will have uneventful runups but will find yourself riding a bucking
bronco after coming up to 100% and generally passing about 1500 feet. By
retarding the power, the engine runs more normally much like a fuel flow
problem. Been there, got the T shirt and do not want another!
The reason I ended up with the wrong mag, was that the case had had
the embosing sanded off.
Just to confuse a little more.
Sorry, hope all works out. Keep us informed.
Doc
----- Original Message -----
From: A. Dennis Savarese
To: yak-list@matronics.com
Sent: 7/29/2006 6:35:32 AM
Subject: Re: Yak-List: M14P misfiring
[LashBack]
Bruce,
I have seen this problem several times before. When it happens, it
typically happens somewhere between the initial 20 and 35 minutes of
flight. It has always been a bad coil breaking down in one of the mags.
The symptom is an engine "cough" which feels like a complete engine
shutdown for a half second or so. It DOES get your attention. You will
have fly the airplane over your airfield for 20 - 40 minutes hoping the
engine cough will show up again. When it does, switch to one mag then
the other. Whichever mag coil has failed will definitely be
discernable. Remove the suspected mag and replace the coil. Bench
testing the coil will show the coil as normal. But do not use this coil
again because under heat and load, it will fail again.
To access the front mag hold-down nut, (a real pain to get to)
purchase an inexpensive 14 mm combination (box end/open end) wrench.
Heat the wrench shaft with an acetylene torch and put a bend in the
shaft of approximately 120 degrees. Use the box end wrench to loosen
and tighten the front hold down nut. That is the easiest way to access
t he front nut. If you put 3 vertical marks between the base of the mag
and the accessory case using a Sharpie pen or similar marking device,
you should be able to remove and replace the mag by lining up the 3
marks and not have to retime the magneto.
Dennis
----- Original Message -----
From: Bruce Thomas
To: yak-list@matronics.com
Sent: Saturday, July 29, 2006 10:50 PM
Subject: Yak-List: M14P misfiring
[LashBack]
Hi All,
I have a problem that I will tell you about in the hope that
somebody can throw some light on it.
Last Wednesday Garry Mitchell of Australian Air ferry and myself
took off from White Waltham Airfield In the UK in my newly acquired Yak
18T.
We were bound for Genoa Italy as the first leg of a long trip
which was to end in Melbourne Australia.
After 30 minutes flying we cleared English airspace and were
handed to Paris control and were given clearance to climb to 8000 ft.
from 2500ft over the English channel, shortly after passing through
3500ft the motor at climb power,82%, the engine gave one cough as if
power was completely turned off then instantly back on.
This concerned us, but it continued to run well and smoothly, Ok
as smoothly as a M14P can , then about one minute later all hell broke
loose; It began coughing and popping and loosing power. The fuel and oil
pressure gauges were oscillating to zero then almost instantly back to
full pressure again ( I don't know if this was a cause or an effect )
however it continued to run albeit without much power, Garry tried
various minor adjustments without being too adventurous as we were over
water at this stage and didn't want to kill what power we had.
.
We declared an emergency and London control vectored us back
towards Shoreham airfield at Brighton, about 12 miles back, luckily we
made it having lost about 2500ft.
As we dropped the gear and flap then went to full fine pitch prior
to landing, the banging and backfiring stopped and we were able to land
normally, the motor ran well during taxi and also ran cleanly at 65% for
30 sec, at shut down.
We rang Russian engineering at White Waltham and ran the symptoms
past Genna and Atur
and they thought it was magnetos, and bought two new units to
Shoreham next morning and fitted them. Did comprehensive run up checks
and pronounced it cured,
Alex Berry , the previous owner, then flew her back to White
Waltham, without incident, to be dissembled and packed into a container
to be shipped to Australia as both Garry and I at this point decided
that we didn't have the confidence to attempt another 12000 mile trip
again.
On reflection we are inclined to think that it was fuel
starvation, rather than magneto's that caused the problem, and will
disassemble the entire fuel supply system when it gets here.
This is where I am looking for assistance, has anybody out there
had a similar occurrence,
or has any suggestions on what it may be and how to cure it once
and for all.
One other point, I fitted an ignition harness from Dennis prior to
the flight and the engine checks
at the 100 hourly indicated smoother running, however this is not
the cause as it has done the same thing previously, but was put down to
carby icing, a reason that I accepted at the time but which I now do not
believe. Incidentally at the time it was CAVOC and 30o C so icing was
impossible on this day as it was on the previous occasion. I have since
found out that the last time it was 24o C and fine.
Sorry about the long winded explanation, but it has me stumped and
I hope some of the vast knowledge available on this list will poin t me
in the right direction to avoid repitition when she arrives home.
Kind Regards Bruce Thomas
Message 5
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Bruce,
FWIW, the misfiring I experienced was in my YAK-52 not the 50. My mistake. As
said before, it was related to a bad coil and occure after 20-30 of flight.
Doc
Roger "Doc" Kemp
viperdoc@mindspring.com
Aint no sound like a Radial
Message 6
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| Subject: | MiG-21 Heads Up Display |
--> Yak-List message posted by: "Tim Gagnon" <NiftyYak50@msn.com>
This is an odd request....
While deployed to Iraq, I came across the heads-up display from an Iraqi MiG-21.
(Just so I am clear, I did NOT remove this from an airworthy MiG-21. I found
it lying in a junkyard north of Balad AB which is 65 klicks or so north of Baghdad)
Anyway, I would like to get it restored to display condition. It is missing the
glass but other wise intact. I figure with all the varying experience with some
unique airplanes, someone here may have some ideas on a source for the restoration.
Anyone...
As a side note: I also could have brought home a rocket pod that was laying near
the HUD... I also found a bunch of 57mm AAA shells that came from a box stamped
Jordainian Armed Forces.....
The AAA site was no longer operational courtesy of some F-15E's.
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=50654#50654
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