Today's Message Index:
----------------------
1. 12:27 AM - Re: EI vs JPI (Gil Alexander)
2. 07:21 AM - Re: EI vs JPI (flyv35b)
3. 07:44 AM - Re: EI vs JPI (flyv35b)
4. 10:36 AM - Re: EI vs JPI (teamgrumman@aol.com)
5. 05:36 PM - Re: EI vs JPI (Gil Alexander)
6. 06:22 PM - Re: EI vs JPI (Gil Alexander)
Message 1
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I believe you can deduce what they used from their documents.
The Lycoming Overhaul Manual Test Run section
specifically calls for a 500F max CHT limit
(table on page 9-2 of my 2002 version) and states
that it is at the "Bayonet Location".
Lycoming documents don't change too much over
time...:^) ...and the reference to Bayonet says
to me that they use a "Bayonet Probe" when they do certification runs.
Older instrumentation in the 60's was MIL-Spec AN
type that got replaced by the MS specifications -
but remained basically the same part.
I have a copy of the 1966 MS 90324 Specification
"Thermocouple, Engine Cylinder, Bayonet Type"
It is definitely a spring loaded device with a
2.5 pound spring force specification at a length
of 2.5 inches. With the AN 4076-1 bayonet
adapter, it is tested in a test fixture with a depth of 1.80 inches.
Can someone measure the depth of a Lycoming CHT
well - I bet it is 1.8 inches deep, or a bit less....:^)
I say that the use of the word "Bayonet", along
with the MIL-Spec standards from the 50s and 60s
when our engines were basically certified say
that it is a spring loaded device that physically
touches the bottom of the CHT well.
Sacramento Sky ranch has a probe picture here -
http://www.sacskyranch.com/acatalog/86251.jpg
The AN 4076 adapter picture is here -
http://www.aircraftspruce.com/catalog/inpages/inmisc/28202.jpg
I think it's all in the word "bayonet"....
gil - the detective...:^)
At 09:21 PM 3/27/2009, teamgrumman@aol.com wrote:
>I called Lycoming about 6 years ago and tried to
>find an engineer who could answer that question.
>=C2 It took about 5 'engineers' saying, "Well,
>[fill in the blank] would know, but, he died."
>before I realized all of the corporate knowledge
>was gone. =C2 I researched it a bit and from what
>I recall, probes similar to the EI probes were used.
>
>I also spent a significant amount of time about
>20 years ago trying to find out which rocker
>when where. =C2 As you may know, the intake rocker
>and the exhaust rocker are different. =C2 IAs on
>my field (Lancaster) and the folks at Lycoming
>were NO HELP AT ALL. =C2 I finally found an
>overhaul manual written in 1955 that described the differences.
>
>
>-----Original Message-----
>From: Richard Mutzman <rcmutz@msn.com>
>To: Team Grumman <teamgrumman-list@matronics.com>
>Sent: Fri, 27 Mar 2009 2:28 pm
>Subject: TeamGrumman-List: EI vs JPI
>
>I have been following the discussion with interest.
>=C2
>One thing that I don't recall being addressed
>(maybe Gary addressed in his article), is, for
>the limits that Lycoming quotes, which probe did
>they use for the testing.=C2 One that measures
>the actual metal temps via conduction, or one
>that measures the air in a well which is heated
>by radiation from the hot metal?=C2 Hmmmm...conduction versus radiation?
>
>Richard Mutzman
>
>
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Message 2
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I called Lycoming about 6 years ago and tried to find an engineer who could
answer that question. It took about 5 'engineers' saying, =22Well, [fill in
the blank] would know, but, he died.=22 before I realized all of the corpora
te knowledge was gone. I researched it a bit and from what I recall, probe
s similar to the EI probes were used.
I would have guessed the other style (spring loaded) as that is what Alcor
used years ago on their analog instruments before JPI or EI were even in ex
istence.
I also spent a significant amount of time about 20 years ago trying to find
out which rocker when where. As you may know, the intake rocker and the e
xhaust rocker are different. IAs on my field (Lancaster) and the folks at
Lycoming were NO HELP AT ALL. I finally found an overhaul manual written i
n 1955 that described the differences.
The older engines had a small hole in the exhaust rocker arm that which was
supposed to squirt a little oil through the valve spring and on to the val
ve stem, if you can believe that. Bill Marvel discovered that an engine th
at he had recently had overhauled by Lycoming had the intake and exhaust ro
cker arms reversed and he had badly worn exhaust guides in a short time (le
ss than 250 hrs as I recall). He wrote a letter to the president of Lycomi
ng about it and they gave him a complete new engine. I think it was as a r
esult of this that Lycoming then changed to use the same exhaust rocker arm
on both the intake and exhaust - so they could not be mixed up by someone
not paying attention. But there are thousands of the older style rocker ar
ms out there in use still, probably many more than there are the later conf
iguration. A much better solution was developed when the IO-540 engine in
new Mooneys were wearing out the exhaust guides in 200-400 hrs and the owne
rs where bitching so bad that Mooney put enough pressure on Lycoming to fin
d a solution and not just blame it on operator technique! Same cylinder an
d head as the O-360 engine uses but Lycoming never would admit they had a p
roblem with any engine besides the specific Mooney model and they would not
sell the parts for retrofit for other engines. But that's the attitude wh
en the attorneys and bean counters are calling the shots.
Cliff
----- Original Message -----
From: teamgrumman@aol.com
To: teamgrumman-list@matronics.com
Sent: Friday, March 27, 2009 9:21 PM
Subject: Re: TeamGrumman-List: EI vs JPI
I called Lycoming about 6 years ago and tried to find an engineer who cou
ld answer that question. It took about 5 'engineers' saying, =22Well, [fill
in the blank] would know, but, he died.=22 before I realized all of the corpo
rate knowledge was gone. I researched it a bit and from what I recall, pro
bes similar to the EI probes were used.
I also spent a significant amount of time about 20 years ago trying to fi
nd out which rocker when where. As you may know, the intake rocker and the
exhaust rocker are different. IAs on my field (Lancaster) and the folks a
t Lycoming were NO HELP AT ALL. I finally found an overhaul manual written
in 1955 that described the differences.
-----Original Message-----
From: Richard Mutzman <rcmutz@msn.com>
To: Team Grumman <teamgrumman-list@matronics.com>
Sent: Fri, 27 Mar 2009 2:28 pm
Subject: TeamGrumman-List: EI vs JPI
I have been following the discussion with interest.
One thing that I don't recall being addressed (maybe Gary addressed in hi
s article), is, for the limits that Lycoming quotes, which probe did they u
se for the testing. One that measures the actual metal temps via conductio
n, or one that measures the air in a well which is heated by radiation from
the hot metal=3F Hmmmm...conduction versus radiation=3F
Richard Mutzman
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I think you're right about this Gil. If so and if there really is a large
difference between the temperatures measured by a JPI EDM700/800 and an EI
instrument with the different style probes then it really does matter which
=22system=22 most accurately represents what Lycoming measured and set the 500
F redline limit by and their statement that for long life the max operating
temp should be 400F. If you believe that the JPI instrumentation most acc
urately represents Lycoming's testing and that EI reads 50F lower, say, the
n you should limit your continuous CHTs to 350F if you are using EI instrum
entation. I'll bet there are many many Tigers out there that are unable to
do this unless operated with excessively rich mixtures to get the extra co
oling needed to keep the temps this low.
Cliff
----- Original Message -----
From: Gil Alexander
To: teamgrumman-list@matronics.com ; teamgrumman-list@matronics.com
Sent: Saturday, March 28, 2009 12:26 AM
Subject: Re: TeamGrumman-List: EI vs JPI
I believe you can deduce what they used from their documents.
The Lycoming Overhaul Manual Test Run section specifically calls for a 50
0F max CHT limit (table on page 9-2 of my 2002 version) and states that it
is at the =22Bayonet Location=22.
Lycoming documents don't change too much over time...:^) ...and the refer
ence to Bayonet says to me that they use a =22Bayonet Probe=22 when they do cer
tification runs.
Older instrumentation in the 60's was MIL-Spec AN type that got replaced
by the MS specifications - but remained basically the same part.
I have a copy of the 1966 MS 90324 Specification =22Thermocouple, Engine C
ylinder, Bayonet Type=22
It is definitely a spring loaded device with a 2.5 pound spring force spe
cification at a length of 2.5 inches. With the AN 4076-1 bayonet adapter,
it is tested in a test fixture with a depth of 1.80 inches.
Can someone measure the depth of a Lycoming CHT well - I bet it is 1.8 in
ches deep, or a bit less....:^)
I say that the use of the word =22Bayonet=22, along with the MIL-Spec standar
ds from the 50s and 60s when our engines were basically certified say that
it is a spring loaded device that physically touches the bottom of the CHT
well.
Sacramento Sky ranch has a probe picture here -
http://www.sacskyranch.com/acatalog/86251.jpg
The AN 4076 adapter picture is here -
http://www.aircraftspruce.com/catalog/inpages/inmisc/28202.jpg
I think it's all in the word =22bayonet=22....
gil - the detective...:^)
At 09:21 PM 3/27/2009, teamgrumman@aol.com wrote:
I called Lycoming about 6 years ago and tried to find an engineer who c
ould answer that question. =C2 It took about 5 'engineers' saying, =22Well, [fi
ll in the blank] would know, but, he died.=22 before I realized all of the co
rporate knowledge was gone. =C2 I researched it a bit and from what I recall,
probes similar to the EI probes were used.
I also spent a significant amount of time about 20 years ago trying to
find out which rocker when where. =C2 As you may know, the intake rocker and
the exhaust rocker are different. =C2 IAs on my field (Lancaster) and the fol
ks at Lycoming were NO HELP AT ALL. =C2 I finally found an overhaul manual wr
itten in 1955 that described the differences.
-----Original Message-----
From: Richard Mutzman <rcmutz@msn.com>
To: Team Grumman <teamgrumman-list@matronics.com>
Sent: Fri, 27 Mar 2009 2:28 pm
Subject: TeamGrumman-List: EI vs JPI
I have been following the discussion with interest.
=C2
One thing that I don't recall being addressed (maybe Gary addressed in
his article), is, for the limits that Lycoming quotes, which probe did they
use for the testing.=C2 One that measures the actual metal temps via conduc
tion, or one that measures the air in a well which is heated by radiation f
rom the hot metal=3F=C2 Hmmmm...conduction versus radiation=3F
Richard Mutzman
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OK, but, it doesn't say what type probe, K, etc, or if it was grounded or no
t. =C2-
Lycoming documents don't change too much over time...:^) ...and the
reference to Bayonet says to me that they use a "Bayonet Probe"
when they do certification runs.
-----Original Message-----
From: Gil Alexander <gilalex@earthlink.net>
Sent: Sat, 28 Mar 2009 12:26 am
Subject: Re: TeamGrumman-List: EI vs JPI
I believe you can deduce what they used from their documents.
The Lycoming Overhaul Manual Test Run section specifically calls for a
500F max CHT limit (table on page 9-2 of my 2002 version) and states that
it is at the "Bayonet Location".
Lycoming documents don't change too much over time...:^) ...and the
reference to Bayonet says to me that they use a "Bayonet Probe"
when they do certification runs.
Older instrumentation in the 60's was MIL-Spec AN type that got replaced
by the MS specifications - but remained basically the same part.
I have a copy of the 1966=C2- MS 90324 Specification
"Thermocouple, Engine Cylinder, Bayonet Type"
It is definitely a spring loaded device with a 2.5 pound spring force
specification at a length of 2.5 inches.=C2- With the AN 4076-1 bayonet
adapter, it is tested in a test fixture with a depth of 1.80
inches.
Can someone measure the depth of a Lycoming CHT well - I bet it is 1.8
inches deep, or a bit less....:^)
I say that the use of the word "Bayonet", along wi
th the
MIL-Spec standards from the 50s and 60s when our engines were basically
certified say that it is a spring loaded device that physically touches
the bottom of the CHT well.
Sacramento Sky ranch has a probe picture here -
http://www.sacskyranch.com/acatalog/86251.jpg
The AN 4076 adapter picture is here -
http://www.aircraftspruce.com/catalog/inpages/inmisc/28202.jpg
I think it's all in the word "bayonet"....
gil - the detective...:^)
At 09:21 PM 3/27/2009, teamgrumman@aol.com wrote:
I called Lycoming about 6 years
ago and tried to find an engineer who could answer that question. =C3=82 It
took about 5 'engineers' saying, "Well, [fill in the blank] would
know, but, he died." before I realized all of the corporate
knowledge was gone. =C3=82 I researched it a bit and from what I recall,
probes similar to the EI probes were used.
I also spent a significant amount of time about 20 years ago trying to
find out which rocker when where. =C3=82 As you may know, the intake rocker
and the exhaust rocker are different. =C3=82 IAs on my field (Lancaster) and
the folks at Lycoming were NO HELP AT ALL. =C3=82 I finally found an overhau
l
manual written in 1955 that described the differences.
-----Original Message-----
From: Richard Mutzman <rcmutz@msn.com>
Sent: Fri, 27 Mar 2009 2:28 pm
Subject: TeamGrumman-List: EI vs JPI
I have been following the discussion with interest.
=C3=82
One thing that I don't recall20being addressed (maybe Gary addressed in
his article), is, for the limits that Lycoming quotes, which probe did
they use for the testing.=C3=82=C2- One that measures the actual metal tem
ps
via conduction, or one that measures the air in a well which is heated by
radiation from the hot metal?=C3=82=C2- Hmmmm...conduction versus
radiation?
Richard Mutzman
Windows Live=84=A2 SkyDrive: Get 25 GB of free online storage.
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Yep... but doesn't Lycoming really set 450F as a
"Climb out" redline in their later "making your engine last" documents?
The 400F number is a max cruise temp..... gil A
At 07:42 AM 3/28/2009, flyv35b wrote:
>I think you're right about this Gil. If so and
>if there really is a large difference between
>the temperatures measured by a JPI EDM700/800
>and an EI instrument with the different style
>probes then it really does matter which "system"
>most accurately represents what Lycoming
>measured and set the 500F redline limit by and
>their statement that for long life the max
>operating temp should be 400F. If you believe
>that the JPI instrumentation most accurately
>represents Lycoming's testing and that EI reads
>50F lower, say, then you should limit your
>continuous CHTs to 350F if you are using EI
>instrumentation. I'll bet there are many many
>Tigers out there that are unable to do this
>unless operated with excessively rich mixtures
>to get the extra cooling needed to keep the temps this low.
>
>Cliff
>----- Original Message -----
>From: <mailto:gilalex@earthlink.net>Gil Alexander
>To:
><mailto:teamgrumman-list@matronics.com>teamgrumman-list@matronics.com
>; <mailto:teamgrumman-list@matronics.com>teamgrumman-list@matronics.com
>Sent: Saturday, March 28, 2009 12:26 AM
>Subject: Re: TeamGrumman-List: EI vs JPI
>
>I believe you can deduce what they used from their documents.
>
>The Lycoming Overhaul Manual Test Run section
>specifically calls for a 500F max CHT limit
>(table on page 9-2 of my 2002 version) and
>states that it is at the "Bayonet Location".
>
>Lycoming documents don't change too much over
>time...:^) ...and the reference to Bayonet says
>to me that they use a "Bayonet Probe" when they do certification runs.
>
>Older instrumentation in the 60's was MIL-Spec
>AN type that got replaced by the MS
>specifications - but remained basically the same part.
>
>I have a copy of the 1966 MS 90324
>Specification "Thermocouple, Engine Cylinder, Bayonet Type"
>
>It is definitely a spring loaded device with a
>2.5 pound spring force specification at a length
>of 2.5 inches. With the AN 4076-1 bayonet
>adapter, it is tested in a test fixture with a depth of 1.80 inches.
>
>Can someone measure the depth of a Lycoming CHT
>well - I bet it is 1.8 inches deep, or a bit less....:^)
>
>I say that the use of the word "Bayonet", along
>with the MIL-Spec standards from the 50s and 60s
>when our engines were basically certified say
>that it is a spring loaded device that
>physically touches the bottom of the CHT well.
>
>Sacramento Sky ranch has a probe picture here -
>
>http://www.sacskyranch.com/acatalog/86251.jpg
>
>The AN 4076 adapter picture is here -
>
>http://www.aircraftspruce.com/catalog/inpages/inmisc/28202.jpg
>
>I think it's all in the word "bayonet"....
>
>gil - the detective...:^)
>
>
>At 09:21 PM 3/27/2009, teamgrumman@aol.com wrote:
>>I called Lycoming about 6 years ago and tried
>>to find an engineer who could answer that
>>question. =C2 It took about 5 'engineers' saying,
>>"Well, [fill in the blank] would know, but, he
>>died." before I realized all of the corporate
>>knowledge was gone. =C2 I researched it a bit and
>>from what I recall, probes similar to the EI probes were used.
>>
>>I also spent a significant amount of time about
>>20 years ago trying to find out which rocker
>>when where. =C2 As you may know, the intake
>>rocker and the exhaust rocker are different. =C2
>>IAs on my field (Lancaster) and the folks at
>>Lycoming were NO HELP AT ALL. =C2 I finally found
>>an overhaul manual written in 1955 that described the differences.
>>
>>
>>-----Original Message-----
>>From: Richard Mutzman <rcmutz@msn.com>
>>To: Team Grumman <teamgrumman-list@matronics.com>
>>Sent: Fri, 27 Mar 2009 2:28 pm
>>Subject: TeamGrumman-List: EI vs JPI
>>
>>I have been following the discussion with interest.
>>=C2
>>One thing that I don't recall being addressed
>>(maybe Gary addressed in his article), is, for
>>the limits that Lycoming quotes, which probe
>>did they use for the testing.=C2 One that
>>measures the actual metal temps via conduction,
>>or one that measures the air in a well which is
>>heated by radiation from the hot metal?=C2 Hmmmm...conduction versus
radiation?
>>
>>Richard Mutzman
>>
>>
>>
>>
>>----------
>>Windows Live=99 SkyDrive: Get 25 GB of free
>>online storage.
>><http://windowslive.com/online/skydrive?ocid=TXT_TAGLM_WL_skydrive_03200
9>Check
>>it out.
>>
>>
>>
>>or?TeamGrumman-List">http://www.matronics.com/Navigator?TeamGrumman-List
>>
>>p://forums.matronics.com
>>
>>ution">http://www.matronics.com/contribution
>>
>>
>>
>>----------
>>A Good Credit Score is 700 or Above.
>>?redir=http:%2F%2Fwww.freecreditreport.com%2Fpm%2Fdefault.aspx%3Fsc%3D66
8072%26hmpgID%3D62%26bcd%3DfebemailfooterNO62">
>>See yours in just 2 easy steps!
>
>
><http://www.matronics.com/Navigator?TeamGrumman-List>http://www.matronics.c
om/Navigator?TeamGrumman-List
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Gary ....Not really relevant to the discussion.
The debate is "Did the original Lycoming
certification probe touch the sell of the cylinder?"
The MS90324 specification defines a Type J
thermocouple (iron-constantan) that is
ungrounded and has a 0.025 ohm resistance, and
does touch the base of the cylinder well.
This the only Mil-Spec engine CHT thermocouple probe listed.
I'm sure Lycoming would have used the MS part (or
it's earlier AN5541 equivalent)
Alcor think the bayonet type are better - from their STC
--------------------------------------
Spring loaded bayonet types are more accurate than simple screw
in types because the probe touches the bottom of
the thermowell and senses metal rather
than air temperature.
--------------------------------------
....and, no surprise, the Alcor bayonet probe is
type J and has the same resistance as the old MS90324 specification.
If you want to know lots of details on
thermocouples, including a DIY sensor, this is interesting....
http://www.aeroelectric.com/articles/excerpt.pdf
gil A
At 10:32 AM 3/28/2009, you wrote:
>OK, but, it doesn't say what type probe, K, etc,
>or if it was grounded or not. =C2
>Lycoming documents don't change too much over
>time...:^) ...and the reference to Bayonet says
>to me that they use a "Bayonet Probe" when they do certification runs.
>
>
>-----Original Message-----
>From: Gil Alexander <gilalex@earthlink.net>
>To: teamgrumman-list@matronics.com; teamgrumman-list@matronics.com
>Sent: Sat, 28 Mar 2009 12:26 am
>Subject: Re: TeamGrumman-List: EI vs JPI
>
>I believe you can deduce what they used from their documents.
>
>The Lycoming Overhaul Manual Test Run section
>specifically calls for a 500F max CHT limit
>(table on page 9-2 of my 2002 version) and
>states that it is at the "Bayonet Location".
>
>Lycoming documents don't change too much over
>time...:^) ...and the reference to Bayonet says
>to me that they use a "Bayonet Probe" when they do certification runs.
>
>Older instrumentation in the 60's was MIL-Spec
>AN type that got replaced by the MS
>specifications - but remained basically the same part.
>
>I have a copy of the 1966=C2 MS 90324
>Specification "Thermocouple, Engine Cylinder, Bayonet Type"
>
>It is definitely a spring loaded device with a
>2.5 pound spring force specification at a length
>of 2.5 inches.=C2 With the AN 4076-1 bayonet
>adapter, it is tested in a test fixture with a depth of 1.80 inche s.
>
>Can someone measure the depth of a Lycoming CHT
>well - I bet it is 1.8 inches deep, or a bit less....:^)
>
>I say that the use of the word "Bayonet", along
>with the MIL-Spec standards from the 50s and 60s
>when our engines were basically certified say
>that it is a spring loaded device that
>physically touches the bottom of the CHT well.
>
>Sacramento Sky ranch has a probe picture here -
>
><http://www.sacskyranch.com/acatalog/86251.jpg>http://www.sacskyranch.com/a
catalog/86251.jpg
>
>The AN 4076 adapter picture is here -
>
><http://www.aircraftspruce.com/catalog/inpages/inmisc/28202.jpg>http://www.
aircraftspruce.com/catalog/inpages/inmisc/28202.jpg
>
>I think it's all in the word "bayonet"....
>
>gil - the detective...:^)
>
>
>At 09:21 PM 3/27/2009, <mailto:teamgrumman@aol.com>teamgrumman@aol.com
wrote:
>>I called Lycoming about 6 years ago and tried
>>to find an engineer who could answer that
>>question. =C3=82 It took about 5 'engineers'
>>saying, "Well, [fill in the blank] would know,
>>but, he died." before I realized all of the
>>corporate knowledge was gone. =C3=82 I researched
>>it a bit and from what I recall, probes similar to the EI probes were
used.
>>
>>I also spent a significant amount of time about
>>20 years ago trying to find out which rocker
>>when where. =C3=82 As you may know, the intake
>>rocker and the exhaust rocker are different. =C3=82
>>IAs on my field (Lancaster) and the folks at
>>Lycoming were NO HELP AT ALL. =C3=82 I finally
>>found an overhaul manual written in 1955 that described the differences.
>>
>>
>>-----Original Message-----
>>From: Richard Mutzman <<mailto:rcmutz@msn.com>rcmutz@msn.com>
>>To: Team Grumman
>><<mailto:teamgrumman-list@matronics.com>teamgrumman-list@matronics.com>
>>Sent: Fri, 27 Mar 2009 2:28 pm
>>Subject: TeamGrumman-List: EI vs JPI
>>
>>I have been following the discussion with interest.
>>=C3=82
>>One thing that I don't recall being addressed
>>(maybe Gary addressed in his article), is, for
>>the limits that Lycoming quotes, which probe
>>did they use for the testing.=C3=82=C2 One that
>>measures the actual metal temps via conduction,
>>or one that measures the air in a well which is
>>heated by radiation from the hot
>>metal?=C3=82=C2 Hmmmm...conduction versus radiation?
>>
>>Richard Mutzman
>>
>>
>>
>>
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