Today's Message Index:
----------------------
1. 06:57 AM - Re: EI vs JPI (Richard Mutzman)
2. 11:42 AM - Re: Re: EI vs JPI (teamgrumman@AOL.COM)
3. 12:03 PM - Re: Re: EI vs JPI (Gil Alexander)
4. 05:40 PM - Re: Re: EI vs JPI (teamgrumman@AOL.COM)
5. 06:42 PM - Re: Re: EI vs JPI (Gil Alexander)
6. 07:04 PM - Re: Re: EI vs JPI (923te)
7. 07:14 PM - Re: Re: EI vs JPI (Gil Alexander)
8. 07:32 PM - Re: Re: EI vs JPI (923te)
9. 07:33 PM - Re: Re: EI vs JPI (923te)
10. 07:33 PM - Re: Re: EI vs JPI (923te)
11. 07:33 PM - Re: Re: EI vs JPI (923te)
12. 07:35 PM - Re: Re: EI vs JPI (flyv35b)
13. 07:46 PM - Re: Re: EI vs JPI (923te)
14. 07:46 PM - Re: Re: EI vs JPI (923te)
15. 07:51 PM - Re: Re: EI vs JPI (Gil Alexander)
16. 07:58 PM - Re: Re: EI vs JPI (Gil Alexander)
17. 08:02 PM - Re: Re: EI vs JPI (linn)
18. 08:04 PM - Re: Re: EI vs JPI (923te)
19. 08:04 PM - Re: Re: EI vs JPI (923te)
20. 08:13 PM - Re: Re: EI vs JPI (Gil Alexander)
21. 08:20 PM - Re: Re: EI vs JPI (923te)
22. 08:27 PM - Re: Re: EI vs JPI (Gil Alexander)
23. 08:32 PM - Re: Re: EI vs JPI (Gil Alexander)
24. 08:36 PM - Re: Re: EI vs JPI (923te)
25. 09:06 PM - Re: Re: EI vs JPI (Gil Alexander)
26. 09:22 PM - Re: Re: EI vs JPI (923te)
Message 1
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Gil=2C
I tend to agree with what you are saying. It does appear that Lycoming use
d the spring loaded type probe which touches the metal. Therefore it seems
logical that if one uses a probe that touches the metal (whether EI or JPI
and installed correctly=2C common or floating ground)=2C observes the temp
limits of 500 and 400=2C one should be ok from a cylinder durability persp
ective. At least from the temp side of the durability "equation".
Thanks for dong the research on this. When I put in a CHT system=2C I will
use the bayonet type probe=2C independent of JPI or EI electronics.
Rich
_________________________________________________________________
Hotmail=AE is up to 70% faster. Now good news travels really fast.
http://windowslive.com/online/hotmail?ocid=TXT_TAGLM_WL_HM_70faster_03200
9
Message 2
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| Subject: | Re: RE: EI vs JPI |
This is only true if, and it's a big IF, the temperatures displayed on today
s instrumentation "WOULD" have displayed the same temperatures as those reco
rded by Lycoming technicians=C2-on the instrumentation used by Lycoming.
=C2-
I don't care what Lycoming's results were. =C2-I don't care what system Ly
coming used, grounded or ungrounded, J or K type probes, etc., whenever it w
as they did their testing. =C2-We don't even know if they tested to destru
ction. =C2-OR. =C2-Did they just get out a metallurgy handbook and look
at aluminum properties and pick a limit from there? =C2-
There are so many 'old wives' tales regarding how to operate EGTs and CHTs a
nd so many recommendations that contradict each other that I'm not convinced
any of them are true. =C2-I would like to see Lycoming step up to the pla
te and do their own testing and comparisons with todays instrumentation.
=C2-Even if I had the same MIL spec probes Lycoming supposedly used, there
is no guarantee that I'd see the same temperatures Lycoming did under the s
ame conditions. =C2-THE ONLY THING I COULD BE SURE OF, using the exact sam
e instrumentation Lycoming did, IS A VIABLE REASON FOR WARRANTEE WORK FROM L
YCOMING should a cylinder fail.
It is obvious, at least to me, that JPI and EI instrumentation give dramatic
ally different temperature read-outs. =C2-Is it just the probe? =C2-Is i
t the difference between grounded or ungrounded thermal couples?
My personal upper CHT limit on climb out, on the JPI 800, i
s 470 degrees. =C2-WHY? =C2-Because, under the same conditions, I saw 39
0-400 on the EI sitting next to my JPI (do back off on power at 440 and lowe
r the nose to keep it below 450). =C2-My high power, 2700 rpm, cruise limi
t is 425 (350 on an EI). =C2-I expect to see something in the neighborhood
of 380 degrees (320 on an EI) at 65% power and 8500 feet. =C2-
Speaking of 'old wives' tales: =C2-Why do we have such strict limitations
on tear-down and inspection if an engine is operated over 2700 rpm? =C2-Wh
ere did the 2700 rpm limit come from? =C2-Why is there a 2700 rpm limit on
airplane engines and a 2900 to 3200 rpm limit on similar engines used in he
licopters? =C2-
-----Original Message-----
From: Richard Mutzman <rcmutz@msn.com>
Sent: Sun, 29 Mar 2009 6:56 am
Subject: TeamGrumman-List: RE: EI vs JPI
Gil,
=C2-
I tend to agree with what you are saying.=C2- It does=C2-appear that Lyc
oming used the spring loaded type probe which touches the metal.=C2- There
fore it seems logical that if one uses a probe that touches the metal (wheth
er EI or JPI and installed correctly, common or floating ground), observes t
he temp limits of 500 and 400, one should be ok from a cylinder durability p
erspective.=C2- At least from the temp side of the durability "equation".
=C2-
=C2-
Thanks for dong the research on this.=C2- When I put in a CHT system, I wi
ll use the bayonet type probe, independe
nt of JPI or EI electronics.
Rich
Hotmail=C2=AE is up to 70% faster. Now good news travels really fast. Find o
ut more.
Message 3
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| Subject: | Re: RE: EI vs JPI |
>This is only true if, and it's a big IF, the
>temperatures displayed on todays instrumentation
>"WOULD" have displayed the same temperatures as
>those recorded by Lycoming technicians=C2 on the
>instrumentation used by Lycoming. =C2
Gary... I don't belief that is a big "IF"...
The electrical characteristics of a type J
thermocouple have been well known from long before WWII.
The electrical instrumentation bit has not
changed over the years as far as the basic
thermocouple, especially when used in an engine
test cell. I bet Lycoming had individual CHT
meters directly connected to the probes, none of
this fancy digital switching, scanning stuff....:^)
Today the probes and the interconnect may be
different, but the a type J thermocouple has
always created the same amount of voltage due to physics.
There is something else going on here in your
plane - and since we are dealing with fractions
of milliVolts, I would personally vote for
grounding issues. You can see from the table
below that 10 degrees Centigrade is about a 1/2
milliVolt change. Try a direct wire from GND on your EI gauge to the
engine.
This is from Sandia labs... gil A
ITS-90 Table for type J thermocouple
=B0C 0 1 2 3 4 5
6 7 8 9 10
Thermoelectric Voltage in mV
0 0.000 0.050 0.101 0.151 0.202 0.253
0.303 0.354 0.405 0.456 0.507
10 0.507 0.558 0.609 0.660 0.711 0.762
0.814 0.865 0.916 0.968 1.019
20 1.019 1.071 1.122 1.174 1.226 1.277
1.329 1.381 1.433 1.485 1.537
30 1.537 1.589 1.641 1.693 1.745 1.797
1.849 1.902 1.954 2.006 2.059
40 2.059 2.111 2.164 2.216 2.269 2.322
2.374 2.427 2.480 2.532 2.585
50 2.585 2.638 2.691 2.744 2.797 2.850
2.903 2.956 3.009 3.062 3.116
60 3.116 3.169 3.222 3.275 3.329 3.382
3.436 3.489 3.543 3.596 3.650
70 3.650 3.703 3.757 3.810 3.864 3.918
3.971 4.025 4.079 4.133 4.187
80 4.187 4.240 4.294 4.348 4.402 4.456
4.510 4.564 4.618 4.672 4.726
90 4.726 4.781 4.835 4.889 4.943 4.997
5.052 5.106 5.160 5.215 5.269
100 5.269 5.323 5.378 5.432 5.487 5.541
5.595 5.650 5.705 5.759 5.814
110 5.814 5.868 5.923 5.977 6.032 6.087
6.141 6.196 6.251 6.306 6.360
120 6.360 6.415 6.470 6.525 6.579 6.634
6.689 6.744 6.799 6.854 6.909
130 6.909 6.964 7.019 7.074 7.129 7.184
7.239 7.294 7.349 7.404 7.459
140 7.459 7.514 7.569 7.624 7.679 7.734
7.789 7.844 7.900 7.955 8.010
150 8.010 8.065 8.120 8.175 8.231 8.286
8.341 8.396 8.452 8.507 8.562
160 8.562 8.618 8.673 8.728 8.783 8.839
8.894 8.949 9.005 9.060 9.115
170 9.115 9.171 9.226 9.282 9.337 9.392
9.448 9.503 9.559 9.614 9.669
180 9.669 9.725 9.780 9.836 9.891 9.947
10.002 10.057 10.113 10.168 10.224
190 10.224 10.279 10.335 10.390 10.446 10.501
10.557 10.612 10.668 10.723 10.779
200 10.779 10.834 10.890 10.945 11.001 11.056
11.112 11.167 11.223 11.278 11.334
210 11.334 11.389 11.445 11.501 11.556 11.612
11.667 11.723 11.778 11.834 11.889
220 11.889 11.945 12.000 12.056 12.111 12.167
12.222 12.278 12.334 12.389 12.445
230 12.445 12.500 12.556 12.611 12.667 12.722
12.778 12.833 12.889 12.944 13.000
240 13.000 13.056 13.111 13.167 13.222 13.278
13.333 13.389 13.444 13.500 13.555
250 13.555 13.611 13.666 13.722 13.777 13.833
13.888 13.944 13.999 14.055 14.110
260 14.110 14.166 14.221 14.277 14.332 14.388
14.443 14.499 14.554 14.609 14.665
270 14.665 14.720 14.776 14.831 14.887 14.942
14.998 15.053 15.109 15.164 15.219
280 15.219 15.275 15.330 15.386 15.441 15.496
15.552 15.607 15.663 15.718 15.773
290 15.773 15.829 15.884 15.940 15.995 16.050
16.106 16.161 16.216 16.272 16.327
Message 4
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| Subject: | Re: RE: EI vs JPI |
There is something else going on here in your plane - and since we are
dealing with fractions of milliVolts, I would personally vote for
grounding issues.=C2-
MY PLANE? =C2-Ok, maybe your right. =C2-The grounds in installed accordi
ng to the STC were done wrong. =C2-Maybe the probes grounding against bran
d new cylinders had corrosion built up in them. =C2-
Maybe planes experiencing CHT readings higher on a JPI than on an EI also fo
llowed the installation instructions.
How about you doing your own testing and report your own results?
-----Original Message-----
From: Gil Alexander <gilalex@earthlink.net>
Sent: Sun, 29 Mar 2009 12:03 pm
Subject: Re: TeamGrumman-List: RE: EI vs JPI
This is only true if, and it's a
big IF, the temperatures displayed on todays instrumentation
"WOULD" have displayed the same temperatures as those recorded
by Lycoming technicians=C3=82 on the instrumentation used by Lycoming. =C3
=82=C2-
Gary... I don't belief that is a big "IF"...
The electrical characteristics of a type J thermocouple have been well
known from long before WWII.
The electrical instrumentation bit has not changed over the years as far
as the basic thermocouple, especially when used in an engine test
cell.=C2- I bet Lycoming had individual CHT meters directly connected
to the probes, none of this fancy digital switching, scanning
stuff....:^)
Today the probes and the interconnect may be different, but the a type J
therm
ocouple has always created the same amount of voltage due to
physics.
There is something else going on here in your plane - and since we are
dealing with fractions of milliVolts, I would personally vote for
grounding issues.=C2- You can see from the table below that 10 degrees
Centigrade is about a 1/2 milliVolt change.=C2- Try a direct wire from
GND on your EI gauge to the engine.
This is from Sandia labs...=C2- gil A
=C2-ITS-90 Table for type J=C2- thermocouple
=C2-=C2=B0C=C2-=C2-=C2-=C2-=C2- 0=C2-=C2-=C2-=C2-=C2-
1=C2-=C2-=C2-=C2-=C2- 2=C2-=C2-=C2-=C2-=C2-
3=C2-=C2-=C2-=C2-=C2- 4=C2-=C2-=C2-=C2-=C2-
5=C2-=C2-=C2-=C2-=C2- 6=C2-=C2-=C2-=C2-=C2-
7=C2-=C2-=C2-=C2-=C2- 8=C2-=C2-=C2-=C2-=C2-
9=C2-=C2-=C2-=C2- 10
=C2-=C2-=C2-=C2-=C2-=C2-=C2-=C2-=C2-=C2-=C2-=C2-=C2
-=C2-=C2-=C2-=C2-=C2-=C2-=C2-=C2-=C2-=C2-=C2-=C2-
=C2-=C2-=C2-=C2-=C2-
Thermoelectric Voltage in mV
=C2-
=C2-=C2- 0=C2- 0.000=C2- 0.050=C2- 0.101=C2- 0.151=C2-
0.202=C2- 0.253=C2- 0.303=C2- 0.354=C2- 0.405=C2- 0.456=C2-
0.507
=C2- 10=C2- 0.507=C2- 0.558=C2- 0.609=C2- 0.660=C2-
0.711=C2- 0.762=C2- 0.814=C2- 0.865=C2- 0.916=C2- 0.968=C2-
1.019
=C2- 20=C2- 1.019=C2- 1.071=C2- 1.122=C2- 1.174=C2-
1.226=C2- 1.277=C2- 1.329=C2- 1.381=C2- 1.433=C2- 1.485=C2-
1.537
=C2- 30=C2- 1.537=C2- 1.589=C2- 1.641=C2- 1.693=C2-
1.745=C2- 1.797=C2- 1.849=C2- 1.902=C2- 1.954=C2- 2.006=C2-
2.059
=C2- 40=C2- 2.059=C2- 2.111=C2- 2.164=C2- 2.216A
0
2.269=C2- 2.322=C2- 2.374=C2- 2.427=C2- 2.480=C2- 2.532=C2-
2.585
=C2-
=C2- 50=C2- 2.585=C2- 2.638=C2- 2.691=C2- 2.744=C2-
2.797=C2- 2.850=C2- 2.903=C2- 2.956=C2- 3.009=C2- 3.062=C2-
3.116
=C2- 60=C2- 3.116=C2- 3.169=C2- 3.222=C2- 3.275=C2-
3.329=C2- 3.382=C2- 3.436=C2- 3.489=C2- 3.543=C2- 3.596=C2-
3.650
=C2- 70=C2- 3.650=C2- 3.703=C2- 3.757=C2- 3.810=C2-
3.864=C2- 3.918=C2- 3.971=C2- 4.025=C2- 4.079=C2- 4.133=C2-
4.187
=C2- 80=C2- 4.187=C2- 4.240=C2- 4.294=C2- 4.348=C2-
4.402=C2- 4.456=C2- 4.510=C2- 4.564=C2- 4.618=C2- 4.672=C2-
4.726
=C2- 90=C2- 4.726=C2- 4.781=C2- 4.835=C2- 4.889=C2-
4.943=C2- 4.997=C2- 5.052=C2- 5.106=C2- 5.160=C2- 5.215=C2-
5.269
=C2-
=C2-100=C2- 5.269=C2- 5.323=C2- 5.378=C2- 5.432=C2-
5.487=C2- 5.541=C2- 5.595=C2- 5.650=C2- 5.705=C2- 5.759=C2-
5.814
=C2-110=C2- 5.814=C2- 5.868=C2- 5.923=C2- 5.977=C2-
6.032=C2- 6.087=C2- 6.141=C2- 6.196=C2- 6.251=C2- 6.306=C2-
6.360
=C2-120=C2- 6.360=C2- 6.415=C2- 6.470=C2- 6.525=C2-
6.579=C2- 6.634=C2- 6.689=C2- 6.744=C2- 6.799=C2- 6.854=C2-
6.909
=C2-130=C2- 6.909=C2- 6.964=C2- 7.019=C2- 7.074=C2-
7.129=C2- 7.184=C2- 7.239=C2- 7.294=C2- 7.349=C2- 7.404=C2-
7.459
=C2-140=C2- 7.459=C2- 7.514=C2- 7.569=C2- 7.624=C2-
7.679=C2- 7.734=C2- 7.789=C2- 7.844=C2- 7.900=C2- 7.955=C2-
8.010
=C2-
=C2-150=C2- 8.010=C2- 8.065=C2- 8.120=C2- 8.175=C2-
8.231=C2- 8.286=C2- 8.341=C2- 8.396=C2- 8.452=C2- 8.507=C2-
8.562
=C2-160=C2- 8.562=C2- 8.618=C2- 8.673C2 8.728=C2-
8.783=C2- 8.839=C2- 8.894=C2- 8.949=C2- 9.005=C2- 9.060=C2-
9.115
=C2-170=C2- 9.115=C2- 9.171=C2- 9.226=C2- 9.282=C2-
9.337=C2- 9.392=C2- 9.448=C2- 9.503=C2- 9.559=C2- 9.614=C2-
9.669
=C2-180=C2- 9.669=C2- 9.725=C2- 9.780=C2- 9.836=C2-
9.891=C2- 9.947 10.002 10.057 10.113 10.168 10.224
=C2-190 10.224 10.279 10.335 10.390 10.446 10.501 10.557 10.612 10.668
10.723 10.779
=C2-
=C2-200 10.779 10.834 10.890 10.945 11.001 11.056 11.112 11.167 11.223
11.278 11.334
=C2-210 11.334 11.389 11.445 11.501 11.556 11.612 11.667 11.723 11.778
11.834 11.889
=C2-220 11.889 11.945 12.000 12.056 12.111 12.167 12.222 12.278 12.334
12.389 12.445
=C2-230 12.445 12.500 12.556 12.611 12.667 12.722 12.778 12.833 12.889
12.944 13.000
=C2-240 13.000 13.056 13.111 13.167 13.222 13.278 13.333 13.389 13.444
13.500 13.555
=C2-
=C2-250 13.555 13.611 13.666 13.722 13.777 13.833 13.888 13.944 13.999
14.055 14.110
=C2-260 14.110 14.166 14.221 14.277 14.332 14.388 14.443 14.499 14.554
14.609 14.665
=C2-270 14.665 14.720 14.776 14.831 14.887 14.942 14.998 15.053 15.109
15.164 15.219
=C2-280 15.219 15.275 15.330 15.386 15.441 15.496 15.552 15.607 15.663
15.718 15.773
=C2-290 15.773 15.829 15.884 15.940 15.995 16.050 16.106 16.161 16.216
16.272 16.327
vigator to browse
Message 5
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| Subject: | Re: RE: EI vs JPI |
Gary,
How many STCs have you installed with
poor/bad/wrong instructions? And the CHT/EGT
monitor STCs are quite "generic" not really airframe specific.
My latest one was my Plane Power voltage
regulator. Works fine, but needed spacers to
clear the "bumps" on the fire wall - hardly a
drop-in exact replacement for the non flat bottom
mechanical regulator - and no mention in the STC instructions.
Your plane seems to be the only test case
reporting the problem. I'm happy with the
Insight GEM in mine with it's probes that touch
the thermowell bottom like I believe the Lycoming
test bayonet probes did during their certification.
As an electronics engineer, I know I would not
design sensitive millivolts equipment using
grounded sensors.... but that's just me.... and
my stuff is (or has been) working in military
aircraft and space vehicles....:^)
gil A
PS ...I like the GEM unit, but I have the "bars
only" version - I would prefer the version with
numbers - a probable future upgrade.
PPS Sorry about the formatting of the mV chart in my previous e-mail
Here is an alternate link to another table of
National Institute of Standards and Technology
output voltages from a Type J thermocouple -
http://www.omega.com/temperature/Z/pdf/z203.pdf
This shows how small the DC voltages are that we are measuring.
At 05:40 PM 3/29/2009, you wrote:
>There is something else going on here in your
>plane - and since we are dealing with fractions
>of milliVolts, I would personally vote for grounding issues.=C2
>
>MY PLANE? =C2 Ok, maybe your right. =C2 The grounds
>in installed according to the STC were done
>wrong. =C2 Maybe the probes grounding against
>brand new cylinders had corrosion built up in them. =C2
>
>Maybe planes experiencing CHT readings higher on
>a JPI than on an EI also followed the installation instructions.
>
>How about you doing your own testing and report your own results?
>
>
>-----Original Message-----
>From: Gil Alexander <gilalex@earthlink.net>
>To: teamgrumman-list@matronics.com
>Sent: Sun, 29 Mar 2009 12:03 pm
>Subject: Re: TeamGrumman-List: RE: EI vs JPI
>
>
>>This is only true if, and it's a big IF, the
>>temperatures displayed on todays
>>instrumentation "WOULD" have displayed the same
>>temperatures as those recorded by Lycoming
>>technicians=C3=82 on the instrumentation used by Lycoming. =C3=82=C2
>
>Gary... I don't belief that is a big "IF"...
>
>The electrical characteristics of a type J
>thermocouple have been well known from long before WWII.
>
>The electrical instrumentation bit has not
>changed over the years as far as the basic
>thermocouple, especially when used in an engine
>test cell.=C2 I bet Lycoming had individual CHT
>meters directly connected to the probes, none of
>this fancy digital switching, scanning stuff....:^)
>
>Today the probes and the interconnect may be
>different, but the a type J thermocouple has
>always created the same amount of voltage due to physics.
>
>There is something else going on here in your
>plane - and since we are dealing with fractions
>of milliVolts, I would personally vote for
>grounding issues.=C2 You can see from the table
>below that 10 degrees Centigrade is about a 1/2
>milliVolt change.=C2 Try a direct wire from GND on your EI gauge to the
engine.
>
>This is from Sandia labs...=C2 gil A
>
>
>=C2 ITS-90 Table for type J=C2 thermocouple
>=C2 =C2=B0C=C2 =C2 =C2 =C2 =C2 0=C2 =C2 =C2 =C2 =C2
>1=C2 =C2 =C2 =C2 =C2 2=C2 =C2 =C2 =C2 =C2
>3=C2 =C2 =C2 =C2 =C2 4=C2 =C2 =C2 =C2 =C2
>5=C2 =C2 =C2 =C2 =C2 6=C2 =C2 =C2 =C2 =C2
>7=C2 =C2 =C2 =C2 =C2 8=C2 =C2 =C2 =C2 =C2
>9=C2 =C2 =C2 =C2 10
>=C2 =C2 =C2 =C2 =C2 =C2 =C2 =C2 =C2 =C2 =C2 =C2 =C2 =C2 =C2 =C2 =C2 =C2 =C2
=C2 =C2 =C2 =C2 =C2 =C2 =C2 =C2 =C2 =C2 =C2
>Thermoelectric Voltage in mV
>=C2
>=C2 =C2 0=C2 0.000=C2 0.050=C2 0.101=C2 0.151=C2
>0.202=C2 0.253=C2 0.303=C2 0.354=C2 0.405=C2 0.456=C2
>0.507
>=C2 10=C2 0.507=C2 0.558=C2 0.609=C2 0.660=C2
>0.711=C2 0.762=C2 0.814=C2 0.865=C2 0.916=C2 0.968=C2
>1.019
>=C2 20=C2 1.019=C2 1.071
> 1.122=C2 1.174=C2
>1.226=C2 1.277=C2 1.329=C2 1.381=C2 1.433=C2 1.485=C2
>1.537
>=C2 30=C2 1.537=C2 1.589=C2 1.641=C2 1.693=C2
>1.745=C2 1.797=C2 1.849=C2 1.902=C2 1.954=C2 2.006=C2
>2.059
>=C2 40=C2 2.059=C2 2.111=C2 2.164=C2 2.216=C2
>2.269=C2 2.322=C2 2.374=C2 2.427=C2 2.480=C2 2.532=C2
>2.585
>=C2
>=C2 50=C2 2.585=C2 2.638=C2 2.691=C2 2.744=C2
>2.797=C2 2.850=C2 2.903=C2 2.956=C2 3.009=C2 3.062=C2
>3.116
>=C2 60=C2 3.116=C2 3.169=C2 3.222=C2 3.275=C2
>3.329=C2 3.382=C2 3.436=C2 3.489=C2 3.543=C2 3.596=C2
>3.650
>=C2 70=C2 3.650=C2 3.703=C2 3.757=C2 3.810=C2
>3.864=C2 3.918=C2 3.971=C2 4.025=C2 4.079=C2 4.133=C2
>4.187
>=C2 80=C2 4.187=C2 4.240=C2 4.294=C2 4.348=C2
>4.402=C2 4.456=C2 4.510=C2 4.564=C2 4.618=C2 4.672=C2
>4.726
>=C2 90=C2 4.726=C2 4.781=C2 4.835=C2 4.889=C2
>4.943=C2 4.997=C2 5.052=C2 5.106=C2 5.160=C2 5.215=C2
>5.269
>=C2
>=C2 100=C2 5.269=C2 5.323=C2 5.378=C2 5.432=C2
>5.487=C2 5.541=C2 5.595=C2 5.650=C2 5.705=C2 5.759=C2
>5.814
>=C2 110=C2 5.814=C2 5.868=C2 5.923=C2 5.977=C2
>6.032=C2 6.087=C2 6.141=C2 6.196=C2 6.251=C2 6.306=C2
>6.360
>=C2 120=C2 6.360=C2 6.415=C2 6.470=C2 6.525=C2
>6.579=C2 6.634=C2 6.689=C2 6.744=C2 6.799=C2 6.854=C2
>6.909
>=C2 130=C2 6.909=C2 6.964=C2 7.019=C2 7.074=C2
>7.129=C2 7.184=C2 7.239=C2 7.294=C2 7.349=C2 7.404=C2
>7.459
>=C2 140=C2 7.4590 7.514=C2 7.569=C2 7.624=C2
>7.679=C2 7.734=C2 7.789=C2 7.844=C2 7.900=C2 7.955=C2
>8.010
>=C2
>=C2 150=C2 8.010=C2 8.065=C2 8.120=C2 8.175=C2
>8.231=C2 8.286=C2 8.341=C2 8.396=C2 8.452=C2 8.507=C2
>8.562
>=C2 160=C2 8.562=C2 8.618=C2 8.673=C2 8.728=C2
>8.783=C2 8.839=C2 8.894=C2 8.949=C2 9.005=C2 9.060=C2
>9.115
>=C2 170=C2 9.115=C2 9.171=C2 9.226=C2 9.282=C2
>9.337=C2 9.392=C2 9.448=C2 9.503=C2 9.559=C2 9.614=C2
>9.669
>=C2 180=C2 9.669=C2 9.725=C2 9.780=C2 9.836=C2
>9.891=C2 9.947 10.002 10.057 10.113 10.168 10.224
>=C2 190 10.224 10.279 10.335 10.390 10.446 10.501 10.557 10.612 10.668
>10.723 10.779
>=C2
>=C2 200 10.779 10.834 10.890 10.945 11.001 11.056 11.112 11.167 11.223
>11.278 11.334
>=C2 210 11.334 11.389 11.445 11.501 11.556 11.612 11.667 11.723 11.778
>11.834 11.889
>=C2 220 11.889 11.945 12.000 12.056 12.111 12.167 12.222 12.278 12.334
>12.389 12.445
>=C2 230 12.445 12.500 12.556 12.611 12.667 12.722 12.778 12.833 12.889
>12.944 13.000
>=C2 240 13.000 13.056 13.111 13.167 13.222 13.278 13.333 13.389 13.444
>13.500 13.555
>=C2
>=C2 250 13.555 13.611 13.666 13.722 13.777 13.833 13.888 13.944 13.999
>14.055 14.110
>=C2 260 14.110 14.166 14.221 14.277 14.332 14.388 14.443 14.499 14.554
>14.609 14.665
>=C2 270 14.665 14.720 14.776 14.831 14.887 14.942 14.998 15.053 15.109
>15.164 15.219
>=C2 280 15.219 15.275 15.330 15.386 15.441 15.496 15.552 15.607 15.663
>15.718 15.773
>=C2 290 15.773 15.829 15.884 15.940 15.995 16.050 16.106 16.161 16.
>216
>16.272 16.327
>
>
>or?TeamGrumman-List">http://www.matronics.com/Navigator?TeamGrumman-List
>p://forums.matronics.com
>ution">http://www.matronics.com/contribution
>========================
>
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>----------
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| Subject: | Re: RE: EI vs JPI |
I started this thread because of similar thread that was started on the
GG. I understood one poster to say that he too had experienced higher
readings with JPI type probes that actually touch the thermowell. He had
both in his Cheetah and found that the probes that touch the head
actually give a higher reading.
So in answer to Gil's post it appears that others have noted the
diffenece in temp readings besides Gary.
Someone at Lycoming needs to answer this question, at least the question
of the type of probe they used. Right now we are just speculating on
what type of probe they used.
Ned
Here is the post I refer to:
----- Original Message -----
From: John Horton
Sent: Tuesday, March 24, 2009 9:19 PM
Subject: RE: Tiger outlet ramps - More Info Req.
Dave,
I would direct you to look at
http://www.bondline.org/wiki/Lower_Cowling_Split
for info about reworking the exit ramps. That link will only provide
info
about
the metal exit ramps but that's half the options.
When you mention that your temps are "warm" be sure to review the GG
archives
about JPI instrumentation vs EI instrumentation. There are differences
in
probe
design that make JPI read higher that EI in what should be the same
cylinder.
So if you have JP CHT and think your running "warm" you might be just
fine if
you had EI CHT. Theres a good bit of reading in the archives on that
topic.
My
consensus after reviewing (and I might still have it wrong) is that JP
CHT
reads
hotter than EI due to the fact that the JP CHT probe actually is spring
loaded
to touch the cyl head. The EI CHT probe screws into a space in the cyl
head.
I
have had both in my plane (Cheetah) and can verify that fact. The probes
are
different and the JP touches the head and reads hotter.
So if you have JP CHT gauge and it reads 420 in climb your most likely
fine.
(Assuming the temp goes down when you level out) The same plane may well
read
385 with a EI CHT and it is fine also. Be sure to know your temp source
(EI
or
JP) and read the archives to get a feel for the differences before you
go and
rework your exit ramps. They might be fine.
I recently reworked my exit ramps on my Cheetah due to a "warmer" than
I'd
like
#4 cyl, cracks in my metal exit ramps and a newly minted A&P ticket that
allowed
me to do it. I have only flown it once and the results looked promising.
Tommorrow I hope to gather more flight data. I currently have a JP
CHT/EGT
and
in climb prior to the ramp work could occasionally hit 450 (my and
Lycomings
redline). I could easily get into the 430's in climb and have to nose
over
and
or throttle back to arrest the CHT rise. When I had the EI CHT gauge I
never
saw anything above 390.
After reworking the ramps I do expect to go faster, climb higher and do
it
all
with 1/3 flaps deployed for less gallons per hour. I just had to throw
that
in
in case there aren't enough emotionally loaded topics to write about.
John Horton
HC Cheetah
Sensenich Prop
----- Original Message -----
From: Gil Alexander
To: teamgrumman-list@matronics.com
Sent: Sunday, March 29, 2009 8:41 PM
Subject: Re: TeamGrumman-List: RE: EI vs JPI
Gary,
How many STCs have you installed with poor/bad/wrong instructions?
And the CHT/EGT monitor STCs are quite "generic" not really airframe
specific.
My latest one was my Plane Power voltage regulator. Works fine, but
needed spacers to clear the "bumps" on the fire wall - hardly a drop-in
exact replacement for the non flat bottom mechanical regulator - and no
mention in the STC instructions.
Your plane seems to be the only test case reporting the problem. I'm
happy with the Insight GEM in mine with it's probes that touch the
thermowell bottom like I believe the Lycoming test bayonet probes did
during their certification.
As an electronics engineer, I know I would not design sensitive
millivolts equipment using grounded sensors.... but that's just me....
and my stuff is (or has been) working in military aircraft and space
vehicles....:^)
gil A
PS ...I like the GEM unit, but I have the "bars only" version - I
would prefer the version with numbers - a probable future upgrade.
PPS Sorry about the formatting of the mV chart in my previous e-mail
Here is an alternate link to another table of National Institute of
Standards and Technology output voltages from a Type J thermocouple -
http://www.omega.com/temperature/Z/pdf/z203.pdf
This shows how small the DC voltages are that we are measuring.
At 05:40 PM 3/29/2009, you wrote:
There is something else going on here in your plane - and since we
are dealing with fractions of milliVolts, I would personally vote for
grounding issues.=C2
MY PLANE? =C2 Ok, maybe your right. =C2 The grounds in installed
according to the STC were done wrong. =C2 Maybe the probes grounding
against brand new cylinders had corrosion built up in them. =C2
Maybe planes experiencing CHT readings higher on a JPI than on an EI
also followed the installation instructions.
How about you doing your own testing and report your own results?
-----Original Message-----
From: Gil Alexander <gilalex@earthlink.net>
To: teamgrumman-list@matronics.com
Sent: Sun, 29 Mar 2009 12:03 pm
Subject: Re: TeamGrumman-List: RE: EI vs JPI
This is only true if, and it's a big IF, the temperatures
displayed on todays instrumentation "WOULD" have displayed the same
temperatures as those recorded by Lycoming technicians=C3, on the
instrumentation used by Lycoming. =C3,=C2
Gary... I don't belief that is a big "IF"...
The electrical characteristics of a type J thermocouple have been
well known from long before WWII.
The electrical instrumentation bit has not changed over the years as
far as the basic thermocouple, especially when used in an engine test
cell.=C2 I bet Lycoming had individual CHT meters directly connected to
the probes, none of this fancy digital switching, scanning stuff....:^)
Today the probes and the interconnect may be different, but the a
type J thermocouple has always created the same amount of voltage due to
physics.
There is something else going on here in your plane - and since we
are dealing with fractions of milliVolts, I would personally vote for
grounding issues.=C2 You can see from the table below that 10 degrees
Centigrade is about a 1/2 milliVolt change.=C2 Try a direct wire from
GND on your EI gauge to the engine.
This is from Sandia labs...=C2 gil A
=C2 ITS-90 Table for type J=C2 thermocouple
=C2 =C2=B0C=C2 =C2 =C2 =C2 =C2 0=C2 =C2 =C2 =C2 =C2
1=C2 =C2 =C2 =C2 =C2 2=C2 =C2 =C2 =C2 =C2
3=C2 =C2 =C2 =C2 =C2 4=C2 =C2 =C2 =C2 =C2
5=C2 =C2 =C2 =C2 =C2 6=C2 =C2 =C2 =C2 =C2
7=C2 =C2 =C2 =C2 =C2 8=C2 =C2 =C2 =C2 =C2
9=C2 =C2 =C2 =C2 10
=C2 =C2 =C2 =C2 =C2 =C2 =C2 =C2 =C2 =C2 =C2 =C2 =C2 =C2 =C2 =C2 =C2 =C2
=C2 =C2 =C2 =C2 =C2 =C2 =C2 =C2 =C2 =C2 =C2 =C2
Thermoelectric Voltage in mV
=C2
=C2 =C2 0=C2 0.000=C2 0.050=C2 0.101=C2 0.151=C2
0.202=C2 0.253=C2 0.303=C2 0.354=C2 0.405=C2 0.456=C2
0.507
=C2 10=C2 0.507=C2 0.558=C2 0.609=C2 0.660=C2
0.711=C2 0.762=C2 0.814=C2 0.865=C2 0.916=C2 0.968=C2
1.019
=C2 20=C2 1.019=C2 1.071
1.122=C2 1.174=C2
1.226=C2 1.277=C2 1.329=C2 1.381=C2 1.433=C2 1.485=C2
1.537
=C2 30=C2 1.537=C2 1.589=C2 1.641=C2 1.693=C2
1.745=C2 1.797=C2 1.849=C2 1.902=C2 1.954=C2 2.006=C2
2.059
=C2 40=C2 2.059=C2 2.111=C2 2.164=C2 2.216=C2
2.269=C2 2.322=C2 2.374=C2 2.427=C2 2.480=C2 2.532=C2
2.585
=C2
=C2 50=C2 2.585=C2 2.638=C2 2.691=C2 2.744=C2
2.797=C2 2.850=C2 2.903=C2 2.956=C2 3.009=C2 3.062=C2
3.116
=C2 60=C2 3.116=C2 3.169=C2 3.222=C2 3.275=C2
3.329=C2 3.382=C2 3.436=C2 3.489=C2 3.543=C2 3.596=C2
3.650
=C2 70=C2 3.650=C2 3.703=C2 3.757=C2 3.810=C2
3.864=C2 3.918=C2 3.971=C2 4.025=C2 4.079=C2 4.133=C2
4.187
=C2 80=C2 4.187=C2 4.240=C2 4.294=C2 4.348=C2
4.402=C2 4.456=C2 4.510=C2 4.564=C2 4.618=C2 4.672=C2
4.726
=C2 90=C2 4.726=C2 4.781=C2 4.835=C2 4.889=C2
4.943=C2 4.997=C2 5.052=C2 5.106=C2 5.160=C2 5.215=C2
5.269
=C2
=C2 100=C2 5.269=C2 5.323=C2 5.378=C2 5.432=C2
5.487=C2 5.541=C2 5.595=C2 5.650=C2 5.705=C2 5.759=C2
5.814
=C2 110=C2 5.814=C2 5.868=C2 5.923=C2 5.977=C2
6.032=C2 6.087=C2 6.141=C2 6.196=C2 6.251=C2 6.306=C2
6.360
=C2 120=C2 6.360=C2 6.415=C2 6.470=C2 6.525=C2
6.579=C2 6.634=C2 6.689=C2 6.744=C2 6.799=C2 6.854=C2
6.909
=C2 130=C2 6.909=C2 6.964=C2 7.019=C2 7.074=C2
7.129=C2 7.184=C2 7.239=C2 7.294=C2 7.349=C2 7.404=C2
7.459
=C2 140=C2 7.4590 7.514=C2 7.569=C2 7.624=C2
7.679=C2 7.734=C2 7.789=C2 7.844=C2 7.900=C2 7.955=C2
8.010
=C2
=C2 150=C2 8.010=C2 8.065=C2 8.120=C2 8.175=C2
8.231=C2 8.286=C2 8.341=C2 8.396=C2 8.452=C2 8.507=C2
8.562
=C2 160=C2 8.562=C2 8.618=C2 8.673=C2 8.728=C2
8.783=C2 8.839=C2 8.894=C2 8.949=C2 9.005=C2 9.060=C2
9.115
=C2 170=C2 9.115=C2 9.171=C2 9.226=C2 9.282=C2
9.337=C2 9.392=C2 9.448=C2 9.503=C2 9.559=C2 9.614=C2
9.669
=C2 180=C2 9.669=C2 9.725=C2 9.780=C2 9.836=C2
9.891=C2 9.947 10.002 10.057 10.113 10.168 10.224
=C2 190 10.224 10.279 10.335 10.390 10.446 10.501 10.557 10.612 10.668
10.723 10.779
=C2
=C2 200 10.779 10.834 10.890 10.945 11.001 11.056 11.112 11.167 11.223
11.278 11.334
=C2 210 11.334 11.389 11.445 11.501 11.556 11.612 11.667 11.723 11.778
11.834 11.889
=C2 220 11.889 11.945 12.000 12.056 12.111 12.167 12.222 12.278 12.334
12.389 12.445
=C2 230 12.445 12.500 12.556 12.611 12.667 12.722 12.778 12.833 12.889
12.944 13.000
=C2 240 13.000 13.056 13.111 13.167 13.222 13.278 13.333 13.389 13.444
13.500 13.555
=C2
=C2 250 13.555 13.611 13.666 13.722 13.777 13.833 13.888 13.944 13.999
14.055 14.110
=C2 260 14.110 14.166 14.221 14.277 14.332 14.388 14.443 14.499 14.554
14.609 14.665
=C2 270 14.665 14.720 14.776 14.831 14.887 14.942 14.998 15.053 15.109
15.164 15.219
=C2 280 15.219 15.275 15.330 15.386 15.441 15.496 15.552 15.607 15.663
15.718 15.773
=C2 290 15.773 15.829 15.884 15.940 15.995 16.050 16.106 16.161 16.
216
16.272 16.327
or?TeamGrumman-List">http://www.matronics.com/Navigator?TeamGrumman-List
p://forums.matronics.com
ution">http://www.matronics.com/contribution
-------------------------------------------------------------------------
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A Good Credit Score is 700 or Above.
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68072%26hmpgID%3D62%26bcd%3DfebemailfooterNO62"> See yours in just 2
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| Subject: | Re: RE: EI vs JPI |
Ned... I believe the GG post you refer to still
references Gary's EI/JPI measurements....:^)
He just says below that the EI non-bayonet probes
read lower - which does not seem to be in dispute....:^)
And do you really think Lycoming used a
non-MIL-Spec probe, especially in the 60's, for
certification? I vote for probes that touch the cylinder.
gil A
At 07:05 PM 3/29/2009, you wrote:
>I started this thread because of similar thread
>that was started on the GG. I understood one
>poster to say that he too had experienced higher
>readings with JPI type probes that actually
>touch the thermowell. He had both in his Cheetah
>and found that the probes that touch the head actually give a higher
reading.
>
>So in answer to Gil's post it appears that
>others have noted the diffenece in temp readings besides Gary.
>
>Someone at Lycoming needs to answer this
>question, at least the question of the type of
>probe they used. Right now we are just
>speculating on what type of probe they used.
>
>Ned
>
>Here is the post I refer to:
>
>
>----- Original Message -----
>From: <mailto:hortonjf@comcast.net>John Horton
>To: <mailto:3d.flyguy@abszero.com>'Dave Kalwick'
>; <mailto:grumman-gang@xmission.com>'GG'
>Sent: Tuesday, March 24, 2009 9:19 PM
>Subject: RE: Tiger outlet ramps - More Info Req.
>
>Dave,
>I would direct you to look at
><http://www.bondline.org/wiki/Lower_Cowling_Split>http://www.bondline.org/w
iki/Lower_Cowling_Split
>for info about reworking the exit ramps. That link will only provide info
>about
>the metal exit ramps but that's half the options.
>
>When you mention that your temps are "warm" be sure to review the GG
archives
>about JPI instrumentation vs EI instrumentation. There are differences in
>probe
>design that make JPI read higher that EI in what should be the same
cylinder.
>So if you have JP CHT and think your running "warm" you might be just fine
if
>you had EI CHT. Theres a good bit of reading in the archives on that
topic.
>My
>consensus after reviewing (and I might still have it wrong) is that JP CHT
>reads
>hotter than EI due to the fact that the JP CHT probe actually is spring
>loaded
>to touch the cyl head. The EI CHT probe screws into a space in the cyl
head.
>I
>have had both in my plane (Cheetah) and can verify that fact. The probes
are
>different and the JP touches the head and reads hotter.
>
>So if you have JP CHT gauge and it reads 420 in climb your most likely
fine.
>(Assuming the temp goes down when you level out) The same plane may well
read
>385 with a EI CHT and it is fine also. Be sure to know your temp source (EI
>or
>JP) and read the archives to get a feel for the differences before you go
and
>rework your exit ramps. They might be fine.
>
>I recently reworked my exit ramps on my Cheetah due to a "warmer" than I'd
>like
>#4 cyl, cracks in my metal exit ramps and a newly minted A&P ticket that
>allowed
>me to do it. I have only flown it once and the results looked promising.
>Tommorrow I hope to gather more flight data. I currently have a JP CHT/EGT
>and
>in climb prior to the ramp work could occasionally hit 450 (my and
Lycomings
>redline). I could easily get into the 430's in climb and have to nose over
>and
>or throttle back to arrest the CHT rise. When I had the EI CHT gauge I
never
>saw anything above 390.
>
>After reworking the ramps I do expect to go faster, climb higher and do it
>all
>with 1/3 flaps deployed for less gallons per hour. I just had to throw that
>in
>in case there aren't enough emotionally loaded topics to write about.
>
>John Horton
>HC Cheetah
>Sensenich Prop
> ----- Original Message -----
>From: <mailto:gilalex@earthlink.net>Gil Alexander
>To: <mailto:teamgrumman-list@matronics.com>teamgrumman-list@matronics.com
>Sent: Sunday, March 29, 2009 8:41 PM
>Subject: Re: TeamGrumman-List: RE: EI vs JPI
>
>Gary,
>
>How many STCs have you installed with
>poor/bad/wrong instructions? And the CHT/EGT
>monitor STCs are quite "generic" not really airframe specific.
>
>My latest one was my Plane Power voltage
>regulator. Works fine, but needed spacers to
>clear the "bumps" on the fire wall - hardly a
>drop-in exact replacement for the non flat
>bottom mechanical regulator - and no mention in the STC instructions.
>
>Your plane seems to be the only test case
>reporting the problem. I'm happy with the
>Insight GEM in mine with it's probes that touch
>the thermowell bottom like I believe the
>Lycoming test bayonet probes did during their certification.
>
>As an electronics engineer, I know I would not
>design sensitive millivolts equipment using
>grounded sensors.... but that's just me.... and
>my stuff is (or has been) working in military
>aircraft and space vehicles....:^)
>
>gil A
>
>PS ...I like the GEM unit, but I have the "bars
>only" version - I would prefer the version with
>numbers - a probable future upgrade.
>
>PPS Sorry about the formatting of the mV chart in my previous e-mail
>
>Here is an alternate link to another table of
>National Institute of Standards and Technology
>output voltages from a Type J thermocouple -
>
>http://www.omega.com/temperature/Z/pdf/z203.pdf
>
>This shows how small the DC voltages are that we are measuring.
>
>At 05:40 PM 3/29/2009, you wrote:
>>There is something else going on here in your
>>plane - and since we are dealing with fractions
>>of milliVolts, I would personally vote for grounding issues.=C2
>>
>>MY PLANE? =C2 Ok, maybe your right. =C2 The grounds
>>in installed according to the STC were done
>>wrong. =C2 Maybe the probes grounding against
>>brand new cylinders had corrosion built up in them. =C2
>>
>>Maybe planes experiencing CHT readings higher
>>on a JPI than on an EI also followed the installation instructions.
>>
>>How about you doing your own testing and report your own results?
>>
>>
>>-----Original Message-----
>>From: Gil Alexander <gilalex@earthlink.net>
>>To: teamgrumman-list@matronics.com
>>Sent: Sun, 29 Mar 2009 12:03 pm
>>Subject: Re: TeamGrumman-List: RE: EI vs JPI
>>
>>
>>>This is only true if, and it's a big IF, the
>>>temperatures displayed on todays
>>>instrumentation "WOULD" have displayed the
>>>same temperatures as those recorded by
>>>Lycoming technicians=C3=82 on the instrumentation used by Lycoming. =C3
=82=C2
>>
>>Gary... I don't belief that is a big "IF"...
>>
>>The electrical characteristics of a type J
>>thermocouple have been well known from long before WWII.
>>
>>The electrical instrumentation bit has not
>>changed over the years as far as the basic
>>thermocouple, especially when used in an engine
>>test cell.=C2 I bet Lycoming had individual CHT
>>meters directly connected to the probes, none
>>of this fancy digital switching, scanning stuff....:^)
>>
>>Today the probes and the interconnect may be
>>different, but the a type J thermocouple has
>>always created the same amount of voltage due to physics.
>>
>>There is something else going on here in your
>>plane - and since we are dealing with fractions
>>of milliVolts, I would personally vote for
>>grounding issues.=C2 You can see from the table
>>below that 10 degrees Centigrade is about a 1/2
>>milliVolt change.=C2 Try a direct wire from GND on your EI gauge to the
engine.
>>
>>This is from Sandia labs...=C2 gil A
>>
>>
>>
>>
>>=C2 ITS-90 Table for type J=C2 thermocouple
>>
>>=C2 =C2=B0C=C2 =C2 =C2 =C2 =C2 0=C2 =C2 =C2 =C2 =C2
>>
>>1=C2 =C2 =C2 =C2 =C2 2=C2 =C2 =C2 =C2 =C2
>>
>>3=C2 =C2 =C2 =C2 =C2 4=C2 =C2 =C2 =C2 =C2
>>
>>5=C2 =C2 =C2 =C2 =C2 6=C2 =C2 =C2 =C2 =C2
>>
>>7=C2 =C2 =C2 =C2 =C2 8=C2 =C2 =C2 =C2 =C2
>>
>>9=C2 =C2 =C2 =C2 10
>>
>>=C2 =C2 =C2 =C2 =C2 =C2 =C2 =C2 =C2 =C2 =C2 =C2 =C2 =C2 =C2 =C2 =C2 =C2
=C2 =C2 =C2 =C2 =C2 =C2 =C2 =C2 =C2 =C2 =C2 =C2
>>
>>Thermoelectric Voltage in mV
>>
>>=C2
>>
>>=C2 =C2 0=C2 0.000=C2 0.050=C2 0.101=C2 0.151=C2
>>
>>0.202=C2 0.253=C2 0.303=C2 0.354=C2 0.405=C2 0.456=C2
>>
>>0.507
>>
>>=C2 10=C2 0.507=C2 0.558=C2 0.609=C2 0.660=C2
>>
>>0.711=C2 0.762=C2 0.814=C2 0.865=C2 0.916=C2 0.968=C2
>>
>>1.019
>>
>>=C2 20=C2 1.019=C2 1.071
>>
>> 1.122=C2 1.174=C2
>>
>>1.226=C2 1.277=C2 1.329=C2 1.381=C2 1.433=C2 1.485=C2
>>
>>1.537
>>
>>=C2 30=C2 1.537=C2 1.589=C2 1.641=C2 1.693=C2
>>
>>1.745=C2 1.797=C2 1.849=C2 1.902=C2 1.954=C2 2.006=C2
>>
>>2.059
>>
>>=C2 40=C2 2.059=C2 2.111=C2 2.164=C2 2.216=C2
>>
>>2.269=C2 2.322=C2 2.374=C2 2.427=C2 2.480=C2 2.532=C2
>>
>>2.585
>>
>>=C2
>>
>>=C2 50=C2 2.585=C2 2.638=C2 2.691=C2 2.744=C2
>>
>>2.797=C2 2.850=C2 2.903=C2 2.956=C2 3.009=C2 3.062=C2
>>
>>3.116
>>
>>=C2 60=C2 3.116=C2 3.169=C2 3.222=C2 3.275=C2
>>
>>3.329=C2 3.382=C2 3.436=C2 3.489=C2 3.543=C2 3.596=C2
>>
>>3.650
>>
>>=C2 70=C2 3.650=C2 3.703=C2 3.757=C2 3.810=C2
>>
>>3.864=C2 3.918=C2 3.971=C2 4.025=C2 4.079=C2 4.133=C2
>>
>>4.187
>>
>>=C2 80=C2 4.187=C2 4.240=C2 4.294=C2 4.348=C2
>>
>>4.402=C2 4.456=C2 4.510=C2 4.564=C2 4.618=C2 4.672=C2
>>
>>4.726
>>
>>=C2 90=C2 4.726=C2 4.781=C2 4.835=C2 4.889=C2
>>
>>4.943=C2 4.997=C2 5.052=C2 5.106=C2 5.160=C2 5.215=C2
>>
>>5.269
>>
>>=C2
>>
>>=C2 100=C2 5.269=C2 5.323=C2 5.378=C2 5.432=C2
>>
>>5.487=C2 5.541=C2 5.595=C2 5.650=C2 5.705=C2 5.759=C2
>>
>>5.814
>>
>>=C2 110=C2 5.814=C2 5.868=C2 5.923=C2 5.977=C2
>>
>>6.032=C2 6.087=C2 6.141=C2 6.196=C2 6.251=C2 6.306=C2
>>
>>6.360
>>
>>=C2 120=C2 6.360=C2 6.415=C2 6.470=C2 6.525=C2
>>
>>6.579=C2 6.634=C2 6.689=C2 6.744=C2 6.799=C2 6.854=C2
>>
>>6.909
>>
>>=C2 130=C2 6.909=C2 6.964=C2 7.019=C2 7.074=C2
>>
>>7.129=C2 7.184=C2 7.239=C2 7.294=C2 7.349=C2 7.404=C2
>>
>>7.459
>>
>>=C2 140=C2 7.4590 7.514=C2 7.569=C2 7.624=C2
>>
>>7.679=C2 7.734=C2 7.789=C2 7.844=C2 7.900=C2 7.955=C2
>>
>>8.010
>>
>>=C2
>>
>>=C2 150=C2 8.010=C2 8.065=C2 8.120=C2 8.175=C2
>>
>>8.231=C2 8.286=C2 8.341=C2 8.396=C2 8.452=C2 8.507=C2
>>
>>8.562
>>
>>=C2 160=C2 8.562=C2 8.618=C2 8.673=C2 8.728=C2
>>
>>8.783=C2 8.839=C2 8.894=C2 8.949=C2 9.005=C2 9.060=C2
>>
>>9.115
>>
>>=C2 170=C2 9.115=C2 9.171=C2 9.226=C2 9.282=C2
>>
>>9.337=C2 9.392=C2 9.448=C2 9.503=C2 9.559=C2 9.614=C2
>>
>>9.669
>>
>>=C2 180=C2 9.669=C2 9.725=C2 9.780=C2 9.836=C2
>>
>>9.891=C2 9.947 10.002 10.057 10.113 10.168 10.224
>>
>>=C2 190 10.224 10.279 10.335 10.390 10.446 10.501 10.557 10.612 10.668
>>
>>10.723 10.779
>>
>>=C2
>>
>>=C2 200 10.779 10.834 10.890 10.945 11.001 11.056 11.112 11.167 11.223
>>
>>11.278 11.334
>>
>>=C2 210 11.334 11.389 11.445 11.501 11.556 11.612 11.667 11.723 11.778
>>
>>11.834 11.889
>>
>>=C2 220 11.889 11.945 12.000 12.056 12.111 12.167 12.222 12.278 12.334
>>
>>12.389 12.445
>>
>>=C2 230 12.445 12.500 12.556 12.611 12.667 12.722 12.778 12.833 12.889
>>
>>12.944 13.000
>>
>>=C2 240 13.000 13.056 13.111 13.167 13.222 13.278 13.333 13.389 13.444
>>
>>13.500 13.555
>>
>>=C2
>>
>>=C2 250 13.555 13.611 13.666 13.722 13.777 13.833 13.888 13.944 13.999
>>
>>14.055 14.110
>>
>>=C2 260 14.110 14.166 14.221 14.277 14.332 14.388 14.443 14.499 14.554
>>
>>14.609 14.665
>>
>>=C2 270 14.665 14.720 14.776 14.831 14.887 14.942 14.998 15.053 15.109
>>
>>15.164 15.219
>>
>>=C2 280 15.219 15.275 15.330 15.386 15.441 15.496 15.552 15.607 15.663
>>
>>15.718 15.773
>>
>>=C2 290 15.773 15.829 15.884 15.940 15.995 16.050 16.106 16.161 16.
>>
>>216
>>
>>16.272 16.327
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>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!
>
>
>href="http://www.matronics.com/Navigator?TeamGrumman-List">http://www.mat
ronics.com/Navigator?TeamGrumman-List
>
>href="http://forums.matronics.com">http://forums.matronics.com
>
>href="http://www.matronics.com/contribution">http://www.matronics.com/c
>
Message 8
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| Subject: | Re: RE: EI vs JPI |
Here is another example given on the GG of others that have found the
same as Gary.
a.. Subject: Re: JPI vs EI probes
b.. From:
c.. Date: Wed, 09 Jan 2008 15:59:45 -0500
-------------------------------------------------------------------------
-----
Had I not had 200 hours on my Tiger with the JPI and KNOWN that the #3
cylinder was within a few degrees of cylinder #4, I would have to agree.
B Yes, had I not had previous experience with my engine and the JPI, and
yes
IF I installed the EI into an unknown condition, then yes, one could say
that
one cylinder runs 80 degrees cooler than the others. But, that is not
the
case.
For what it's worth, the testing on the new cowling is being done with
EI
gauges, calibrated by EI for the FAA. These probes are calibrated to
read
within 1 degree. These also show, on the average, on ALL 4 CYLINDERS, 50
to
80 degrees cooler than the data downloaded from the JPI. Different
plane.
B Different engine. Different baffles. And 50 to 80 degrees difference
in
temps.
I talked to JPI. Their probes and analyzers are calibrated to within 1
degree.
Mount a JPI CHT probe in a piece of steel 4 inches thick simulating the
mounting in a cylinder. Mount the EI gauge in a hole in the steel. Heat
the other side with a torch. You'll get different readings.
LyCon has a customer in Wyoming (Wildoming) with a Husky. He changed
from EI
to JPI after and engine overhaul. He chased around 70 degree higher
temps
for a long time. And by chasing, I mean they pulled the engine and sent
it
back to LyCon for inspection. LyCon ran the engine without baffles and
it
was never over 380. They concluded the JPI must read higher. I had
talked
to Ken in the past about doing a side-by-side test of JPI and EI. Never
done. We talked when his customer sent the engine back.
I installed a JPI 700 in a Comanche following an engine overhaul. The
engine
overhaul was a complete firewall forward with all new baffles and seals.
The
owner complained of temps going over 450 on climb-out. I couldn't
convince
him it was the analyzer and not his engine. I just heard that he
recently
had the EI re-installed. He couldn't deal with seeing the temps going
over
450 on climb-out. He told me that he now sees temps in the 380 range and
he
likes that better.
Both readings of temperature are correct. They are measuring different
temperatures. One measures the temp of the air in the well, the other
measures the temperature of the aluminum.
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| Subject: | Re: RE: EI vs JPI |
Gil,
I'm confused by your post below.
Don't you mean for Gary to try a direct wire from GND on you JPI gauge
to the engine?
As EI are not grounded probes....
ned
There is something else going on here in your plane - and since we are
dealing with fractions of milliVolts, I would personally vote for
grounding issues. You can see from the table below that 10 degrees
Centigrade is about a 1/2 milliVolt change. Try a direct wire from GND
on your EI gauge to the engine.
This is from Sandia labs... gil A
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| Subject: | Re: RE: EI vs JPI |
Perhaps there was a milspec probe like the one EI uses today in use on
Lycomings certification tests...
Like Isaid earlier we are just speculating
----- Original Message -----
From: Gil Alexander
To: teamgrumman-list@matronics.com
Sent: Sunday, March 29, 2009 9:13 PM
Subject: Re: TeamGrumman-List: RE: EI vs JPI
Ned... I believe the GG post you refer to still references Gary's
EI/JPI measurements....:^)
He just says below that the EI non-bayonet probes read lower - which
does not seem to be in dispute....:^)
And do you really think Lycoming used a non-MIL-Spec probe, especially
in the 60's, for certification? I vote for probes that touch the
cylinder.
gil A
At 07:05 PM 3/29/2009, you wrote:
I started this thread because of similar thread that was started on
the GG. I understood one poster to say that he too had experienced
higher readings with JPI type probes that actually touch the thermowell.
He had both in his Cheetah and found that the probes that touch the head
actually give a higher reading.
So in answer to Gil's post it appears that others have noted the
diffenece in temp readings besides Gary.
Someone at Lycoming needs to answer this question, at least the
question of the type of probe they used. Right now we are just
speculating on what type of probe they used.
Ned
Here is the post I refer to:
----- Original Message -----
From: John Horton
To: 'Dave Kalwick' ; 'GG'
Sent: Tuesday, March 24, 2009 9:19 PM
Subject: RE: Tiger outlet ramps - More Info Req.
Dave,
I would direct you to look at
http://www.bondline.org/wiki/Lower_Cowling_Split
for info about reworking the exit ramps. That link will only
provide info
about
the metal exit ramps but that's half the options.
When you mention that your temps are "warm" be sure to review the GG
archives
about JPI instrumentation vs EI instrumentation. There are
differences in
probe
design that make JPI read higher that EI in what should be the same
cylinder.
So if you have JP CHT and think your running "warm" you might be
just fine if
you had EI CHT. Theres a good bit of reading in the archives on
that topic.
My
consensus after reviewing (and I might still have it wrong) is that
JP CHT
reads
hotter than EI due to the fact that the JP CHT probe actually is
spring
loaded
to touch the cyl head. The EI CHT probe screws into a space in the
cyl head.
I
have had both in my plane (Cheetah) and can verify that fact. The
probes are
different and the JP touches the head and reads hotter.
So if you have JP CHT gauge and it reads 420 in climb your most
likely fine.
(Assuming the temp goes down when you level out) The same plane may
well read
385 with a EI CHT and it is fine also. Be sure to know your temp
source (EI
or
JP) and read the archives to get a feel for the differences before
you go and
rework your exit ramps. They might be fine.
I recently reworked my exit ramps on my Cheetah due to a "warmer"
than I'd
like
#4 cyl, cracks in my metal exit ramps and a newly minted A&P ticket
that
allowed
me to do it. I have only flown it once and the results looked
promising.
Tommorrow I hope to gather more flight data. I currently have a JP
CHT/EGT
and
in climb prior to the ramp work could occasionally hit 450 (my and
Lycomings
redline). I could easily get into the 430's in climb and have to
nose over
and
or throttle back to arrest the CHT rise. When I had the EI CHT
gauge I never
saw anything above 390.
After reworking the ramps I do expect to go faster, climb higher and
do it
all
with 1/3 flaps deployed for less gallons per hour. I just had to
throw that
in
in case there aren't enough emotionally loaded topics to write
about.
John Horton
HC Cheetah
Sensenich Prop
----- Original Message -----
From: Gil Alexander
To: teamgrumman-list@matronics.com
Sent: Sunday, March 29, 2009 8:41 PM
Subject: Re: TeamGrumman-List: RE: EI vs JPI
Gary,
How many STCs have you installed with poor/bad/wrong instructions?
And the CHT/EGT monitor STCs are quite "generic" not really airframe
specific.
My latest one was my Plane Power voltage regulator. Works fine,
but needed spacers to clear the "bumps" on the fire wall - hardly a
drop-in exact replacement for the non flat bottom mechanical regulator -
and no mention in the STC instructions.
Your plane seems to be the only test case reporting the problem.
I'm happy with the Insight GEM in mine with it's probes that touch the
thermowell bottom like I believe the Lycoming test bayonet probes did
during their certification.
As an electronics engineer, I know I would not design sensitive
millivolts equipment using grounded sensors.... but that's just me....
and my stuff is (or has been) working in military aircraft and space
vehicles....:^)
gil A
PS ...I like the GEM unit, but I have the "bars only" version - I
would prefer the version with numbers - a probable future upgrade.
PPS Sorry about the formatting of the mV chart in my previous
e-mail
Here is an alternate link to another table of National Institute
of Standards and Technology output voltages from a Type J thermocouple -
http://www.omega.com/temperature/Z/pdf/z203.pdf
This shows how small the DC voltages are that we are measuring.
At 05:40 PM 3/29/2009, you wrote:
There is something else going on here in your plane - and
since we are dealing with fractions of milliVolts, I would personally
vote for grounding issues.=C2
MY PLANE? =C2 Ok, maybe your right. =C2 The grounds in installed
according to the STC were done wrong. =C2 Maybe the probes grounding
against brand new cylinders had corrosion built up in them. =C2
Maybe planes experiencing CHT readings higher on a JPI than on
an EI also followed the installation instructions.
How about you doing your own testing and report your own
results?
-----Original Message-----
From: Gil Alexander <gilalex@earthlink.net>
To: teamgrumman-list@matronics.com
Sent: Sun, 29 Mar 2009 12:03 pm
Subject: Re: TeamGrumman-List: RE: EI vs JPI
This is only true if, and it's a big IF, the temperatures
displayed on todays instrumentation "WOULD" have displayed the same
temperatures as those recorded by Lycoming technicians=C3, on the
instrumentation used by Lycoming. =C3,=C2
Gary... I don't belief that is a big "IF"...
The electrical characteristics of a type J thermocouple have
been well known from long before WWII.
The electrical instrumentation bit has not changed over the
years as far as the basic thermocouple, especially when used in an
engine test cell.=C2 I bet Lycoming had individual CHT meters directly
connected to the probes, none of this fancy digital switching, scanning
stuff....:^)
Today the probes and the interconnect may be different, but the
a type J thermocouple has always created the same amount of voltage due
to physics.
There is something else going on here in your plane - and since
we are dealing with fractions of milliVolts, I would personally vote for
grounding issues.=C2 You can see from the table below that 10 degrees
Centigrade is about a 1/2 milliVolt change.=C2 Try a direct wire from
GND on your EI gauge to the engine.
This is from Sandia labs...=C2 gil A
=C2 ITS-90 Table for type J=C2 thermocouple
=C2 =C2=B0C=C2 =C2 =C2 =C2 =C2 0=C2 =C2 =C2 =C2 =C2
1=C2 =C2 =C2 =C2 =C2 2=C2 =C2 =C2 =C2 =C2
3=C2 =C2 =C2 =C2 =C2 4=C2 =C2 =C2 =C2 =C2
5=C2 =C2 =C2 =C2 =C2 6=C2 =C2 =C2 =C2 =C2
7=C2 =C2 =C2 =C2 =C2 8=C2 =C2 =C2 =C2 =C2
9=C2 =C2 =C2 =C2 10
=C2 =C2 =C2 =C2 =C2 =C2 =C2 =C2 =C2 =C2 =C2 =C2 =C2 =C2 =C2 =C2 =C2 =C2
=C2 =C2 =C2 =C2 =C2 =C2 =C2 =C2 =C2 =C2 =C2 =C2
Thermoelectric Voltage in mV
=C2
=C2 =C2 0=C2 0.000=C2 0.050=C2 0.101=C2 0.151=C2
0.202=C2 0.253=C2 0.303=C2 0.354=C2 0.405=C2
0.456=C2
0.507
=C2 10=C2 0.507=C2 0.558=C2 0.609=C2 0.660=C2
0.711=C2 0.762=C2 0.814=C2 0.865=C2 0.916=C2
0.968=C2
1.019
=C2 20=C2 1.019=C2 1.071
1.122=C2 1.174=C2
1.226=C2 1.277=C2 1.329=C2 1.381=C2 1.433=C2
1.485=C2
1.537
=C2 30=C2 1.537=C2 1.589=C2 1.641=C2 1.693=C2
1.745=C2 1.797=C2 1.849=C2 1.902=C2 1.954=C2
2.006=C2
2.059
=C2 40=C2 2.059=C2 2.111=C2 2.164=C2 2.216=C2
2.269=C2 2.322=C2 2.374=C2 2.427=C2 2.480=C2
2.532=C2
2.585
=C2
=C2 50=C2 2.585=C2 2.638=C2 2.691=C2 2.744=C2
2.797=C2 2.850=C2 2.903=C2 2.956=C2 3.009=C2
3.062=C2
3.116
=C2 60=C2 3.116=C2 3.169=C2 3.222=C2 3.275=C2
3.329=C2 3.382=C2 3.436=C2 3.489=C2 3.543=C2
3.596=C2
3.650
=C2 70=C2 3.650=C2 3.703=C2 3.757=C2 3.810=C2
3.864=C2 3.918=C2 3.971=C2 4.025=C2 4.079=C2
4.133=C2
4.187
=C2 80=C2 4.187=C2 4.240=C2 4.294=C2 4.348=C2
4.402=C2 4.456=C2 4.510=C2 4.564=C2 4.618=C2
4.672=C2
4.726
=C2 90=C2 4.726=C2 4.781=C2 4.835=C2 4.889=C2
4.943=C2 4.997=C2 5.052=C2 5.106=C2 5.160=C2
5.215=C2
5.269
=C2
=C2 100=C2 5.269=C2 5.323=C2 5.378=C2 5.432=C2
5.487=C2 5.541=C2 5.595=C2 5.650=C2 5.705=C2
5.759=C2
5.814
=C2 110=C2 5.814=C2 5.868=C2 5.923=C2 5.977=C2
6.032=C2 6.087=C2 6.141=C2 6.196=C2 6.251=C2
6.306=C2
6.360
=C2 120=C2 6.360=C2 6.415=C2 6.470=C2 6.525=C2
6.579=C2 6.634=C2 6.689=C2 6.744=C2 6.799=C2
6.854=C2
6.909
=C2 130=C2 6.909=C2 6.964=C2 7.019=C2 7.074=C2
7.129=C2 7.184=C2 7.239=C2 7.294=C2 7.349=C2
7.404=C2
7.459
=C2 140=C2 7.4590 7.514=C2 7.569=C2 7.624=C2
7.679=C2 7.734=C2 7.789=C2 7.844=C2 7.900=C2
7.955=C2
8.010
=C2
=C2 150=C2 8.010=C2 8.065=C2 8.120=C2 8.175=C2
8.231=C2 8.286=C2 8.341=C2 8.396=C2 8.452=C2
8.507=C2
8.562
=C2 160=C2 8.562=C2 8.618=C2 8.673=C2 8.728=C2
8.783=C2 8.839=C2 8.894=C2 8.949=C2 9.005=C2
9.060=C2
9.115
=C2 170=C2 9.115=C2 9.171=C2 9.226=C2 9.282=C2
9.337=C2 9.392=C2 9.448=C2 9.503=C2 9.559=C2
9.614=C2
9.669
=C2 180=C2 9.669=C2 9.725=C2 9.780=C2 9.836=C2
9.891=C2 9.947 10.002 10.057 10.113 10.168 10.224
=C2 190 10.224 10.279 10.335 10.390 10.446 10.501 10.557 10.612 10.668
10.723 10.779
=C2
=C2 200 10.779 10.834 10.890 10.945 11.001 11.056 11.112 11.167 11.223
11.278 11.334
=C2 210 11.334 11.389 11.445 11.501 11.556 11.612 11.667 11.723 11.778
11.834 11.889
=C2 220 11.889 11.945 12.000 12.056 12.111 12.167 12.222 12.278 12.334
12.389 12.445
=C2 230 12.445 12.500 12.556 12.611 12.667 12.722 12.778 12.833 12.889
12.944 13.000
=C2 240 13.000 13.056 13.111 13.167 13.222 13.278 13.333 13.389 13.444
13.500 13.555
=C2
=C2 250 13.555 13.611 13.666 13.722 13.777 13.833 13.888 13.944 13.999
14.055 14.110
=C2 260 14.110 14.166 14.221 14.277 14.332 14.388 14.443 14.499 14.554
14.609 14.665
=C2 270 14.665 14.720 14.776 14.831 14.887 14.942 14.998 15.053 15.109
15.164 15.219
=C2 280 15.219 15.275 15.330 15.386 15.441 15.496 15.552 15.607 15.663
15.718 15.773
=C2 290 15.773 15.829 15.884 15.940 15.995 16.050 16.106 16.161 16.
216
16.272 16.327
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Message 11
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| Subject: | Re: RE: EI vs JPI |
Gil,
You didn't read the post very well. I removed all but the one sentence
from the post that you missed. Want to change your belief?
Ned
----- Original Message -----
From: Gil Alexander
Sent: Sunday, March 29, 2009 9:13 PM
Subject: Re: TeamGrumman-List: RE: EI vs JPI
Ned... I believe the GG post you refer to still references Gary's EI/JPI
measurements....:^)
He just says below that the EI non-bayonet probes read lower - which
does not seem to be in dispute....:^)
And do you really think Lycoming used a non-MIL-Spec probe, especially
in the 60's, for certification? I vote for probes that touch the
cylinder.
gil A
"I have had both in my plane (Cheetah) and can verify that fact. The
probes are
different and the JP touches the head and reads hotter."
Message 12
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| Subject: | Re: RE: EI vs JPI |
Maybe you guys need to ask Steve Peach about the two different styles of EI
probes, bayonet and standard P-100, that he tested and found very little d
ifference between the two. The large differences in temperature mentioned
are between JPI with the bayonet and EI with the fixed probe. And all the
accusations, or implications at least, are that the fixed EI probe does not
measure the true temperature. There is a real possibility that it could b
e due to something completely different.
Cliff
----- Original Message -----
From: Gil Alexander
To: teamgrumman-list@matronics.com
Sent: Sunday, March 29, 2009 7:13 PM
Subject: Re: TeamGrumman-List: RE: EI vs JPI
Ned... I believe the GG post you refer to still references Gary's EI/JPI
measurements....:^)
He just says below that the EI non-bayonet probes read lower - which does
not seem to be in dispute....:^)
And do you really think Lycoming used a non-MIL-Spec probe, especially in
the 60's, for certification=3F I vote for probes that touch the cylinder.
gil A
At 07:05 PM 3/29/2009, you wrote:
I started this thread because of similar thread that was started on the
GG. I understood one poster to say that he too had experienced higher read
ings with JPI type probes that actually touch the thermowell. He had both i
n his Cheetah and found that the probes that touch the head actually give a
higher reading.
So in answer to Gil's post it appears that others have noted the diffen
ece in temp readings besides Gary.
Someone at Lycoming needs to answer this question, at least the questio
n of the type of probe they used. Right now we are just speculating on what
type of probe they used.
Ned
Here is the post I refer to:
----- Original Message -----
From: John Horton
To: 'Dave Kalwick' ; 'GG'
Sent: Tuesday, March 24, 2009 9:19 PM
Subject: RE: Tiger outlet ramps - More Info Req.
Dave,
I would direct you to look at
http://www.bondline.org/wiki/Lower=5FCowling=5FSplit
for info about reworking the exit ramps. That link will only provide i
nfo
about
the metal exit ramps but that's half the options.
When you mention that your temps are =22warm=22 be sure to review the GG ar
chives
about JPI instrumentation vs EI instrumentation. There are differences
in
probe
design that make JPI read higher that EI in what should be the same cyl
inder.
So if you have JP CHT and think your running =22warm=22 you might be just f
ine if
you had EI CHT. Theres a good bit of reading in the archives on that t
opic.
My
consensus after reviewing (and I might still have it wrong) is that JP
CHT
reads
hotter than EI due to the fact that the JP CHT probe actually is spring
loaded
to touch the cyl head. The EI CHT probe screws into a space in the cyl
head.
I
have had both in my plane (Cheetah) and can verify that fact. The probe
s are
different and the JP touches the head and reads hotter.
So if you have JP CHT gauge and it reads 420 in climb your most likely
fine.
(Assuming the temp goes down when you level out) The same plane may wel
l read
385 with a EI CHT and it is fine also. Be sure to know your temp source
(EI
or
JP) and read the archives to get a feel for the differences before you
go and
rework your exit ramps. They might be fine.
I recently reworked my exit ramps on my Cheetah due to a =22warmer=22 than
I'd
like
#4 cyl, cracks in my metal exit ramps and a newly minted A&P ticket tha
t
allowed
me to do it. I have only flown it once and the results looked promising
.
Tommorrow I hope to gather more flight data. I currently have a JP CHT/
EGT
and
in climb prior to the ramp work could occasionally hit 450 (my and Lyco
mings
redline). I could easily get into the 430's in climb and have to nose
over
and
or throttle back to arrest the CHT rise. When I had the EI CHT gauge I
never
saw anything above 390.
After reworking the ramps I do expect to go faster, climb higher and do
it
all
with 1/3 flaps deployed for less gallons per hour. I just had to throw
that
in
in case there aren't enough emotionally loaded topics to write about.
John Horton
HC Cheetah
Sensenich Prop
----- Original Message -----
From: Gil Alexander
To: teamgrumman-list@matronics.com
Sent: Sunday, March 29, 2009 8:41 PM
Subject: Re: TeamGrumman-List: RE: EI vs JPI
Gary,
How many STCs have you installed with poor/bad/wrong instructions=3F A
nd the CHT/EGT monitor STCs are quite =22generic=22 not really airframe specifi
c.
My latest one was my Plane Power voltage regulator. Works fine, but
needed spacers to clear the =22bumps=22 on the fire wall - hardly a drop-in exa
ct replacement for the non flat bottom mechanical regulator - and no mentio
n in the STC instructions.
Your plane seems to be the only test case reporting the problem. I'm
happy with the Insight GEM in mine with it's probes that touch the thermow
ell bottom like I believe the Lycoming test bayonet probes did during their
certification.
As an electronics engineer, I know I would not design sensitive milli
volts equipment using grounded sensors.... but that's just me.... and my st
uff is (or has been) working in military aircraft and space vehicles....:^)
gil A
PS ...I like the GEM unit, but I have the =22bars only=22 version - I wou
ld prefer the version with numbers - a probable future upgrade.
PPS Sorry about the formatting of the mV chart in my previous e-mail
Here is an alternate link to another table of National Institute of S
tandards and Technology output voltages from a Type J thermocouple -
http://www.omega.com/temperature/Z/pdf/z203.pdf
This shows how small the DC voltages are that we are measuring.
At 05:40 PM 3/29/2009, you wrote:
There is something else going on here in your plane - and since w
e are dealing with fractions of milliVolts, I would personally vote for gro
unding issues.=C2
MY PLANE=3F =C2 Ok, maybe your right. =C2 The grounds in installed accord
ing to the STC were done wrong. =C2 Maybe the probes grounding against brand
new cylinders had corrosion built up in them. =C2
Maybe planes experiencing CHT readings higher on a JPI than on an E
I also followed the installation instructions.
How about you doing your own testing and report your own results=3F
-----Original Message-----
From: Gil Alexander <gilalex@earthlink.net>
To: teamgrumman-list@matronics.com
Sent: Sun, 29 Mar 2009 12:03 pm
Subject: Re: TeamGrumman-List: RE: EI vs JPI
This is only true if, and it's a big IF, the temperatures display
ed on todays instrumentation =22WOULD=22 have displayed the same temperatures a
s those recorded by Lycoming technicians=C3, on the instrumentation used by L
ycoming. =C3,=C2
Gary... I don't belief that is a big =22IF=22...
The electrical characteristics of a type J thermocouple have been w
ell known from long before WWII.
The electrical instrumentation bit has not changed over the years a
s far as the basic thermocouple, especially when used in an engine test cel
l.=C2 I bet Lycoming had individual CHT meters directly connected to the pro
bes, none of this fancy digital switching, scanning stuff....:^)
Today the probes and the interconnect may be different, but the a t
ype J thermocouple has always created the same amount of voltage due to phy
sics.
There is something else going on here in your plane - and since we
are dealing with fractions of milliVolts, I would personally vote for groun
ding issues.=C2 You can see from the table below that 10 degrees Centigrade
is about a 1/2 milliVolt change.=C2 Try a direct wire from GND on your EI ga
uge to the engine.
This is from Sandia labs...=C2 gil A
=C2 ITS-90 Table for type J=C2 thermocouple
=C2 =C2=B0C=C2 =C2 =C2 =C2 =C2 0=C2 =C2 =C2 =C2 =C2
1=C2 =C2 =C2 =C2 =C2 2=C2 =C2 =C2 =C2 =C2
3=C2 =C2 =C2 =C2 =C2 4=C2 =C2 =C2 =C2 =C2
5=C2 =C2 =C2 =C2 =C2 6=C2 =C2 =C2 =C2 =C2
7=C2 =C2 =C2 =C2 =C2 8=C2 =C2 =C2 =C2 =C2
9=C2 =C2 =C2 =C2 10
=C2 =C2 =C2 =C2 =C2 =C2 =C2 =C2 =C2 =C2 =C2 =C2 =C2 =C2 =C2 =C2 =C2 =C2 =C2 =C2
=C2 =C2 =C2 =C2 =C2 =C2 =C2 =C2 =C2 =C2
Thermoelectric Voltage in mV
=C2
=C2 =C2 0=C2 0.000=C2 0.050=C2 0.101=C2 0.151=C2
0.202=C2 0.253=C2 0.303=C2 0.354=C2 0.405=C2
0.456=C2
0.507
=C2 10=C2 0.507=C2 0.558=C2 0.609=C2 0.660=C2
0.711=C2 0.762=C2 0.814=C2 0.865=C2 0.916=C2
0.968=C2
1.019
=C2 20=C2 1.019=C2 1.071
1.122=C2 1.174=C2
1.226=C2 1.277=C2 1.329=C2 1.381=C2 1.433=C2
1.485=C2
1.537
=C2 30=C2 1.537=C2 1.589=C2 1.641=C2 1.693=C2
1.745=C2 1.797=C2 1.849=C2 1.902=C2 1.954=C2
2.006=C2
2.059
=C2 40=C2 2.059=C2 2.111=C2 2.164=C2 2.216=C2
2.269=C2 2.322=C2 2.374=C2 2.427=C2 2.480=C2
2.532=C2
2.585
=C2
=C2 50=C2 2.585=C2 2.638=C2 2.691=C2 2.744=C2
2.797=C2 2.850=C2 2.903=C2 2.956=C2 3.009=C2
3.062=C2
3.116
=C2 60=C2 3.116=C2 3.169=C2 3.222=C2 3.275=C2
3.329=C2 3.382=C2 3.436=C2 3.489=C2 3.543=C2
3.596=C2
3.650
=C2 70=C2 3.650=C2 3.703=C2 3.757=C2 3.810=C2
3.864=C2 3.918=C2 3.971=C2 4.025=C2 4.079=C2
4.133=C2
4.187
=C2 80=C2 4.187=C2 4.240=C2 4.294=C2 4.348=C2
4.402=C2 4.456=C2 4.510=C2 4.564=C2 4.618=C2
4.672=C2
4.726
=C2 90=C2 4.726=C2 4.781=C2 4.835=C2 4.889=C2
4.943=C2 4.997=C2 5.052=C2 5.106=C2 5.160=C2
5.215=C2
5.269
=C2
=C2 100=C2 5.269=C2 5.323=C2 5.378=C2 5.432=C2
5.487=C2 5.541=C2 5.595=C2 5.650=C2 5.705=C2
5.759=C2
5.814
=C2 110=C2 5.814=C2 5.868=C2 5.923=C2 5.977=C2
6.032=C2 6.087=C2 6.141=C2 6.196=C2 6.251=C2
6.306=C2
6.360
=C2 120=C2 6.360=C2 6.415=C2 6.470=C2 6.525=C2
6.579=C2 6.634=C2 6.689=C2 6.744=C2 6.799=C2
6.854=C2
6.909
=C2 130=C2 6.909=C2 6.964=C2 7.019=C2 7.074=C2
7.129=C2 7.184=C2 7.239=C2 7.294=C2 7.349=C2
7.404=C2
7.459
=C2 140=C2 7.4590 7.514=C2 7.569=C2 7.624=C2
7.679=C2 7.734=C2 7.789=C2 7.844=C2 7.900=C2
7.955=C2
8.010
=C2
=C2 150=C2 8.010=C2 8.065=C2 8.120=C2 8.175=C2
8.231=C2 8.286=C2 8.341=C2 8.396=C2 8.452=C2
8.507=C2
8.562
=C2 160=C2 8.562=C2 8.618=C2 8.673=C2 8.728=C2
8.783=C2 8.839=C2 8.894=C2 8.949=C2 9.005=C2
9.060=C2
9.115
=C2 170=C2 9.115=C2 9.171=C2 9.226=C2 9.282=C2
9.337=C2 9.392=C2 9.448=C2 9.503=C2 9.559=C2
9.614=C2
9.669
=C2 180=C2 9.669=C2 9.725=C2 9.780=C2 9.836=C2
9.891=C2 9.947 10.002 10.057 10.113 10.168 10.224
=C2 190 10.224 10.279 10.335 10.390 10.446 10.501 10.557 10.612 10.668
10.723 10.779
=C2
=C2 200 10.779 10.834 10.890 10.945 11.001 11.056 11.112 11.167 11.223
11.278 11.334
=C2 210 11.334 11.389 11.445 11.501 11.556 11.612 11.667 11.723 11.778
11.834 11.889
=C2 220 11.889 11.945 12.000 12.056 12.111 12.167 12.222 12.278 12.334
12.389 12.445
=C2 230 12.445 12.500 12.556 12.611 12.667 12.722 12.778 12.833 12.889
12.944 13.000
=C2 240 13.000 13.056 13.111 13.167 13.222 13.278 13.333 13.389 13.444
13.500 13.555
=C2
=C2 250 13.555 13.611 13.666 13.722 13.777 13.833 13.888 13.944 13.999
14.055 14.110
=C2 260 14.110 14.166 14.221 14.277 14.332 14.388 14.443 14.499 14.554
14.609 14.665
=C2 270 14.665 14.720 14.776 14.831 14.887 14.942 14.998 15.053 15.109
15.164 15.219
=C2 280 15.219 15.275 15.330 15.386 15.441 15.496 15.552 15.607 15.663
15.718 15.773
=C2 290 15.773 15.829 15.884 15.940 15.995 16.050 16.106 16.161 16.
216
16.272 16.327
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Message 13
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| Subject: | Re: RE: EI vs JPI |
Yeah I just Read Steve's post again. Steve didn't use JPI and JPI
probers. He used solely EI equipment
His post last year is here:
http://grumman.net/archive/2008/msg00193.html
I think that the idea that it is the EI fixed probe that is in error is
a new idea recently introduced into this year and a half long thread.
Last year and in Gary's article in the STAR the conclusion was that the
JPI probe did not represent what Lycoming measured.
At this point it is just speculation as to what type probe was used by
Lycoming or perhaps even if they used a probe.
Like Sgt Friday says lets just say with the facts... just the facts
----- Original Message -----
From: flyv35b
To: teamgrumman-list@matronics.com
Sent: Sunday, March 29, 2009 9:35 PM
Subject: Re: TeamGrumman-List: RE: EI vs JPI
Maybe you guys need to ask Steve Peach about the two different styles
of EI probes, bayonet and standard P-100, that he tested and found very
little difference between the two. The large differences in temperature
mentioned are between JPI with the bayonet and EI with the fixed probe.
And all the accusations, or implications at least, are that the fixed EI
probe does not measure the true temperature. There is a real
possibility that it could be due to something completely different.
Cliff
----- Original Message -----
From: Gil Alexander
To: teamgrumman-list@matronics.com
Sent: Sunday, March 29, 2009 7:13 PM
Subject: Re: TeamGrumman-List: RE: EI vs JPI
Ned... I believe the GG post you refer to still references Gary's
EI/JPI measurements....:^)
He just says below that the EI non-bayonet probes read lower - which
does not seem to be in dispute....:^)
And do you really think Lycoming used a non-MIL-Spec probe,
especially in the 60's, for certification? I vote for probes that touch
the cylinder.
gil A
At 07:05 PM 3/29/2009, you wrote:
I started this thread because of similar thread that was started
on the GG. I understood one poster to say that he too had experienced
higher readings with JPI type probes that actually touch the thermowell.
He had both in his Cheetah and found that the probes that touch the head
actually give a higher reading.
So in answer to Gil's post it appears that others have noted the
diffenece in temp readings besides Gary.
Someone at Lycoming needs to answer this question, at least the
question of the type of probe they used. Right now we are just
speculating on what type of probe they used.
Ned
Here is the post I refer to:
----- Original Message -----
From: John Horton
To: 'Dave Kalwick' ; 'GG'
Sent: Tuesday, March 24, 2009 9:19 PM
Subject: RE: Tiger outlet ramps - More Info Req.
Dave,
I would direct you to look at
http://www.bondline.org/wiki/Lower_Cowling_Split
for info about reworking the exit ramps. That link will only
provide info
about
the metal exit ramps but that's half the options.
When you mention that your temps are "warm" be sure to review the
GG archives
about JPI instrumentation vs EI instrumentation. There are
differences in
probe
design that make JPI read higher that EI in what should be the
same cylinder.
So if you have JP CHT and think your running "warm" you might be
just fine if
you had EI CHT. Theres a good bit of reading in the archives on
that topic.
My
consensus after reviewing (and I might still have it wrong) is
that JP CHT
reads
hotter than EI due to the fact that the JP CHT probe actually is
spring
loaded
to touch the cyl head. The EI CHT probe screws into a space in the
cyl head.
I
have had both in my plane (Cheetah) and can verify that fact. The
probes are
different and the JP touches the head and reads hotter.
So if you have JP CHT gauge and it reads 420 in climb your most
likely fine.
(Assuming the temp goes down when you level out) The same plane
may well read
385 with a EI CHT and it is fine also. Be sure to know your temp
source (EI
or
JP) and read the archives to get a feel for the differences before
you go and
rework your exit ramps. They might be fine.
I recently reworked my exit ramps on my Cheetah due to a "warmer"
than I'd
like
#4 cyl, cracks in my metal exit ramps and a newly minted A&P
ticket that
allowed
me to do it. I have only flown it once and the results looked
promising.
Tommorrow I hope to gather more flight data. I currently have a JP
CHT/EGT
and
in climb prior to the ramp work could occasionally hit 450 (my and
Lycomings
redline). I could easily get into the 430's in climb and have to
nose over
and
or throttle back to arrest the CHT rise. When I had the EI CHT
gauge I never
saw anything above 390.
After reworking the ramps I do expect to go faster, climb higher
and do it
all
with 1/3 flaps deployed for less gallons per hour. I just had to
throw that
in
in case there aren't enough emotionally loaded topics to write
about.
John Horton
HC Cheetah
Sensenich Prop
----- Original Message -----
From: Gil Alexander
To: teamgrumman-list@matronics.com
Sent: Sunday, March 29, 2009 8:41 PM
Subject: Re: TeamGrumman-List: RE: EI vs JPI
Gary,
How many STCs have you installed with poor/bad/wrong
instructions? And the CHT/EGT monitor STCs are quite "generic" not
really airframe specific.
My latest one was my Plane Power voltage regulator. Works fine,
but needed spacers to clear the "bumps" on the fire wall - hardly a
drop-in exact replacement for the non flat bottom mechanical regulator -
and no mention in the STC instructions.
Your plane seems to be the only test case reporting the problem.
I'm happy with the Insight GEM in mine with it's probes that touch the
thermowell bottom like I believe the Lycoming test bayonet probes did
during their certification.
As an electronics engineer, I know I would not design sensitive
millivolts equipment using grounded sensors.... but that's just me....
and my stuff is (or has been) working in military aircraft and space
vehicles....:^)
gil A
PS ...I like the GEM unit, but I have the "bars only" version -
I would prefer the version with numbers - a probable future upgrade.
PPS Sorry about the formatting of the mV chart in my previous
e-mail
Here is an alternate link to another table of National Institute
of Standards and Technology output voltages from a Type J thermocouple -
http://www.omega.com/temperature/Z/pdf/z203.pdf
This shows how small the DC voltages are that we are measuring.
At 05:40 PM 3/29/2009, you wrote:
There is something else going on here in your plane - and
since we are dealing with fractions of milliVolts, I would personally
vote for grounding issues.=C2
MY PLANE? =C2 Ok, maybe your right. =C2 The grounds in
installed according to the STC were done wrong. =C2 Maybe the probes
grounding against brand new cylinders had corrosion built up in them.
=C2
Maybe planes experiencing CHT readings higher on a JPI than on
an EI also followed the installation instructions.
How about you doing your own testing and report your own
results?
-----Original Message-----
From: Gil Alexander <gilalex@earthlink.net>
To: teamgrumman-list@matronics.com
Sent: Sun, 29 Mar 2009 12:03 pm
Subject: Re: TeamGrumman-List: RE: EI vs JPI
This is only true if, and it's a big IF, the temperatures
displayed on todays instrumentation "WOULD" have displayed the same
temperatures as those recorded by Lycoming technicians=C3, on the
instrumentation used by Lycoming. =C3,=C2
Gary... I don't belief that is a big "IF"...
The electrical characteristics of a type J thermocouple have
been well known from long before WWII.
The electrical instrumentation bit has not changed over the
years as far as the basic thermocouple, especially when used in an
engine test cell.=C2 I bet Lycoming had individual CHT meters directly
connected to the probes, none of this fancy digital switching, scanning
stuff....:^)
Today the probes and the interconnect may be different, but
the a type J thermocouple has always created the same amount of voltage
due to physics.
There is something else going on here in your plane - and
since we are dealing with fractions of milliVolts, I would personally
vote for grounding issues.=C2 You can see from the table below that 10
degrees Centigrade is about a 1/2 milliVolt change.=C2 Try a direct
wire from GND on your EI gauge to the engine.
This is from Sandia labs...=C2 gil A
=C2 ITS-90 Table for type J=C2 thermocouple
=C2 =C2=B0C=C2 =C2 =C2 =C2 =C2 0=C2 =C2 =C2 =C2 =C2
1=C2 =C2 =C2 =C2 =C2 2=C2 =C2 =C2 =C2 =C2
3=C2 =C2 =C2 =C2 =C2 4=C2 =C2 =C2 =C2 =C2
5=C2 =C2 =C2 =C2 =C2 6=C2 =C2 =C2 =C2 =C2
7=C2 =C2 =C2 =C2 =C2 8=C2 =C2 =C2 =C2 =C2
9=C2 =C2 =C2 =C2 10
=C2 =C2 =C2 =C2 =C2 =C2 =C2 =C2 =C2 =C2 =C2 =C2 =C2 =C2 =C2 =C2 =C2 =C2
=C2 =C2 =C2 =C2 =C2 =C2 =C2 =C2 =C2 =C2 =C2 =C2
Thermoelectric Voltage in mV
=C2
=C2 =C2 0=C2 0.000=C2 0.050=C2 0.101=C2 0.151=C2
0.202=C2 0.253=C2 0.303=C2 0.354=C2 0.405=C2
0.456=C2
0.507
=C2 10=C2 0.507=C2 0.558=C2 0.609=C2 0.660=C2
0.711=C2 0.762=C2 0.814=C2 0.865=C2 0.916=C2
0.968=C2
1.019
=C2 20=C2 1.019=C2 1.071
1.122=C2 1.174=C2
1.226=C2 1.277=C2 1.329=C2 1.381=C2 1.433=C2
1.485=C2
1.537
=C2 30=C2 1.537=C2 1.589=C2 1.641=C2 1.693=C2
1.745=C2 1.797=C2 1.849=C2 1.902=C2 1.954=C2
2.006=C2
2.059
=C2 40=C2 2.059=C2 2.111=C2 2.164=C2 2.216=C2
2.269=C2 2.322=C2 2.374=C2 2.427=C2 2.480=C2
2.532=C2
2.585
=C2
=C2 50=C2 2.585=C2 2.638=C2 2.691=C2 2.744=C2
2.797=C2 2.850=C2 2.903=C2 2.956=C2 3.009=C2
3.062=C2
3.116
=C2 60=C2 3.116=C2 3.169=C2 3.222=C2 3.275=C2
3.329=C2 3.382=C2 3.436=C2 3.489=C2 3.543=C2
3.596=C2
3.650
=C2 70=C2 3.650=C2 3.703=C2 3.757=C2 3.810=C2
3.864=C2 3.918=C2 3.971=C2 4.025=C2 4.079=C2
4.133=C2
4.187
=C2 80=C2 4.187=C2 4.240=C2 4.294=C2 4.348=C2
4.402=C2 4.456=C2 4.510=C2 4.564=C2 4.618=C2
4.672=C2
4.726
=C2 90=C2 4.726=C2 4.781=C2 4.835=C2 4.889=C2
4.943=C2 4.997=C2 5.052=C2 5.106=C2 5.160=C2
5.215=C2
5.269
=C2
=C2 100=C2 5.269=C2 5.323=C2 5.378=C2 5.432=C2
5.487=C2 5.541=C2 5.595=C2 5.650=C2 5.705=C2
5.759=C2
5.814
=C2 110=C2 5.814=C2 5.868=C2 5.923=C2 5.977=C2
6.032=C2 6.087=C2 6.141=C2 6.196=C2 6.251=C2
6.306=C2
6.360
=C2 120=C2 6.360=C2 6.415=C2 6.470=C2 6.525=C2
6.579=C2 6.634=C2 6.689=C2 6.744=C2 6.799=C2
6.854=C2
6.909
=C2 130=C2 6.909=C2 6.964=C2 7.019=C2 7.074=C2
7.129=C2 7.184=C2 7.239=C2 7.294=C2 7.349=C2
7.404=C2
7.459
=C2 140=C2 7.4590 7.514=C2 7.569=C2 7.624=C2
7.679=C2 7.734=C2 7.789=C2 7.844=C2 7.900=C2
7.955=C2
8.010
=C2
=C2 150=C2 8.010=C2 8.065=C2 8.120=C2 8.175=C2
8.231=C2 8.286=C2 8.341=C2 8.396=C2 8.452=C2
8.507=C2
8.562
=C2 160=C2 8.562=C2 8.618=C2 8.673=C2 8.728=C2
8.783=C2 8.839=C2 8.894=C2 8.949=C2 9.005=C2
9.060=C2
9.115
=C2 170=C2 9.115=C2 9.171=C2 9.226=C2 9.282=C2
9.337=C2 9.392=C2 9.448=C2 9.503=C2 9.559=C2
9.614=C2
9.669
=C2 180=C2 9.669=C2 9.725=C2 9.780=C2 9.836=C2
9.891=C2 9.947 10.002 10.057 10.113 10.168 10.224
=C2 190 10.224 10.279 10.335 10.390 10.446 10.501 10.557 10.612 10.668
10.723 10.779
=C2
=C2 200 10.779 10.834 10.890 10.945 11.001 11.056 11.112 11.167 11.223
11.278 11.334
=C2 210 11.334 11.389 11.445 11.501 11.556 11.612 11.667 11.723 11.778
11.834 11.889
=C2 220 11.889 11.945 12.000 12.056 12.111 12.167 12.222 12.278 12.334
12.389 12.445
=C2 230 12.445 12.500 12.556 12.611 12.667 12.722 12.778 12.833 12.889
12.944 13.000
=C2 240 13.000 13.056 13.111 13.167 13.222 13.278 13.333 13.389 13.444
13.500 13.555
=C2
=C2 250 13.555 13.611 13.666 13.722 13.777 13.833 13.888 13.944 13.999
14.055 14.110
=C2 260 14.110 14.166 14.221 14.277 14.332 14.388 14.443 14.499 14.554
14.609 14.665
=C2 270 14.665 14.720 14.776 14.831 14.887 14.942 14.998 15.053 15.109
15.164 15.219
=C2 280 15.219 15.275 15.330 15.386 15.441 15.496 15.552 15.607 15.663
15.718 15.773
=C2 290 15.773 15.829 15.884 15.940 15.995 16.050 16.106 16.161 16.
216
16.272 16.327
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| Subject: | Re: RE: EI vs JPI |
Steve's conclusion "the EI longer P-101 probe does indeed read hotter
than the short P-100 probe by about 3.5 degrees F"
----- Original Message -----
From: flyv35b
To: teamgrumman-list@matronics.com
Sent: Sunday, March 29, 2009 9:35 PM
Subject: Re: TeamGrumman-List: RE: EI vs JPI
Maybe you guys need to ask Steve Peach about the two different styles
of EI probes, bayonet and standard P-100, that he tested and found very
little difference between the two. The large differences in temperature
mentioned are between JPI with the bayonet and EI with the fixed probe.
And all the accusations, or implications at least, are that the fixed EI
probe does not measure the true temperature. There is a real
possibility that it could be due to something completely different.
Cliff
----- Original Message -----
From: Gil Alexander
To: teamgrumman-list@matronics.com
Sent: Sunday, March 29, 2009 7:13 PM
Subject: Re: TeamGrumman-List: RE: EI vs JPI
Ned... I believe the GG post you refer to still references Gary's
EI/JPI measurements....:^)
He just says below that the EI non-bayonet probes read lower - which
does not seem to be in dispute....:^)
And do you really think Lycoming used a non-MIL-Spec probe,
especially in the 60's, for certification? I vote for probes that touch
the cylinder.
gil A
At 07:05 PM 3/29/2009, you wrote:
I started this thread because of similar thread that was started
on the GG. I understood one poster to say that he too had experienced
higher readings with JPI type probes that actually touch the thermowell.
He had both in his Cheetah and found that the probes that touch the head
actually give a higher reading.
So in answer to Gil's post it appears that others have noted the
diffenece in temp readings besides Gary.
Someone at Lycoming needs to answer this question, at least the
question of the type of probe they used. Right now we are just
speculating on what type of probe they used.
Ned
Here is the post I refer to:
----- Original Message -----
From: John Horton
To: 'Dave Kalwick' ; 'GG'
Sent: Tuesday, March 24, 2009 9:19 PM
Subject: RE: Tiger outlet ramps - More Info Req.
Dave,
I would direct you to look at
http://www.bondline.org/wiki/Lower_Cowling_Split
for info about reworking the exit ramps. That link will only
provide info
about
the metal exit ramps but that's half the options.
When you mention that your temps are "warm" be sure to review the
GG archives
about JPI instrumentation vs EI instrumentation. There are
differences in
probe
design that make JPI read higher that EI in what should be the
same cylinder.
So if you have JP CHT and think your running "warm" you might be
just fine if
you had EI CHT. Theres a good bit of reading in the archives on
that topic.
My
consensus after reviewing (and I might still have it wrong) is
that JP CHT
reads
hotter than EI due to the fact that the JP CHT probe actually is
spring
loaded
to touch the cyl head. The EI CHT probe screws into a space in the
cyl head.
I
have had both in my plane (Cheetah) and can verify that fact. The
probes are
different and the JP touches the head and reads hotter.
So if you have JP CHT gauge and it reads 420 in climb your most
likely fine.
(Assuming the temp goes down when you level out) The same plane
may well read
385 with a EI CHT and it is fine also. Be sure to know your temp
source (EI
or
JP) and read the archives to get a feel for the differences before
you go and
rework your exit ramps. They might be fine.
I recently reworked my exit ramps on my Cheetah due to a "warmer"
than I'd
like
#4 cyl, cracks in my metal exit ramps and a newly minted A&P
ticket that
allowed
me to do it. I have only flown it once and the results looked
promising.
Tommorrow I hope to gather more flight data. I currently have a JP
CHT/EGT
and
in climb prior to the ramp work could occasionally hit 450 (my and
Lycomings
redline). I could easily get into the 430's in climb and have to
nose over
and
or throttle back to arrest the CHT rise. When I had the EI CHT
gauge I never
saw anything above 390.
After reworking the ramps I do expect to go faster, climb higher
and do it
all
with 1/3 flaps deployed for less gallons per hour. I just had to
throw that
in
in case there aren't enough emotionally loaded topics to write
about.
John Horton
HC Cheetah
Sensenich Prop
----- Original Message -----
From: Gil Alexander
To: teamgrumman-list@matronics.com
Sent: Sunday, March 29, 2009 8:41 PM
Subject: Re: TeamGrumman-List: RE: EI vs JPI
Gary,
How many STCs have you installed with poor/bad/wrong
instructions? And the CHT/EGT monitor STCs are quite "generic" not
really airframe specific.
My latest one was my Plane Power voltage regulator. Works fine,
but needed spacers to clear the "bumps" on the fire wall - hardly a
drop-in exact replacement for the non flat bottom mechanical regulator -
and no mention in the STC instructions.
Your plane seems to be the only test case reporting the problem.
I'm happy with the Insight GEM in mine with it's probes that touch the
thermowell bottom like I believe the Lycoming test bayonet probes did
during their certification.
As an electronics engineer, I know I would not design sensitive
millivolts equipment using grounded sensors.... but that's just me....
and my stuff is (or has been) working in military aircraft and space
vehicles....:^)
gil A
PS ...I like the GEM unit, but I have the "bars only" version -
I would prefer the version with numbers - a probable future upgrade.
PPS Sorry about the formatting of the mV chart in my previous
e-mail
Here is an alternate link to another table of National Institute
of Standards and Technology output voltages from a Type J thermocouple -
http://www.omega.com/temperature/Z/pdf/z203.pdf
This shows how small the DC voltages are that we are measuring.
At 05:40 PM 3/29/2009, you wrote:
There is something else going on here in your plane - and
since we are dealing with fractions of milliVolts, I would personally
vote for grounding issues.=C2
MY PLANE? =C2 Ok, maybe your right. =C2 The grounds in
installed according to the STC were done wrong. =C2 Maybe the probes
grounding against brand new cylinders had corrosion built up in them.
=C2
Maybe planes experiencing CHT readings higher on a JPI than on
an EI also followed the installation instructions.
How about you doing your own testing and report your own
results?
-----Original Message-----
From: Gil Alexander <gilalex@earthlink.net>
To: teamgrumman-list@matronics.com
Sent: Sun, 29 Mar 2009 12:03 pm
Subject: Re: TeamGrumman-List: RE: EI vs JPI
This is only true if, and it's a big IF, the temperatures
displayed on todays instrumentation "WOULD" have displayed the same
temperatures as those recorded by Lycoming technicians=C3, on the
instrumentation used by Lycoming. =C3,=C2
Gary... I don't belief that is a big "IF"...
The electrical characteristics of a type J thermocouple have
been well known from long before WWII.
The electrical instrumentation bit has not changed over the
years as far as the basic thermocouple, especially when used in an
engine test cell.=C2 I bet Lycoming had individual CHT meters directly
connected to the probes, none of this fancy digital switching, scanning
stuff....:^)
Today the probes and the interconnect may be different, but
the a type J thermocouple has always created the same amount of voltage
due to physics.
There is something else going on here in your plane - and
since we are dealing with fractions of milliVolts, I would personally
vote for grounding issues.=C2 You can see from the table below that 10
degrees Centigrade is about a 1/2 milliVolt change.=C2 Try a direct
wire from GND on your EI gauge to the engine.
This is from Sandia labs...=C2 gil A
=C2 ITS-90 Table for type J=C2 thermocouple
=C2 =C2=B0C=C2 =C2 =C2 =C2 =C2 0=C2 =C2 =C2 =C2 =C2
1=C2 =C2 =C2 =C2 =C2 2=C2 =C2 =C2 =C2 =C2
3=C2 =C2 =C2 =C2 =C2 4=C2 =C2 =C2 =C2 =C2
5=C2 =C2 =C2 =C2 =C2 6=C2 =C2 =C2 =C2 =C2
7=C2 =C2 =C2 =C2 =C2 8=C2 =C2 =C2 =C2 =C2
9=C2 =C2 =C2 =C2 10
=C2 =C2 =C2 =C2 =C2 =C2 =C2 =C2 =C2 =C2 =C2 =C2 =C2 =C2 =C2 =C2 =C2 =C2
=C2 =C2 =C2 =C2 =C2 =C2 =C2 =C2 =C2 =C2 =C2 =C2
Thermoelectric Voltage in mV
=C2
=C2 =C2 0=C2 0.000=C2 0.050=C2 0.101=C2 0.151=C2
0.202=C2 0.253=C2 0.303=C2 0.354=C2 0.405=C2
0.456=C2
0.507
=C2 10=C2 0.507=C2 0.558=C2 0.609=C2 0.660=C2
0.711=C2 0.762=C2 0.814=C2 0.865=C2 0.916=C2
0.968=C2
1.019
=C2 20=C2 1.019=C2 1.071
1.122=C2 1.174=C2
1.226=C2 1.277=C2 1.329=C2 1.381=C2 1.433=C2
1.485=C2
1.537
=C2 30=C2 1.537=C2 1.589=C2 1.641=C2 1.693=C2
1.745=C2 1.797=C2 1.849=C2 1.902=C2 1.954=C2
2.006=C2
2.059
=C2 40=C2 2.059=C2 2.111=C2 2.164=C2 2.216=C2
2.269=C2 2.322=C2 2.374=C2 2.427=C2 2.480=C2
2.532=C2
2.585
=C2
=C2 50=C2 2.585=C2 2.638=C2 2.691=C2 2.744=C2
2.797=C2 2.850=C2 2.903=C2 2.956=C2 3.009=C2
3.062=C2
3.116
=C2 60=C2 3.116=C2 3.169=C2 3.222=C2 3.275=C2
3.329=C2 3.382=C2 3.436=C2 3.489=C2 3.543=C2
3.596=C2
3.650
=C2 70=C2 3.650=C2 3.703=C2 3.757=C2 3.810=C2
3.864=C2 3.918=C2 3.971=C2 4.025=C2 4.079=C2
4.133=C2
4.187
=C2 80=C2 4.187=C2 4.240=C2 4.294=C2 4.348=C2
4.402=C2 4.456=C2 4.510=C2 4.564=C2 4.618=C2
4.672=C2
4.726
=C2 90=C2 4.726=C2 4.781=C2 4.835=C2 4.889=C2
4.943=C2 4.997=C2 5.052=C2 5.106=C2 5.160=C2
5.215=C2
5.269
=C2
=C2 100=C2 5.269=C2 5.323=C2 5.378=C2 5.432=C2
5.487=C2 5.541=C2 5.595=C2 5.650=C2 5.705=C2
5.759=C2
5.814
=C2 110=C2 5.814=C2 5.868=C2 5.923=C2 5.977=C2
6.032=C2 6.087=C2 6.141=C2 6.196=C2 6.251=C2
6.306=C2
6.360
=C2 120=C2 6.360=C2 6.415=C2 6.470=C2 6.525=C2
6.579=C2 6.634=C2 6.689=C2 6.744=C2 6.799=C2
6.854=C2
6.909
=C2 130=C2 6.909=C2 6.964=C2 7.019=C2 7.074=C2
7.129=C2 7.184=C2 7.239=C2 7.294=C2 7.349=C2
7.404=C2
7.459
=C2 140=C2 7.4590 7.514=C2 7.569=C2 7.624=C2
7.679=C2 7.734=C2 7.789=C2 7.844=C2 7.900=C2
7.955=C2
8.010
=C2
=C2 150=C2 8.010=C2 8.065=C2 8.120=C2 8.175=C2
8.231=C2 8.286=C2 8.341=C2 8.396=C2 8.452=C2
8.507=C2
8.562
=C2 160=C2 8.562=C2 8.618=C2 8.673=C2 8.728=C2
8.783=C2 8.839=C2 8.894=C2 8.949=C2 9.005=C2
9.060=C2
9.115
=C2 170=C2 9.115=C2 9.171=C2 9.226=C2 9.282=C2
9.337=C2 9.392=C2 9.448=C2 9.503=C2 9.559=C2
9.614=C2
9.669
=C2 180=C2 9.669=C2 9.725=C2 9.780=C2 9.836=C2
9.891=C2 9.947 10.002 10.057 10.113 10.168 10.224
=C2 190 10.224 10.279 10.335 10.390 10.446 10.501 10.557 10.612 10.668
10.723 10.779
=C2
=C2 200 10.779 10.834 10.890 10.945 11.001 11.056 11.112 11.167 11.223
11.278 11.334
=C2 210 11.334 11.389 11.445 11.501 11.556 11.612 11.667 11.723 11.778
11.834 11.889
=C2 220 11.889 11.945 12.000 12.056 12.111 12.167 12.222 12.278 12.334
12.389 12.445
=C2 230 12.445 12.500 12.556 12.611 12.667 12.722 12.778 12.833 12.889
12.944 13.000
=C2 240 13.000 13.056 13.111 13.167 13.222 13.278 13.333 13.389 13.444
13.500 13.555
=C2
=C2 250 13.555 13.611 13.666 13.722 13.777 13.833 13.888 13.944 13.999
14.055 14.110
=C2 260 14.110 14.166 14.221 14.277 14.332 14.388 14.443 14.499 14.554
14.609 14.665
=C2 270 14.665 14.720 14.776 14.831 14.887 14.942 14.998 15.053 15.109
15.164 15.219
=C2 280 15.219 15.275 15.330 15.386 15.441 15.496 15.552 15.607 15.663
15.718 15.773
=C2 290 15.773 15.829 15.884 15.940 15.995 16.050 16.106 16.161 16.
216
16.272 16.327
or?TeamGrumman-List">http://www.matronics.com/Navigator?TeamGrumman-List
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Message 15
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| Subject: | Re: RE: EI vs JPI |
Not according to the govt. web site that has specification records
back to the 60's
That's why I put it above speculation.... gil A
At 07:31 PM 3/29/2009, you wrote:
>Perhaps there was a milspec probe like the one EI uses today in use
>on Lycomings certification tests...
>
>Like Isaid earlier we are just speculating
>----- Original Message -----
>From: <mailto:gilalex@earthlink.net>Gil Alexander
>To: <mailto:teamgrumman-list@matronics.com>teamgrumman-list@matronics.com
>Sent: Sunday, March 29, 2009 9:13 PM
>Subject: Re: TeamGrumman-List: RE: EI vs JPI
>
>Ned... I believe the GG post you refer to still references Gary's
>EI/JPI measurements....:^)
>
>He just says below that the EI non-bayonet probes read lower - which
>does not seem to be in dispute....:^)
>
>And do you really think Lycoming used a non-MIL-Spec probe,
>especially in the 60's, for certification? I vote for probes that
>touch the cylinder.
>
>gil A
>
>At 07:05 PM 3/29/2009, you wrote:
>>I started this thread because of similar thread that was started on
>>the GG. I understood one poster to say that he too had experienced
>>higher readings with JPI type probes that actually touch the
>>thermowell. He had both in his Cheetah and found that the probes
>>that touch the head actually give a higher reading.
>>
>>So in answer to Gil's post it appears that others have noted the
>>diffenece in temp readings besides Gary.
>>
>>Someone at Lycoming needs to answer this question, at least the
>>question of the type of probe they used. Right now we are just
>>speculating on what type of probe they used.
><big snip>
Message 16
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| Subject: | Re: RE: EI vs JPI |
Sorry... I mixed up the vendors...
I think the "touch the metal probes" (like the Mil-Spec ones)
probably read higher.
However, in agreement with Cliff - there well could be other things
in play here when milliVolts are being measured.
Grounds and differences in grounds, even along the wire to the
instrument, could affect readings.
That is why I suggest playing around with extra ground wires to see
if the differences between the instruments change. The instrument
ground to the engine case would seem to be the first obvious wire to try.
gil A
At 07:35 PM 3/29/2009, you wrote:
>Gil,
>
>You didn't read the post very well. I removed all but the one
>sentence from the post that you missed. Want to change your belief?
>Ned
>
>----- Original Message -----
>From: <mailto:gilalex@earthlink.net>Gil Alexander
>To: <mailto:teamgrumman-list@matronics.com>teamgrumman-list@matronics.com
>Sent: Sunday, March 29, 2009 9:13 PM
>Subject: Re: TeamGrumman-List: RE: EI vs JPI
>Ned... I believe the GG post you refer to still references Gary's
>EI/JPI measurements....:^)
>
>He just says below that the EI non-bayonet probes read lower - which
>does not seem to be in dispute....:^)
>
>And do you really think Lycoming used a non-MIL-Spec probe,
>especially in the 60's, for certification? I vote for probes that
>touch the cylinder.
>
>gil A
>
>
>"I have had both in my plane (Cheetah) and can verify that fact. The
>probes are
>different and the JP touches the head and reads hotter."
>
Message 17
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| Subject: | Re: RE: EI vs JPI |
Are we really getting anal over 3.5 degrees??? Less than 1% error?
Linn
923te wrote:
> Steve's conclusion "the EI longer P-101 probe does indeed read hotter
> than the short P-100 probe by about 3.5 degrees F"
>
> ----- Original Message -----
>
Message 18
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| Subject: | Re: RE: EI vs JPI |
I'm curious about the wire runs from the thermocouple to the instrument
head. I know that some types like the old Alcor wires could not be cut.
EI and JPI CAN be cut. I'm curious about that and about the effect for
different length and routing under cylinders were the heat is higher. I
think the theory behind teh system is to have one hot source (at the
cylinder head) and one cold source ( at the gauge). I'd like to know
more about the effects of multiple hot and cold sources along the wire
----- Original Message -----
From: Gil Alexander
To: teamgrumman-list@matronics.com
Sent: Sunday, March 29, 2009 9:56 PM
Subject: Re: TeamGrumman-List: RE: EI vs JPI
Sorry... I mixed up the vendors...
I think the "touch the metal probes" (like the Mil-Spec ones) probably
read higher.
However, in agreement with Cliff - there well could be other things in
play here when milliVolts are being measured.
Grounds and differences in grounds, even along the wire to the
instrument, could affect readings.
That is why I suggest playing around with extra ground wires to see if
the differences between the instruments change. The instrument ground
to the engine case would seem to be the first obvious wire to try.
gil A
At 07:35 PM 3/29/2009, you wrote:
Gil,
You didn't read the post very well. I removed all but the one
sentence from the post that you missed. Want to change your belief?
Ned
----- Original Message -----
From: Gil Alexander
To: teamgrumman-list@matronics.com
Sent: Sunday, March 29, 2009 9:13 PM
Subject: Re: TeamGrumman-List: RE: EI vs JPI
Ned... I believe the GG post you refer to still references Gary's
EI/JPI measurements....:^)
He just says below that the EI non-bayonet probes read lower - which
does not seem to be in dispute....:^)
And do you really think Lycoming used a non-MIL-Spec probe,
especially in the 60's, for certification? I vote for probes that touch
the cylinder.
gil A
"I have had both in my plane (Cheetah) and can verify that fact. The
probes are
different and the JP touches the head and reads hotter."
Message 19
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| Subject: | Re: RE: EI vs JPI |
No Linn, the difference in question is more like 70 deg F
----- Original Message -----
From: linn
To: teamgrumman-list@matronics.com
Sent: Sunday, March 29, 2009 11:04 PM
Subject: Re: TeamGrumman-List: RE: EI vs JPI
Are we really getting anal over 3.5 degrees??? Less than 1% error?
Linn
923te wrote:
Steve's conclusion "the EI longer P-101 probe does indeed read
hotter than the short P-100 probe by about 3.5 degrees F"
----- Original Message -----
Message 20
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| Subject: | Re: RE: EI vs JPI |
Ned... try this for a starter... gil A
http://www.aeroelectric.com/articles/excerpt.pdf
At 08:06 PM 3/29/2009, you wrote:
>I'm curious about the wire runs from the thermocouple to the
>instrument head. I know that some types like the old Alcor wires
>could not be cut. EI and JPI CAN be cut. I'm curious about that and
>about the effect for different length and routing under cylinders
>were the heat is higher. I think the theory behind teh system is to
>have one hot source (at the cylinder head) and one cold source ( at
>the gauge). I'd like to know more about the effects of multiple hot
>and cold sources along the wire
>----- Original Message -----
>From: <mailto:gilalex@earthlink.net>Gil Alexander
>To: <mailto:teamgrumman-list@matronics.com>teamgrumman-list@matronics.com
>Sent: Sunday, March 29, 2009 9:56 PM
>Subject: Re: TeamGrumman-List: RE: EI vs JPI
>
>Sorry... I mixed up the vendors...
>
>I think the "touch the metal probes" (like the Mil-Spec ones)
>probably read higher.
>
>However, in agreement with Cliff - there well could be other things
>in play here when milliVolts are being measured.
>
>Grounds and differences in grounds, even along the wire to the
>instrument, could affect readings.
>
>That is why I suggest playing around with extra ground wires to see
>if the differences between the instruments change. The instrument
>ground to the engine case would seem to be the first obvious wire to try.
>
>gil A
>
>At 07:35 PM 3/29/2009, you wrote:
>>Gil,
>>
>>You didn't read the post very well. I removed all but the one
>>sentence from the post that you missed. Want to change your belief?
>>Ned
>>
>>----- Original Message -----
>>From: <mailto:gilalex@earthlink.net>Gil Alexander
>>To: <mailto:teamgrumman-list@matronics.com>teamgrumman-list@matronics.com
>>Sent: Sunday, March 29, 2009 9:13 PM
>>Subject: Re: TeamGrumman-List: RE: EI vs JPI
>>Ned... I believe the GG post you refer to still references Gary's
>>EI/JPI measurements....:^)
>>
>>He just says below that the EI non-bayonet probes read lower -
>>which does not seem to be in dispute....:^)
>>
>>And do you really think Lycoming used a non-MIL-Spec probe,
>>especially in the 60's, for certification? I vote for probes that
>>touch the cylinder.
>>
>>gil A
>>
>>
>>"I have had both in my plane (Cheetah) and can verify that fact.
>>The probes are
>>different and the JP touches the head and reads hotter."
>
>
>href="http://www.matronics.com/Navigator?TeamGrumman-List">http://www.matronics.com/Navigator?TeamGrumman-List
>
>href="http://forums.matronics.com">http://forums.matronics.com
>
>href="http://www.matronics.com/contribution">http://www.matronics.com/c
>
Message 21
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| Subject: | Re: RE: EI vs JPI |
I'm a big fan of Bob Knuckolls. We even had him speak at our Pulsar
builders convention. I've read this before but I'll read it again. A
brief scan seems to indicate no address of my questions tho...
I have these questions because I know how Gary has routed his wires.
Very nice hidden installation but it always mae me wonder if the under
cylinder heat may have an affect
----- Original Message -----
From: Gil Alexander
To: teamgrumman-list@matronics.com
Sent: Sunday, March 29, 2009 10:12 PM
Subject: Re: TeamGrumman-List: RE: EI vs JPI
Ned... try this for a starter... gil A
http://www.aeroelectric.com/articles/excerpt.pdf
At 08:06 PM 3/29/2009, you wrote:
I'm curious about the wire runs from the thermocouple to the
instrument head. I know that some types like the old Alcor wires could
not be cut. EI and JPI CAN be cut. I'm curious about that and about the
effect for different length and routing under cylinders were the heat is
higher. I think the theory behind teh system is to have one hot source
(at the cylinder head) and one cold source ( at the gauge). I'd like to
know more about the effects of multiple hot and cold sources along the
wire
----- Original Message -----
From: Gil Alexander
To: teamgrumman-list@matronics.com
Sent: Sunday, March 29, 2009 9:56 PM
Subject: Re: TeamGrumman-List: RE: EI vs JPI
Sorry... I mixed up the vendors...
I think the "touch the metal probes" (like the Mil-Spec ones)
probably read higher.
However, in agreement with Cliff - there well could be other
things in play here when milliVolts are being measured.
Grounds and differences in grounds, even along the wire to the
instrument, could affect readings.
That is why I suggest playing around with extra ground wires to
see if the differences between the instruments change. The instrument
ground to the engine case would seem to be the first obvious wire to
try.
gil A
At 07:35 PM 3/29/2009, you wrote:
Gil,
You didn't read the post very well. I removed all but the one
sentence from the post that you missed. Want to change your belief?
Ned
----- Original Message -----
From: Gil Alexander
To: teamgrumman-list@matronics.com
Sent: Sunday, March 29, 2009 9:13 PM
Subject: Re: TeamGrumman-List: RE: EI vs JPI
Ned... I believe the GG post you refer to still references
Gary's EI/JPI measurements....:^)
He just says below that the EI non-bayonet probes read lower -
which does not seem to be in dispute....:^)
And do you really think Lycoming used a non-MIL-Spec probe,
especially in the 60's, for certification? I vote for probes that touch
the cylinder.
gil A
"I have had both in my plane (Cheetah) and can verify that fact.
The probes are
different and the JP touches the head and reads hotter."
href="
http://www.matronics.com/Navigator?TeamGrumman-List
">http://www.matronics.com/Navigator?TeamGrumman-List
href="
http://forums.matronics.com">http://forums.matronics.com
href="
http://www.matronics.com/contribution
">http://www.matronics.com/c
Message 22
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| Subject: | Re: RE: EI vs JPI |
The GEM also allows for cutting of the wire leads.
This is probably due to modern electronics using FET transistor input
devices with very high input resistances.
The older specifications made a big deal of the thermocouple
resistance, which makes me think that the older Alcor instruments
were affected by total resistance in the leads with a completely
different input circuit.
This bit is definite, but informed, speculation...:^)
Some more far out speculation - the lead connections could have
changed over the last period of a few years due to the removal of
lead from solder by EU and Japanese regulations - the RoHS Directive.
Manufacturers have changed the plating composition on connectors that
may come into play at the probe to lead wire connections. In lots of
commercial cases (and a few Mil-Spec cases, unfortunately) these
changes have NOT been reflected in part number changes.
gil A
At 08:06 PM 3/29/2009, you wrote:
>I'm curious about the wire runs from the thermocouple to the
>instrument head. I know that some types like the old Alcor wires
>could not be cut. EI and JPI CAN be cut. I'm curious about that and
>about the effect for different length and routing under cylinders
>were the heat is higher. I think the theory behind teh system is to
>have one hot source (at the cylinder head) and one cold source ( at
>the gauge). I'd like to know more about the effects of multiple hot
>and cold sources along the wire
>----- Original Message -----
>From: <mailto:gilalex@earthlink.net>Gil Alexander
>To: <mailto:teamgrumman-list@matronics.com>teamgrumman-list@matronics.com
>Sent: Sunday, March 29, 2009 9:56 PM
>Subject: Re: TeamGrumman-List: RE: EI vs JPI
>
>Sorry... I mixed up the vendors...
>
>I think the "touch the metal probes" (like the Mil-Spec ones)
>probably read higher.
>
>However, in agreement with Cliff - there well could be other things
>in play here when milliVolts are being measured.
>
>Grounds and differences in grounds, even along the wire to the
>instrument, could affect readings.
>
>That is why I suggest playing around with extra ground wires to see
>if the differences between the instruments change. The instrument
>ground to the engine case would seem to be the first obvious wire to try.
>
>gil A
>
>At 07:35 PM 3/29/2009, you wrote:
>>Gil,
>>
>>You didn't read the post very well. I removed all but the one
>>sentence from the post that you missed. Want to change your belief?
>>Ned
>>
>>----- Original Message -----
>>From: <mailto:gilalex@earthlink.net>Gil Alexander
>>To: <mailto:teamgrumman-list@matronics.com>teamgrumman-list@matronics.com
>>Sent: Sunday, March 29, 2009 9:13 PM
>>Subject: Re: TeamGrumman-List: RE: EI vs JPI
>>Ned... I believe the GG post you refer to still references Gary's
>>EI/JPI measurements....:^)
>>
>>He just says below that the EI non-bayonet probes read lower -
>>which does not seem to be in dispute....:^)
>>
>>And do you really think Lycoming used a non-MIL-Spec probe,
>>especially in the 60's, for certification? I vote for probes that
>>touch the cylinder.
>>
>>gil A
>>
>>
>>"I have had both in my plane (Cheetah) and can verify that fact.
>>The probes are
>>different and the JP touches the head and reads hotter."
>
>
>href="http://www.matronics.com/Navigator?TeamGrumman-List">http://www.matronics.com/Navigator?TeamGrumman-List
>
>href="http://forums.matronics.com">http://forums.matronics.com
>
>href="http://www.matronics.com/contribution">http://www.matronics.com/c
>
Message 23
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|
| Subject: | Re: RE: EI vs JPI |
At 08:22 PM 3/29/2009, you wrote:
>I'm a big fan of Bob Knuckolls. We even had him speak at our Pulsar
>builders convention. I've read this before but I'll read it again. A
>brief scan seems to indicate no address of my questions tho...
>
>I have these questions because I know how Gary has routed his wires.
>Very nice hidden installation but it always mae me wonder if the
>under cylinder heat may have an affect
The critical portion would be not the leads themselves but the
probe/lead connection, which is only a short distance from the
probes, and in the hot area by your description above. gil A
Message 24
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|
| Subject: | Re: RE: EI vs JPI |
Interesting Gil,
we know that temperature affects resistance. Also, Length of wire is a
concern. for example, if you cut the thermocouple wires and make them
different lengths from the heat source to the cold source so that some
stay hotter than others and resistance is not constant what effect would
that have on the algorithm that puts the numbers on the the gauge?
----- Original Message -----
From: Gil Alexander
To: teamgrumman-list@matronics.com
Sent: Sunday, March 29, 2009 10:26 PM
Subject: Re: TeamGrumman-List: RE: EI vs JPI
The GEM also allows for cutting of the wire leads.
This is probably due to modern electronics using FET transistor input
devices with very high input resistances.
The older specifications made a big deal of the thermocouple
resistance, which makes me think that the older Alcor instruments were
affected by total resistance in the leads with a completely different
input circuit.
This bit is definite, but informed, speculation...:^)
Some more far out speculation - the lead connections could have
changed over the last period of a few years due to the removal of lead
from solder by EU and Japanese regulations - the RoHS Directive.
Manufacturers have changed the plating composition on connectors that
may come into play at the probe to lead wire connections. In lots of
commercial cases (and a few Mil-Spec cases, unfortunately) these changes
have NOT been reflected in part number changes.
gil A
At 08:06 PM 3/29/2009, you wrote:
I'm curious about the wire runs from the thermocouple to the
instrument head. I know that some types like the old Alcor wires could
not be cut. EI and JPI CAN be cut. I'm curious about that and about the
effect for different length and routing under cylinders were the heat is
higher. I think the theory behind teh system is to have one hot source
(at the cylinder head) and one cold source ( at the gauge). I'd like to
know more about the effects of multiple hot and cold sources along the
wire
----- Original Message -----
From: Gil Alexander
To: teamgrumman-list@matronics.com
Sent: Sunday, March 29, 2009 9:56 PM
Subject: Re: TeamGrumman-List: RE: EI vs JPI
Sorry... I mixed up the vendors...
I think the "touch the metal probes" (like the Mil-Spec ones)
probably read higher.
However, in agreement with Cliff - there well could be other
things in play here when milliVolts are being measured.
Grounds and differences in grounds, even along the wire to the
instrument, could affect readings.
That is why I suggest playing around with extra ground wires to
see if the differences between the instruments change. The instrument
ground to the engine case would seem to be the first obvious wire to
try.
gil A
At 07:35 PM 3/29/2009, you wrote:
Gil,
You didn't read the post very well. I removed all but the one
sentence from the post that you missed. Want to change your belief?
Ned
----- Original Message -----
From: Gil Alexander
To: teamgrumman-list@matronics.com
Sent: Sunday, March 29, 2009 9:13 PM
Subject: Re: TeamGrumman-List: RE: EI vs JPI
Ned... I believe the GG post you refer to still references
Gary's EI/JPI measurements....:^)
He just says below that the EI non-bayonet probes read lower -
which does not seem to be in dispute....:^)
And do you really think Lycoming used a non-MIL-Spec probe,
especially in the 60's, for certification? I vote for probes that touch
the cylinder.
gil A
"I have had both in my plane (Cheetah) and can verify that fact.
The probes are
different and the JP touches the head and reads hotter."
href="
http://www.matronics.com/Navigator?TeamGrumman-List
">http://www.matronics.com/Navigator?TeamGrumman-List
href="
http://forums.matronics.com">http://forums.matronics.com
href="
http://www.matronics.com/contribution
">http://www.matronics.com/c
Message 25
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|
| Subject: | Re: RE: EI vs JPI |
Ned... more stuff.
Excellent description - with pics - of grounded vs. ungrounded -
interesting that grounded are faster respnse, but ungrounded are
better in electrically noisy environments
http://www.omega.com/custom/faq.html#9
Interesting comments on wire length and high impedance sensors here
http://www.omega.com/prodinfo/ThermocoupleWire.html
A good detailed reference - I need to absorb this one...
http://www.omega.com/temperature/Z/pdf/z021-032.pdf
more
http://www.omega.com/techref/thermoref.html
As you might guess, Omega is a premier US source of thermocouples....:^)
A bit more basic one here...
http://www.status.co.uk/data/handbook_sections_1_to_4.pdf
Enough here to guarantee you will fall asleep quickly...:^) gil A
>I'm a big fan of Bob Knuckolls. We even had him speak at our Pulsar
>builders convention. I've read this before but I'll read it again. A
>brief scan seems to indicate no address of my questions tho...
>
>I have these questions because I know how Gary has routed his wires.
>Very nice hidden installation but it always mae me wonder if the
>under cylinder heat may have an affect
>----- Original Message -----
>From: <mailto:gilalex@earthlink.net>Gil Alexander
>To: <mailto:teamgrumman-list@matronics.com>teamgrumman-list@matronics.com
>Sent: Sunday, March 29, 2009 10:12 PM
>Subject: Re: TeamGrumman-List: RE: EI vs JPI
>
>Ned... try this for a starter... gil A
>
>http://www.aeroelectric.com/articles/excerpt.pdf
>
>
>At 08:06 PM 3/29/2009, you wrote:
>>I'm curious about the wire runs from the thermocouple to the
>>instrument head. I know that some types like the old Alcor wires
>>could not be cut. EI and JPI CAN be cut. I'm curious about that and
>>about the effect for different length and routing under cylinders
>>were the heat is higher. I think the theory behind teh system is to
>>have one hot source (at the cylinder head) and one cold source ( at
>>the gauge). I'd like to know more about the effects of multiple hot
>>and cold sources along the wire
>>----- Original Message -----
Message 26
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|
| Subject: | Re: RE: EI vs JPI |
Thanks Gil.
I was chasing rabbits whilst looking for some references. have most of
the Omega books...guess I should dust them off...noooo it's just easier
to use the net;)
The rabbit...Interesting article on the history of temp / heat
measurement
http://www.springerlink.com/content/r1n5773kug453405/fulltext.pdf
Actually got me to chase a rabbit to colditz Where there is a clay
called the colditz clay that was used to make the secret formulae, at
the time, porcelain.
Back in the 1700's the king of Saxonia (east germany) evidently had teh
European market on this typr of porclain...
I keyed in on colditz because of its' significance during WWI and WWII
as using their castle as a prisoner of war camp...the unescapable
prison where during WWII the prisoners were constructing a GLIDER to
launch from the top of the castle, thus the birdmen of colditz movie
Isn't this forum great! no nanny to kick me off!
----- Original Message -----
From: Gil Alexander
To: teamgrumman-list@matronics.com
Sent: Sunday, March 29, 2009 11:05 PM
Subject: Re: TeamGrumman-List: RE: EI vs JPI
Ned... more stuff.
Excellent description - with pics - of grounded vs. ungrounded -
interesting that grounded are faster respnse, but ungrounded are better
in electrically noisy environments
http://www.omega.com/custom/faq.html#9
Interesting comments on wire length and high impedance sensors here
http://www.omega.com/prodinfo/ThermocoupleWire.html
A good detailed reference - I need to absorb this one...
http://www.omega.com/temperature/Z/pdf/z021-032.pdf
more
http://www.omega.com/techref/thermoref.html
As you might guess, Omega is a premier US source of
thermocouples....:^)
A bit more basic one here...
http://www.status.co.uk/data/handbook_sections_1_to_4.pdf
Enough here to guarantee you will fall asleep quickly...:^) gil A
I'm a big fan of Bob Knuckolls. We even had him speak at our Pulsar
builders convention. I've read this before but I'll read it again. A
brief scan seems to indicate no address of my questions tho...
I have these questions because I know how Gary has routed his wires.
Very nice hidden installation but it always mae me wonder if the under
cylinder heat may have an affect
----- Original Message -----
From: Gil Alexander
To: teamgrumman-list@matronics.com
Sent: Sunday, March 29, 2009 10:12 PM
Subject: Re: TeamGrumman-List: RE: EI vs JPI
Ned... try this for a starter... gil A
http://www.aeroelectric.com/articles/excerpt.pdf
At 08:06 PM 3/29/2009, you wrote:
I'm curious about the wire runs from the thermocouple to the
instrument head. I know that some types like the old Alcor wires could
not be cut. EI and JPI CAN be cut. I'm curious about that and about the
effect for different length and routing under cylinders were the heat is
higher. I think the theory behind teh system is to have one hot source
(at the cylinder head) and one cold source ( at the gauge). I'd like to
know more about the effects of multiple hot and cold sources along the
wire
----- Original Message -----
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