Hercules Engines

"Tom Mosher" wrote in message
om...


RR Speys don't have TIT - they use ITT (interstage turbine
temperature).

My idiot, jet engines use T0 thru T8, with some stations skipped.

Besides that sub-idiot tommy, have you considered this?

"Gord Beaman" wrote in message
.. .
"Jim Knoyle" wrote:

Hang on here a second now Jim, you still need two samples. As Dan
says you need 'static pressure' to read the altitude from and you
need 'pitot pressure' (ram air pressure) as well as the static
pressure to derive the airspeed reading from. Sounds like you're
saying that you can read 'both' from just the 'ram air pressure'
alone. Or did I misunderstand you?

Jim has finally figued out what a pitot tube is, but somehow he still wants
to be correct in his archive troll. It is a great paradox.


I know...ain't life a bitch John

--

-Gord.

You don't know what a pitot tube is either, do you, sub-idiot Mosher?

"Jim Knoyle" wrote in message
...

"Gord Beaman" wrote in message
.. .
"Jim Knoyle" wrote:

Hang on here a second now Jim, you still need two samples. As Dan
says you need 'static pressure' to read the altitude from and you
need 'pitot pressure' (ram air pressure) as well as the static
pressure to derive the airspeed reading from. Sounds like you're
saying that you can read 'both' from just the 'ram air pressure'
alone. Or did I misunderstand you?

Jim has finally figued out what a pitot tube is, but somehow he still wants
to be correct in his archive troll. It is a great paradox.


I know...ain't life a bitch John

--

-Gord.

"Jim Yanik" wrote in message
.. .

You wire thermocouples in series and the voltage outputs add
together(sum).Parallel them,and one voltage bucks against the other.
Paralleling thermocouples is like parallelling two batteries of different
voltages.One works against the other.

What if the thermocouples are wired in parallel, to a totalizer?

Go back to sleep, Jim.

"B2431" wrote in message
...
From: Jim Yanik
Date: 1/16/2004 6:53 PM Central Standard Time
Message-id:

"John R Weiss" wrote in
news:Sp%Nb.73504$nt4.98595@attbi_s51:

"Phil Miller" wrote...

Yes really, on every jet engine TIT is Total Inlet Temperature.

Yep.

I ask because I came across an interesting paragraph in the T56-A-15
service manual yesterday. Went like this...

...measures the turbine inlet temperature by means of
thermocouples...Eighteen thermocouple assemblies are mounted in the
turbine inlet casing of each engine...One thermocouple of each
assembly is connected to the turbine inlet temperature indicating
system, and...one...is connected to the electronic datum control
system. The 18 indicating system thermocouples are connected in
parallel [!!] by the indicator turbine thermocouple harness assembly,

I'm surprised you ever doubted the truth on this one!


So, let's revise.

That's going a bit too far... Nobody can revise the Tarver
Chronicles! :-)


bimetallic thermocouples generate millivolt signals,and paralleling them
would not work.Standard practice is to series-connect them,and compare to
a
reference junction.Do these assemblies include signal processing to
convert
the mV signal to a digital form,which could then be sent on a parallel
bus?

--
Jim Yanik
jyanik-at-kua.net

On every aircraft I ever worked on thermocouples were in parallel if there
were
two or more.

Dan, U.S. Air Force, retired

Dan, we went through this early last year I think it was and Tarver was
shown to be wrong as per normal. On T56 engines the thermocouples are
connected in parallel and pick up TIT, the signal is then averaged. They
are averaged due to the non-uniform temperatures that occur at the turbine
inlet due to the short time of spraying fuel from the nozzle, to fuel
ignition, to introducing the hot gasses at high velocity to the turbine
inlet. The hot gases are not completely mixed and so there are some
stratifications of hotter and cooler areas at the turbine inlet. The
temperature averaging function of the parallel thermocouple circuits
compensates for these non-uniform temperatures.

Scet

"Jim Yanik" wrote in message
.. .
"John R Weiss" wrote in
news:Sp%Nb.73504$nt4.98595@attbi_s51:

"Phil Miller" wrote...

Yes really, on every jet engine TIT is Total Inlet Temperature.

Yep.

I ask because I came across an interesting paragraph in the T56-A-15
service manual yesterday. Went like this...

...measures the turbine inlet temperature by means of
thermocouples...Eighteen thermocouple assemblies are mounted in the
turbine inlet casing of each engine...One thermocouple of each
assembly is connected to the turbine inlet temperature indicating
system, and...one...is connected to the electronic datum control
system. The 18 indicating system thermocouples are connected in
parallel [!!] by the indicator turbine thermocouple harness assembly,

I'm surprised you ever doubted the truth on this one!


So, let's revise.

That's going a bit too far... Nobody can revise the Tarver
Chronicles! :-)


bimetallic thermocouples generate millivolt signals,and paralleling them
would not work.Standard practice is to series-connect them,and compare to
a
reference junction.Do these assemblies include signal processing to
convert
the mV signal to a digital form,which could then be sent on a parallel
bus?

--
Jim Yanik
jyanik-at-kua.net

Sorry Jim, but it does work.

Scet

"Jim Yanik" wrote in message
...
(B2431) wrote in
:

From: Jim Yanik
Date: 1/16/2004 6:53 PM Central Standard Time
Message-id:

"John R Weiss" wrote in
news:Sp%Nb.73504$nt4.98595@attbi_s51:

"Phil Miller" wrote...

Yes really, on every jet engine TIT is Total Inlet Temperature.

Yep.

I ask because I came across an interesting paragraph in the
T56-A-15 service manual yesterday. Went like this...

...measures the turbine inlet temperature by means of
thermocouples...Eighteen thermocouple assemblies are mounted in the
turbine inlet casing of each engine...One thermocouple of each
assembly is connected to the turbine inlet temperature indicating
system, and...one...is connected to the electronic datum control
system. The 18 indicating system thermocouples are connected in
parallel [!!] by the indicator turbine thermocouple harness
assembly,

I'm surprised you ever doubted the truth on this one!


So, let's revise.

That's going a bit too far... Nobody can revise the Tarver
Chronicles! :-)


bimetallic thermocouples generate millivolt signals,and paralleling
them would not work.Standard practice is to series-connect them,and
compare to a reference junction.Do these assemblies include signal
processing to convert the mV signal to a digital form,which could then
be sent on a parallel bus?

--
Jim Yanik
jyanik-at-kua.net

On every aircraft I ever worked on thermocouples were in parallel if
there were two or more.

Dan, U.S. Air Force, retired


Well,I guess they aren't bimetallic thermocouples,then.
Anyone have any speculation on what sort of signal will work with a
parallel connection?

--
Jim Yanik
jyanik-at-kua.net

Yep, an averaged TIT signal on a T56.

Scet

"Tarver Engineering" wrote in message
...

"Rick" wrote in message
news
B2431 wrote:

If you mount them in series you get plus -- minus -- plus-- minus
etc. This
will introduce one heck of an error if it works at all.

They will produce voltage and current, but like you wrote,
series connecting them will introduce errors which make them
unsuitable for instrumentation or measurement use because of
the higher current flow through each junction.

No, but parallel is better, although any way you look at it the sensor
system produces a Total.



Wrong John, average on a T56

Scet

"Jim Yanik" wrote in message
.. .
(B2431) wrote in
:

From: Jim Yanik
Date: 1/17/2004 10:17 AM Central Standard Time
Message-id:

(B2431) wrote in
:

From: Jim Yanik
Date: 1/16/2004 6:53 PM Central Standard Time
Message-id:

"John R Weiss" wrote in
news:Sp%Nb.73504$nt4.98595@attbi_s51:

"Phil Miller" wrote...

Yes really, on every jet engine TIT is Total Inlet Temperature.

Yep.

I ask because I came across an interesting paragraph in the
T56-A-15 service manual yesterday. Went like this...

...measures the turbine inlet temperature by means of
thermocouples...Eighteen thermocouple assemblies are mounted in
the turbine inlet casing of each engine...One thermocouple of
each assembly is connected to the turbine inlet temperature
indicating system, and...one...is connected to the electronic
datum control system. The 18 indicating system thermocouples are
connected in parallel [!!] by the indicator turbine thermocouple
harness assembly,

I'm surprised you ever doubted the truth on this one!


So, let's revise.

That's going a bit too far... Nobody can revise the Tarver
Chronicles! :-)


bimetallic thermocouples generate millivolt signals,and paralleling
them would not work.Standard practice is to series-connect them,and
compare to a reference junction.Do these assemblies include signal
processing to convert the mV signal to a digital form,which could
then be sent on a parallel bus?

--
Jim Yanik
jyanik-at-kua.net

On every aircraft I ever worked on thermocouples were in parallel if
there were two or more.

Dan, U.S. Air Force, retired


Well,I guess they aren't bimetallic thermocouples,then.
Anyone have any speculation on what sort of signal will work with a
parallel connection?

--
Jim Yanik
jyanik-at-kua.net


All thermocouples are bi-metallic.

OK, try this on for size. Jet engines use chromal-alumal (type K) and
recips use iron-constantan (type J) thermocouples.

The different bi-metal combos generate different volts/degree.

The wires are also
made of the same type of material. If you mount several thermocouples
in parallel then all plus wires match and all minus wires match. As
far as the cold junction end is conserned the hot end has one
thermocouple.

If you mount them in series you get plus -- minus -- plus-- minus
etc. This will introduce one heck of an error if it works at all.

Just connecting them to a copper wire bus makes another bi-metal
junction,too,although it's not in the area being measured,and thus more
stable.


If you ever get a chance to look at a jet engine look at the EGT ring
of thermocouples. You will see they are in parallel.

Dan, U. S. Air Force, retired

You wire thermocouples in series and the voltage outputs add
together(sum).Parallel them,and one voltage bucks against the other.
Paralleling thermocouples is like parallelling two batteries of different
voltages.One works against the other.

I worked on thermocouple calibration while in the USAF,as a PMEL
technician(Precision Measurement Electronics Laboratory).


--
Jim Yanik
jyanik-at-kua.net

That is not how it works on the T56 Jim. The voltages don't buck or work
agaianst each other. It's not mysterious untried technology, it's been
around for decades and there is plenty of info around on it.

Scet

"Tarver Engineering" wrote in message
...

"Phil Miller" wrote in message
...
On Fri, 16 Jan 2004 07:13:54 -0800, "Tarver Engineering"
wrote:


"Phil Miller" wrote in message
news
Hey Splappy,

Do you remember this series of pronouncements;

From: "Tarver Engineering"
Newsgroups: rec.aviation.military
Subject: Do Hercules military aircraft use the same fuel as
civilian
aircraft?
Date: Fri, 8 Nov 2002 19:19:37 -0800
snip
wrote in message
Not really. On the T56 engine TIT = (T)urbine (I)nlet (T)empreture.

Yes really, on every jet engine TIT is Total Inlet Temperature.

Yep.

I ask because I came across an interesting paragraph in the T56-A-15
service manual yesterday. Went like this...

Same for any MM, the data does not need to be accurate.

Any engine temperature station using more than one probe is a Total.

That is how it works.

No it isn't John and you know it from the discussion we had on this subject
last time....you were wrong then and you are wrong now.

Scet

Tarver Engineering wrote:

What if the thermocouples are wired in parallel, to a totalizer?

So now you are using the "p" word as if you knew it all
along ... geez, Tarver, you are a piece of work.

Now tell us what this "totalizer" thing is that somehow
processes whatever you think thermocouples manufacture.

Rick