Hercules Engines

T-56's don't have TAT probes Jackass

On Fri, 16 Jan 2004 18:55:11 -0800, "Tarver Engineering"
wrote:


"JL Grasso" wrote in message
...
On Fri, 16 Jan 2004 17:57:34 -0800, "Tarver Engineering"
wrote:


"Bertie the Bunyip" wrote in message
.. .
"Tarver Engineering" wrote in
:


"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.

Nope.

Yep, the individually wired theromcouples are sent to a Totalizer, when
they
are not wired in series. That is why the datum is a total.

One has to wonder if the trolls of ram will ever catch a clue.

The irony of it all.

Total Air Temperature (TAT)is the maximum temperature attainable by air
when brought to rest adiabatically.

Total Air Temperature is the total of several probes at the inlet of the
engine. (ie T1)

The word "Total", when used to
describe the type of temperature reading that a probe is reporting, has
nothing to do with totalizers or wiring connections.

The term "total" has to do with the use of multiple probes. Wiring
thermocoulpes in seris gives a Total temperature. Where the probes are
wired in parallel, a Totalizer is used downstream to add the thermocouple
outputs together.

Why do you post, Grasso, when it is clear that there is no subject WRT
aircraft that you know? Perhaps you would do better sticking to your parts
catalogs and forget about pretending you understand anything about aircraft.
Otherwise, you are likely to become a hazard to aviation.

That is the most ridiculous statement I've heard from you yet, Tarver,
what are you smoking??? You are in my book as being seriously demented
now, whats wrong with you? Where do you come up with that kind of off
the wall crap??? I seriously hope our Govt doesn't do business with
you, or you are not on a Govt project, I'd drop a dime on you for
being a Jackass.

On Sat, 17 Jan 2004 08:23:33 -0800, "Tarver Engineering"
wrote:


"running with scissors" wrote in
message om...
"Tarver Engineering" wrote in message
...
"Phil Miller" wrote in message
...

snip
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.

grief !
so if that were the case, then a generic manual would suffice.

Nope, the manual has to be close enough to do the work. Errors in MMs are
commomplace and not any real hazard. Just as B-52 operators don't really
need to know how their wing works, mechanics don't really need to know how a
system works.

"Scet" wrote in message
...

"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

Don't hide behind Google John, we all know you are wrong and know nothing
about the subject. If you want to reply using Google hoping that most guys
won't read your **** that's fine but it only makes you look stupider than
you are( If that's possible) post your answers here for everones benefit, at
the very least it is worth a laugh.

Scet

"fudog50" wrote in message
...
Tarver, you were "totally" wrong in your original response dated Nov
8th, 2002 about T-56's and TIT.

Nope, but thanks for playing.

Did you figure out that sailors call those things you think are "ships",
"boats" yet?

I mean, Funny dude, if you can't figure out what is going on right where you
are, how can we believe anything you write about what is farther away?

"Turbine Inlet Temperature".

Turbine inlet temperature is a linear function, my idiot.

"B2431" wrote in message
...
From: "Tarver Engineering"
Date: 1/21/2004 8:29 PM Central Standard Time
Message-id:


"Scet" wrote in message
...

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.

I am still correct, the only difference is that I proved it in this
thread.

You are making a fool of yourself, Scat.

Tarver, at the risk of a barrage of filth from you, can you provide a web
site
other than yours that shows TIT or EGT thermocouples in series?

You are too confused for me to even respond, Dan.

"Scet" wrote in
:


"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




Well,then it violates basic physics.If you have two voltage sources of
slightly different voltages,currents DO flow between them.That's a basic
principle. And bimetal TCs are simply millivolt voltage sources.



--
Jim Yanik
jyanik-at-kua.net

"Scet" wrote in
:




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




I fail to see how the separate thermocouples outputs will be
"averaged",because any individual TC cannot rise in output,as all the
others parallelled will prevent any rise in voltage.Or current would flow
from a higher V to a lower one,just as if you wired batteries of different
voltages together,you end up with circulating currents until all cells are
of equal voltage..
Seems to me that parallelling them is only for the possibility of an
individual thermocouple to be burned out or open.

--
Jim Yanik
jyanik-at-kua.net

"fudog50" wrote in message
...
That is the most ridiculous statement I've heard from you yet, Tarver,
what are you smoking??? You are in my book as being seriously demented
now, whats wrong with you? Where do you come up with that kind of off
the wall crap??? I seriously hope our Govt doesn't do business with
you, or you are not on a Govt project, I'd drop a dime on you for
being a Jackass.


The B-52 wing aerodynamics were discussed here at ram and then in about a
dozen .sci threads. The USAF teaches that small amounts of spoiler acutally
increase lift, but that is incorrect. Buffdrver, a real B-52 pilot has
already written to USAF about their error. USAF, of course, doesn't need
their pilots to understand how the wing actually works.

Did you figure out where the "boats" are yet, dog?

"Jim Yanik" wrote in message
.. .
"Scet" wrote in
:




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.

I fail to see how the separate thermocouples outputs will be
"averaged",because any individual TC cannot rise in output,as all the
others parallelled will prevent any rise in voltage.Or current would flow
from a higher V to a lower one,just as if you wired batteries of different
voltages together,you end up with circulating currents until all cells are
of equal voltage..

Also, Jim, the "total" is what you want for such small signals. Averaging
would only reduce: accuracy, reliability simplicity.

Scet is just being ignorant.

"Jim Yanik" wrote in message
.. .

Well,then it violates basic physics.If you have two voltage sources of
slightly different voltages,currents DO flow between them.That's a basic
principle. And bimetal TCs are simply millivolt voltage sources.

I always wanted to take one of the series connection wiring on out J-75's
TIT ring, but I was afraid I would get an Article 15.