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Turbine air start -- too cold?



 
 
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  #21  
Old January 15th 05, 10:02 PM
Juan Jimenez
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"ChuckSlusarczyk" wrote in message
...
In article , Juan Jimenez
says...

Monkey see, monkey do. I guess it's true that retards feed from each
other.


Guess your right Hmmm let's see jim zoom campbell and jaun jaminiz
(spelled
wrong on purpose) :-)


Gee, what can I say, only a putz like you would consider it a privilege to
brag about his unilingual ignorance, to the point that you think it
necessary to point out that you can't spell, in English _or_ Spanish.

Chuck (I designed my own plane ,did you?) S RAH-15/1 ret


Juan (I pay my son for his work, don't have any drug addicts in my family
and no one in my family has ever had his children taken away by the
state....) :-)



Ads
  #23  
Old January 15th 05, 10:53 PM
Colibri
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Sean Trost wrote:
I stand corrected. Thanks Jim. Learned somthing new everyday.
Sean

Jim Carriere wrote:
Sean Trost wrote:

Juan
I believe that N1 is related to the velocity of the airstream
introduced. Which is good. But not related to the ignition problem
Now You have said that you have an excellent spark and good fuel. the
only other thing you need for start is the right airflow. or volumn.
Dont know about your engine specifically but most everything else runs
right around 14 to 1 on the ratio wise.



Actually, jets are a different beast from piston engines. Between about
25:1 and 50:1 is normal, even for lightoff fuel flow. Stoichiometrically
correct combustion is too hot.


50:1 would be the total airflow:fuel ratio through the engine core. Of
those 50 parts air, 15 are primary air that mixes with the fuel for
stoichiometrically correct combustion.

The other 35 parts are secondary air (not to be confused with a turbofan's
bypass air, which doesn't pass through the core). Some secondary air passes
around the exterior of the combustion chamber liner to cool it, and some
passes through holes into the chamber to shape the flame and hold it away
from the liner wall to prevent damage.

None of this is impingement starting air, which hits the turbine blades and
then goes right out the exhaust duct.
  #24  
Old January 15th 05, 11:45 PM
Jim Carriere
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Colibri wrote:
Sean Trost wrote:

I stand corrected. Thanks Jim. Learned somthing new everyday.
Sean

Jim Carriere wrote:

Sean Trost wrote:

Juan
I believe that N1 is related to the velocity of the airstream
introduced. Which is good. But not related to the ignition problem
Now You have said that you have an excellent spark and good fuel.
the only other thing you need for start is the right airflow. or
volumn. Dont know about your engine specifically but most everything
else runs right around 14 to 1 on the ratio wise.



Actually, jets are a different beast from piston engines. Between
about 25:1 and 50:1 is normal, even for lightoff fuel flow.
Stoichiometrically correct combustion is too hot.



50:1 would be the total airflow:fuel ratio through the engine core. Of
those 50 parts air, 15 are primary air that mixes with the fuel for
stoichiometrically correct combustion.

The other 35 parts are secondary air (not to be confused with a
turbofan's bypass air, which doesn't pass through the core). Some
secondary air passes around the exterior of the combustion chamber liner
to cool it, and some passes through holes into the chamber to shape the
flame and hold it away from the liner wall to prevent damage.


This is a better explanation than I gave, but I'll elaborate further
to this that while technically only 15 of those parts of air are
"burned" (use to support combustion), and the secondary air begins
mixing with the flame very close to where the fuel nozzle(s) are
located. Depending on the design of the engine, some or even all the
secondary air flowing around the combustor liner mixes with the
primary air/flame before entering the turbine.

Complex engines will route some of the secondary air through tiny
cooling passages in the turbine blades themselves (I'm pretty sure
you, Colibri, understand this, I'm speaking to the group and not
trying to insult you), but I strongly doubt this is the case with
Juan's engine.

None of this is impingement starting air, which hits the turbine blades
and then goes right out the exhaust duct.


This is an important distinction, so is the difference between
secondary and bypass.

  #26  
Old January 16th 05, 05:47 PM
Juan Jimenez
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"B2431" wrote in message
...

And you have never proved Chuck has either so please don't bring it up
again.


Who cares who proves what Chuck "has either"? I certainly don't. Get over
it, dannyboy.



  #27  
Old January 16th 05, 05:48 PM
Juan Jimenez
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Posts: n/a
Default


"Jim Carriere" wrote in message
...

This is a better explanation than I gave, but I'll elaborate further to
this that while technically only 15 of those parts of air are "burned"
(use to support combustion), and the secondary air begins mixing with the
flame very close to where the fuel nozzle(s) are located. Depending on
the design of the engine, some or even all the secondary air flowing
around the combustor liner mixes with the primary air/flame before
entering the turbine.

Complex engines will route some of the secondary air through tiny cooling
passages in the turbine blades themselves (I'm pretty sure you, Colibri,
understand this, I'm speaking to the group and not trying to insult you),
but I strongly doubt this is the case with Juan's engine.


You are correct. My engine is not a turbofan, it is a turbojet, circa 1973.

None of this is impingement starting air, which hits the turbine blades
and then goes right out the exhaust duct.


This is an important distinction, so is the difference between secondary
and bypass.




  #28  
Old January 16th 05, 05:49 PM
Juan Jimenez
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Default


"RobertR237" wrote in message
...

You waste your effort Dan, just ploink the lying fool and life will seem
much
better. Nobody here believes anything he says anyway.


Sure, kiddo, you keep believing that and watching Disney movies, maybe it
will all come true for you some day.



  #29  
Old January 16th 05, 05:55 PM
Juan Jimenez
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Posts: n/a
Default

That was YOU in the truck???!!! HAHAHAHAHAHAHAHAHAHAH!!!!!!

"Richard Riley" wrote in message
...
On 15 Jan 2005 09:18:40 -0800, ChuckSlusarczyk
wrote:

:Guess your right Hmmm let's see jim zoom campbell and jaun jaminiz
(spelled
:wrong on purpose) :-)

Chuck, I'm told Juan doesn't trust Zoom to test fly his airplane, so
Juan's getting in some practice time before he takes it up for first
flight.

http://tinyurl.com/4fkgz




  #30  
Old January 16th 05, 11:36 PM
Matt Whiting
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Juan Jimenez wrote:
"B2431" wrote in message
...

And you have never proved Chuck has either so please don't bring it up
again.



Who cares who proves what Chuck "has either"? I certainly don't. Get over
it, dannyboy.




Probably the same number of people who care about seeing your childish
attacks on Chuck. I'm guessing zero.

Matt

 




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