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Using ship fuel as aviation fuel?



 
 
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  #21  
Old April 17th 04, 08:30 AM
Fred J. McCall
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"John R Weiss" wrote:

:In the US navy, the nuclear powered carriers only carry JP4 or JP8 (and all
n-board diesel-powered equipment use the JP), so any smaller ships that refuel
:from the carrier (a relatively common practice) get the jet fuel.

The US Navy uses neither of these fuels at sea, even to fill aircraft,
much less to fill large ship's tanks. The Navy switched from JP4
(which is a hideously dangerous fuel) to JP5 about half a century ago.
The Air Force later switched from JP4 to JP8 (essentially Jet-A).

The Navy currently uses JP8 ashore (because it's cheaper and easier to
get) and JP5 at sea (because it's safer).

--
"Insisting on perfect safety is for people who don't have the balls to
live in the real world." -- Mary Shafer, NASA Dryden
  #22  
Old April 17th 04, 11:23 AM
scott s.
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Fred J. McCall wrote in
:

"John R Weiss" wrote:

:In the US navy, the nuclear powered carriers only carry JP4 or JP8
and all on-board diesel-powered equipment use the JP), so any smaller
:ships that refuel from the carrier (a relatively common practice) get
:the jet fuel.

The US Navy uses neither of these fuels at sea, even to fill aircraft,
much less to fill large ship's tanks. The Navy switched from JP4
(which is a hideously dangerous fuel) to JP5 about half a century ago.
The Air Force later switched from JP4 to JP8 (essentially Jet-A).


IIRC the minimum allowed flash point is 140F. I uderstand that even
a little JP4, if mixed with JP5, can dangerously lower flash point.

scott s.
..
  #23  
Old April 17th 04, 01:55 PM
Friedrich Ostertag
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Hi Mr. Tarver,

Diesel engines cannot "detonate". The term "detonation" applies

to
preignition of part of the charge before ignition or before the
flamefront has reached that portion of the charge.

Detonation refers to more energy being imparted to the fuel air

mixture by
compression heating than can be absorbed without igniting the

fuel.

On a diesel, the fuel is not there until the very moment when it is
supposed to ignite. You cannot ignite pure air, no matter how much
energy you impart on it.


In a turbine engine what you write is true, but you are going to have

to
educate me as to the process further to make me believe.


What exactly is it you don't understand? You surely are aware, that a
diesel engine will intake pure air, compress it (much further than a
gasoline engine compresses the mixture - temperatures get really hot
just from the adiabatic compression), and then injects the fuel into
the compressed (and hot!) air, where it immediately ignites due to the
high temperature of the compressed air. Thus my comment, that the fuel
cannot preignite, as it is not there prior to the time it is supposed
to ignite. No preignition - no detonation.

Note that not all
diesels are the same and I believe I have heard detonation in diesel

engines
on starting fluid.


Now that's a different question, of course. As starting fluid is mixed
with the intake air, it will (on a diesel) ignite at a time of it's
choosing, when the compressed air is just hot enough.

But this has nothing to do with the question of detonation during
regular operation of a diesel engine on jetfuel.

Detonation damages rod bearings and is a serious problem over the

long
term
in reciprocating engines.


Detonation can do much more than that, serious detonation can kill

an
engine within seconds. I have personally seen melted pistons after

such
an event. But still detonation is only possible in spark ignition
engines, or to be more precise, in engines with external mixture
building.


I don't buy it.


You do now?

regards,
Friedrich

--
bitte für persönliche Antworten die offensichtliche Änderung an meiner
Adresse vornehmen

  #24  
Old April 17th 04, 01:58 PM
Friedrich Ostertag
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Hi John,

Detonation refers to more energy being imparted to the fuel air

mixture by
compression heating than can be absorbed without igniting the fuel.
Detonation damages rod bearings and is a serious problem over the

long
term
in reciprocating engines.


John, every power stroke of a diesel engine fits that definition.
Diesels, by definition, compress the fuel & air to the point the
fuel ignites.


only air is compressed, but well beyond the point where fuel will
ignite! But the fuel is only added at the moment when it is supposed to
ignite.

regards,
Friedrich

--
for personal email please remove "entfernen" from my adress


  #25  
Old April 17th 04, 02:49 PM
Vince Brannigan
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Friedrich Ostertag wrote:

Hi Mr. Tarver,


Diesel engines cannot "detonate". The term "detonation" applies


to

preignition of part of the charge before ignition or before the
flamefront has reached that portion of the charge.

Detonation refers to more energy being imparted to the fuel air

mixture by

compression heating than can be absorbed without igniting the


fuel.

On a diesel, the fuel is not there until the very moment when it is
supposed to ignite. You cannot ignite pure air, no matter how much
energy you impart on it.


In a turbine engine what you write is true, but you are going to have


to

educate me as to the process further to make me believe.



What exactly is it you don't understand? You surely are aware, that a
diesel engine will intake pure air, compress it (much further than a
gasoline engine compresses the mixture - temperatures get really hot
just from the adiabatic compression), and then injects the fuel into
the compressed (and hot!) air, where it immediately ignites due to the
high temperature of the compressed air. Thus my comment, that the fuel
cannot preignite, as it is not there prior to the time it is supposed
to ignite. No preignition - no detonation.


actually you were fine down to this point. what you mean is that when
ther is no "premixing" there is no detonation. Detonation involves a
supersonic combustion wave moving through the mixture.

good discussion at http://www.safetynet.de/Seiten/articles/CMRNov99.pdf


  #26  
Old April 17th 04, 03:03 PM
Peter Stickney
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In article ,
"Friedrich Ostertag" writes:
Hi John,

Detonation refers to more energy being imparted to the fuel air

mixture by
compression heating than can be absorbed without igniting the fuel.
Detonation damages rod bearings and is a serious problem over the

long
term
in reciprocating engines.


John, every power stroke of a diesel engine fits that definition.
Diesels, by definition, compress the fuel & air to the point the
fuel ignites.


only air is compressed, but well beyond the point where fuel will
ignite! But the fuel is only added at the moment when it is supposed to
ignite.


Just so, Friedfrich.
To get to teh original point, In the U.S.,(Or NATO, for that matter,
Kerosene, #1 Diesel, and Jet-A type (JP-5 and JP-8) are considered
interchangable.
The U.S. Army, and, IIRC, all of NATO, by now, is using JP-8 as its
sole aviation adn diesel fuel. in order to ease logistical demands.
Jet-B type fuels, (Jet-B, JP-4), aren't considered suitable for use in
Diesels. (THey've got gasoline in them)

#2 Diesel fuel, used in warmer climates in the U.S., had a higher
sulphur content (It doesn't anymore, pollution, you know) and some
engines used the greater viscosity that they brought about to
lubricate parts of teh fuel system (Injector pumps, usually). Of
course, without the sulphur, it doesn't do that anymore, so there are
additives available for the engines which need it. (Sort of like the
aftermarket Lead Substitutes for older gasoline engines).
# Heating Oil is similar, but doesn't have the Dyes placed in U.S. #2
Diesel fuel to show that the necessary fuel taxes have been paid.
(Note for homeowners between Heating Oil deliveries - These dyes tend
to leave residues in the cumbustor of the furnace that can shorten its
life. If you need a small dollop of additional fuel, use Kerosene
instead)

I note the Tarver has popped in. Just to translate from Tarver to
English, "Cut and Paste" means Performed Research - in this case,
sources are Chevron's Technical Notes on Fuels, and the NATO logistics
manuals. Mine are hard copies, buy they are probably available on the
Web.
As for hands-on experience, current Diesels in the family Truck Park
include a 1945 Cable-Lift Catepillar D-6, and a 1959 Mack B61.

--
Pete Stickney
A strong conviction that something must be done is the parent of many
bad measures. -- Daniel Webster
  #27  
Old April 17th 04, 05:00 PM
Tarver Engineering
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"John Keeney" wrote in message
...

"Tarver Engineering" wrote in message
...

"Friedrich Ostertag" wrote in

message
...
Hi NG,

The high compression ratios for diesel piston engines cause
detonation using
wide cut jet fuel.

Diesel engines cannot "detonate". The term "detonation" applies to
preignition of part of the charge before ignition or before the
flamefront has reached that portion of the charge.


Detonation refers to more energy being imparted to the fuel air mixture

by
compression heating than can be absorbed without igniting the fuel.
Detonation damages rod bearings and is a serious problem over the long

term
in reciprocating engines.


John, every power stroke of a diesel engine fits that definition.
Diesels, by definition, compress the fuel & air to the point the
fuel ignites.


Then I am correct that the diesel reciprocating engine can experiance
detonation from too short a carbon molecule.

Thanks, Mr. Keeney, the thread was starting to confuse me.


  #28  
Old April 17th 04, 05:02 PM
Tarver Engineering
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Default


"Friedrich Ostertag" wrote in message
...
Hi Mr. Tarver,

Diesel engines cannot "detonate". The term "detonation" applies

to
preignition of part of the charge before ignition or before the
flamefront has reached that portion of the charge.

Detonation refers to more energy being imparted to the fuel air
mixture by
compression heating than can be absorbed without igniting the

fuel.

On a diesel, the fuel is not there until the very moment when it is
supposed to ignite. You cannot ignite pure air, no matter how much
energy you impart on it.


In a turbine engine what you write is true, but you are going to have

to
educate me as to the process further to make me believe.


What exactly is it you don't understand? You surely are aware, that a
diesel engine will intake pure air, compress it (much further than a
gasoline engine compresses the mixture - temperatures get really hot
just from the adiabatic compression), and then injects the fuel into
the compressed (and hot!) air, where it immediately ignites due to the
high temperature of the compressed air. Thus my comment, that the fuel
cannot preignite, as it is not there prior to the time it is supposed
to ignite. No preignition - no detonation.


So then a diesel engine is like a turbojet? Are the two stroke diesels the
same as the 4 stroke version in this?


  #29  
Old April 17th 04, 05:07 PM
Tarver Engineering
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Default


"Peter Stickney" wrote in message
...

#2 Diesel fuel, used in warmer climates in the U.S., had a higher
sulphur content (It doesn't anymore, pollution, you know) and some
engines used the greater viscosity that they brought about to
lubricate parts of teh fuel system (Injector pumps, usually).


Nice cut and paste Pete, but there is more to #2 diesel than what you write.
California made #2 diesel madatory, so that the injector clearances can be
tightened. More recently, California has required additives to #2 diesel
that cause the engine's seals to disintegrate. This change has managed to
run this County's long haul trucking businesses to Oklahoma and other
operators to evade California road taxes by filling up before entering the
State.


  #30  
Old April 17th 04, 05:34 PM
David Lesher
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"Friedrich Ostertag" writes:


As said before, Diesel engines will burn jetfuel, however the
lubrication properties are much lower so the injection system has to be
designed to live with that.


Indeed. When I worked on a pipeline delivering JetA to CLE, we'd
chat with the mechanics that maintained the refueling trucks. They
were run on JetA, as was much of the ramp lice. The logistical
advantage of doing so must have exceeded the cost difference of
trucking in #2.

The mechanics told me that neither Detroit or Cummings recommended
#1, and it likely reduced the time between overhauls, but it still
made sense on the bottom line.
--
A host is a host from coast to
& no one will talk to a host that's close........[v].(301) 56-LINUX
Unless the host (that isn't close).........................pob 1433
is busy, hung or dead....................................20915-1433
 




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