Using ship fuel as aviation fuel?

(QDurham) wrote:

We run (perhaps ran might be more accurate) large recip aircraft engines at
'10% lean from best power' (by manually
leaning them during cruise) for many thousands of hours and they worked fine
in that condition, matter of fact they'll continue to run fine as much as about
30% lean before they get unstable, they seem to love lean mixtures!..

Been there. Done that (R3350s). One problem is that the power curve is quite
steep on the lean side -- pilot has to be more careful. Never did it but have
been told if one can see the exhaust stacks, it is easier at night. One leans
until one gets the shape/color of exhaust flame that is "correct." Beyond me.

Quent

That might be so Quent, these were 3350's also but the engineer
can't see the stacks from his position so that's out. I've looked
at them from the overwing hatch window at night and it's hard to
see any flame, just a pale blue flame maybe a few inches out of
the stack, you should see the flame at full power during
takeoff!...bright orange/red/yellow right back off the rear of
the wing! wooHoo...
--

-Gord.

you should see the flame at full power during
takeoff!...bright orange/red/yellow right back off the rear of
the wing! wooHoo...

Oh Indeeedy! WooooooooHoooooooo!!!!!!!

I was in P2V Neptunes. Seem to recall exhaust flames were quite visible. Long
time ago.

Quent

On two cycle diesels, Detroit Diesels are what I am familiar with,
number 1 fuel is not recommended because of its poor lubricating
quality. Diesel fuel must cool and lubricate the mechanical injectors.
To prevent the wax in #2 from falling out of suspension in cold weather
it can be mixed with #1 to lower the pour point.
It's usually better to lower the pour point on on road applications
chemically but you do what you have to do to keep them running.
Ron

Hi Gord,

Not so much on us automotive engineers today... A lot of modern
automotive engines are run right along the knock limit for
efficiency, with knock control constantly operating. To do this,
there has to be a knock event every now and then for the knock
control to be able to detect the limit. (Knock control just detects
knock events and retards the ignition. When there is no knock,
ignition is advanced again until the next knock occurs.) This
normally works fine. However on some (not all) engine types, on high
load testbed runs this has recently led to very rare statistical
occurence of "super-knock" events, with disastrous results.


Yes, that's quite interesting to me, and it backs my opinion of
using low test fuel in my cars...I never use high test fuel at
all, mind you, I only use standard domestic vehicles but I
consider high test wasteful in modern engines with 'knock
control'.

Well, it depends...

Normally you won't damage an engine with knock control by using lower
grade fuel than recommended, however within limits. If you use very low
octane fuel on a high compression or a turbocharged engine, ignition
might occur before the spark just from the compression, as we
discussed. There is nothing knock control can do about that. Also,
depending on your driving profile, you might find that fuel consumption
increases with the lower grade fuel, as retarded ignition reduces
engine efficiency. This is especially valid at high engine loads and
low engine speed, where the biggest retard is neccessary. Wether the
increase in consumption will eat up the price advantage of the lower
grade can only be determined by experiment.

Yes, I understand that, another good system that GAMI is looking
at is their accurate fuel injectors to enable automobile engines
to be run lean.

Now that is a new one to me! I know about GAMIs injectors for GA piston
engines and all the LOP-operation stuff, wich are around for a while
now, and which I think are a big improvement. I didn't know that they
are planning on entering the automotive market and I'm quite surprised.
Automotive engines, different from aviation, run stoechiometric
basically anywhere on the map exept full load. (stoechiometric mixture
is more or less peak EGT). Due to their design, mostly liquid cooled,
temperatures are not a problem. Of course you could run such an engine
lean (LOP), but you won't pass any emissions test for sure. I don't
think you really need special injectors to do it, but you would need to
retune the ECU. And the fuel savings compared to running stoechiometric
are only a fraction of what you save if otherwise you have to run rich.

The Japanese car makers had lean running engines on the market for a
while, and some of the direct injection gaoline engines being developed
now also run lean by creating a stratified charge. But that's far
beyond an aftermarket improvement.

We run (perhaps ran might be more accurate) large
recip aircraft engines at '10% lean from best power' (by manually
leaning them during cruise) for many thousands of hours and they
worked fine in that condition, matter of fact they'll continue to
run fine as much as about 30% lean before they get unstable, they
seem to love lean mixtures!...

Do you by chance know whether these had direct injection (injecting the
fuel into the cylinder instead of the manifold)? To my knowledge there
have been direct injection piston engines among the big radials, but I
haven't found any further information about it so far.

regards,
Friedrich

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

On Wed, 21 Apr 2004 01:46:47 GMT, "Thomas Schoene"
wrote:

KDR wrote:

Many thanks for all the replies. Compared with F-76, how expensive is
JP-5?

http://www.sd.fisc.navy.mil/FUEL/FUEL-INFOR-PAGE.HTML

JP-5 $1.03/gallon
DFM $0.98/gallon (DFM is Diesel fuel, Marine, another term for F-76)

That's roughly 5% difference. It may not seem like much, but considering
the Navy's overall fuels budget, it can really add up.


Is there any official move in the RN or USN to adopt JP-5 as a
single universal fuel?

Not that I've ever heard of.

As long ago as 1960, my Diesel-powered ship made a NATO exercise and
was refueled during the exercise with JP-5 (the oilers were carrying
no Diesel fuel). I believe the fuel comsumption was slightly worse.
I don't know the long-term effects on the Diesel engines, as JP-5 is
missing some lubricant as compared to JP-5, I understand. This was
just one two-month exercise, of course, but the matter was being
considered even then.

Do modern gas turbine powered ships use Diesel fuel, or is there yet
another formulation of fuel for them?

In article . net, "Thomas
Schoene" wrote:

KDR wrote:

Many thanks for all the replies. Compared with F-76, how expensive is
JP-5?

http://www.sd.fisc.navy.mil/FUEL/FUEL-INFOR-PAGE.HTML

JP-5 $1.03/gallon
DFM $0.98/gallon (DFM is Diesel fuel, Marine, another term for F-76)

In the tutorial URL I posted, they made a definite distinction between
F-76 and DFM.


That's roughly 5% difference. It may not seem like much, but considering
the Navy's overall fuels budget, it can really add up.

That's $500 for a 10K gallon fill up. Substantial enough savings.
Anyone know how much fuel a DDG takes on at a time?


Is there any official move in the RN or USN to adopt JP-5 as a
single universal fuel?

Not that I've ever heard of.

Just proposals.

--
Harry Andreas
Engineering raconteur

Harry Andreas wrote:
In article . net,
"Thomas Schoene" wrote:
JP-5 $1.03/gallon
DFM $0.98/gallon (DFM is Diesel fuel, Marine, another term
for F-76)

In the tutorial URL I posted, they made a definite distinction between
F-76 and DFM.

No, they made a distinction between F-76 and *commercial* marine distillate
fuel. Commercial fuel can be all over the map quality-wise.

The term "DFM" is used throughout the Navy as a synonym for F-76 (the NATO
supply code for the same fuel). Technically, it seems that DFM might not be
specific enough, as F-76 implies conformance to a specific MIL-SPEC while
DFM does not. But the two terms seem to be interchangable in everyday use.

For example:

www.msc.navy.mil/instructions/doc/35007b.doc
"Ships requiring DFM (NATO Symbol F-76) may be accomplished via barge or
ship."

http://www.nor.fisc.navy.mil/home/Su.../18APR03SC.pdf
"Zuiderkruis took on 19,000 barrels of diesel fuel marine (DFM/F-76)..."

http://www.jiatfs.southcom.mil/j4/Ma...PuertoRico.doc
"(U) Fuel. DFM (F-76) and JP-5 (F-44) available."


That's roughly 5% difference. It may not seem like much, but
considering the Navy's overall fuels budget, it can really add up.

That's $500 for a 10K gallon fill up. Substantial enough savings.
Anyone know how much fuel a DDG takes on at a time?

From a quick search, an UNREP of 150,000 gallons would seem to be typical.

I figure a destroyer's total capacity is around 500,000 gallons. That's
based on F-76 at 300 gallons per ton and the Combat Fleets figure that a
Spruance carries 1,650 tons of fuel. No fuel figures available for DDGs,
but that's a decent ballpark estimate anyway. Plenty of money to be saved
here.

--
Tom Schoene Replace "invalid" with "net" to e-mail
"Our country, right or wrong. When right, to be kept right, when
wrong to be put right." - Senator Carl Schurz, 1872

"Friedrich Ostertag" wrote:

We run (perhaps ran might be more accurate) large
recip aircraft engines at '10% lean from best power' (by manually
leaning them during cruise) for many thousands of hours and they
worked fine in that condition, matter of fact they'll continue to
run fine as much as about 30% lean before they get unstable, they
seem to love lean mixtures!...

Do you by chance know whether these had direct injection (injecting the
fuel into the cylinder instead of the manifold)? To my knowledge there
have been direct injection piston engines among the big radials, but I
haven't found any further information about it so far.

regards,
Friedrich

Well, just a comment about domestic automobiles, I didn't mean to
indicate that I operate them below the manufacturers specified
octane ratings, after all, I believe that the manufacturer knows
his engine best and I'd never try to second guess him, but I have
all kinds of friends and relatives who use hi octane fuel in
their cars even though low octane is recommended. (complete waste
I feel) Another thing that I NEVER do is 'recommend to anyone'
what fuel to use. You're bound to get blamed sometime in your
life because a friend's wife got preggy if you do...

About the direct injection, the Argus (ASW aircraft) used by the
Canadian Armed Forces had Wright R-3350-EA1 engines (3700 BHP)
which had direct fuel injection into the cylinder (not just prior
to the intake valve). The Wright R-3350-89A fitted to the
Fairchild C-119 Packet had 'spinner injection', where the fuel
was injected into the spinner of the supercharger, and the P2V-7
Neptune was set up this way too.

--

-Gord.

Hi Gord,

Well, just a comment about domestic automobiles, I didn't mean to
indicate that I operate them below the manufacturers specified
octane ratings, after all, I believe that the manufacturer knows
his engine best and I'd never try to second guess him, but I have
all kinds of friends and relatives who use hi octane fuel in
their cars even though low octane is recommended. (complete waste
I feel)

Ah, you're absolutely right there! Sorry for the misunderstanding.
There is no point in using higher octane than what the engine was
designed for. Even knock control will not advance ignition beyond the
calibrated map for the designated fuel.

However a lot of people over here fell for a marketing trick of Shell
Oil: Instead of the 98 octane highest grade fuel sold in Germany and
most euroean countries they offered a 100 octane (by the way, this is
ROZ, not ROZ+MOZ/2 as in the US) fuel called "V-power" with supposedly
all kinds of mysterious additives at 10 ct / Liter premium over other
oil company's 98 octane. Lots of car magazines and also the ADAC (your
AA) tested it in various models and found no difference whatsoever in
power and consumption. Yet Shell sells 10% of it's turnout in V-Power
while the other's only sell 5% 98. Talk about snake oil...

Another thing that I NEVER do is 'recommend to anyone'
what fuel to use. You're bound to get blamed sometime in your
life because a friend's wife got preggy if you do...

:-)

About the direct injection, the Argus (ASW aircraft) used by the
Canadian Armed Forces had Wright R-3350-EA1 engines (3700 BHP)
which had direct fuel injection into the cylinder (not just prior
to the intake valve). The Wright R-3350-89A fitted to the
Fairchild C-119 Packet had 'spinner injection', where the fuel
was injected into the spinner of the supercharger, and the P2V-7
Neptune was set up this way too.

I always find it intriguing, that almost everything we develop today as
supposedly latest techology has been there half a century ago. The only
really new thing in engines today is electronic control.

regards,
Friedrich

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

"Friedrich Ostertag" wrote:


I always find it intriguing, that almost everything we develop today as
supposedly latest techology has been there half a century ago. The only
really new thing in engines today is electronic control.

regards,
Friedrich

Exactly...and it's one of the reasons that, although I consider
myself quite knowledgeable engine wise, when I open the hood of
an ailing engine I quickly close it and get on the fone for a
towtruck...there's just so much complication in all the
electronic sensors, computers etc to squeeze every ounce of
efficiency out of a litre of fuel that I find it daunting.

My wife's Corolla just finished it's lease and I bought it and
leased another Toyota for her. A 'Matrix'. They have an
intriguing feature called VVTi (Variable Valve Timing). Neat
system!...hope it's rugged!...

Cheers
--

-Gord.