Experimental Exhibition Fuel

[Robert Bates]

Are there any restrictions for fuels used in experimental exhibition
aircraft? I once encountered a Mig 15 that was burning a blend of diesel
and gasoline for a lower priced fuel.

[Ron Wanttaja]

On Mon, 08 Mar 2004 04:04:22 GMT, "Robert Bates" >
wrote:

>Are there any restrictions for fuels used in experimental exhibition
>aircraft? I once encountered a Mig 15 that was burning a blend of diesel
>and gasoline for a lower priced fuel.

I'm sure there are no "automatic" restrictions. The only restriction the
FAA might impose is a limitation on carrying passengers, and unless it's
the trainer version of the -15, that point would be moot.

Besides, even for a certified airplane, all the FAA can do is require you
use the fuel the aircraft/engine manufacturer specifies. The Russians were
pretty ingenious when it came to low-tech solutions; they may even have
approved a diesel/gas mixture for the MiG-15 as an expedient combat
logistics solution.

Ron Wanttaja

[Orval Fairbairn]

In article >,
Ron Wanttaja > wrote:

> On Mon, 08 Mar 2004 04:04:22 GMT, "Robert Bates" >
> wrote:
>
> >Are there any restrictions for fuels used in experimental exhibition
> >aircraft? I once encountered a Mig 15 that was burning a blend of diesel
> >and gasoline for a lower priced fuel.
>
> I'm sure there are no "automatic" restrictions. The only restriction the
> FAA might impose is a limitation on carrying passengers, and unless it's
> the trainer version of the -15, that point would be moot.
>
> Besides, even for a certified airplane, all the FAA can do is require you
> use the fuel the aircraft/engine manufacturer specifies. The Russians were
> pretty ingenious when it came to low-tech solutions; they may even have
> approved a diesel/gas mixture for the MiG-15 as an expedient combat
> logistics solution.
>
> Ron Wanttaja

In Don Engen's book, "Wings and Warriors," he tells us that the Navy
fueled the early carrier jets with 115/145, because they had to share
fuel with Corsairs and Skyraiders. BTW, gasoline does not yield as much
thrust as kerosene.

The main thing you have to watch out for in jets is water contamination
in Diesel fuel, as the water will freeze at altitude and ruin your day.

[Robert Bates]

OK, here's the part where I get flamed. On other newsgroups I have been
reading about guys burning biodiesel and atf in diesel engines so would a
turbine tolerate this?


"Orval Fairbairn" > wrote in message
...
> In article >,
> Ron Wanttaja > wrote:
>
> > On Mon, 08 Mar 2004 04:04:22 GMT, "Robert Bates" >
> > wrote:
> >
> > >Are there any restrictions for fuels used in experimental exhibition
> > >aircraft? I once encountered a Mig 15 that was burning a blend of
diesel
> > >and gasoline for a lower priced fuel.
> >
> > I'm sure there are no "automatic" restrictions. The only restriction
the
> > FAA might impose is a limitation on carrying passengers, and unless it's
> > the trainer version of the -15, that point would be moot.
> >
> > Besides, even for a certified airplane, all the FAA can do is require
you
> > use the fuel the aircraft/engine manufacturer specifies. The Russians
were
> > pretty ingenious when it came to low-tech solutions; they may even have
> > approved a diesel/gas mixture for the MiG-15 as an expedient combat
> > logistics solution.
> >
> > Ron Wanttaja
>
> In Don Engen's book, "Wings and Warriors," he tells us that the Navy
> fueled the early carrier jets with 115/145, because they had to share
> fuel with Corsairs and Skyraiders. BTW, gasoline does not yield as much
> thrust as kerosene.
>
> The main thing you have to watch out for in jets is water contamination
> in Diesel fuel, as the water will freeze at altitude and ruin your day.

[Corky Scott]

On Wed, 10 Mar 2004 15:42:28 GMT, "Robert Bates"
> wrote:

>OK, here's the part where I get flamed. On other newsgroups I have been
>reading about guys burning biodiesel and atf in diesel engines so would a
>turbine tolerate this?

My understanding is that, short term, a turbine engine will burn
anything that will flow and burn. Whether the turbine will tolerate
odd fuels that may burn at different temperatures than what the engine
was designed for over the long term is another question.

Corky Scott

[Jim Carriere]

"Corky Scott" > wrote in message
...
> On Wed, 10 Mar 2004 15:42:28 GMT, "Robert Bates"
> > wrote:
>
> >OK, here's the part where I get flamed. On other newsgroups I have been
> >reading about guys burning biodiesel and atf in diesel engines so would a
> >turbine tolerate this?
>
> My understanding is that, short term, a turbine engine will burn
> anything that will flow and burn. Whether the turbine will tolerate
> odd fuels that may burn at different temperatures than what the engine
> was designed for over the long term is another question.

I completely agree that a turbine engine will work if it can burn fuel.

I disagree with your thinking about flame temperature affecting the engine.

[I hope none of this sounds condescending, that isn't what I intend. It's
just some basic applied engine theory, pretty straightforward stuff.]

For a given output, gas turbines will burn at about the same temperature
regardless of fuel types. This is mainly because the air:fuel ratio is very
lean (ballpark 50:1) compared to piston engines. The output at a given gas
temperature depends on the properties of the gas. Since only about 30% of
the air is used to support combustion, and of that most of it is nitrogen
anyway, this is why type of fuel doesn't have a great effect on a gas
turbine. Fuel flow is increased or decreased until a desired output is
achieved, and the gas temperature and engine rpm pretty much "find"
themselves.

Where fuel type does matter is in the fuel system and on turbine blade
materials. The fuel system is affected in different operating environments-
hot, cold, high and low altitude. Turbine blades materials and the lead in
avgas are a bad idea. Turbine blades are also more sensetive to dirty
exhaust (soot, etc) than, say, the exhaust valve in a piston engine.

On the other hand, back to what you said about if the fuel burns... As long
as the fuel can consistently get to the combustor (for liquid fuel,
vaporizing or gelling in the fuel lines are the main concerns) it will burn.
This is what is great about gas turbines- they run on cheap fuel. Octane
or cetane properties are irrelevant, because the combustion in a gas turbine
is constant like a blowtorch.

Back to the MiG 15 fuel, JP-4 is often described as a blend of gasoline and
kerosene.

[Big John]

Jim

Long time ago in a land far away we used JP-1 (kerosene) in the J-33
engine. If we got caught out and there was no jet fuel at the base we
landed at we could fill up with gasoline to get to a jet fuel base or
get home. If we were using gasoline, we had to check TPT and not over
temp it. Bottom line was staying in engine specs we had less range
with gas than kerosene.

Big John

On Wed, 10 Mar 2004 21:41:16 -0500, "Jim Carriere"
> wrote:

>"Corky Scott" > wrote in message
...
>> On Wed, 10 Mar 2004 15:42:28 GMT, "Robert Bates"
>> > wrote:
>>[i]
>> >OK, here's the part where I get flamed. On other newsgroups I have been
>> >reading about guys burning biodiesel and atf in diesel engines so would a
>> >turbine tolerate this?
>>
>> My understanding is that, short term, a turbine engine will burn
>> anything that will flow and burn. Whether the turbine will tolerate
>> odd fuels that may burn at different temperatures than what the engine
>> was designed for over the long term is another question.
>
>I completely agree that a turbine engine will work if it can burn fuel.
>
>I disagree with your thinking about flame temperature affecting the engine.
>
>
>
>For a given output, gas turbines will burn at about the same temperature
>regardless of fuel types. This is mainly because the air:fuel ratio is very
>lean (ballpark 50:1) compared to piston engines. The output at a given gas
>temperature depends on the properties of the gas. Since only about 30% of
>the air is used to support combustion, and of that most of it is nitrogen
>anyway, this is why type of fuel doesn't have a great effect on a gas
>turbine. Fuel flow is increased or decreased until a desired output is
>achieved, and the gas temperature and engine rpm pretty much "find"
>themselves.
>
>Where fuel type does matter is in the fuel system and on turbine blade
>materials. The fuel system is affected in different operating environments-
>hot, cold, high and low altitude. Turbine blades materials and the lead in
>avgas are a bad idea. Turbine blades are also more sensetive to dirty
>exhaust (soot, etc) than, say, the exhaust valve in a piston engine.
>
>On the other hand, back to what you said about if the fuel burns... As long
>as the fuel can consistently get to the combustor (for liquid fuel,
>vaporizing or gelling in the fuel lines are the main concerns) it will burn.
>This is what is great about gas turbines- they run on cheap fuel. Octane
>or cetane properties are irrelevant, because the combustion in a gas turbine
>is constant like a blowtorch.
>
>Back to the MiG 15 fuel, JP-4 is often described as a blend of gasoline and
>kerosene.
>

[Peter Dohm]

Robert Bates wrote:
>
> OK, here's the part where I get flamed. On other newsgroups I have been
> reading about guys burning biodiesel and atf in diesel engines so would a
> turbine tolerate this?
>
Personally, my biggest worry would be salt; and that would also be my worry
using it in a diesel. I hope, but do not know, that hard parrticles and
corrosives (such as salt) are removed in some sort of refining process.

Peter

> "Orval Fairbairn" > wrote in message
> ...
> > In article >,
> > Ron Wanttaja > wrote:
> >
> > > On Mon, 08 Mar 2004 04:04:22 GMT, "Robert Bates" >
> > > wrote:
> > >
> > > >Are there any restrictions for fuels used in experimental exhibition
> > > >aircraft? I once encountered a Mig 15 that was burning a blend of
> diesel
> > > >and gasoline for a lower priced fuel.
> > >
> > > I'm sure there are no "automatic" restrictions. The only restriction
> the
> > > FAA might impose is a limitation on carrying passengers, and unless it's
> > > the trainer version of the -15, that point would be moot.
> > >
> > > Besides, even for a certified airplane, all the FAA can do is require
> you
> > > use the fuel the aircraft/engine manufacturer specifies. The Russians
> were
> > > pretty ingenious when it came to low-tech solutions; they may even have
> > > approved a diesel/gas mixture for the MiG-15 as an expedient combat
> > > logistics solution.
> > >
> > > Ron Wanttaja
> >
> > In Don Engen's book, "Wings and Warriors," he tells us that the Navy
> > fueled the early carrier jets with 115/145, because they had to share
> > fuel with Corsairs and Skyraiders. BTW, gasoline does not yield as much
> > thrust as kerosene.
> >
> > The main thing you have to watch out for in jets is water contamination
> > in Diesel fuel, as the water will freeze at altitude and ruin your day.