Light weight Euro-diesels

wrote:


It _is_ pretty impressive technology. Though the European-ness of it is
really isn't that big of a deal. All the car companies are pan-global
entities these days.

Diesel is still cheaper than jet fuel. Or isn't it?
Jet A1 is a little bit cheaper, but it need oil addition (2 strokes oil is
good but normal oil would be ok) for high pressure pump.

I've been too afraid to go to the pump the past few days :-) At current
prices biodiesel does become cost effective if one could find a suitable
anti-gel agent.
No anti-froze agent needed, just an fuel/water heat exchange and the whole
tank become warmer when the engine is runnig. For pure biodiesel, the car
choice is an exhaust/fuel heat exchange.

I just wait for a new design from daihatsu: a 2 cylinder, 2 strokes
superchared, turbocharged 85HP.
I'm waiting for weight info, the 2 strokes only may achieve same weight
than mogas engine.

By
--
Pub: http://www.slowfood.fr/france
Philippe Vessaire Ò¿Ó¬

Philippe Vessaire wrote:
wrote:


It _is_ pretty impressive technology. Though the European-ness of it is
really isn't that big of a deal. All the car companies are pan-global
entities these days.

Diesel is still cheaper than jet fuel. Or isn't it?
Jet A1 is a little bit cheaper, but it need oil addition (2 strokes oil is
good but normal oil would be ok) for high pressure pump.

I've been too afraid to go to the pump the past few days :-) At current
prices biodiesel does become cost effective if one could find a suitable
anti-gel agent.
No anti-froze agent needed, just an fuel/water heat exchange and the whole
tank become warmer when the engine is runnig. For pure biodiesel, the car
choice is an exhaust/fuel heat exchange.

I just wait for a new design from daihatsu: a 2 cylinder, 2 strokes
superchared, turbocharged 85HP.
I'm waiting for weight info, the 2 strokes only may achieve same weight
than mogas engine.

By
--
Pub: http://www.slowfood.fr/france
Philippe Vessaire =D2=BF=D3=AC


Have you heard of anyone cutting Jet A like your describing? I would
expect those engines are quite sensative. I'd be really nervous about
fuel/oil ratios doing that!

Interesting thought on plumbing the coolant to the fuel tanks. Have you
heard of anybody doing this on an aircraft? (I know the car guys do it
all the time) That might make aircraft designed with header tanks more
appropriate for diesels. (Easier to build the heat sink)

It might even be possible to just ignore the radiator completely and
turn the skin of the aircraft into the heat sink. Basically you'd route
several flows of 3/8" aluminum tubing strategically about the airplane.
You could end up with a deicing system instead of a radiator! It would
probably take more line/water than was in the radiator, but it might
make up for it in aerodynamics. (No radiator hanging in the breeze) I'd
have to crunch the numbers, it probably isn't feasable, but it's a
thought.=20

-Matt

wrote

It might even be possible to just ignore the radiator completely and
turn the skin of the aircraft into the heat sink. Basically you'd route
several flows of 3/8" aluminum tubing strategically about the airplane.
You could end up with a deicing system instead of a radiator! It would
probably take more line/water than was in the radiator, but it might
make up for it in aerodynamics. (No radiator hanging in the breeze) I'd
have to crunch the numbers, it probably isn't feasable, but it's a
thought.

Before you get carried away with that idea, there are a lot of problems with
that idea. You can google the threads on them, but I'll point out a few of
the problems with the idea.

1. A cooling system has to be reliable, to the max. Adding a bunch of
lines and fittings is a good place to have problems pop up.

2. Weight. You add all of the lines, and fluid, and you have added a bunch
of weight.

3. De-ice takes a lot of heat to do a decent job. Even if you used all of
the BTU's from burning 100% of the gas that the engine would be burning,
there is not enough heat in the gas to thaw out a wing. Take the
approximate 50% heat output of the engine, subtract the realistic efficiency
of getting all of that heat to the wing, (you would have to bond that tube
to the wing mechanically) and you have cut the amount of heat trying to melt
the ice by even more.

4. Heat transfer from the hot wing skins to the air is really poor. This
is because of the stagnant layer of air sitting right on the surface of the
wing. Simply put, the air is not carrying the heat away from the wing very
well, at all.

Those are just the high points. Think of it this way; if this idea would
work well, lots of planes in the past and present would have been using
them. They are not.
--
Jim in NC

Hey, you're gonna have to heat the diesel fuel to keep it from gelling so
why not use the fuel as a coolant. If the tanks are of the wet wing type,
you're almost home free. (I actually had a guy ask me how that would cool
the engine if I ran out of fuel.)

Bill Daniels


"Morgans" wrote in message
...

wrote

It might even be possible to just ignore the radiator completely and
turn the skin of the aircraft into the heat sink. Basically you'd route
several flows of 3/8" aluminum tubing strategically about the airplane.
You could end up with a deicing system instead of a radiator! It would
probably take more line/water than was in the radiator, but it might
make up for it in aerodynamics. (No radiator hanging in the breeze) I'd
have to crunch the numbers, it probably isn't feasable, but it's a
thought.

Before you get carried away with that idea, there are a lot of problems
with
that idea. You can google the threads on them, but I'll point out a few
of
the problems with the idea.

1. A cooling system has to be reliable, to the max. Adding a bunch of
lines and fittings is a good place to have problems pop up.

2. Weight. You add all of the lines, and fluid, and you have added a
bunch
of weight.

3. De-ice takes a lot of heat to do a decent job. Even if you used all of
the BTU's from burning 100% of the gas that the engine would be burning,
there is not enough heat in the gas to thaw out a wing. Take the
approximate 50% heat output of the engine, subtract the realistic
efficiency
of getting all of that heat to the wing, (you would have to bond that tube
to the wing mechanically) and you have cut the amount of heat trying to
melt
the ice by even more.

4. Heat transfer from the hot wing skins to the air is really poor. This
is because of the stagnant layer of air sitting right on the surface of
the
wing. Simply put, the air is not carrying the heat away from the wing
very
well, at all.

Those are just the high points. Think of it this way; if this idea would
work well, lots of planes in the past and present would have been using
them. They are not.
--
Jim in NC

Bill Daniels wrote:
Hey, you're gonna have to heat the diesel fuel to keep it from gelling so
why not use the fuel as a coolant. If the tanks are of the wet wing type,
you're almost home free. (I actually had a guy ask me how that would cool
the engine if I ran out of fuel.)

Bill Daniels


"Morgans" wrote in message
...

wrote

It might even be possible to just ignore the radiator completely and
turn the skin of the aircraft into the heat sink. Basically you'd route
several flows of 3/8" aluminum tubing strategically about the airplane.
You could end up with a deicing system instead of a radiator! It would
probably take more line/water than was in the radiator, but it might
make up for it in aerodynamics. (No radiator hanging in the breeze) I'd
have to crunch the numbers, it probably isn't feasable, but it's a
thought.

Before you get carried away with that idea, there are a lot of problems
with
that idea. You can google the threads on them, but I'll point out a few
of
the problems with the idea.

1. A cooling system has to be reliable, to the max. Adding a bunch of
lines and fittings is a good place to have problems pop up.

2. Weight. You add all of the lines, and fluid, and you have added a
bunch
of weight.

3. De-ice takes a lot of heat to do a decent job. Even if you used all of
the BTU's from burning 100% of the gas that the engine would be burning,
there is not enough heat in the gas to thaw out a wing. Take the
approximate 50% heat output of the engine, subtract the realistic
efficiency
of getting all of that heat to the wing, (you would have to bond that tube
to the wing mechanically) and you have cut the amount of heat trying to
melt
the ice by even more.

4. Heat transfer from the hot wing skins to the air is really poor. This
is because of the stagnant layer of air sitting right on the surface of
the
wing. Simply put, the air is not carrying the heat away from the wing
very
well, at all.

Those are just the high points. Think of it this way; if this idea would
work well, lots of planes in the past and present would have been using
them. They are not.
--
Jim in NC


I would guess you could have cooked oil in the engine block after shut
down. Isn't that what kills a lot of turbos? So you'd end up with
crusty bits in your go-juice. Which I understand is a fairly painfull
condition. :-)

Perhaps using an electric instead of mechanical coolant pump would do
the trick. That way you could keep coolant flow constant befure and
after shut down.

-Matt

"Bill Daniels" wrote in message
...
Hey, you're gonna have to heat the diesel fuel to keep it from gelling so
why not use the fuel as a coolant. If the tanks are of the wet wing type,
you're almost home free. (I actually had a guy ask me how that would cool
the engine if I ran out of fuel.)

The real question is, how will the engine cool, once you have the fuel to
the boiling point, and also how rapidly can you boil off a tank of fuel.
--
Jim in NC

"Morgans" wrote in message
...

"Bill Daniels" wrote in message
...
Hey, you're gonna have to heat the diesel fuel to keep it from gelling
so
why not use the fuel as a coolant. If the tanks are of the wet wing
type,
you're almost home free. (I actually had a guy ask me how that would
cool
the engine if I ran out of fuel.)

The real question is, how will the engine cool, once you have the fuel to
the boiling point, and also how rapidly can you boil off a tank of fuel.
--
Jim in NC


Why would the fuel boil? Glycol/water coolant doesn't boil if the engine
temps are normal. I seem to recall the boiling point of diesel is greater
than glycol/water. That would depend on the rate the heat was rejected by
the 'radiator' and the pressure of the cooling system. If heat input was
less than the heat rejection capacity of the radiator, then the fuel
"coolant" wouldn't overheat.

Using fuel as a coolant is a respected technique used by rocket engines and
the SR-71.

Bill Daniels

"Bill Daniels" wrote in message
...

"Morgans" wrote in message
...

"Bill Daniels" wrote in message
...
Hey, you're gonna have to heat the diesel fuel to keep it from gelling
so
why not use the fuel as a coolant. If the tanks are of the wet wing
type,
you're almost home free. (I actually had a guy ask me how that would
cool
the engine if I ran out of fuel.)

The real question is, how will the engine cool, once you have the fuel
to
the boiling point, and also how rapidly can you boil off a tank of fuel.
--
Jim in NC


Why would the fuel boil? Glycol/water coolant doesn't boil if the engine
temps are normal. I seem to recall the boiling point of diesel is greater
than glycol/water. That would depend on the rate the heat was rejected by
the 'radiator' and the pressure of the cooling system. If heat input was
less than the heat rejection capacity of the radiator, then the fuel
"coolant" wouldn't overheat.

Using fuel as a coolant is a respected technique used by rocket engines
and
the SR-71.

Bill Daniels


It doesn't boil because it's under pressure. You wanna pressurize your
Nimbus wings to, say, 32 feet of water pressure?

Tim Ward

"Bill Daniels" wrote

Why would the fuel boil? Glycol/water coolant doesn't boil if the engine
temps are normal.

How are the temps going to stay normal, once the fuel has gotten up to
engine operating temperature? Remember the premise that the skins will not
get rid of the heat fast enough? Someone has proven it here before. The
fuel will then get hotter and hotter, until it is boiling. The change of
state may then keep the engine from melting down, at least until all of the
fuel is gone.

Using fuel as a coolant is a respected technique used by rocket engines
and
the SR-71.

Rocket engines only use the fuel one time for cooling, and that is on the
way into the combustion chamber. If it had to recirculate to keep the
engine cool, the fuel would over pressure and over temp in a short period of
time.

The SR-71 does not use the fuel to cool the engine, but uses the fuel to
cool the hot parts of the airframe, or in other words, redistribute the hot
skin temps. It should also be noted that the fuel was very special, and
only available at a few sites around the world. Are you planning on cooling
your skins, and where are you going to get SR-71 fuel?

Sorry, but your examples are not valid. If it worked, racers would do it,
and so would some others. It does not work. those are my final words on
the subject. See ya. -)
--
Jim in NC

Morgans wrote:
wrote

It might even be possible to just ignore the radiator completely and
turn the skin of the aircraft into the heat sink. Basically you'd route
several flows of 3/8" aluminum tubing strategically about the airplane.
You could end up with a deicing system instead of a radiator! It would
probably take more line/water than was in the radiator, but it might
make up for it in aerodynamics. (No radiator hanging in the breeze) I'd
have to crunch the numbers, it probably isn't feasable, but it's a
thought.

Before you get carried away with that idea, there are a lot of problems with
that idea. You can google the threads on them, but I'll point out a few of
the problems with the idea.

1. A cooling system has to be reliable, to the max. Adding a bunch of
lines and fittings is a good place to have problems pop up.

2. Weight. You add all of the lines, and fluid, and you have added a bunch
of weight.

3. De-ice takes a lot of heat to do a decent job. Even if you used all of
the BTU's from burning 100% of the gas that the engine would be burning,
there is not enough heat in the gas to thaw out a wing. Take the
approximate 50% heat output of the engine, subtract the realistic efficiency
of getting all of that heat to the wing, (you would have to bond that tube
to the wing mechanically) and you have cut the amount of heat trying to melt
the ice by even more.

4. Heat transfer from the hot wing skins to the air is really poor. This
is because of the stagnant layer of air sitting right on the surface of the
wing. Simply put, the air is not carrying the heat away from the wing very
well, at all.

Those are just the high points. Think of it this way; if this idea would
work well, lots of planes in the past and present would have been using
them. They are not.
--
Jim in NC

I had considered the first 2 issues. Like I said, some numbers would
have to be crunched to determine viability. The upthread-post was
regarding running water lines to the tanks. So my post was based on the
assumption that the safety of running lines had already been resolved.
Given somebody is running a aero diesel added weight is a foregone
conclusion.

Regarding points 3 and 4: if the boundary layer acts as an insulator,
then heating the skin should be easier, not harder. Right? Less wicking
of heat should cause the skin to retain more heat. If ones primary
purpose was to take the radiator out of the equation and heat the
tanks, the gain in skin temperature is ancillary. It doesn't have to
solve icing completely, just be more resistant to it. Better is good
enough if it's free.

The other possibility would be to stick a radiator in each wing root
and funnel ram air through the radiator into the wing cavity. The
warmed air would then be the heating element. I wonder if that would be
sufficient to prevent gelling and also provide some minor wing heat
without all the complexity.

-Matt