Cozy, Long ezy, and diesel engine.

"Morgans" wrote in message
...

"LCT Paintball" wrote in message
news:F7QQd.5629$4D6.3605@attbi_s51...
True, but that issue can be fixed.

That comment was about fuel jelling. What are your fixes? Will it
end
up
making the cost higher? What happens when you go to other airports
that
don't have auto diesel fuel?


The first fix would be to pump extra fuel through the system so that it
can
be warmed by the engine, then returned to the tank. Perhaps you could
even
run it through the oil cooler before sending it to the engine. There are
also additives that are routinely used to keep the fuel from jelling.

The additives will be the best bet, but expensive, when you add that to
the
price for fuel. Truckers use it, but they are only dealing with negative
in
the teens, not 20 to 30 below, with a huge moving air factor, around the
fuel. All that fuel, basicly in direct contact with the air, with Al's
great thermal conductivity. You would need to insulate the tank. Not
easy,
and more weight. Now add in whatever fuel heat exchangers, lines, and
pumps, and more weight, and also, complexity. (read ways to bring you down
before you wanted to) I didn't do any calcs, but you would need to
capture
almost all of the engine's waste heat to do this without additives.

I realize that you would not be in that kind of temperatures all of the
time, but all you need is one time where things were colder than you
thought, and......

Many around here will talk about the hassles of using your own auto fuel,
and what happens when you travel away from home. That is what the
airplane
you are describing will be good at; great economy, and legs.

Shoot, one nutcase that hangs out around here even made his own fuel truck
to feed his habit. g

The old saying about asking how much fuel that yacht burns? If you have
to
ask how much fuel it burns, you can't afford the boat.

Same thing here. Jet fuel is not that bad, it will give you great
economy,
and it is available, and won't end up killing you. Just my humble
opinions.
--
Jim in NC



You could use the fuel as an engine coolant in a liquid cooled diesel like
the Deltahawk.

With a wet wing, you'd get hot wing anti-ice capability and a skin radiator
in the bargain.

'Course, it wouldn't work if you ran out of fuel.....

Bill Daniels

In article , "Bill Daniels" wrote:



You could use the fuel as an engine coolant in a liquid cooled diesel like
the Deltahawk.

With a wet wing, you'd get hot wing anti-ice capability and a skin radiator
in the bargain.

1960's vintage Allis Chalmers crawlers using the diesel fuel as a cooling
medium and working medium for the torque converter. Worked well.
tom

In article ,
wrote:

In article , "Bill Daniels"
wrote:



You could use the fuel as an engine coolant in a liquid cooled diesel like
the Deltahawk.

With a wet wing, you'd get hot wing anti-ice capability and a skin radiator
in the bargain.

1960's vintage Allis Chalmers crawlers using the diesel fuel as a cooling
medium and working medium for the torque converter. Worked well.
tom

would a mazda/wankle-rotary run on Jet-A, JP-4, etc?

"Dan Nafe" wrote


You could use the fuel as an engine coolant in a liquid cooled diesel
like
the Deltahawk.

With a wet wing, you'd get hot wing anti-ice capability and a skin
radiator
in the bargain.

1960's vintage Allis Chalmers crawlers using the diesel fuel as a
cooling
medium and working medium for the torque converter. Worked well.
tom

would a mazda/wankle-rotary run on Jet-A, JP-4, etc?

If it did, it would come the closest chance of having waste heat deice the
wing. Wankel engines do not have a high enough compression ratio, I
believe.

The other issues have been kicked around before.

1.) Wings make poor radiators. The boundary layer of air does not move
enough, to carry the heat away efficiently. It was tried, even in the early
years of air racing.

2.) Internal combustion engines do not produce enough waste heat to deice a
wing, even if 100% of the exhaust heat and engine cooling heat was captured,
and put onto the wing. 100% will never happen, and that makes the
possibilities even more unlikely.
--
Jim in NC

"Morgans" wrote in message
...

"Dan Nafe" wrote


You could use the fuel as an engine coolant in a liquid cooled diesel
like
the Deltahawk.

With a wet wing, you'd get hot wing anti-ice capability and a skin
radiator
in the bargain.

1960's vintage Allis Chalmers crawlers using the diesel fuel as a
cooling
medium and working medium for the torque converter. Worked well.
tom

would a mazda/wankle-rotary run on Jet-A, JP-4, etc?

If it did, it would come the closest chance of having waste heat deice the
wing. Wankel engines do not have a high enough compression ratio, I
believe.

The other issues have been kicked around before.

1.) Wings make poor radiators. The boundary layer of air does not move
enough, to carry the heat away efficiently. It was tried, even in the
early
years of air racing.

2.) Internal combustion engines do not produce enough waste heat to deice
a
wing, even if 100% of the exhaust heat and engine cooling heat was
captured,
and put onto the wing. 100% will never happen, and that makes the
possibilities even more unlikely.
--
Jim in NC


Seems counter to say that a skin radiator won't cool an engine but won't
de-ice either. Last I checked, ice melted at 32F and coolant is usually
180-200F. If the skin radiator won't transfer heat to the airstream, it'll
get damn hot. If the heat won't melt ice, it's going somewhere.

I'd bet a 180F wing would melt ice pretty damn well with an OAT of 28F.
Actually, the golden air age racers with skin radiators worked pretty well.

BTW, if heat won't transfer through a wing boundary layer, why should it
transfer through the boundary layer on a cooling fin?

Bill Daniels

"Bill Daniels" wrote

Seems counter to say that a skin radiator won't cool an engine but won't
de-ice either. Last I checked, ice melted at 32F and coolant is usually
180-200F. If the skin radiator won't transfer heat to the airstream,
it'll
get damn hot. If the heat won't melt ice, it's going somewhere.

It takes a lot of energy to melt ice. What is it, specific heat? I can
never remember if it is that, or latent heat, from my high school chemestry.

Ever notice how small the radiators are, in a auto engine homebuilt? Lots
of the 4.3 Liter V-6's are using 2 Chevy air conditioner evaporators. How
much surface area, if it were all spread out? 3 or 4 square feet would be
my guess. Now take the wing of of a RV. What are they, 100, 120 sf? That
makes it 200 or 240 square feet, top and bottom. Oh, let's take off 20% for
ailerons and flaps... 190 or so. 47 times more surface on the wing, than
the radiator. How hot do you think that will get, with all of that air
zooming by at 150 + MPH. Yes, if you made the whole wing a radiator, the
coolant will get cooled. How much will all of it weigh?

Some time ago, someone in the group did some calculations, that pretty much
proved the case. They used the efficiency of an IC engine, then assumed
that all the rest of the BTU's produced by burning, say 10 gal/hr, that were
not used for HP went into the wing. They started with a thin layer of ice
over a given surface area, and calculated how much heat it wuld take to melt
that ice. The waste BTU's in that gas were far short of melting all of it.

I'd bet a 180F wing would melt ice pretty damn well with an OAT of 28F.

If you put the heat in a small surface area, say the first 6" of the leading
edge, yes. What happens after it runs back and re-freezes? Seems to me, a
commuter plane model had a problem with that type of thing, and a couple
crashed, a few years back.

If the wing was 180 without the ice, how well would the engine be cooling.
(or overheating)

Actually, the golden air age racers with skin radiators worked pretty
well.

Cites?

BTW, if heat won't transfer through a wing boundary layer, why should it
transfer through the boundary layer on a cooling fin?

Bill Daniels

I am not an aerodynamoisist, but I think there is something you are not
understanding, here.

I do not believe boundry layers apply, when the air is being forced past the
surface, with nowhere else to go, with a pressure differential.

Ever notice the lip on the cooling intake of a P-51? It is away from the
surface of the belly by a few inches, away from the boundry layer, to get to
where the air is flowing fast, and energetic, and pressure can be developed,
due to ram effect. The other big part of the equation is the negative
pressure behind the lip of the outlet.

How does your cite of boundry layer apply to a radiator?

For my final argument, why are wing radiators not commonplace? If you could
get the engine cooled, for no drag penalty, why is it not being done?
Surely Dick Rutan would have used it in Voyager, to eliminate the cooling
drag. What is cooling drag in a piston airplane? I seem to recall around
20% on most designs. 20% on Voyager would have been HUGE!
--
Jim in NC

Morgans wrote:

"Bill Daniels" wrote

Seems counter to say that a skin radiator won't cool an engine but won't
de-ice either. Last I checked, ice melted at 32F and coolant is usually
180-200F. If the skin radiator won't transfer heat to the airstream,

it'll

get damn hot. If the heat won't melt ice, it's going somewhere.


It takes a lot of energy to melt ice. What is it, specific heat? I can
never remember if it is that, or latent heat, from my high school chemestry.

Ever notice how small the radiators are, in a auto engine homebuilt? Lots
of the 4.3 Liter V-6's are using 2 Chevy air conditioner evaporators. How
much surface area, if it were all spread out? 3 or 4 square feet would be
my guess. Now take the wing of of a RV. What are they, 100, 120 sf? That
makes it 200 or 240 square feet, top and bottom. Oh, let's take off 20% for
ailerons and flaps... 190 or so. 47 times more surface on the wing, than
the radiator. How hot do you think that will get, with all of that air
zooming by at 150 + MPH. Yes, if you made the whole wing a radiator, the
coolant will get cooled. How much will all of it weigh?

I don't know the area of a typical car radiator either, but I'm betting
it is much more than 3-4 square feet. Also, keep in mind that you only
need to de-ice the leading edge of the wing (look at how much boots
cover). So the area is probably closer to 2' times the wingspan which
means 50-80 sq. ft. one a typical light airplane.

And you don't need to coolant at 180F+ to deice a wing, so you can push
the coolant through a lot more area than a radiator and still keep
sufficient temperature to melt or prevent ice.


Some time ago, someone in the group did some calculations, that pretty much
proved the case. They used the efficiency of an IC engine, then assumed
that all the rest of the BTU's produced by burning, say 10 gal/hr, that were
not used for HP went into the wing. They started with a thin layer of ice
over a given surface area, and calculated how much heat it wuld take to melt
that ice. The waste BTU's in that gas were far short of melting all of it.

Preventing it is easier than melting an accumulation to be sure. This
holds with other systems such as TKS as well.


For my final argument, why are wing radiators not commonplace? If you could
get the engine cooled, for no drag penalty, why is it not being done?
Surely Dick Rutan would have used it in Voyager, to eliminate the cooling
drag. What is cooling drag in a piston airplane? I seem to recall around
20% on most designs. 20% on Voyager would have been HUGE!

I'd guess cost and complexity would be two big reasons.


Matt

"Bill Daniels" wrote

With a wet wing, you'd get hot wing anti-ice capability and a skin
radiator
in the bargain.

'Course, it wouldn't work if you ran out of fuel.....

Bill Daniels

Couple years back, someone did a pretty good set of calculations on that.
If you captured 100% of the engine waste heat, It wouldn't be even close
enough to de-ice a wing.

Turbines do it, cause they burn tons of fuel. IC engines don't come close.
--
Jim in NC