Cozy, Long ezy, and diesel engine.

"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

"Richard Riley" wrote in message
...
On Mon, 21 Feb 2005 12:32:27 -0500, Dan Nafe
wrote:

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

Google "Wankle Deere SCORE"

Ah, that ugly little factor of weight and diesel engines, rears it's ugly
head again. ;-)
--
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

"Matt Whiting" wrote in message
...
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

Could you add cooling fins to a wing? Would a serious set of vortex
generators add enough area?

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.

Yes, car radiators are much larger than 3 or 4 square feet. Car radiators
have to sit in traffic, not moving, in 110 degrees. Also, they have even
hotter air blowing past them, from the AC radiator in front of it.
Automatic transmission cars also have to cool the tranny fluid, by running
it through the radiator. That represents a huge amount of heat.

Most water cooled homebuilts do not tolerate sitting on the taxiway more
than a few minutes. How do I know that? By talking to the owners of them,
when they are deciding about when to taxi, and how long they can stand it.
There are exceptions; some have figured out how to cool their engines,
sitting on the ground for a long time. They are the exception, in the
homebuilt world. So really, that is how they get away with such small
radiators. Lots of cool fast moving air.

Also, keep in mind that you only
need to de-ice the leading edge of the wing (look at how much boots
cover).

Different princples at work. If you *melted* the first few inches of ice,
it would run back and re-freeze, before it got off the wing. Bad thing.
VERY bad thing, as in guaranteed crash, after about 1/4" of ice.

So the area is probably closer to 2' times the wingspan which
means 50-80 sq. ft. one a typical light airplane.

Nope, see above. Good for crashing, if it did stay hot enough to melt ice.

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.

You will have to add another pump (more weight) to move that "cooler" water,
then. ALL of the water that comes out of the engine is at 180 degrees.

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

Different, once again. Preventing it from forming on the leading edges, and
letting it freeze further back does no good. TKS keeps everything that runs
back from freezing, because the antifreez has mixed with all of the water
running back, to make a mixture that is above freezing.

If you melt it at the front of the wing with heat, the water must stay hot
enough to run ALL OF THE WAY back, and off of the wing. Jet engines have
enough waste heat to do that. IC engines DO NOT. Get that through your
head! It is not done, because it CAN NOT be done! Get it?

For my final argument, why are wing radiators not commonplace?

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

Yes, but you missed the biggest one. Weight. Weight. Weight. If it were
cost and complexity, someone would still do it. They *will not* sacrifice
the weight.
--
Jim in NC

Matt Whiting wrote:

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.

I do. The radiators that several guys have been using to cool their 13B
rotaries have about 14,000sq.in. of radiator surface area. That nearly
100sq.ft. There are alot of very thin fold of aluminum sheet that are
exposed front and back. You'll need both sides of your wings and the
fuselage belly.

Add to that, the radiator is design to turbulate the air in order to mix
it up. A wing is designed to keep the air smooth, and won't fly if you
mix it up enough to to make it a decent radiator.

If you melt the ice on the leading edge, it will refreeze just behind
the leading edge, unless you can keep the laminar layer warm enough.

There could possibly be some benefit to heating the bottom of the wing.
The laminar layer is much thinner, and the heated air would add some
lift energy. But the weight penalty of containing the coolant would be
prohibitive.

Maybe you could have an open system. A hose would spray coolant or
engine heated oil on the inside of the wing skin and then flow back to a
collector. Wouldn't deal with all the engine heat, but it could take a
fair amount of it away.

"Ernest Christley" wrote

The radiators that several guys have been using to cool their 13B
rotaries have about 14,000sq.in. of radiator surface area. That nearly
100sq.ft.

What kind of radiator is it? A custom racing job? I would be interested.
How does it do on extended ground idle?

You know what I was talking about, with the GM AC condensers, right? I
believe that is what Tracy is running with his Mazda pusher. How much area
would you suppose is in one of those?
--
Jim in NC

Morgans wrote:
"Ernest Christley" wrote


The radiators that several guys have been using to cool their 13B
rotaries have about 14,000sq.in. of radiator surface area. That nearly
100sq.ft.


What kind of radiator is it? A custom racing job? I would be interested.
How does it do on extended ground idle?

You know what I was talking about, with the GM AC condensers, right? I
believe that is what Tracy is running with his Mazda pusher. How much area
would you suppose is in one of those?

Those are the ones I'm talking about. I got the numbers from measuring
a sample area in the radiator I have and calculating what that would be
over the entire radiator surface.

If you're really interested, the FlyRotary mailing list archives will
reveal that quite a few planes are flying with this setup now.
Unfortunately, I'm not one of them yet. Most had overheating problems
initially, and had to make a modification or two to get things under
control, but there are now quite a few examples of how to get 170Hp out
of a rotary without overheating using a couple GM condenser cores. It
the last few to report first flights have not had heating problems.