Surface radiators for water cooled engines

On 7 Jul 2003 12:43:45 -0700, (Jay) wrote:

A car radiator, while being
small and available, is also exceedingly draggy, which is why its not
an optimal choice choice for a fast airplane. The auto radiator is
designed for different conditions mainly:
1) High disipation at low air flow speeds
2) Clean air entering front surface (Reynolds number less than 10,000)
2) Drag not an issue

An aircraft/cowl-surface scenario doesn't have the condition of high
power output and low airflow and thustly should not besigned for this
condition. Even on the climb out, while the IAS may be low, the prop
wash is turbulent and higher in velocity than the speed of the vehicle
itself.

Regards

Right, auto radiators don't work that well in airplanes for a number
of reasons. That's why you don't see many of them in airplanes. But
if you have the room to install them and can slow the air that passes
through them enough, they do work.

A lot of people who need a liquid heat exchanger go to the companies
that build them for the racing scene, or use something more compact,
like an air conditioning evaporator core. Those aren't optimal either
because they tend to have a dense fin spacing which makes passing the
air through them problematic.

But there are several firms in the US that build heat exchangers
designed for the speeds airplanes encounter and can be custom built to
your specifications. This pretty much solves the problem. If you do
your homework correctly and give them the proper specifications, and
plan your ducting properly, your engine will cool properly.

Corky Scott

Barnyard BOb -- wrote in message . ..
The auto radiator is
designed for different conditions mainly:
1) High disipation at low air flow speeds
2) Clean air entering front surface (Reynolds number less than 10,000)
2) Drag not an issue

An aircraft/cowl-surface scenario doesn't have the condition of high
power output and low airflow and thustly should not besigned for this
condition. Even on the climb out, while the IAS may be low, the prop
wash is turbulent and higher in velocity than the speed of the vehicle
itself.

Regards



Well, since you already have it all figured out and know all the answers what
are you waiting for, do it. We are obviously unknowing of the solutions which
you have worked out and are waiting to be proved wrong.

Bob Reed
+++++++++++++++++++++++++++++++++++++++++++

This is the same class of dreamer and wannabee that
was discussed earlier. This ilk will not only reinvent the
wheel with Unobtainium, but is also famous for wasting
perfectly good restaurant paper napkins at lunch time.


Barnyard BOb -- Have sharp stick. Will travel.


Watch it there Barnyard, Half the parts on my airplane originated on a paper napkin

Ed Sullivan - the original curmudgeon if you will recall

Earlier, (Jay) wrote:

...and thustly should not besigned for this...

Oh, gosh, can I quote you on that?

;}

Bob K.

"Barnyard BOb --" wrote in message


Barnyard BOb -- Have sharp stick. Will travel.

Be careful not to poke your eye out! g
--
Jim in NC

Sure, be my guest.

(Bob Kuykendall) wrote in message om...
Earlier, (Jay) wrote:

...and thustly should not besigned for this...

Oh, gosh, can I quote you on that?

;}

Bob K.

"Jay" wrote in message om...

I'd put forth the idea that the worst
case environment for an aircraft is always better than the worst case
for an automobile. Does anyone disagree on this point?

Yeah, I do. Many cars typically don't operate at 80% of rated power for long
periods.

Therefor, a cooling surface directly exposed to the prop wash does not
have to be as large in area as that of the radiator orginally designed
for that automobile.

Cars have fans too.

On Tue, 08 Jul 2003 13:12:05 -0500, Big John
wrote:

Ralph

Please. Smokey may have been 'creative' in his race cars but he didn't
hold a candle to our A.J. (pride of Houston).

Smokey couldn't rassle like AJ, that's for sure. And cuss, the man
can cuss a blue streak without breaking a sweat. Watch a race, he's
never featured on the pit-to-car radio chatter. For a f*cking good
reason :-)



Big John
Pilot, ROC Air Force


On 7 Jul 2003 18:25:41 -0700, (Ralph DuBose) wrote:

----clip----

By the way, Mr. Yunick was famous for creative cheating in race
car construction.

----clip----

--
dillon

The pen may be mightier than the sword,
but a .sig never beat a SIG

Dillon

Heard that until he got caught, he put NOX (is that right) inside the
tubing of his race car frame. On last lap he vented it to the carb and
blew everyone away. That's thinking out of the box G

Big John
Point of the sword



On Wed, 09 Jul 2003 19:50:20 GMT, Dillon Pyron
wrote:

On Tue, 08 Jul 2003 13:12:05 -0500, Big John
wrote:

Ralph

Please. Smokey may have been 'creative' in his race cars but he didn't
hold a candle to our A.J. (pride of Houston).

Smokey couldn't rassle like AJ, that's for sure. And cuss, the man
can cuss a blue streak without breaking a sweat. Watch a race, he's
never featured on the pit-to-car radio chatter. For a f*cking good
reason :-)



Big John
Pilot, ROC Air Force


On 7 Jul 2003 18:25:41 -0700, (Ralph DuBose) wrote:

----clip----

By the way, Mr. Yunick was famous for creative cheating in race
car construction.

----clip----

"Ron Natalie" wrote in message om...
"Jay" wrote in message om...

I'd put forth the idea that the worst
case environment for an aircraft is always better than the worst case
for an automobile. Does anyone disagree on this point?

Yeah, I do. Many cars typically don't operate at 80% of rated power for long
periods.

Depends on how you define "long period". For the puposes of this
discussion, any amount of time over the amount of time it takes to
heat the water volume and block I would call "long" Thats probably on
the order of a several minutes. Driving up a long grade on a hot day
(which is where I see all the blown radiators) seems like it would
meet the high output for "long" time case.

Therefor, a cooling surface directly exposed to the prop wash does not
have to be as large in area as that of the radiator orginally designed
for that automobile.

Cars have fans too.

I'm not sure its fair to compare a 10" 1/4 HP electric fan to a 150HP
propeller.

I'd put forth the idea that the worst
case environment for an aircraft is always better than the worst case
for an automobile. Does anyone disagree on this point?

Yeah, I do. Many cars typically don't operate at 80% of rated power for
long
periods.

Worst case environment for an automobile is sitting in stop and go traffic
on hot sunny day for long periods of time.

Nope.
Popular misconception at best.

Most cars have absolutely no
trouble staying cool while screaming down the highway at full throttle.

Wrong again....
Most cars screaming down the highway get tickets or crash
long before they sustain 80% for long periods. Lots of variables,
but... speeds at 80% power could readily be exceeding 100 mph.


Barnyard BOb --