Steve Dorr discovered and uploaded this web site.

http://tinyurl.com/3uc3ed3

Produced by the National Automotive Radiator Association (NARSA) and
by Richard
F. Crook, Transpro, Inc.

The author maintains that all rads, no matter how good or
bad, always only drop the temperature 10 degrees F.

I was skeptical at first and then it dawned on me why.
The water coming out of the rad always goes back into the block
and then back into the rad 10 degrees hotter.

"That is, for a given [HEAT LOAD] and coolant [FLOW RATE], the
coolant temperature drop through the radiator will be constant, and
nothing anyone can do to the design of the radiator can change that.
Adding rows or fins or face area or whatever will not change the
temperature drop through the radiator."

Here is where the problem arises. If you add rows of tubes that will
lower the resistance of the rad. Since the amount of water a
centrifugal pump can pump depends on the total resistance in the
cooling system the total water flow rate will increase. So the above
sentence is not strictly true.

This is so typical of any cooling system. A change in one factor will
create a change in one or more other factors. This is what makes cooling
systems so hard to optimize.

I can highly recommend this $100 book.
"Compact Heat Exchangers by Kays and London."

It is the bible of cooling system design.

I cover some of the main points in my book "How to Cool Your Wankel"
available direct from me for $30 cash only. Contact me for a copy.

Paul Lamar

Paul,

After reading the radiator/cooling article, it seems to me your
cross-counterflow rad is like increasing the face area with out the extra
radiator hanging out in the wind. A bit of a generalization but sums it up to
me. Definitely confirms your stance on better water pumps. This is in relation
to engines with a low duty cycle even. AC at 75% power require paying
attention to this. The article in Kitplanes that covered engine related
accidents showed a fairly high cooling system failures in auto conversions as
the cause. Fuel systems and electrical were also higher than certified which
would indicate to me that builders should make more use of the IA's and
experienced builders close to them. In car clubs there are people with all
kinds of knowledge and abilities for members to draw on. Maybe kit builders
could/should get a little more organized this way. If not the man will step in
for us :-((((.

Your book on cooling a Rotary is in my mind mandatory reading for anyone
bolting one in an AC kit. When building a car or plane, you need to do lots of
research and question asking first. Then you make a plan and STICK TO THAT
PLAN. If you do not it gets expensive real fast and stupid things (schmidt)
happen. You pay for stuff two or more times depending on the number of changes
and mistakes happen.

Dale Davies