From: "Marvin Kaye" <marv@lancaironline.net>
Subject: Re: [FlyRotary] Re: weird cooling ideas, part 2
To: flyrotary
Date: Wed, 19 Mar 2003 19:56:38 -0500
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Posted for "Ed Anderson" <eanderson@carolina.rr.com>:

> Now, consider what Rusty has done.  He takes the coolant and spreads it in
a
> thin layer, all of which is in direct contact with the 'tube' wall.
>    His flat 'tube' has a much higher surface area to volume ratio,
> allowing the heat to transfer to the tube wall more efficiently. Instead
of
> transfering the heat to a fin for the air to pick up, the tube itself is
it's
> own fin.  The heat only has to cross from the inside to the outside of the
> tube wall.  Once the heat is on the outside, there is no interaction with
an
> adjacent fin, and it can be arranged such that the entire surface area of
the
> tube is exposed to cool air at once.

I understand your point, Ernest, and   I agree that only the coolant in
contact with the wall is going to transfer any significant heat out of the
system and the more coolant in contact with the wall is clearly better.
However, I don't know how you make a good comparison.  If my math was a fair
approximation of the fin area of one of my radiators and if effectively 1/2
(50%) of my fin area is not rejecting any significant heat for the reasons
you mentioned, then lets say my effective fin area went down from 12,000  to
6,000 square inches.  If I take a flat plate and assuming I get cooling from
both sides of it then I would need one side of approx 3000 square inches.
So a 30x100 inch plate radiator would be required to do the job. or a  3 ft
x 7 ft plate would give me a 2 sided (3000 square inches each side) 6000 sq
inch radiator.    I content that would not be practical in an aircraft and
remember that is equivlent to only one of the two radiator's I fly with.

But, I agree that it would be interesting to see the basic parameters of
Rusty's experiment and his data.  If indeed he gains the same degree of
cooling  with only 5% of my fin area (under similar operating parameters)
then we need to seriously look at some custom flat plate radiators. But, I
can't help but believe that if the flat plate radiator was that effective we
would have long ago seen it at least in race cars in not our automobiles.
But, Hey!, I've been wrong before and will be again {:>)

Ed Anderson