OK, Bob and Jay, chill out. You're both cool engineers and have a lot to
contribute. Lets just rattle the idea around a bit and see what comes out.

The skin radiator was been tried on the Schneider Cup seaplane racers in the
1930's and it worked, at least for that purpose. It probably worked much
better than the flat plate alternative seen on other aircraft from that era.
It might not have as much advantage over a highly efficient ducted radiator
like the P-51 used.

Skin radiators weren't really tried on military aircraft in WWII, at least
as far as I know, probably out of concern they would be very vulnerable to
enemy fire. After the war, people interested in performance were into jets
and not too interested in some weird pre-war radiator design even though it
might work fine.

Then there is a question of the effect of heating the boundary layer. Some
say that it will thicken and separate if the wing skin is heated. On the
other hand, some say it will have a turbulator effect and energize the
boundary layer. The Schneider Cup racers did not have laminar flow airfoils
so any effects, good or bad, might not have been noticed.

I have read a bit of work on "Hot Wing" aerodynamics and the results were
inconclusive as far as effects on the extent of laminar flow on the wing but
seemed to suggest a reduction in L/D which would be expected if the heating
disturbed the boundary layer.

It's possible, even likely, that a skin radiator would work best for cooling
and have the least negative effects on laminar flow if the surface chosen
were already subject to turbulent flow. The wing leading edge behind the
prop comes to mind.

Bill Daniels

"Jay" wrote in message
om...
(Bob Kuykendall) wrote in message
If you think you have a good idea, then fine, try it. Make a
prototype, test it under representative conditions, and publish your
results. If the results bear out your assertions, you will be hailed
as an insightful genius. If there are competitive advantages to your
idea, you can expect to see swift application of it to a wide variety
of heat exchange situations.

I think its too soon make that step, I'm not sure what the proportions
need to be.

Anyhow, yammering about your idea here on Usenet accomplishes less
than zero, since it takes up time that you could otherwise be using to
implement and test your idea. From the fact that you persist in
arguing about it in this forum, I can only conclude that you are more
interested in the argument that in the idea under discussion.

"Listen, I'm not here for an argument..." (Python)
I didn't come to the newsgroup to as advice. The idea was to have a 2
way discussion, I guess you could call that yammering. Sometimes in
the early stages of a development you just brain storm and bounce
ideas off different people's heads. Its a fun excercise for people
who like to think and interact. Its true, the CNC isn't chewing
aluminum and there aren't any flames yet, so it isn't quiet as
exciting, but until you think you've got the theory understood, you're
wasting time and material trying to construct something that will
likely take an inordinate amount of experimentation to optimize.
Thats the difference between an engineer and a tech I guess.

And that's a shame, since your surface radiator idea would be pretty
easy to prototype. All you need is an old pickup truck, an old car
hood, a bunch of copper tubing, a bunch of cheap plumber's solder, and
a propane torch. Oh, and a driver's license...

You need a propeller and cowl as well. The success of the idea may
hinge on the turbulence in the prop wash which decays very quickly as
you get further from the prop blade.

I mean, I think it's a dead-end idea, but I'm prepared to be
demonstrated wrong. But if you persist in just telling folks that
they're wrong without a shred of either empirical evidence or
engineering support, you're gonna stay pigeonholed in a lot of folks'
chucklehead files.

In a discussion its okay to disagree with someone as long as you can
supply a reason. The other person, can then attempt to address that
issue. This goes on and on until you've either come to the same
conclusion or some fundamental point on which there is a disagreement
which must be settled by experimental data or a more detailed off-line
analysis.

Thanks, and best regards to all

Bob K.
http://www.hpaircraft.com