Mailing List flyrotary@lancaironline.net Message #41995
From: Ed Anderson <eanderson@carolina.rr.com>
Subject: Re: [FlyRotary] Re: Emailing: Inclinded Radiators.doc
Date: Wed, 19 Mar 2008 20:27:58 -0400
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Hi Charlie,

Yes, several folks have pointed out variables that may have contributed to
the "increased" effectiveness of the inclined radiator.  Al, pointed out that the inlet appeared to be the old "sinsodal" type which almost guaranteed early flow separation and poorer cooling.  So then if you incline a larger radiator - the added area alone would contribute to better cooling - and if inclining it had a
favorable influence on "smoothing" out the air flow - the cooling would
appear more effective with an inclined radiator that a perpendicular one. Whereas a perpendicular one of the same size as the inclinded one would beat.

Ah! Such fun!

How are you and Tupper doing?  Going to S&F this year?

Ed

----- Original Message ----- From: "Charlie England" <ceengland@bellsouth.net>
To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
Sent: Wednesday, March 12, 2008 3:59 PM
Subject: [FlyRotary] Re: Emailing: Inclinded Radiators.doc


Ed Anderson wrote:
Here is an extract out of an article on race car cooling that is very
interesting about use of inclined radiators.  Unfortunately, I could not
find any reference as to where this information was derived from - but,
if correct, is fairly significant.
 It basically states that inclining a radiator from 0 deg to 20-30 deg
will decrease cooling and increase drag - not terribly surprising,
however, the article continues saying that at approx. 55 dig of
inclination the cooling effectiveness is 30% greater than a radiator with
no inclination and the drag is 20% less!!!  Now I found that surprising -
but, then air flow does take surprising twists (no pun intended).
 While I find that claim very interesting - I have not found any
collaborating documents.  But, thought the group might find it
interesting
 For your information
 Ed

I learned a long time ago (Maybe it was Mr. Wizard & blocks sliding down a
ramp...??) that with physics, what looks right or sounds right probably
isn't.

But this one looks like a trick question. Notice the mention of 'larger
radiator'? Perhaps the original inlet vs. core density wasn't set up
correctly & they were trying to force too much air through the core. When
they tilted the radiator, they apparently also made it bigger, meaning
more fin area *and* more open area for the same inlet/outlet areas.

But like I said, what sounds right, rarely is, if it's me doing the
listening...

Charlie

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