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From: "William" <wschertz@ispwest.com>
To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
References: <list-607427@logan.com>
Subject: Re: [FlyRotary] Re: Welcome to the Club was Re: [FlyRotary] Nomore ACRE (for me)
Date: Sat, 15 Jan 2005 19:29:54 -0600
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Hi guys,
If you can arrange true *counter flow* you can get the exit air hotter than 
the exit water. My understanding of Todds setup is that it is similiar to 
mine -- two evaporator cores, in cross flow arrangement.

With that arrangement, it is *highly unlikely* to get the exit air hotter 
than the exit water, integrated over the surface of the exchanger. Heat has 
to flow downhill.

If you use the charts that I had in my article, you can do your own 
calculations. I used Todd's numbers because he actually measured the flow in 
the plane cooling loop.  My results indicate that it works okay in cool 
flying conditions, but might be marginal in hot conditions with high power.

Bill Schertz
KIS Cruiser # 4045
----- Original Message ----- 
From: "Ernest Christley" <echristl@cisco.com>
To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
Sent: Friday, January 14, 2005 12:58 PM
Subject: [FlyRotary] Re: Welcome to the Club was Re: [FlyRotary] Nomore ACRE 
(for me)


> On Fri, 2005-01-14 at 13:22, Bob White wrote:
>> Here is a link to the analysis Bill Schertz did on Todd Bartram's
>> cooling system: http://www.acre-media.org/schertz/EWP_analysis.html
>> Bill's analysis would indicate that Todd's system was marginally
>> adequate given the assumptions used.  Some were overly conservative, and
>> Todd has reported better results than would be expected from the
>> analysis.
>
> Is the 'first approximation', that the cooling air will never get hotter
> than the exiting water, a good one?
>
> It would seem to me that if you arranged a multipass radiator such that
> it entered in the rear and left at the front, the exiting air would be
> closer to the temperature of the radiator's hot side.
>
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