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Date: Fri, 2 May 2008 10:03:10 -0600
From: Bob White <bob@bob-white.com>
To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
Subject: Re: [FlyRotary] Re: radiator orientation?
Message-Id: <20080502100310.33dcec29.bob@bob-white.com>
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On Thu, 1 May 2008 20:14:48 EDT
Lehanover@aol.com wrote:

>  
> In a message dated 5/1/2008 3:31:46 PM Pacific Daylight Time, silvius@gwi.net 
> writes:
> 
> Anyone see any issues of concern with installing the radiators in the
> vertical orientation as opposed to their normal orientation with the inlets
> and outlet on the top. These are evaporator cores from a JMC Jimmy- Chevy
> Blazer
> 
> Michael in Maine
> 
> Make at least one outlet at the top. Inlet at the bottom.
>  
> Lynn E. Hanover
> 
> 
> 
Hi Lynn,

I had to sleep on that advice to get it straight in my head.  I believe
it's good advice, but could still be connected in a detrimental way.
It's important to feed the water pump from the bottom of one of the
coolers.  If the coolers are in series, the outlet and inlet would both
be on the bottom with a straight connection between the top fittings
connected together.  That would simplify the plumbing as well as insure
that in the event of a cooling leak, the second core would remain full
of water at least until the first core was nearly empty.  Using the top
fittings for outlet and inlet would still make one of them flow bottom
to top, but would be detrimental if there were a loss of fluid.

With the cores in parallel, I'm not so sure bottom to top flow for one
of them would be a good idea.  It would complicate the plumbing, and
make it more likely that flow rates would be unequal between the
cores.  But if one did connect them that way, it would still be
important to make the outlet near the bottom of the radiator.

I had always wondered why Mazda designed the engine with the water pump
so near the top of the engine which results in a lack of flow with just
a small amount of water loss.  It seemed to be a design flaw.  After
starting to disassemble the RX-7, I now realize that the engine is
setting so low relative to the radiator in the car that is isn't any
more of a problem than most cars.  In general, the radiator is
usually relatively low in the airplane installations which make the
pump location less than ideal.

Bob W. (Need something better to think about when I can't fall asleep.) 


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