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Date: Fri, 07 Jan 2005 22:35:40 -0500
Subject: Re: [FlyRotary] Re: oi/water Exchanger  [FlyRotary] Re: fluidyne
	oil cooler
From: Bulent Aliev <atlasyts@bellsouth.net>
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
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On 1/7/05 8:46 PM, "daveleonard@cox.net" <daveleonard@cox.net> wrote:

> I was considering the idea when I was planning my installation and one big
> question kept popping into my mind: which side of the rad do you put the
> interchanger?
> 
> If you put the interchanger on the hot water coming out of the block, that
> water is at least 180deg.  This hot water will have a very hard time cooling
> that oil, and best case could only get it down to 190 or 200.  Likewise the
> water is likely to boil before it get to the radiator since it is starting at
> 180 (at least) and going up from there.
> 
> If you put the interchanger after the radiator it will probably do a good job
> of cooling the oil, but now you will be heating the water right before it goes
> back into the engine.  In order to keep the water from overheating in the
> engine it will have to come out of the heat exchanger relatively cool, which
> mean it has to come out of the rad really cool.  To get it that cold comming
> out of the rad that cold (assuming you had a big enough rad), the temperature
> gradient really has to drop and the rad becomes very inefficient as it is
> trying to cool the coolant that extra 20 deg.
> 
> I decided the only efficient way to do it was to have two rads, one after the
> interchanger and one before it.  I suppose that would work if you were using 2
> evap cores in series, but for me the obvious solution was to use an oil/air
> cooler.
> 
> Dave Leonard
> 
>>  
>> Good points of course, but I still can't help but be drawn to the simplicity
>> of having only one scoop, one duct, and one radiator.  Even as I type, I'm
>> trying to figure out where I can put a bigger radiator (within cosmetic
>> limits this time)  :-)    I'm even warming back up (so to speak) to the idea
>> of using the stock 1st gen oil/water exchanger for the single rotor.  It was
>> pointed out to me that the stock unit took hot water from the heater outlet,
>> which doesn't really give the heat exchanger the best chance of success.
>>  
>> If I get Ken's oil/water exchanger, I'll be mighty tempted to hook it up to
>> the current two radiators to see how it does on the ground.  Since I'm not
>> opposed to changing out the evap cores, there might be a way to enlarge the
>> capacity some.  Barring all that, it'll make a nice paperweight.
>>  
>> Cheers,
>> Rusty (now collecting oil coolers instead of manifolds)
>>  
>>  

Only oil/water exchangers I have seen that work are on boats. They are
cooled with COLD water and they work very well. If you are trying to cool
hot oil with hot water, I don't think so! Just get an efficient radiator
Rusty.
Buly