Mailing List flyrotary@lancaironline.net Message #40299
From: Mark Steitle <msteitle@gmail.com>
Subject: Re: [FlyRotary] Dimensions of my oil/water heat exchanger
Date: Sun, 11 Nov 2007 18:00:58 -0600
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Doug,
As we all know, there's no free lunch.  What I have discovered is that
if you go with the oil/water exchanger, you must have enough excess
radiator capacity to handle the extra btu's from the oil.  I have
tried different configurations and what I have now seems to work best
(for me).  Keep in mind that my oil temps were in the 230-240* on
shallow climbs.  They would come down when I leveled off, but not as
much as I would have liked.  However, water temps were always well
within limits, bordering on too cold.  Through the use of the
oil/water exchanger, I was able to shift some of the heat load to the
water.  A side benefit of this system is that the oil and water now
track within 5* of each other.

My latest configuration is to run the oil from the engine into the
oil/air exchanger first, then into the oil/water exchanger, and
finally into the engine.  This way I'm dumping the most heat directly
into the air.  The remaining heat is transferred into the water.  I
flew today and the oil and water temps barely went over 200 in a
pretty aggressive sustained climb, and both came down into the
170-175* range during my economy cruise settings (1700 prop rpm, 5100
engine rpm, full throttle).  (Yes, I have a constant speed prop.)
This is on the low side of my targeted temps.  So, I'll probably leave
it like it is and concentrate on some of the other issues.

Mark S.

On Nov 11, 2007 8:17 AM,  <DLOMHEIM@aol.com> wrote:
>
>
> Mark:
>
> Did yours come with AN fittings all around or just on the oil hookups?  I
> have seen a couple with tubing connections for water and AN for the oil.  I
> think I will start looking for one and install right from the start since I
> think I should have some excess radiator capacity with the Griffin and a
> goal of only producing 160-170 hp...
>
> Doug Lomheim
> RV-9A, OK City, OK  FWF
>
>
>
>
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