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From: "Leon" <peon@pacific.net.au>
To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
References: <list-595621@logan.com>
Subject: Re: [FlyRotary] Re: Coolant Flow : oi/water Exchanger Take 2
Date: Sun, 9 Jan 2005 07:37:17 +1100
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Yo Dave,

There is no reason why it can't or won't work if correctly plumbed.  The
only proviso is that the rad obviously has to be big enough to dissipate ALL
the heat of the engine at WOT. The oil heat exchanger can be fitted anywhere
that's convenient,  but MUST be fed with water from the COLD side of the
rad,  just like the engine itself.

What happens sometimes is that people don't think these issues through.
Then they make false conclusions based on incorrect assumptions.  I've been
using oil/water heat exchangers for 25 years.  Mainly on boats,  but in cars
as well.  So there is no reason why an oil/water heat exchanger can't be
used in aero applications as well.  Doesn't matter if it's the stock Mazda
unit or a custom one like the pic Ken posted.  As long as they have a flow
of cold water through them,  they MUST work.

Cheers,

Leon


----- Original Message ----- 
From: "DaveLeonard" <daveleonard@cox.net>
To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
Sent: Sunday, January 09, 2005 2:45 AM
Subject: [FlyRotary] Re: Coolant Flow was Re: [FlyRotary] Re: oi/water
Exchanger


> Oh, now that makes sense.  Leon to the rescue again.
>
> BTW, my previous post was supposed to be a reason for not using an
> exchanger, not so much a request for a solution.  But now with your input
it
> could be feasible IF, like Ed says, your installation really only has room
> for a large Rad but not an oil cooler.
>
> Dave Leonard
>
> > The Mazda one
> > will work just as efficiently if you feed it with water from the COLD
side
> > of the rad.  It's a really robust unit,  and I've never seen one leak.
> >
> > Hope this clarifies the situation ...
> >
> > Cheers,
> >
> > Leon
> >
> > P.S.
> > I get my cold water under pressure by drilling & tapping into the
> > water pump
> > housing just before it goes into the block. Works a treat!!
> >
> >
> > ----- Original Message -----
> > From: <daveleonard@cox.net>
> > To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
> > Sent: Saturday, January 08, 2005 12:46 PM
> > Subject: [FlyRotary] Re: oi/water Exchanger [FlyRotary] Re: fluidyne oil
> > cooler
> >
> >
> > > 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)
> > > >
> > > >
> > > >
> > > >
> > >
> > >
> > > >>  Homepage:  http://www.flyrotary.com/
> > > >>  Archive:   http://lancaironline.net/lists/flyrotary/List.html
> > >
> >
> >
> > >>  Homepage:  http://www.flyrotary.com/
> > >>  Archive:   http://lancaironline.net/lists/flyrotary/List.html
>
>
> >>  Homepage:  http://www.flyrotary.com/
> >>  Archive:   http://lancaironline.net/lists/flyrotary/List.html
>