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A fellow rotary flyer attempted parallel cores (coolant)
without success. He found that the flow through each core depended (in
part) on the engine rpm (pump rpm). He even tried an adjustable "flow
diverter" to ensure that the same amount of coolant flow through each
core. He reported that while he could balance the flow between the
two cores at one rpm, that at a different rpm the share of coolant flow would be
different. He finally gave up and went back to cores in
series.
That said, on the other hand, Tracy Crook has been
flying with parallel flow cores since day one and certainly has adequate
cooling. As best I recall he had rather small lines - line 5/8" dia
flowing from his thermostat housing to each core. It could be that having
the division of the flow all the way back (almost) to the pump might alleviate
some of the flow division problems. I also suspect that the because he
takes the flow from what I would call a mini-plenum (the volume of the
thermostat housing) that might also assist evening the flow - but just
speculation.
Like Lynn said, both parallel and series configuration
have been make to work just fine. Like most things we wrestle with there
are pros/cons to each.
Ed
----- Original Message -----
Sent: Sunday, May 07, 2006 8:22 AM
Subject: [FlyRotary] Re: oil cooler
lines
I agree that flow can be balanced, however you would have to be able to
measure the flow in order to do that, and most installations do not have that
capability. Just assuming that they are balanced is frought with the peril
that they might not be due to irregularities that are not obvious.
Bill
--------------
Original message --------------
From: "george lendich"
<lendich@optusnet.com.au>
Bill,
There must be there a way of balancing/
equalising the pressures and flow through
parallel radiators with the use of regulators
or some such auto or pre-set resistors or balance tubes etc.
George (down under)
----- Original Message -----
Sent: Sunday, May 07, 2006 9:49
AM
Subject: [FlyRotary] Re: oil cooler
lines
Maybe -- maybe not. The hydraulic resistance for the two flow paths
may be different, then the flows will not be the same.
I have mine plumbed parallel, and took pains to make all hose
connections equal length. We will see when I get it started whether it
works as planned.
Bill Schertz
--------------
Original message --------------
From: Bulent Aliev
<atlasyts@bellsouth.net>
> Bill, I would think they
will even out by equalizing the back
> pressure from the cooler?
> Buly
> On May 6, 2006, at 9:24 AM, wschertz@comcast.net
wrote:
>
> > Buly,
> > You are correct that
parallel coolers will be more efficient, IF
> > the liquid
flow through the coolers are the same.
> > Bill Schertz
> >
> > -------------- Original message
--------------
> > From: Bulent Aliev
> >
> > > I believe
parallel coolers will be more efficient due to the higher
> >
> delta T. In a serial set up, the liquid in the second cooler will
be
> > > lower temp. and less efficient heat transfer will
take place.
> > Jus t an
> > > opinion of an
eyeball engineer?
> > > Buly
> > > On May 5,
2006, at 11:34 PM, Kelly Troyer wrote:
> > >
> >
> > Bob,
> > > > One other comment........There is
some difference of opinion
> > > > among the group
> > > > whether connecting coolers (oil or coolent) in
series (as you
> > > > propose) or in
> > >
> parallel is the most efficient method.........We have group
> > members
> > > > currently
> >
> > flying with both methods........Most that I am aware of that
use
> > > > both methods
> > &g t; >
are for coolent systems as not many are using two oil
> > >
> coolers........I personally
> > > > lean toward a
parallel coolent system........Any comments from
> > > >
others in the
> > > > group about this question would be
welcome as I know we have
> > > > several with
>
> > > experience or training in this area !! What would be most
> > efficient
> > > > for one
> >
> > system should probably apply to the other.......IMHO
>
> > > --
> > > > Kelly Troyer
> >
> > Dyke Delta/13B/RD1C/EC2
> > > >
> >
> >
> > > >
> > > >
> >
> > -------------- Original message from kenpowell@comcast.net:
> > > > --------------
> > > >
>
> > > Bob,
> > > > I think you should have made
the lines larger to help lower
> > presure
> > >
> drop in the long lines. I understand that the extra oil in the
> > > > lines will be heavy but the pressure drop would
be a tradeoff that
> > & gt; > I wouldn't want to make.
> > > >
> > > > Ken Powell
> >
> > Bryant, Arkansas
> > > > 501-847-4721
>
> > > C150 / RV-4 under construction
> > > >
> > > > -------------- Original message --------------
> > > > From: BMears9413@aol.com
> > > >
I'm running two oil coolers in the Spitfire. Due to the lengthe of
> > > > the lines and volume of the two coolers I
reduced my oil lines to
> > > > AN8 (I think stock they
were 10?) Now, before I close
> > everything up
> >
> > I'm having second guessing. My total line length will be
around
> > > > 12'. I had planned on running the lines
to one oil cooler, then
> > the
> > > > other,
then back to the motor.
> > > > Any comments?
>
> > >
> > > > ; Bob Mears
> > >
> > > Buly
> > > http://tinyurl.com/dcy36
> > >
> > >
> > >
> >
>
> > > --
> > > Homepage:
http://www.flyrotary.com/
> > > Archive and UnSub:
http://ma il.lancaironline.net/lists/flyrotary/
>
> Buly
> http://tinyurl.com/dcy36
>
>
>
>
> --
> Homepage: http://www.flyrotary.com/
>
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