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From: "Ed Anderson" <eanderson@carolina.rr.com>
To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
References: <list-401902@logan.com>
Subject: Re: [FlyRotary] Re: Photos of Core tanks internals
Date: Wed, 8 Sep 2004 09:03:57 -0400
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Given you experience with the Brazing rod, I can certainly understand the
preference for welding.  My viewpoint is somewhat colored by the number of
cores I went through before getting two successfully welded - actually
brazed on{:>).

I agree if you find someone good with a TIG welder, welded bungs are
preferable.

Ed

Ed Anderson
RV-6A N494BW Rotary Powered
Matthews, NC
----- Original Message ----- 
From: "Steve Brooks" <steve@tsisp.com>
To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
Sent: Wednesday, September 08, 2004 7:44 AM
Subject: [FlyRotary] Re: Photos of Core tanks internals


> Ed,
> I had brazed my fittings with the aluminum brazing rod, but when I ran the
> engine and built up pressure on the system, one broke off on one side.  I
> decided after that to have them welded, so I took a chisel and rapped on
the
> bungs.  They popped off pretty easy.  The brazing rod melts easily enough,
> but it just doesn't seem to grip real well to the cores.  I heated mine
with
> a MAP gas torch, and had them pretty hot when I brazed them.
>
> I took them to the same place that welded my intake for me, and he TIG
> welded them with no trouble at all.  Of course this welder has been doing
it
> for 30 years, and welds all sorts of materials.  I have much better peace
of
> mind with those bungs welded, and not having to worry about one popping
off
> while up flying.
>
> Regards,
> Steve Brooks
>
>
>  -----Original Message-----
> From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net]  On
> Behalf Of Ed Anderson
> Sent: Tuesday, September 07, 2004 6:30 PM
> To: Rotary motors in aircraft
> Subject: [FlyRotary] Re: Photos of Core tanks internals
>
> David, I'll check on the thickness of the end plates (I believe that is
what
> you ask for the thickness on).  But from recollection, its a bit more than
> 1/8".  Regarding welding, actually some of the newer aluminum brazing rods
> would probably work better.  I finally found a radiator shop who repaired
> radiators and they simply brazed the fittings on.  But, clearly Rusty and
> others had better luck than I did with the welding approach.
>
> Ed
>
> Ed Anderson
> RV-6A N494BW Rotary Powered
> Matthews, NC
> ----- Original Message -----
> From: "David Carter" <dcarter@datarecall.net>
> To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
> Sent: Tuesday, September 07, 2004 4:25 PM
> Subject: [FlyRotary] Re: Photos of Core tanks internals
>
>
> > Ed, great pictures and info!!  Thanks a lot.
> >
> > The larger tube on my cores is exactly 3/4" OD.  The end seems to have a
> > 1/2" long insert in it - insert has OD of 0.678, which is the ID of the
> 3/4"
> > main tube.  If I cut off that 1/2" "tip" of the larger 3/4" OD tube to
> > eliminate the "insert" (which has a smaller ID of 0.565), then I'll have
a
> > tube with 3/4" OD and .678 ID.
> >
> > On the other end cap the tubing is exactly 1/2" OD and about .460 ID -
and
> > has the little filter inside.
> >
> > I plan to run my 2 evap cores in parallel - to get greater flow than
would
> > be possible running them in series.
> >     -  I will use two home-made splitter blocks, each to have a standard
> > radiator hose on one side (attached to engine "hot" outlet or water
pump,
> > respectively) and two smaller 3/4" ID hoses on the other side (to attach
> to
> > evap cores, inlet or outlet, respectively).
> >
> > After I modify each core to replace the 1/2" OD tubing with 3/4" OD, so
> each
> > core has a 3/4" ID inlet and a 3/4" ID outlet, these inlets and outlets
> will
> > have an inner area of 0.361 sq inches.
> >     -   With two cores, I'll have a combined inlet area (and outlet
area)
> of
> > 2 times that, or .722 sq inches, to be "fed" by a single automotive
> radiator
> > hose via the 2 splitters.
> >     -  Given "required area" of .722 (minimum), the "main single hoses"
> and
> > any associated fittings must have at least .722 sq inch area which
equates
> > to an ID of 0.9588 inches (or more - use of "stock" hose and fittings
> sizes
> > may result in "next size bigger" than 1" ID).
> >     -  Looking at just one website for hoses & fittings, a fitting for
1"
> ID
> > hose had an inner bore ID of 0.84 inches.  To get a fitting bore ID of
> > approximately 1" requires going to a 1 1/4" ID hose.
> >
> >     -  What is the standard sized water hose used on an RX-7?  1 1/4"? 1
> > 1/2"?
> > . . . . . -- I'll  use whatever fits the stock pump and a stock
radiator,
> > and run it to my home-made "splitter" blocks.
> >
> >     -  Coming out of the splitter block to my 3/4" OD "inlet" tube on
each
> > core, I'll use smaller "heater hose" of 3/4" ID to slip over 3/4"OD
tubes
> on
> > cores.  I'll select the tubing coming out of/going into my 2 splitter
> blocks
> > to be identical to that 3/4" OD tubing on the cores.
> >
> >     -  Using water hose instead of AN fittings, where do I look/go to
find
> > "bungs" on  3/4" OD tubes and 1 1/4" ID hose bungs?  I'd want to use 2
> water
> > hose clamps to hold hoses securely.  I haven't found a good website or
> > source for the "bungs" to weld onto the evap cores. (I'll be putting
> orange
> > "fire sleeve" on all hoses - and wiring? - in the engine compartment.)
> >
> > In case I wanted to get even more flow than the 3/4 inch OD tubing on
the
> > evap cores would allow, is there room in those little flat spots on the
> end
> > caps to weld on a fitting or tubing with 1" OD (with approx ID of 0.964
> > inches or so if wall thickness is 0.036 + or -)?
> >     -  I held my core in my lap with an "end cap" on each side, the 13
> > coolant tubes running horizontally left & right; I laid my ruler on the
> core
> > and measured 1" or maybe 1 1/8" from "inside" side of "end cap" to the
> > narrow (wasp waist) of the segments of the end cap.
> > . . . . - - Ed, I just reviewed your web 1998 web document on how many
> cores
> > you went thru before you found a good welder and how the low temp alloy
of
> > the cores would melt when using the higher temps required to weld on the
> fat
> > fittings.
> > . . . .  ---- Looks like going to a "max size fitting" of 1" or so might
> get
> > the welding heat too close to the seams and not be worth the risk of
> ruining
> > the core.  I'm thinking I'll stick with 3/4" OD tubing on the cores.
Just
> > wondered if you could measure one of those "sample cores" to get the
> > dimension "perpendicular" to the nominal 3" thickness of the end caps
that
> > is available for welding.
> >
> > David
> >
> > ----- Original Message -----
> > From: "Ed Anderson" <eanderson@carolina.rr.com>
> > To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
> > Sent: Tuesday, September 07, 2004 11:38 AM
> > Subject: [FlyRotary] Photos of Core tanks internals
> >
> >
> > > Well, David,  I just went down to the shop through the pouring
remnants
> of
> > > Frances and cut open each side tank of a core I had taken from the
> > junkyard
> > > years ago.
> > >
> > > The photos are attached and speak for themselves - no dividers or
other
> > > impediments to coolant flow in the tanks - pretty clean channel from
top
> > to
> > > bottom.  Each "row" has 5 approx 1/8" (perhaps slightly larger) dia
> holes
> > > that conduct the water through the core to the opposite side tank.  So
> 14
> > > rows * 5 * area of 1/8-3/16" dia hole would give a cross flow channel
> area
> > > of around 0.86 sq inches to 1.93 sq inches - probably toward the
larger
> > > figure.
> > >
> > > So as Bill suggested they may have redesigned the heat exchangers to
> take
> > a
> > > different approach to recondensing the refrigerant calling for the
> divider
> > > plate.  Given the relatively small cross channels, it is my opinion
that
> a
> > > serpentine cooler is probably offering considerably more resistance to
> > flow.
> > > Some of the radiator shop webpages give an estimate of the increase in
> > flow
> > > resistance of a Serpentine core over the straight through - as best I
> > recall
> > > it was something like 4 times as best I recall.
> > >
> > > So, its clear that not all GM evaporator cores are created the same
way.
> > > This one was from the an late 80s early 90s Cadillac.  I looked all
over
> > for
> > > some identifying model number but could not find anything.  I do
recall
> it
> > > had a yellow sticker with a black C on it when I yanked it.
> > >
> > > In any case, it looks like we can not simply order just any GM cooler
> > core.
> > > I suspect that when they switched over to the more environmental
> friendly
> > > refrigerant then  there could have been some redesign of the core, but
> > just
> > > speculation on my part.
> > >
> > > Here's the photos
> > >
> > > Ed.
> > >
> > >
> > > Ed Anderson
> > > RV-6A N494BW Rotary Powered
> > > Matthews, NC
> > > ----- Original Message -----
> > > From: "David Carter" <dcarter@datarecall.net>
> > > To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
> > > Sent: Tuesday, September 07, 2004 11:55 AM
> > > Subject: [FlyRotary] Re: Water pump problem
> > >
> > >
> > > > Thanks, Ed.
> > > >
> > > > I wonder Steve Brooks's core with a "plate" is different from the
> > > > GM/Harrison cores that I have (Chev'y Caprice).
> > > >     - When I probed my core last night and found no plates in the
end
> > cap
> > > > with the larger of the two welded tubes, I DIDN'T check the other
> side -
> > > > those smaller 1/2" OD tubes turn 90 degrees and run about a foot, so
I
> > > never
> > > > probed that side.  That is the side that has the little "filter"
> and/or
> > > > "expansion jet" thing sitting about an inch down inside.  Perhaps
> > there's
> > > a
> > > > plate on that side that matches what has been discussed recently.
> > > >
> > > > If Steve's core is a typical GM/Harrison core, then I'd like to
> > understand
> > > > more about which end "the plate" is in and tell us more about "the
> tube
> > > that
> > > > was removed".  I've not yet cut into any of my cores to mod the
> > fittings,
> > > so
> > > > am ignorant of the insides.
> > > >
> > > > David
> > > >
> > > > ----- Original Message -----
> > > > From: "Ed Anderson" <eanderson@carolina.rr.com>
> > > > To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
> > > > Sent: Tuesday, September 07, 2004 6:54 AM
> > > > Subject: [FlyRotary] Re: Water pump problem
> > > >
> > > >
> > > > > Hey, David, not to worry.  We have all hit the "Send" button on an
e
> > > mail
> > > > or
> > > > > two and later wondered why we did. {:>)
> > > > >
> > > > > Ed
> > > > >
> > > > > Ed Anderson
> > > > > RV-6A N494BW Rotary Powered
> > > > > Matthews, NC
> > > >
> > > >
> > > >
> > > > >>  Homepage:  http://www.flyrotary.com/
> > > > >>  Archive:   http://lancaironline.net/lists/flyrotary/List.html
> > > >
> > >
> >
> >
>
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> >
> >
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> > >
> >
> >
> >
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>
>
>
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