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Pulling a couple of sentences on 1 topic from the e-mail down below:
"> You can mount either system anywhere. They don't need to be higher than
> anything to work. <snip> >The Mazda bottle can be mounted ANYWHERE so
long as it is upright. And "anywhere" can be a handy
> location." Quoted from a message from Lynn E. Hanover."
The "early Mazda" (and late 90's Ford Taurus) "pressurized expansion tank"
can serve TWO functions, if mounted so its 'hot" coolant level is ABOVE the
"top of engine air/steam vent line fitting":
....Function 1: Expansion tank (traditional purpose, hence its name) -
holds expanded fluid temporarily. a) This is the ONLY purpose of
UNPRESSURIZED "auto" expansion tanks, to "temporarily hold" expanded
coolant, then allow it to be reclaimed by the "closed system" when engine
cools down - - this has limits as stated by Lynn. b) The PRESSURIZED tank
also collects expanded coolant, but "returns" it in a totally different way
(gravity), and thus MAY provide a 2nd function;
....Function 2: "Liquid top off tank & air/steam purge tank" - only the
PRESSURIZED "Mazda/Ford expansion tank MAY serve as a CONTINUOUS
REPLENISHMENT tank and ALWAYS keep "closed system" 100% full of liquid with
zero air anywhere in the system (engine block & radiators, granting there is
air in top of pressurized expansion tank) - but only IF
......... 1) MOUNTED with coolant level AT OR ABOVE highest point of engine
(where air bleed line is installed) , and
......... 2) PLUMBED out bottom of pressurized expansion tank down to a T
fitting in water hose - or metal pipe - coming out of bottom of radiator
(lowest" spot in coolant system) - the hose that goes toward the water pump
inlet.
..............I don't see how this "replenishment"/"keep the closed system
full of liquid" function can occur if the FLUID LEVEL of the pressurized
"Mazda/Ford" expansion tank is BELOW the top of the engine (top air vent
fitting). If we mount tank lower so fluid level is below, and then assume
we have an air bubble in the top of the engine - for any reason (not
"burped" after filling system, or a leak allowing in air), then IF the air
stays in the top of the engine (doesn't "mix and flow with coolant", then
the air won't "flow" downhill from the vent fitting to the expansion tank.
Instead, the air vent line from top of engine DOWN to the low mounted
pressurized expansion tank will become an AIR TRAP, not an AIR VENT.
I realize that I am on shakey ground disagreeing with Lynn on how high/where
to mount the pressurized expansion tank. He is, in my opinion, the greatest
contributor and source of practical experience we have on cooling systems.
I'm only trying to get a better understanding of this "air purge" thing
before I finalize my cooling system design. I don't think we are far apart
on understanding the basics.
David
----- Original Message -----
From: "sqpilot@earthlink" <sqpilot@earthlink.net>
To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
Sent: Thursday, March 04, 2004 7:02 AM
Subject: [FlyRotary] Re: ready to start?
> Hi, Mark....I was reading a recent post on this site from Lynn Hanover, in
> which he talks about the advantages of using a pressurized expansion tank.
> He calls it the Mazda system (ie the way they used to do it) and calls the
> unpressurized system the "auto system" (the way most still do it-but not
> all).
> snip..".With the pressure cap in the system between the radiator and the
> recovery bottle, any coolant that gets by the cap and into the bottle
cannot
> be recovered until the engine has cooled to ambient, or close to it. Only
> then will the system pressure drop below ambient and coolant in the bottle
> will be at ambient, and thus at a higher pressure, so it replaces the
> coolant lost by the system. (Not all of it, but close). snip....Earlier
> rotary powered cars had a plastic bottle on the firewall, and that bottle
> had the pressure cap on it. The advantage here was that the engine didn't
> have to cool all the way down to recover coolant from the recovery bottle.
> Small volume changes from changes in heat load would cause fluid exchange
> from the pressurized bottle to the top of the radiator. Coolant entered
the
> bottle from the bottom, so a slug of air forced out of the radiator would
> pop to the top of the recovery bottle and when power (and heat) was
reduced
> in the engine it would recover only water from the bottle."
> "The advantages to the old Mazda system are: it will return all of
the
> coolant in the bottle to the engine in case of a leak. You get nothing
back
> from the "car" system until the plane is on the ground and cold. this
system
> is much better at removing air from an operating system. The weights are
> about the same for both.
> You can mount either system anywhere. They don't need to be higher
than
> anything to work.
> The car system is just a little less well off when mounted
> low but not a problem, but it is open to ambient.
>The Mazda bottle can be mounted ANYWHERE so long as it is upright. And
"anywhere" can be a handy
> location." Quoted from a message from Lynn E. Hanover.
>
> I was trying to copy this system, so that I could mount the expansion
tank
> anywhere. It just turned out that the firewall was pretty close, and
would
> only require two short hoses. I may have missed some important items
here.
> If you would like, I can probably scan the entire message and e-mail it if
> you are interested in reading the complete e-mail? Hope you find this
> interesting. Paul Conner
> ----- Original Message -----
> From: "Mark Steitle" <msteitle@mail.utexas.edu>
> To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
> Sent: Wednesday, March 03, 2004 8:24 AM
> Subject: [FlyRotary] Re: ready to start?
>
>
> > Paul,
> > Good luck on your first run. That's a big milestone. I see that your
> radiator
> > is a dual pass design. From what I see in the picture, I would put a
> small
> > fitting on the
> > uppermost point of the left tank and run it back to the side fitting of
> the
> > expansion
> > tank. Otherwise, I don't see how air pockets can be cleared. Also, the
> exp.
> > tank needs to be higher than the thermostat housing else you can never
> fully
> > fill the system.
> >
> > Mark S.
> >
> > At 12:20 AM 3/3/2004 -0500, you wrote:
> > >Hi, fellow rotary enthusiasts....Here are a couple of pictures of my
13b
> > >engine installation. I'm getting ready to start it and only run it for
> > >possibly 30 seconds and then check for leaks, etc. I would appreciate
> any
> > >comments regarding anything that doesen't look right. The alternator
> belt
> > >is not on in this picture, but it will be. Also, the oil cooler is
> > >temporarily bypassed just to see if it runs, then I'm taking the banjo
> > >fittings to the local hydraulic shop to have hoses crimped on. I
checked
> > >for spark, and it appears adequate. Thanks for any and all input. Paul
> > >Conner
> > >
> > >
> > > >> 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
>
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