Thanks Bill,

One question.  Did you have a thermostat in the engine when you did
these measurements?  That would effect the pressure and flow rates.

Of course what I need to know is how much flow is sufficient for full
power cooling.  If I take the crossing point of the 'two core' data and
the 5594 RPM data as an indication, it looks like around 9 psi and 33
GPM is what the factory pump is providing.  This should be similar to
Tracy Crook's situation.  Am I looking at that correctly?

Bob White

On Sun, 7 Nov 2004 09:09:56 -0600
"William" <wschertz@ispwest.com> wrote:

Bob,
Attached is a graph of the performance of a Mazda mechanical pump at
different rpm. Several things about the performance can be deduced.
The measurements were taken by pumping water from a barrel through the
engine and back to the barrel. Flow was measured by the time required
to fill a 5 gallon bucket, and pressure drop was measured into and out
of the engine water pump.

First, at zero flow, the pump is generating its maximum pressure. At
zero pressure, the pump is generating its maximum flow. Since the
measurements are made at the inlet and outlet of  the pump, the
pressure drop of the engine core is included. If you look at the three
rpm curves, at 2448 rpm, the pump can generate just under 5psi head,
and a no head flow of ~20gpm. this means that the pressure drop
through the core is 5 psi at 20 gpm.

At 3730 rpm you get 8.5 psi and 33 gpm, at 5594 you get 19psi and 44
gpm.

I also measured the pressure drop across GM evap cores as a function
of flow. Data is plotted on the curve.

Bill Schertz
KIS Cruiser # 4045
----- Original Message ----- From: "Bob White" <bob@bob-white.com>
To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
Sent: Saturday, November 06, 2004 9:39 PM
Subject: [FlyRotary] Re: EWP Info


> On Sat, 6 Nov 2004 20:52:55 -0600
> "Russell Duffy" <13brv3@bellsouth.net> wrote:
>
> > Hi Bob, somehow these numbers do not pass the "smell test". There
> > is no way you can pump 20 GPM with the back pressure in the system
> > on 5 Amps alone. Larry's observations below make sense. A little
> > air blower motor moving air uses 5 Amps. Bulent
> >
> >
> > Hi Bulent,
> >
> > You're starting to sound like a disbeliever.  We're not going to
> > have to banish you to the other list are we :-)
> >
> > Rusty (I believe)
> >
>
> Now now!  Let's not have any banishing around here. :)
>
> I don't know what the numbers mean but I will let you know how it
> works out.  Todd reported his pump measured 4.3 amps at 9.3 gpm (if
> I understood his last post).  Mezarie may be reporting the "no load"
> pumping capacity, or Summit may have the current wrong.  I should
> have the pumps sometime next week.
>
> Any idea what a ball park figure for the pressure drop across the
> engine and an evap core would be?  I could simulate it on the bench.
>
> Bob White
>
>
> -- > http://www.bob-white.com
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