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From: "Bob Perkinson" <bobperk@bellsouth.net>
To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
Subject: RE: [FlyRotary] Re: Coolant Leak
Date: Sun, 26 Jun 2005 08:38:59 -0500
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Importance: Normal

Even with a cushion of air the pump will still produce the same amount of
pressure.  The Pressure in the system will still be able to go to what ever
the relief setting of the radiator cap is.  The heater core will see this
pressure at some point.

Bob Perkinson
Hendersonville, TN.
RV9A N658RP Reserved
If nothing changes
Nothing changes


-----Original Message-----
From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net]On
Behalf Of John Slade
Sent: Sunday, June 26, 2005 8:08 AM
To: Rotary motors in aircraft
Subject: [FlyRotary] Re: Coolant Leak


So, would it be better to remove some coolant and HAVE a cushion of air, and
thereby reduce the pressure and stress on cooling system components? I have
a heater core up front. I'd hate to have it burst. Is it really seeing 20+
PSI when it was probably designed to take less?
John

>  >
> > This may be related to Al Wicks reason for running with a cup of air
> > trapped in his system, a buffer if you will.....Tim Andres
> >
> I do notice that after I have refilled the coolant system (and before the
> air is all flushed out), that I do not get the immediate surge of
> pressure
> to 21-24 psi on start up.  It will slowly climb to 8-12 psi depending on
> power settings and airspeed.    However, after several flights and the
> system is purged of air this phenomena starts to occur.  Again,
> no coolant
> leak associated with it.  I suspect that with the air purged, that this
> surge has to do with the coolant volumetric area.  With no
> cushion, then any
> movement of coolant is likely to be sensed as a pressure increase
> - once the
> block has warmed up and coolant passages, etc, have warmed up (and
> expanded), I think there is a slight increase in coolant passage
> volume and
> the pressure decrease as a results.  Just a SWAG of course.
>
> Ed A
>
>
>
> >>  Homepage:  http://www.flyrotary.com/
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