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From: "Ed Anderson" <eanderson@carolina.rr.com>
To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
References: <list-1021975@logan.com>
Subject: Re: [FlyRotary] Re: Coolant Leak
Date: Sun, 26 Jun 2005 10:05:16 -0400
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Good question, John

If the analysis is correct, it may indeed be better to have a small cushion 
of air at as an absorber.  All of my coolant components take at least 250 
psi (radiator cap and water pump seals excepted).  The only concern I have 
with higher pressure is blowing out the seal around the water pump shaft - 
don't have any idea how much pressure that might take.

Ed
----- Original Message ----- 
From: "John Slade" <sladerj@bellsouth.net>
To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
Sent: Sunday, June 26, 2005 9:07 AM
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/
>> >>  Archive:   http://lancaironline.net/lists/flyrotary/List.html
>
>
>>>  Homepage:  http://www.flyrotary.com/
>>>  Archive:   http://lancaironline.net/lists/flyrotary/List.html