Mailing List flyrotary@lancaironline.net Message #7602
From: sqpilot@earthlink <sqpilot@earthlink.net>
Subject: Re: [FlyRotary] Re: FW: Sad story
Date: Sun, 25 Apr 2004 12:54:09 -0500
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Re: [FlyRotary] Re: FW: Sad story
 
----- Original Message -----
Sent: Sunday, April 25, 2004 11:02 AM
Subject: [FlyRotary] Re: FW: Sad story

----- Original Message -----
From: Al Gietzen
Sent: Sunday, April 25, 2004 11:37 AM
Subject: [FlyRotary] Re: FW: Sad story

 

On 4/24/04 7:53 PM, "Tracy Crook" <lors01@msn.com> wrote:


 It's possible I misunderstood the explanation but the theory of why this happened seems unlikely.  The sudden expansion of coolant would have to be incredibly fast to cause an overpressure due to not being able to get out through the overflow tube fast enough.
 
Tracy

 

I just learned it was a ¼” line; i.d about 1/8”.  Trying to squirt a pint or more through that in; what; less than a minute? That could do it.  I currently have a ¼” line on mine as an overflow from the pressure bottle.  The pressure would release from the cap (through the upper gasket) but I would lose coolant in a similar scenario.  I’m going to rework that to a 3/8”.  That will give 4 times the flow area.

 

Al

 

 

I guess its still not clear to me how that situation would cause a line to blow off.  The max coolant pressure I have seen was around 24 psi and that should not cause a line to blow off unless it was inadequately clamped or some other defect.  Hard to believe the pressure increase due to the heat build up would be that fast.  But, a larger flow area should indeed relieve the pressure build up.

 

Ed

 

It would seem that 24 psi should not be a problem with a hose as far as it's structual integrity.  A standard, inexpensive air hose made in China will withstand 125 psi from my air compressor, and one fitting on the end of my air hose is only secured with a standard worm-gear type hose clamp. (The hose was damaged after being run over by a tractor-trailer, so I cut it and re-used the quick disconnect fitting by just inserting it back into the hose and securing it with a hose clamp). Of course the diameter of the air hose is larger. I'm just commenting on the ability of a hose to take the pressure.  I realize that this is air pressure, not water pressure, but 125 psi is probably more pressure than we would develop in our radiators.

      I might be missing something, but shouldn't the radiator cap release the over-pressure instead of a hose failing, or is it that once the radiator cap released it's pressure, and the only escape path was through this small line?  Not sure I totally understood the scenario.  Thanks for any efforts in making this clearer to me.  Paul Conner

      

 

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