Sender: "Marvin Kaye" <marv@lancaironline.net>
To: lml@lancaironline.net
Date: Wed, 09 Feb 2005 15:10:11 -0500
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From: "Mike S. Reinath" <Michael.S.Reinath@nasa.gov>
Subject: Re: Hydraulic pressure:LNC2
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Gerard,

I have pressure gauges on my 360. I have not noticed a tendency of 
the high pressure to increase because the temperature is usually 
cooler at altitude, and the pressure usually decreases a little 
during a flight. However, I have noticed the low pressure increasing 
over time, especially after a flight at altitude in the cooler air 
when, after landing, the plane sits in the sun on a warm day. 
Initially, the low pressure will be 500 psi, but as the fluid warms 
up, the pressure may go as high as 900 psi or more. What is 
interesting is that my pressure relief valve is set a little under 
600 psi, maybe about 560 or 570. I have checked this many times when 
adjusting the low pressure switch (set the switch above the relief 
valve setting and the pump will run continuously revealing the relief 
valve setting). Apparently, the relief valves behave differently if 
the pressure is increased gradually as compared to rapidly.

Mike Reinath
LNC2 at 450 hrs TT
San Jose, CA (RHV)