Sender: <marv@lancaironline.net> (Marvin Kaye)
To: lml
Date: Thu, 21 Aug 2003 12:49:37 -0400
Message-ID: <redirect-2536524@logan.com>
Mime-Version: 1.0
From: "Mike S. Reinath" <Michael.S.Reinath@nasa.gov>
Subject: [LML] LNC2 and Legacy gear
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<<  1) if you note the hyd pump light blink in-flight or hear the hyd
pump for a sec when you turn the master on, you have a leak...  >>


Don't forget about the effect of ambient temperature on the system 
pressure. If I pressurize the down circuit in the afternoon when it's 
90 degrees F, in the cool of the next morning the pressure will be 
near zero. I can watch the pressure climb back up to 500 -- I have 
pressure gauges on my panel -- as the ambient temperature climbs back 
to 90. Same thing goes for raising the gear when it's hot down low 
and climbing to a high altitude for a long cross country where it's 
significantly cooler. Typically, my high pressure will start out at 
about 1200 psi. After about an hour at 12,500 ft, the high pressure 
may be as low as 800 psi, and the pump may come on once to bring the 
pressure back up -- I've noticed that the pressure-switch hysteresis 
can be quite large when the pressure decreases slowly like this. I 
have no leaks in my system. The pressure will hold for days at 
constant ambient temperature.

Mike Reinath
N3602M
Std. Build 360