Mailing List lml@lancaironline.net Message #62910
From: Chris Zavatson <chris_zavatson@yahoo.com>
Sender: <marv@lancaironline.net>
Subject: Re: [LML] Re: Thermal influence on Hydraulic Pressure
Date: Tue, 04 Sep 2012 16:18:53 -0400
To: <lml@lancaironline.net>
Danny,
No affect on gear movement.
I should add however that elevated high-side pressure is one of the contributing factors to gear extension failures in a standard system set up.  My low pressure setting is higher than the nominal 550 psi.  It is set to 800 psi to avoid the pressure spike that propogates through the system when gear down is selected.
see "Failure to Extend" on page 10 for more detail.
 
Chris Zavatson
N91CZ
360std
 

From: Danny <danny@n107sd.com>
To: lml@lancaironline.net
Sent: Monday, September 3, 2012 11:54 AM
Subject: [LML] Re: Thermal influence on Hydraulic Pressure

Chris,
What was the impact on the gear movement?
 
Danny
LNC2-360
N 38° 43' 25.7"
W 77° 30' 38.6"
 
From: Chris Zavatson [mailto:chris_zavatson@yahoo.com]
Sent: Saturday, September 01, 2012 11:32 PM
To: lml@lancaironline.net
Subject: [LML] Thermal influence on Hydraulic Pressure
 
-took this photo after a descent from 16.5k to 1,500 ft.
OAT went from 42 to 94 degrees.
High Pressure gauge is pegged at 2,000+ psi
-Didn't get a photo, but the opposite happened on the ramp in Spokane. After sitting for an hour, the low pressure gauge was pegged at 1,200 psi+.  Spokane might not be the warmest spot in the country, but at 85 deg F, it was 55 degrees warmer than the cold soak on the previous leg.
Temperature changes have a big impact on system pressure. 
 
Chris Zavatson
N91CZ
360std
http://www.n91cz.net/


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