Mailing List lml@lancaironline.net Message #69806
From: Thorn, Valin B. (JSC-VA411) <valin.b.thorn@nasa.gov>
Sender: <marv@lancaironline.net>
Subject: RE: [LML] Gear Down...INOP
Date: Tue, 22 Apr 2014 15:04:35 -0400
To: <lml@lancaironline.net>

Thanks Chris. 

 

At lunch I looked over your excellent report on the 320/360 and Legacy hydraulic systems.  We have the pre-2005 Legacy hydraulic pump we’d modified for 28 VDC and changed to the high capacity pump.  I’d never heard anything from Lancair about a change in the internals as you described it – symmetric spool, spool centering springs, 150 psi backpressure circuit removed, etc.

 

Of course we have the three way dump valve to handle the hydraulic cylinder rod retraction/extension on dump valve activation.  But, it seems everything thing else must be 320/360 type internal on the spool and backpressure circuit. 

 

I’m not sure what changes we should make, if any, to have a system that isn’t prone to these pressure lock ups with temperature changes…  Suggestions?  I think William Ford’s Legacy kit number is close to ours so he likely has a similar setup…

 

Thanks again,

 

Valin Thorn

Legacy Project

Boulder, Colorado

 

 

From: Lancair Mailing List [mailto:lml@lancaironline.net] On Behalf Of Chris Zavatson
Sent: Monday, April 21, 2014 9:44 AM
To: lml@lancaironline.net
Subject: [LML] Gear Down...INOP

 

William,

My email has been bouncing LML messages recently.  I saw your question on the archive list.

see page 10 here

The above describes the extension failure mode in a 320/360.  I haven't studied the Legacy system relative to this failure mode  -may or may not be applicable.  Do you have pressure gauges?  The readings during gear extensions and especially during this failure would be most helpful in identifying the cause.

 

Chris Zavatson

N91CZ

360std

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