X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Wed, 13 Apr 2011 08:25:51 -0400 Message-ID: X-Original-Return-Path: Received: from web36907.mail.mud.yahoo.com ([209.191.85.75] verified) by logan.com (CommuniGate Pro SMTP 5.4c3j) with SMTP id 4943927 for lml@lancaironline.net; Tue, 12 Apr 2011 09:20:28 -0400 Received-SPF: none receiver=logan.com; client-ip=209.191.85.75; envelope-from=chris_zavatson@yahoo.com Received: (qmail 53795 invoked by uid 60001); 12 Apr 2011 13:19:53 -0000 DomainKey-Signature:a=rsa-sha1; q=dns; c=nofws; s=s1024; d=yahoo.com; h=Message-ID:X-YMail-OSG:Received:X-Mailer:References:Date:From:Subject:To:In-Reply-To:MIME-Version:Content-Type; b=PUOmwzBwJm811UrKqxZA2DKTPCIsmrYLOCWHPnIZvZAhXB4RsYpBhIrSpWB9Ap4AFnScRs1Pt/9HBW4SGie2PfX/MxahzH34x9NzFFP9jMvo6QPffCB2vkw44p/7oh4cc3/1/2QkYaraHRMGuBjGLY4fwNC+qTrXQ0fM5Pq0KzQ=; X-Original-Message-ID: <330843.52596.qm@web36907.mail.mud.yahoo.com> X-YMail-OSG: Cr6X5hsVM1lWLUg.DENjG8SrU6kQOKjiiwy83SSRgsQLTTs gLqk2LouubusQg8dkcf75Kz21fL8I0nazwk.K2eSfc3XPKNHpTn1fRCQ2Iki vjhUfY2vFTZzS_.AMbtS4f40ZZCzFnRUqzZ34PKfC1D_lRYSWgxbVHZ_5SGa kx0jntQTCc7Y0yV3oKtvN8HQhOCUqvy53q0EMUp.WZQnWsCo6jjtKXh0GZfM MI_UcCT9LNoXc3OGyzbVO14Ll9ffw2qDB731OPPRwBAPHjpBOEwH7DA5YhIi WqsV.YyOJJy63cGlFGseLnY0TofN2Ifb8xhyLMFwNBWOVpHCuEPCZdOn91ME jj.M6IH93dfpUh.LW5nW6w6dPq7Z30_KRTSnbzlnFFVnS_duQ9ZA03Q6_tgP tdhl4HVRuYEOMMQ-- Received: from [99.140.56.34] by web36907.mail.mud.yahoo.com via HTTP; Tue, 12 Apr 2011 06:19:53 PDT X-Mailer: YahooMailRC/559 YahooMailWebService/0.8.109.295617 References: X-Original-Date: Tue, 12 Apr 2011 06:19:53 -0700 (PDT) From: Chris Zavatson Subject: Re: [LML] Re: LNC2 Gear Hydraulics X-Original-To: Lancair Mailing List In-Reply-To: MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="0-201648448-1302614393=:52596" --0-201648448-1302614393=:52596 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: quoted-printable A symmetric back-pressure circuit and spool will eliminate the possibility = of =0Ainstalling the spool backwards as happened with pumps manufactured in= about the =0A'96 through '98 time frame.=A0 The spool must still remain in= place after the pump =0Ashuts down to prevent both high and low circuits f= rom locking up simultaneously.=0AUsing o-ring=A0013-70 requires 30 g's to m= ove the spool.=0AUsing o-ring=A0013-90 requires 70 g's to move the spool.= =0AThis includes the return force generated by the poppet springs (410462).= =A0 =0AThe difference between the two o-rings is durometer.=A0 I have been = using the =0Asofter one without any problems.=A0 The stiffer o-ring (intend= ed for pumps with =0Aback pressure circuits) should leave no doubt.=A0 The = first thing to do with a =0Apump that has a history of locking up both side= s is to measure the return force =0Afor the spool and make sure it has an o= -ring installed.=0A=0AChris Zavatson=0AN91CZ=0A360std=0Awww.N91CZ.net=0A=0A= =0A=0A________________________________=0AFrom: Wolfgang =0ATo: lml@lancaironline.net=0ASent: Mon, April 11, 2011 4:56:57 AM=0ASubj= ect: [LML] Re: LNC2 Gear Hydraulics=0A=0A=0AWhen I first got into this prob= lem with the hydraulic pumps last year, I had a =0Afew conversations with t= he product manager of the Oildyne 108 pump. There have =0Abeen many changes= in it's production life and one of them was to make the spool =0Asymmetric= al and have the relief circuit the same both ways.=0A=A0=0AWolfgang=0A=0A__= ______________________________=0A=0AWolfgang,=0AYes, I have considered this= . =A0The spool with O-ring is a very tight fight. =0A=A0While I have not tr= ied to measure the force to move it, I would estimate =0Asomething over 50 = g's to move it (I'll measure this the next time I have a pump =0Aopened up)= =A0Could it be that a pump somehow ended up mounted such that it was =0Asu= bjected to some resonant frequency? =A0Seems like a remote possibilty given= all =0Athe variables and the mass of the pump. =A0 =A0How about wear and t= ear?=A0=A0Perhaps =0Asitting dry and idle for ten years would do it. =A0A m= issing O-ring or a spool =0Athat doesn't utilize an O-ring would allow the = spool to move very easily. =0A=A0Parker does make spools that don't even ha= ve O-rings. =A0Did these end up getting =0Ainstalled by chance?=0A=0ABased = on reports from the LML, the behavior seems to be rather binary. =A0On the = =0Aone hand we have planes with over 1000 hours and more than ten years of = service =0Athat have never once had the spool move off the poppet. =A0On th= e other hand, we =0Ahave planes with circuits that lock up right out of the= box (put into service).=0AThis leads me to believe there is a difference i= n configuration. =A0The easiest =0Away to verify this is to simply open up = a pump that is known to lock up hi and =0Alow circuits simultaneously.=0A= =0AWhile I have opened up several pumps (primarily to flip around spool val= ves), I =0Ahave not yet worked on one that had this lock up issue. =A0I am = optimistic the =0Adifference will be quite obvious upon inspection. =A0=0A= =0AChris Zavatson=0AN91CZ=0A360std=0Awww.N91CZ.net=0A=0A=0ASent from my iPa= d=0A=0AOn Apr 7, 2011, at 11:53 AM, "Wolfgang" wrote:= =0A=0A=0AChris, have you considered what effect airframe vibration has on t= he position of =0Athe spool in the pump and the problem in general ?=0A>=A0= =0A>Wolfgang=0A>=0A________________________________=0A=0A>From: Chris =0A>Sender: =0A>Subject: Re:= [LML] Re: LNC2 Gear Hydraulics =0A>Date: Wed, 06 Apr 2011 07:38:35 -0400 = =0A>To: lml@lancaironline.net =0A>I would like to extend the offer to the= whole group. =A0I think the entire =0A>community would benefit from unders= tanding why some pumps are allowing the =0A>system to lock up. =A0If anyone= has a pump that exhibits this behavior and could =0A>part with it for a we= ek, I am willing to check it out on the test stand and =0A>examine the inte= rnal configuration.=0A>=0A>=0A>Chris Zavatson=0A>N91CZ=0A>360std=0A>www.N91= CZ.net --0-201648448-1302614393=:52596 Content-Type: text/html; charset=iso-8859-1 Content-Transfer-Encoding: quoted-printable
A symmetric back-pressure circuit and spool will eliminate the po= ssibility of installing the spool backwards as happened with pumps manufact= ured in about the '96 through '98 time frame.  The spool must still re= main in place after the pump shuts down to prevent both high and low circui= ts from locking up simultaneously.
=0A
Using o-ring 013-70 re= quires 30 g's to move the spool.
=0A
Using o-ring 013-90 requ= ires 70 g's to move the spool.
This includes the return force generated = by the poppet springs (410462). 
=0A
The difference between = the two o-rings is durometer.  I have been using the softer one withou= t any problems.  The stiffer o-ring (intended for pumps with back pres= sure circuits) should leave no doubt.  The first thing to do with a pu= mp that has a history of locking up both sides is to measure the return for= ce for the spool and make sure it has an o-ring installed.
=0A
&nb= sp;
=0A
Chris Zavatson
=0A
N91CZ
=0A
360std=0A=0A

=0A=
=0A
=0AFrom: Wolfgang <Wolfgang@MiCom.net>To: lml@lancaironline.net<= BR>Sent: Mon, April 11, 201= 1 4:56:57 AM
Subject: [L= ML] Re: LNC2 Gear Hydraulics

=0A=0A=0A
When I first got into this problem with the hydrau= lic pumps last year, I had a few conversations with the product manager of = the Oildyne 108 pump. There have been many changes in it's production life = and one of them was to make the spool symmetrical and have the relief circu= it the same both ways.
=0A
 
=0A
Wolfgang
=0A=
=0A
=0A
=0A
=0A
=0A=
Wolfgang,
=0A
Yes, I have considered this.  The spool wi= th O-ring is a very tight fight.  While I have not tried to measure th= e force to move it, I would estimate something over 50 g's to move it (I'll= measure this the next time I have a pump opened up)  Could it be that= a pump somehow ended up mounted such that it was subjected to some resonan= t frequency?  Seems like a remote possibilty given all the variables a= nd the mass of the pump.    How about wear and tear?  Perha= ps sitting dry and idle for ten years would do it.  A missing O-ring o= r a spool that doesn't utilize an O-ring would allow the spool to move very= easily.  Parker does make spools that don't even have O-rings.  = Did these end up getting installed by chance?
=0A

=0A
Based on reports from the LML, the behavior seems to be rather binary. &= nbsp;On the one hand we have planes with over 1000 hours and more than ten = years of service that have never once had the spool move off the poppet. &n= bsp;On the other hand, we have planes with circuits that lock up right out = of the box (put into service).
=0A
This leads me to believe there is a difference in configuration. &nb= sp;The easiest way to verify this is to simply open up a pump that is known= to lock up hi and low circuits simultaneously.
=0A

=0A
While I have opened up several pumps (primarily to flip around s= pool valves), I have not yet worked on one that had this lock up issue. &nb= sp;I am optimistic the difference will be quite obvious upon inspection. &n= bsp;
=0A

=0A
Chris Zavatson
=0A
N91CZ
= =0A
360std
=0A=0A

=0A

Sent from my iPad
=0A

On Apr 7, 201= 1, at 11:53 AM, "Wolfgang" <Wolfgang@MiCom.net= > wrote:

=0A
=0A
=0A
=0A
Chris, have you considered wha= t effect airframe vibration has on the position of the spool in the pump an= d the problem in general ?
=0A
=  
=0A
Wolfgang=0A
=0A
=0A
=0A
=0A=0A=0A=0A=0A=0A=0A=0A=0A=0A=0A=0A=0A=0A=0A=0A=0A= =0A=0A=0A=0A=0A
=0A=0A
From:= Chris <chris_zavatson@yahoo.com>
Sender:<marv@lancaironline.n= et>
Subject:Re: [LML] Re: LNC2 Gear Hydraulics
Date:Wed, 0= 6 Apr 2011 07:38:35 -0400
To:=0A<= A href=3D"mailto:lml@lancaironline.net" rel=3Dnofollow target=3D_blank ymai= lto=3D"mailto:lml@lancaironline.net">= lml@lancaironline.net
=0A=0A=0A
I would like to extend the offer to t= he whole group.  I think the entire community would benefit from under= standing why some pumps are allowing the system to lock up.  If anyone= has a pump that exhibits this behavior and could part with it for a week, = I am willing to check it out on the test stand and examine the internal con= figuration.
=0A

=0A
Chris Zavatson
=0A
N91C= Z
=0A
360std
=0A
--0-201648448-1302614393=:52596--