X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Fri, 08 Apr 2011 15:54:11 -0400 Message-ID: X-Original-Return-Path: Received: from smtp115-mob.biz.mail.ne1.yahoo.com ([98.138.88.252] verified) by logan.com (CommuniGate Pro SMTP 5.4c2) with SMTP id 4935969 for lml@lancaironline.net; Thu, 07 Apr 2011 17:57:15 -0400 Received-SPF: none receiver=logan.com; client-ip=98.138.88.252; envelope-from=chris_zavatson@yahoo.com Received: (qmail 33520 invoked from network); 7 Apr 2011 21:56:40 -0000 DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=s1024; d=yahoo.com; h=DKIM-Signature:Received:X-Yahoo-SMTP:X-YMail-OSG:X-Yahoo-Newman-Property:References:In-Reply-To:X-Apple-Yahoo-Original-Message-Folder:Mime-Version:Content-Type:Received:Message-Id:Content-Transfer-Encoding:X-Mailer:X-Ymail-Umid:From:X-Apple-Yahoo-Replied-Msgid:Subject:Date:To; b=jbRKIETBjb3u5jUPM5kyu3N0wCY4vT0SS4A8NRtxWcQ3zjPgKapxzP7j9oqUW583b/7FRVGoZ2yjJfyQVb2iXZClX8TZaltSOhw+jm4arrDgppR7x4KNxPdbtWJv5DTFh83pt5SaJpRsbsypIZohnBbMEL7rw/+4pWKfLlm+UJs= ; Received: from [10.99.217.246] (chris_zavatson@166.205.139.237 with xymcookie) by smtp115-mob.biz.mail.ne1.yahoo.com with SMTP; 07 Apr 2011 14:56:34 -0700 PDT X-Yahoo-SMTP: 076hgjCswBC.G6e0vm7vgvZ9JJ0zmeBo_Oyw X-YMail-OSG: 16dW7lcVM1mz3d.jx9vRiUS12H3K57l92Zs_l54QV8l7Ytw 3s9rcp_xQ.vwzbUOG0P5NT7utZ1buBL_7nNCgqk9fwmIzjd.7PHC8jES9pDu 3o8XDKZH7WjpN3viTyIfti8OA1hDEtVx0OYIud9InnXwHeU4rM8XwiXQ2Umb VQEuE6pmHgQBuz7hr_6c.16vhEGrUFsrAvQn7FkNPtHsj5uHF_qUm7gISWq2 _u.5E2jkA2TBHSLrwj56zOvWNXtTmzYg9ucPeb4lDkfjGmXwp0Cm4otErZ5K Cq_danCUM7Q2xHZ8gtcYxYFtyxff78hRgk3524i8ChfV53dbYKAxq3pBxf3g .oEzKP1D1nEZfu4xPJ2jpcOg- X-Yahoo-Newman-Property: ymail-3 References: In-Reply-To: X-Apple-Yahoo-Original-Message-Folder: Inbox Mime-Version: 1.0 (iPad Mail 8C148) Content-Type: multipart/alternative; boundary=Apple-Mail-9--363836421 Received: from [12.130.164.194] by web36904.mail.mud.yahoo.com via HTTP; Mon, 04 Apr 2011 11:58:13 PDT X-Original-Message-Id: <6F561D57-811D-44E9-A821-29E4B711045C@yahoo.com> Content-Transfer-Encoding: 7bit X-Mailer: YahooMailRC/559 X-Ymail-Umid: 1_7114_AEhVv9EAAMNmTZoUxQiE/FdxU/g From: Chris X-Apple-Yahoo-Replied-Msgid: 1_11560835_AEZVv9EAAJLRTZ4R/gnNhEXh8dY Subject: Re: [LML] Re: LNC2 Gear Hydraulics X-Original-Date: Thu, 7 Apr 2011 14:56:25 -0700 X-Original-To: Lancair Mailing List --Apple-Mail-9--363836421 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=us-ascii Wolfgang, Yes, I have considered this. The spool with O-ring is a very tight fight. W= hile I have not tried to measure the force to move it, I would estimate some= thing over 50 g's to move it (I'll measure this the next time I have a pump o= pened up) Could it be that a pump somehow ended up mounted such that it was= subjected to some resonant frequency? Seems like a remote possibilty given= all the variables and the mass of the pump. How about wear and tear? Pe= rhaps sitting dry and idle for ten years would do it. A missing O-ring or a= spool that doesn't utilize an O-ring would allow the spool to move very eas= ily. Parker does make spools that don't even have O-rings. Did these end u= p getting installed by chance? Based on reports from the LML, the behavior seems to be rather binary. On t= he one hand we have planes with over 1000 hours and more than ten years of s= ervice that have never once had the spool move off the poppet. On the other= hand, we have planes with circuits that lock up right out of the box (put i= nto service). This leads me to believe there is a difference in configuration. The easies= t way to verify this is to simply open up a pump that is known to lock up hi= and low circuits simultaneously. While I have opened up several pumps (primarily to flip around spool valves)= , I have not yet worked on one that had this lock up issue. I am optimistic= the difference will be quite obvious upon inspection. =20 Chris Zavatson N91CZ 360std www.N91CZ.net Sent from my iPad On Apr 7, 2011, at 11:53 AM, "Wolfgang" wrote: > Chris, have you considered what effect airframe vibration has on the posit= ion of the spool in the pump and the problem in general ? > =20 > Wolfgang > From: Chris > Sender: > Subject: Re: [LML] Re: LNC2 Gear Hydraulics > Date: Wed, 06 Apr 2011 07:38:35 -0400 > To: lml@lancaironline.net > I would like to extend the offer to the whole group. I think the entire c= ommunity would benefit from understanding why some pumps are allowing the sy= stem 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 configuration. >=20 > Chris Zavatson > N91CZ > 360std > www.N91CZ.net --Apple-Mail-9--363836421 Content-Transfer-Encoding: quoted-printable Content-Type: text/html; charset=utf-8
Wolfgang,
Yes, I ha= ve considered this.  The spool with O-ring is a very tight fight.  = ;While I have not tried to measure the force to move it, I would estimate so= mething over 50 g's to move it (I'll measure this the next time I have a pum= p opened up)  Could it be that a pump somehow ended up mounted such tha= t it was subjected to some resonant frequency?  Seems like a remote pos= sibilty given all the variables and the mass of the pump.    How a= bout wear and tear?  Perhaps sitting dry and idle for ten years= would do it.  A missing O-ring or a spool that doesn't utilize an O-ri= ng would allow the spool to move very easily.  Parker does make spools t= hat don't even have O-rings.  Did these end up getting installed by cha= nce?

Based on reports from the LML, the b= ehavior seems to be rather binary.  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.  On the other hand, we have planes with= circuits that lock up right out of the box (put into service).
=


Sent from my iPad

On Apr 7= , 2011, at 11:53 AM, "Wolfgang" <Wolfgang@MiCom.net> wrote:

Chris, have you considered what effect a= irframe=20 vibration has on the position of the spool in the pump and the problem in=20= general ?
 
Wolfgang
From: Chris=20 <chris_zavatson@yahoo.com>
Sender: <marv@lancaironline.net>
Subject: Re: [LML] Re: LNC2 Gear=20 Hydraulics
Date: Wed, 06 Apr 2011 07:38:35 -0400<= /td>
To: lml@lancaironline.net
I would like to extend the offer to the whole group.  I thin= k=20 the entire community would benefit from understanding why some pumps a= re=20 allowing the system to lock up.  If anyone has a pump that exhibi= ts=20 this behavior and could part with it for a week, I am willing to check= it=20 out on the test stand and examine the internal configuration.

Chris Zavatson
N91CZ
360std
=
= --Apple-Mail-9--363836421--