X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Fri, 23 Oct 2009 09:49:24 -0400 Message-ID: X-Original-Return-Path: Received: from QMTA01.emeryville.ca.mail.comcast.net ([76.96.30.16] verified) by logan.com (CommuniGate Pro SMTP 5.2.16) with ESMTP id 3896103 for lml@lancaironline.net; Thu, 22 Oct 2009 20:54:31 -0400 Received-SPF: pass receiver=logan.com; client-ip=76.96.30.16; envelope-from=rbelshe@comcast.net Received: from OMTA06.emeryville.ca.mail.comcast.net ([76.96.30.51]) by QMTA01.emeryville.ca.mail.comcast.net with comcast id w0X01c00Z16AWCUA10tpuk; Fri, 23 Oct 2009 00:53:49 +0000 Received: from desk ([67.188.65.67]) by OMTA06.emeryville.ca.mail.comcast.net with comcast id w0ty1c0011T3zJT8S0tysB; Fri, 23 Oct 2009 00:53:58 +0000 From: "Bob B." X-Original-To: "'Lancair Mailing List'" References: Subject: RE: [LML] Re: LNC2 Hydraulic Gear Operation Fix X-Original-Date: Thu, 22 Oct 2009 17:53:56 -0700 X-Original-Message-ID: <67EF41B4414940BE86A0A7E653E83443@desk> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit X-Mailer: Microsoft Office Outlook 11 Thread-Index: AcpQ4u/UXRZ8Ywj2QsqgKFlhgNgLEQCkvGUg In-Reply-To: X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.5579 X-Antivirus: avast! (VPS 091022-0, 10/22/2009), Outbound message X-Antivirus-Status: Clean Randy, I have spent too much time trying to analyze your hydraulic "fix". You say "The ONLY way to approach this work around for the Oildyne pump problem is to REMOVE the pressure from the Lo side. Relieving the expanding hydraulic fluid and put it back in the reservoir where it belongs!!!! This type of "Fix" that simply bypasses the open Lo sensor and does not relieve the expanding hydraulic fluid is insane and it's a ticking time bomb for gear failure!!!" In fact, it appears to me that your circuit DOES bypass the open low pressure switch, which starts the pump and ADDS pressure to the low side. Then, when the high pressure switch drops out, it immediately reverses the pump to restore the up pressure. If this analysis is incorrect, please let the group know. Bob Belshe EE '61 Lancair 235/320 900+ hours PS: Why do you think so many Lancairs, including mine, have never experienced this problem? -----Original Message----- From: Lancair Mailing List [mailto:lml@lancaironline.net] On Behalf Of Randy Sent: Monday, October 19, 2009 10:38 AM To: lml@lancaironline.net Subject: [LML] Re: LNC2 Hydraulic Gear Operation Fix This looks like a relay that when it senses the Hi pressure switch being open, while the gear is up, shorts and closes the Lo pressure circuit. This will bypass the Lo pressure sensor when the sensor opens from the hydraulic fluid expanding. This type of fix does not stop the hydraulic fluid from expanding more and more as it heats up. The hydraulic fluid expansion can damage the hydraulic system. I have monitored this problem and have seen the Lo side exceed 2000 psi during this heat expansion in the summer months. If this relay sticks the Lo sensor circuit will be on all the time regardless of the pressure sensor. The ONLY way to approach this work around for the Oildyne pump problem is to REMOVE the pressure from the Lo side. Relieving the expanding hydraulic fluid and put it back in the reservoir where it belongs!!!! This type of "Fix" that simply bypasses the open Lo sensor and does not relieve the expanding hydraulic fluid is insane and it's a ticking time bomb for gear failure!!! Randy Stuart LNC-2