X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Wed, 24 Jun 2009 07:44:29 -0400 Message-ID: X-Original-Return-Path: Received: from vms173003pub.verizon.net ([206.46.173.3] verified) by logan.com (CommuniGate Pro SMTP 5.2.14) with ESMTP id 3700521 for lml@lancaironline.net; Tue, 23 Jun 2009 07:52:18 -0400 Received-SPF: pass receiver=logan.com; client-ip=206.46.173.3; envelope-from=n5zq@verizon.net Received: from newness ([173.72.139.201]) by vms173003.mailsrvcs.net (Sun Java(tm) System Messaging Server 6.3-7.04 (built Sep 26 2008; 32bit)) with ESMTPA id <0KLO00HVIWY5A293@vms173003.mailsrvcs.net> for lml@lancaironline.net; Tue, 23 Jun 2009 06:51:42 -0500 (CDT) X-Original-Message-id: <0533F729442F4B6CA9E42C9A4DC40AFE@newness> From: "Bill" X-Original-To: "Lancair Mailing List" References: Subject: Re: [LML] Hydraulic problem with 320 landing gear -- help wanted! X-Original-Date: Tue, 23 Jun 2009 07:52:22 -0400 MIME-version: 1.0 Content-type: multipart/alternative; boundary="----=_NextPart_000_0077_01C9F3D7.8A726200" X-Priority: 3 X-MSMail-priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2900.5512 X-MIMEOLE: Produced By Microsoft MimeOLE V6.00.2900.5579 This is a multi-part message in MIME format. ------=_NextPart_000_0077_01C9F3D7.8A726200 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Hi Bill, I had a similar problem when our 320 first flew many years ago. We did a = lot of trouble shooting, including changing out the dump valve, adding = high and low pressure gauges and isolating each actuator individually (a = messy process involving plugs and caps). It turned out to be a scratch = inside one of the gear actuator tubes. When the gear was up, the o-ring = was on a smooth portion of the tube interior and held pressure. When the = gear was down, the o-ring was over the scratch allowing it to leak = internally. Isolating the actuators one at a time would be a logical = step in the trouble shooting process. (buy several caps and plugs and = invest in a large supply of paper towels :-) Hope that this helps. Bill Harrelson N5ZQ 320 1,650 hrs N6ZQ IV under construction ----- Original Message -----=20 From: Bill Kennedy=20 To: lml@lancaironline.net=20 Sent: Monday, June 22, 2009 10:52 PM Subject: [LML] Hydraulic problem with 320 landing gear -- help wanted! Intermittent problem: With the landing gear down, my pump will = sometimes run continuously. No problem if the gear is up (just an = occasional chirp). If I pop and reset the circuit breaker, it will often = stop running. I don't have a pressure gauge to help troubleshoot. There are no external leaks. There are no other functional problems with the landing gear system. Since the gear down is the low pressure side, it seems unlikely that = if there was a low to high leak in a cylinder, that there wouldn't also = be a high to low leak with the gear up. My gut feeling is that it's an internal cylinder leaks (low to high), = but it doesn't make perfect sense. Could a faulty pressure switch on the pump cause a problem like this? What else could cause it? Anyone have a identical problem? Thanks in advance -- Bill Kennedy ------=_NextPart_000_0077_01C9F3D7.8A726200 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Hi Bill,
 
I had a similar problem when our 320 first flew = many years=20 ago. We did a lot of trouble shooting, including changing out = the dump=20 valve, adding high and low pressure gauges and isolating each actuator=20 individually (a messy process involving plugs and caps). It turned out = to be a=20 scratch inside one of the gear actuator tubes. When the gear was up, the = o-ring=20 was on a smooth portion of the tube interior and held pressure. When the = gear=20 was down, the o-ring was over the scratch allowing it to leak = internally.=20 Isolating the actuators one at a time would be a logical step in the = trouble=20 shooting process. (buy several caps and plugs and invest in a large = supply=20 of paper towels :-)  Hope that this helps.
 
 
Bill Harrelson
N5ZQ 320 1,650 hrs
N6ZQ  IV under construction
 
 
 
----- Original Message -----
From:=20 Bill Kennedy
Sent: Monday, June 22, 2009 = 10:52=20 PM
Subject: [LML] Hydraulic = problem with 320=20 landing gear -- help wanted!

Intermittent problem: With the landing gear down, my = pump will=20 sometimes run continuously. No problem if the gear is up (just an = occasional=20 chirp). If I pop and reset the circuit breaker, it will often stop=20 running.

I don't have a pressure gauge to help=20 troubleshoot.

There are no external leaks.

There are no = other=20 functional problems with the landing gear system.

Since the = gear down=20 is the low pressure side, it seems unlikely that if there was a low to = high=20 leak in a cylinder, that there wouldn't also be a high to low leak = with the=20 gear up.

My gut feeling is that it's an internal cylinder leaks = (low to=20 high), but it doesn't make perfect sense.

Could a faulty = pressure=20 switch on the pump cause a problem like this?

What else could = cause=20 it?

Anyone have a identical problem?

Thanks in advance = -- Bill=20 Kennedy
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