X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Mon, 28 Apr 2014 07:59:09 -0400 Message-ID: X-Original-Return-Path: Received: from [107.14.166.227] (HELO cdptpa-oedge-vip.email.rr.com) by logan.com (CommuniGate Pro SMTP 6.0.9e) with ESMTP id 6849238 for lml@lancaironline.net; Sun, 27 Apr 2014 19:03:14 -0400 Received-SPF: none receiver=logan.com; client-ip=107.14.166.227; envelope-from=Wolfgang@MiCom.net X-Original-Return-Path: Received: from [74.218.201.50] ([74.218.201.50:2473] helo=lobo) by cdptpa-oedge03 (envelope-from ) (ecelerity 3.5.0.35861 r(Momo-dev:tip)) with ESMTP id A8/C4-10911-F8C8D535; Sun, 27 Apr 2014 23:02:39 +0000 X-Original-Message-ID: <8D534337FAB445468FE05C76C9B85285@lobo> From: "Wolfgang" X-Original-To: "Chris Zavatson" , References: Subject: Re: Gear Down...INOP X-Original-Date: Sun, 27 Apr 2014 19:02:36 -0400 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0030_01CF624B.407B5ED0" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2900.5512 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.5512 X-RR-Connecting-IP: 107.14.168.142:25 X-Cloudmark-Score: 0 This is a multi-part message in MIME format. ------=_NextPart_000_0030_01CF624B.407B5ED0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Chris, I remain unconvinced with your theory. You have suggested that the pump = will somehow shut down immediately after it has started up due to some = pressure pulse. The mechanisim of which you have yet to clarify, let = alone demonstrated. I'm tired of your kibitzing and since you have proven that you can't let = it go, I will and leave you to humor yourself. Wolfgang ----- Original Message -----=20 From: Chris Zavatson=20 To: lml@lancaironline.net=20 Sent: Saturday, April 26, 2014 1:28 PM Subject: Gear Down...INOP Wolfgang, <<=E2=80=9CI believe in redundancy and it looks like you = don't=E2=80=A6.=E2=80=9D>> I am a big proponent of redundancy. That is redundancy defined as a = true back-up to an otherwise trouble-free system. First, I have redundant switches to power the pump solenoids. This = allows me to raise and lower the gear in case of the failure of either = of the pressure switches. It doesn=E2=80=99t happen very often, but it = does happen - twice in 17 years of flying my 360. =20 I also have redundant gear down indications. Two completely separate = systems, separate switches, separate wires and separate indicators. The = second set of switches is mounted directly on the over-center links.=20 I even carry two iPads and a iPhone - just in case <<=E2=80=9CThe pressure pulse you're talking about will subside (glad = you agree) and as it does, because the cylinder is only partially = extended, the cylinder will continues to extend, the low switch will = close again, and enable the pump to continue . .=E2=80=9D>> The part you seem to be missing here is that the momentary pulse is = not directly turning off the pump. Thus when the pulse subsides, the = pump doesn=E2=80=99t just spring back to life. The pulse pushes the = spool in the wrong direction -against the pump flow. This locks the = poppet that the pump just opened up a fraction of a second earlier. = When this happens, the high side begins to pressurize along with the low = side. As soon as both sides reach the low side pressure setting, the = pump is turned off. This is why you see both high and low circuits = pressurized to the same value in Lorn=E2=80=99s photo. To prevent this, the low side pressure settings should be raised. 800 = psi has proven sufficient. The high volume gear pump will reduce the = size of the pulse since the higher volume pump is able to absorb = incoming fluid at a higher rate. I highly recommend pressure gauges for both high and low circuit be = installed in a location visible to the pilot. The state of the system = can always be verified. One can immediately diagnose any in-flight = problem. Leaks can be caught early. And adjusting pressure settings is = no longer guess work. Chris Zavatson N91CZ 360std www.N91CZ.net ------=_NextPart_000_0030_01CF624B.407B5ED0 Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable =EF=BB=BF
Chris,
 
I remain unconvinced with your theory. = You have=20 suggested that the pump will somehow shut down immediately after it has = started=20 up due to some pressure pulse. The mechanisim of which you have yet to = clarify,=20 let alone demonstrated.
 
I'm tired of your kibitzing and since = you have=20 proven that you can't let it go, I will and leave you to humor=20 yourself.
 
Wolfgang
 
----- Original Message -----
From:=20 Chris=20 Zavatson
Sent: Saturday, April 26, 2014 = 1:28=20 PM
Subject: Gear Down...INOP

Wolfgang,

<<=E2=80=9CI=20 believe in redundancy and it looks like you=20 don't=E2=80=A6.=E2=80=9D>>

I=20 am a big proponent of redundancy. =20 That is redundancy defined as a true back-up to an otherwise=20 trouble-free system.

First, I have redundant switches to power the pump = solenoids.  This allows me to raise and = lower the=20 gear in case of the failure of either of the pressure switches.  It doesn=E2=80=99t happen = very often, but it=20 does happen - twice in 17 years of flying my 360. 

I=20 also have redundant gear down indications.  Two completely separate = systems,=20 separate switches, separate wires and separate indicators.  The second set of switches = is mounted=20 directly on the over-center links.

I=20 even carry two iPads and a iPhone - just in case

<<=E2=80=9CThe=20 pressure pulse you're talking about will subside (glad you agree) and = as it=20 does, because the cylinder is only partially extended, the = cylinder will=20 continues to extend, the low switch will close again, and enable the = pump to=20 continue . .=E2=80=9D>>

The=20 part you seem to be missing here is that the momentary pulse is not = directly=20 turning off the pump.  = Thus when=20 the pulse subsides, the pump doesn=E2=80=99t just spring back to = life.  The pulse pushes the spool = in the=20 wrong direction -against the pump flow. =20 This locks the poppet that the pump just opened up a fraction = of a=20 second earlier.  When = this=20 happens, the high side begins to pressurize along with the low = side.  As soon as both sides reach = the low=20 side pressure setting, the pump is turned off.  This is why you see both = high and low=20 circuits pressurized to the same value in Lorn=E2=80=99s = photo.

To=20 prevent this, the low side pressure settings should be raised.  800 psi has proven = sufficient.  The high volume gear pump = will reduce=20 the size of the pulse since the higher volume pump is able to absorb = incoming=20 fluid at a higher rate.

I=20 highly recommend pressure gauges for both high and low circuit be = installed in=20 a location visible to the pilot. =20 The state of the system can always be verified.  One can immediately diagnose = any=20 in-flight problem.  = Leaks can be=20 caught early.  And = adjusting=20 pressure settings is no longer guess work.
Chris=20 Zavatson
N91CZ 360std www.N91CZ.net ------=_NextPart_000_0030_01CF624B.407B5ED0--