X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Tue, 15 Oct 2013 12:48:44 -0400 Message-ID: X-Original-Return-Path: Received: from p3plex2out01.prod.phx3.secureserver.net ([184.168.131.12] verified) by logan.com (CommuniGate Pro SMTP 6.0.7) with ESMTP id 6541614 for lml@lancaironline.net; Tue, 15 Oct 2013 11:32:30 -0400 Received-SPF: none receiver=logan.com; client-ip=184.168.131.12; envelope-from=pete@leapfrogventures.com Received: from P3PW5EX1HT002.EX1.SECURESERVER.NET ([72.167.180.20]) by p3plex2out01.prod.phx3.secureserver.net with secureserver.net id dTXx1m0070SoFT401TXxEG; Tue, 15 Oct 2013 08:31:57 -0700 Received: from P3PW5EX1MB14.EX1.SECURESERVER.NET ([10.6.135.86]) by P3PW5EX1HT002.EX1.SECURESERVER.NET ([72.167.180.20]) with mapi; Tue, 15 Oct 2013 08:31:57 -0700 From: "pete@leapfrogventures.com" X-Original-To: Paul Miller , "lml@lancaironline.net" X-Original-Date: Tue, 15 Oct 2013 08:31:54 -0700 Subject: RE: [LML] Re: Removing vacuum pump? (LIVP) Thread-Topic: [LML] Re: Removing vacuum pump? (LIVP) Thread-Index: Ac7JjZdPDFoElywVQo6YrGidVc9gDQALXWoA X-Original-Message-ID: <2A14E6258A8534418F5498D73CCA51EF2257AF13A8@P3PW5EX1MB14.EX1.SECURESERVER.NET> References: In-Reply-To: Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: acceptlanguage: en-US Content-Type: multipart/alternative; boundary="_000_2A14E6258A8534418F5498D73CCA51EF2257AF13A8P3PW5EX1MB14E_" MIME-Version: 1.0 --_000_2A14E6258A8534418F5498D73CCA51EF2257AF13A8P3PW5EX1MB14E_ Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable Nope. No vacuum is necessary to run the Dukes. The only purpose for the v= acuum connection is to pull the bellows open when pin 4 is grounded. The Dukes head operates on the pressure differential between outside and ca= bin pressure. It is effectively powered by the pressurized air coming into= the cabin. The pressure head only uses electricity to operate the solenoi= d connected to pin 4 (and a second solenoid connected to pin 13) and for a = motor that moves a bleed valve in concert with the position of the cabin pr= essure control on the dash. When pin 4 and pin 13 are not grounded, the va= cuum connection is completely sealed off from the pressure head. It truly is a mechanical marvel when operating properly. Pete From: Paul Miller [mailto:pjdmiller@gmail.com] Sent: Monday, October 14, 2013 5:14 AM To: lml@lancaironline.net Subject: Re: [LML] Re: Removing vacuum pump? (LIVP) If the pressure controller on the panel has rate of climb and cabin altitud= e settings (like a Garrett), it likely uses the vacuum line to modulate the= outflow valves (pull them open). That modulation is what provides the sig= nal to allow the cabin to climb or descend. I don't know what controller = is in place but the vacuum is for cabin differential control. The squat sw= itch is for ground use or emergency and simple opens the outflow to a maxim= um. In a typical situation, the outflow closes with wheels up then the vac= uum signal starts to open the valves to provide the differential required t= o either climb or hold the cabin as set by the controller. If the vacuum is disconnected, I suspect you simply are running with a full= y closed outflow valve and the cabin pressure is an open loop with whatever= pressure is supplied from the firewall. Does that sound about right? What I am missing is if there is no vacuum line then why install the contro= ller? How does it control anything? Those controllers can't be cheap. On 12 October 2013 17:00, jeffrey liegner > wrote: The device might function better (although I can't prove that), but it is= not necessary. I recall that it is to help the valve move initially (and = has no value after that first movement) and effect a seal early --_000_2A14E6258A8534418F5498D73CCA51EF2257AF13A8P3PW5EX1MB14E_ Content-Type: text/html; charset="us-ascii" Content-Transfer-Encoding: quoted-printable

Nope.  No vacuum is necessary t= o run the Dukes.  The only purpose for the vacuum connection is to pul= l the bellows open when pin 4 is grounded.

 

The Dukes head operates on the pressure = differential between outside and cabin pressure.  It is effectively po= wered by the pressurized air coming into the cabin.  The pressure head= only uses electricity to operate the solenoid connected to pin 4 (and a se= cond solenoid connected to pin 13) and for a motor that moves a bleed valve= in concert with the position of the cabin pressure control on the dash.&nb= sp; When pin 4 and pin 13 are not grounded, the vacuum connection is comple= tely sealed off from the pressure head.

 

It truly is a mechanical marvel when operat= ing properly.

 

<= span style=3D'font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F= 497D'>Pete

 

=

From:<= /font> Paul Miller [mailto:pjdmiller@gmail.com] Sent: Monday, October 14, = 2013 5:14 AM
To: lml@lanc= aironline.net
Subject: Re= : [LML] Re: Removing vacuum pump? (LIVP)

 

<= font size=3D3 face=3D"Times New Roman">If = the pressure controller on the panel has rate of climb and cabin altitude s= ettings (like a Garrett), it likely uses the vacuum line to modulate the ou= tflow valves (pull them open).  That modulation is what provides the s= ignal to allow the cabin to climb or descend.   I don't know what cont= roller is in place but the vacuum is for cabin differential control.  = The squat switch is for ground use or emergency and simple opens the outflo= w to a maximum.  In a typical situation, the outflow closes with wheel= s up then the vacuum signal starts to open the valves to provide the differ= ential required to either climb or hold the cabin as set by the controller.=

 

If the vacuum is disconnected, = I suspect you simply are running with a fully closed outflow valve and the = cabin pressure is an open loop with whatever pressure is supplied from the = firewall.  Does that sound about right?

 

<= p class=3DMsoNormal>What I am missing is if there is no vacuum line then why = install the controller?  How does it control anything?  Those con= trollers can't be cheap.

=  

On 12 October 2013 17:00, jeffrey liegner <liegner@ptd.net> wrote:

  The device might functio= n better (although I can't prove that), but it is not necessary.  I re= call that it is to help the valve move initially (and has no value after th= at first movement) and effect a seal early 

= --_000_2A14E6258A8534418F5498D73CCA51EF2257AF13A8P3PW5EX1MB14E_--