Return-Path: Sender: (Marvin Kaye) To: lml Date: Fri, 13 Dec 2002 00:31:22 -0500 Message-ID: X-Original-Return-Path: Received: from granger.mail.mindspring.net ([207.69.200.148] verified) by logan.com (CommuniGate Pro SMTP 4.0.2) with ESMTP id 1910408 for lml@lancaironline.net; Thu, 12 Dec 2002 21:35:16 -0500 Received: from h-66-167-250-5.phlapafg.covad.net ([66.167.250.5] helo=scott) by granger.mail.mindspring.net with smtp (Exim 3.33 #1) id 18MffW-0007SW-00 for lml@lancaironline.net; Thu, 12 Dec 2002 21:35:15 -0500 X-Original-Message-ID: <004001c2a250$b58b8be0$6401a8c0@mindspring.com> Reply-To: "Scott Turner" From: "Scott Turner" X-Original-To: "Lancair Mailing List" Subject: IV-P Cabin Air System Dukes Valve with An All Electric Panel X-Original-Date: Thu, 12 Dec 2002 21:38:24 -0500 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_003D_01C2A226.CC586FC0" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2600.0000 X-MIMEOLE: Produced By Microsoft MimeOLE V6.00.2600.0000 This is a multi-part message in MIME format. ------=_NextPart_000_003D_01C2A226.CC586FC0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable After going over LML Posts, talking to Pat Patrick at Dukes and applying = all this knowledge gathered, I feel quite certain the following will get = the Dukes valve to operate as designed. The solution is to simply use the engine manifold vacuum, tapped off of = the manifold pressure line to the manifold pressure gauge. Put a check = valve in after the tap off to prevent a positive pressure form being = applied to the Dukes valve. Run the vacuum line directly to the Dukes = valve. I am planning on using a check valve from McMasters - $2.90. It was concluded that the engine will provide sufficient vacuum until = the throttle is pushed in for take off. The check valve will hold the = vacuum and Dukes valve open until the valve control system takes over. The logistics of several approaches were gone over with Pat Patrick. He = acknowledged the findings and confirms that the manifold system should = work well. Pat also acknowledged the problem with the Venturi concept = is that air has to be streaming into the cabin before the Venturi draws = a vacuum on the Dukes valve. By that time, a pressure will build up in = the cabin and the occupants will feel a pressure surge. Alternatives = were discussed, such as, using the door seal pump and a separate pump. = All the other approaches appear to require more complex or involved = procedures to get them to work properly. One further advantage to the manifold vacuum approach is that all the = parts should be inexpensive stock items. If anyone is interested, I will submit what should be a short bill of = materials and a simple diagram of my final system after getting it = installed. Be aware, though, it will be awhile before this approach is = put to the acid test. Thanks for your help. Scott Turner ------=_NextPart_000_003D_01C2A226.CC586FC0 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
After going over LML Posts, talking to = Pat Patrick=20 at Dukes and applying all this knowledge gathered, I feel quite certain = the=20 following will get the Dukes valve to operate as designed.
 
The solution is to simply use the = engine manifold=20 vacuum, tapped off of the manifold pressure line to the manifold = pressure=20 gauge.  Put a check valve in after the tap off to prevent a = positive=20 pressure form being applied to the Dukes valve.  Run the vacuum = line=20 directly to the Dukes valve.  I am planning on using a check valve = from=20 McMasters - $2.90.
 
It was concluded that the engine = will provide=20 sufficient vacuum until the throttle is pushed in for take off.  = The check=20 valve will hold the vacuum and Dukes valve open until the valve = control=20 system takes over.
 
The logistics of several approaches = were gone over=20 with Pat Patrick. He acknowledged the findings and  confirms that = the=20 manifold system should work well.  Pat also acknowledged the = problem with=20 the Venturi concept is that air has to be streaming into the cabin = before the=20 Venturi draws a vacuum on the Dukes valve.  By that time, a = pressure will=20 build up in the cabin and the occupants will feel a pressure = surge. =20 Alternatives were discussed, such as, using the door seal pump and a = separate=20 pump.  All the other approaches appear to require more complex or = involved=20 procedures to get them to work properly.
 
One further advantage to the manifold = vacuum=20 approach is that all the parts should be inexpensive stock = items.
 
If anyone is interested, I will submit = what should=20 be a short bill of materials and a simple diagram of my final system = after=20 getting it installed.  Be aware, though, it will be awhile before = this=20 approach is put to the acid test.
 
Thanks for your help.
 
Scott Turner
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