X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from EXHUB003-4.exch003intermedia.net ([207.5.74.111] verified) by logan.com (CommuniGate Pro SMTP 5.3c3) with ESMTPS id 3991212 for flyrotary@lancaironline.net; Wed, 25 Nov 2009 16:08:51 -0500 Received-SPF: none receiver=logan.com; client-ip=207.5.74.111; envelope-from=jwhaley@datacast.com Received: from EXVMBX003-5.exch003intermedia.net ([207.5.74.45]) by EXHUB003-4.exch003intermedia.net ([207.5.74.111]) with mapi; Wed, 25 Nov 2009 13:08:13 -0800 From: Jeff Whaley To: 'Rotary motors in aircraft' Date: Wed, 25 Nov 2009 13:10:32 -0800 Subject: Vacuum System Regulation Basics Thread-Topic: Vacuum System Regulation Basics Thread-Index: AcpuE7lXiK6krR/hSg6o+orGCMTpoA== Message-ID: 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_C03ABB0A7362B84BB53D544B3C305E0E0153A41BD53FEXVMBX0035e_" MIME-Version: 1.0 --_000_C03ABB0A7362B84BB53D544B3C305E0E0153A41BD53FEXVMBX0035e_ Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable Can anyone explain the following: I have a 9" venturi on side of fuselage - connected with a 3/8" hose, the s= uction gauge reads 9". This is too much for gyros, so I put a restrictor i= n the line expecting to get less vacuum - instead it goes to >10". This wo= uld imply that if hose was larger, vacuum would be less. If I was to install a regulator should it go between venturi and gauges? or= after gauges between them and filter? I'm getting the feeling that a regulator is actually a "controlled leak" - = adjusted by a needle-valve? True or False? If True, it would make sense to put a controlled leak between venturi and g= auges, as any dust would get sucked out of cabin without passing through ga= uges. Jeff --_000_C03ABB0A7362B84BB53D544B3C305E0E0153A41BD53FEXVMBX0035e_ Content-Type: text/html; charset="us-ascii" Content-Transfer-Encoding: quoted-printable

Can anyone explain the following:

I have a 9” venturi on side of fuselage – = connected with a 3/8” hose, the suction gauge reads 9”.  This is too much for gyros, so I put a restrictor in the line expecting to get less vac= uum – instead it goes to >10”.  This would imply that if hose was larger, vacuum would be less.

If I was to install a regulator should it go between v= enturi and gauges? or after gauges between them and filter?

I’m getting the feeling that a regulator is actu= ally a “controlled leak” – adjusted by a needle-valve? True or False?

If True, it would make sense to put a controlled leak = between venturi and gauges, as any dust would get sucked out of cabin without passi= ng through gauges.

Jeff

 

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