X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Fri, 18 Nov 2005 22:59:16 -0500 Message-ID: X-Original-Return-Path: Received: from [64.89.70.9] (HELO smtp03.gnvlscdb.sys.nuvox.net) by logan.com (CommuniGate Pro SMTP 5.0.1) with ESMTPS id 835158 for lml@lancaironline.net; Fri, 18 Nov 2005 08:33:46 -0500 Received-SPF: none receiver=logan.com; client-ip=64.89.70.9; envelope-from=cjensen@dts9000.com Received: from lucky.dts.local (66.83.119.58.nw.nuvox.net [66.83.119.58]) by smtp03.gnvlscdb.sys.nuvox.net (8.12.11/8.12.11) with ESMTP id jAIDX2Ul008553 for ; Fri, 18 Nov 2005 08:33:03 -0500 Content-class: urn:content-classes:message MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----_=_NextPart_001_01C5EC44.54BDF596" Subject: RE: [LML] Re: Exhaust leak X-MimeOLE: Produced By Microsoft Exchange V6.5.7226.0 X-Original-Date: Fri, 18 Nov 2005 08:31:07 -0500 X-Original-Message-ID: X-MS-Has-Attach: X-MS-TNEF-Correlator: Thread-Topic: [LML] Re: Exhaust leak Thread-Index: AcXsAt2Gucck4fnCRWeqiK0+D/73rwAQEQ7A From: "Chuck Jensen" X-Original-To: "Lancair Mailing List" This is a multi-part message in MIME format. ------_=_NextPart_001_01C5EC44.54BDF596 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: quoted-printable Scott, =20 I hadn't seen those numbers before but they seem consistent with the general experience. Even the Velocity pusher can, with bad luck, suck some exhaust forward if it's in the engine compartment, though it's rare. Generally, there is enough in leakage around the front nose gear and elevator that air flow is still toward the rear.=20 =20 Even though the FAA doesn't mandate a CO monitor, given their low cost and dire consequences of an exhaust leak, I wouldn't leave home without one. =20 Chuck =20 =20 =20 Chuck, =20 I have yet to hear of an unpressurized high performance composite aircraft with a positive cabin pressure - even when all the cabin vents are open - even when it is rear engined. =20 One of the tests that should be done in phase 1 is opening the static to the cabin at cruise and slow flight, with and without vents open to understand the speed and altitude changes (higher altitude, faster indicated speed) you will see using such alternate static. It should be recorded in your POH or placarded. =20 As I reported once before, at 180 KIAS, the pressure drop in my cabin is .38" Hg less or about 380 feet higher at 3000 feet. There is only a .05" Hg increase when the vent is opened while using cabin static pressure. At approach speed (110 KIAS), the difference was about .1" Hg. or a 100 foot higher reading. I don't have access to my pressure/air-speed table and I can't remember the exact speed change numbers. =20 The fact that the cabin is alway less pressure than the lower cowling (it is always more than static) and static means that bad stuff can enter firewall openings (front or rear engine) or other openings that exhaust fumes pass by. =20 Scott Krueger ------_=_NextPart_001_01C5EC44.54BDF596 Content-Type: text/html; charset="US-ASCII" Content-Transfer-Encoding: quoted-printable

            = Scott,

 

        = ;   I hadn’t seen those numbers before but they seem consistent with the general experience.  Even = the Velocity pusher can, with bad luck, suck some exhaust forward if = it’s in the engine compartment, though it’s rare.  Generally, there is enough in = leakage around the front nose gear and elevator that air flow is still toward = the rear.

 

        = ;    Even though the FAA doesn’t mandate a CO monitor, given their low cost = and dire consequences of an exhaust leak, I wouldn’t leave home = without one.

 

        = ;    Chuck

 

        = ;   

 

Chuck,

 

I have yet to hear of an unpressurized high performance composite aircraft with = a positive cabin pressure - even when all the cabin vents are open - even = when it is rear engined.

 

One of the tests that should be done in phase 1 is opening the static to = the cabin at cruise and slow flight, with and without vents open to = understand the speed and altitude changes (higher altitude, faster indicated speed) you will see using such alternate = static.  It should be recorded in your POH or = placarded.

 

As I reported once before, at 180 KIAS, the pressure drop in my cabin is = .38" Hg less or about 380 feet higher at 3000 feet.  There is only a = .05" Hg increase when the vent is opened while using cabin static = pressure.  At approach speed (110 KIAS), the difference was about .1" Hg. or = a 100 foot higher reading.  I don't have access to my pressure/air-speed = table and I can't remember the exact speed change = numbers.

 

The fact that the cabin is alway less pressure than the lower cowling (it is = always more than static) and static means that bad stuff can enter firewall = openings (front or rear engine) or other openings that exhaust fumes pass = by.

 

Scott Krueger

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