Return-Path: Sender: To: lml@lancaironline.net Date: Fri, 11 Nov 2005 10:53:43 -0500 Message-ID: X-Original-Return-Path: Received: from imo-d22.mx.aol.com ([205.188.144.208] verified) by logan.com (CommuniGate Pro SMTP 5.0.1) with ESMTP id 827128 for lml@lancaironline.net; Thu, 10 Nov 2005 21:31:44 -0500 Received-SPF: pass receiver=logan.com; client-ip=205.188.144.208; envelope-from=Sky2high@aol.com Received: from Sky2high@aol.com by imo-d22.mx.aol.com (mail_out_v38_r6.3.) id q.1c0.359a8282 (18555) for ; Thu, 10 Nov 2005 21:30:55 -0500 (EST) From: Sky2high@aol.com X-Original-Message-ID: <1c0.359a8282.30a55c5f@aol.com> X-Original-Date: Thu, 10 Nov 2005 21:30:55 EST Subject: Re: [LML] Re: OAT probe location X-Original-To: lml@lancaironline.net MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="-----------------------------1131676255" X-Mailer: 9.0 Security Edition for Windows sub 5300 X-Spam-Flag: NO -------------------------------1131676255 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit Wherever the probe is located compressibility will affect the temperature at our operational speeds. If the probe is attached to an intelligent device that also knows the airspeed and altitude, then the True Air Temperature along with the True Airspeed can be computed and presented. This is true of the Rocky Mountain Instruments micro-encoder and probably the fancy glass panels. We are past the Cessna "stick your pinky in the wind" era. A venturi can affect a temperature probe in the following ways. If the probe is located where incoming air is compressed, such compression can cause a rise in the temperature and if it is in an area where the air is expanding, there is a cooling effect. Gas laws explain this fact. BTW, I have a secondary OAT probe (VM EPI 800 system) located in an insulated place thru the fuselage fillet where it protrudes into an area forward of the flap hinge. Scott Krueger AKA Grayhawk Lancair N92EX IO320 SB 89/96 Aurora, IL (KARR) -------------------------------1131676255 Content-Type: text/html; charset="US-ASCII" Content-Transfer-Encoding: quoted-printable

Wherever the probe is located compressibility will affect the temperatu= re=20 at our operational speeds. If the probe is attached to an intelligent=20 device that also knows the airspeed and altitude, then the True Air=20 Temperature along with the True Airspeed can be computed=20 and presented. This is true of the Rocky Mountain Instruments=20 micro-encoder and probably the fancy glass panels. We are past the Ces= sna=20 "stick your pinky in the wind" era.

A venturi can affect a temperature probe in the following ways. I= f=20 the probe is located where incoming air is compressed, such compression= can=20 cause a rise in the temperature and if it is in an area where the air is=20 expanding, there is a cooling effect. Gas laws explain this fact.

BTW, I have a secondary OAT probe (VM EPI 800 system) located in an=20 insulated place thru the fuselage fillet where it=20 protrudes into an area forward of the flap hinge. =20

Scott Krueger=20 AKA Grayhawk
Lancair N92EX IO320 SB 89/96
Aurora, IL=20 (KARR)

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