X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Sun, 19 Aug 2012 09:36:52 -0400 Message-ID: X-Original-Return-Path: Received: from mtaz1.mailnet.ptd.net ([204.186.29.65] verified) by logan.com (CommuniGate Pro SMTP 6.0c1) with ESMTP id 5717736 for lml@lancaironline.net; Sat, 18 Aug 2012 21:22:43 -0400 Received-SPF: pass receiver=logan.com; client-ip=204.186.29.65; envelope-from=liegner@ptd.net Received: from mb7.mailnet.ptd.net (mb7.mailnet.ptd.net [204.186.29.17]) by mtaz1.mailnet.ptd.net (Postfix) with ESMTP id 1DE9B3205AE for ; Sat, 18 Aug 2012 21:22:07 -0400 (EDT) X-Original-Date: Sat, 18 Aug 2012 21:22:07 -0400 (EDT) From: jeffrey liegner X-Original-To: Lancair Mailing List Subject: re: Question about TAS Error (and Winds Calculation) based on OAT (in a LIVP) X-Original-Message-ID: <09876ea9-acc4-4023-adbc-bda3c2b443ec@mb7.mailnet.ptd.net> In-Reply-To: <8939abad-bd31-451e-8c23-38981b1b5fb9@mb7.mailnet.ptd.net> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit MIME-Version: 1.0 X-Originating-IP: [184.6.215.58] X-Mailer: Zimbra 7.1.3_GA_3374 (ZimbraWebClient - SAF3 (Mac)/7.1.3_GA_3346) Recall my question (same subject) about the accuracy of OAT, and its efect on TAS and Winds. SInce I rendere pireps including winds and OAT, the accuracy of this report is now in question. Many have suggested reloacting the OAT to another place, different from the Lancair recommendation along the fuselage. This is not an easy thing, putting the probe out on the wing, wiring coming into and through the wing root, into the pressure vessel (different from the current OAT location). I performed the flight TAS calculation recommended by several. Whether three measurements with headings 120 degrees apart, or three orthogonal headings, the results are the same. The Chelton presents a TAS 216 and the calculator renders TAS 205 based on the n flight measurement. I wonder if I can change the compressibility quotient used by Chelton to adjust the OAT reading. Suggestions? Jeff L N334P