X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Sun, 09 Dec 2007 16:46:31 -0500 Message-ID: X-Original-Return-Path: Received: from [66.192.64.50] (HELO server16.crescentpark.com) by logan.com (CommuniGate Pro SMTP 5.2c1) with ESMTP id 2572683 for lml@lancaironline.net; Sat, 08 Dec 2007 16:40:59 -0500 Received-SPF: none receiver=logan.com; client-ip=66.192.64.50; envelope-from=dtaylor@crescentpark.com X-MimeOLE: Produced By Microsoft Exchange V6.5 Content-class: urn:content-classes:message MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----_=_NextPart_001_01C839E2.EE62DDB5" Subject: RE: [LML] Computing TAS from GPS tracks X-Original-Date: Sat, 8 Dec 2007 16:40:13 -0500 X-Original-Message-ID: In-Reply-To: X-MS-Has-Attach: X-MS-TNEF-Correlator: Thread-Topic: [LML] Computing TAS from GPS tracks Thread-Index: Acg5L0AuvHCOX+QMT9mS4QBMocJ4cgAsv6Lg References: From: "Taylor, David" X-Original-To: "Lancair Mailing List" This is a multi-part message in MIME format. ------_=_NextPart_001_01C839E2.EE62DDB5 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable Mike - you have the right idea. This website also does the calc: http://www.csgnetwork.com/tasgpscalc.html =20 Or you can just find the wind direction and fly into the wind and then turn 180 and fly out of the wind and just average your groundspeeds. This is also TAS. But it's tricky finding the wind direction. You need to line up your heading and your track to find it. =20 My GRT in my Legacy was computing a TAS that is 5 knots too high for instance. GRT lets you calibrate this so now its more accurate! =20 Dave T. Legacy RG=20 =20 From: Lancair Mailing List [mailto:lml@lancaironline.net] On Behalf Of Michael Newman Sent: Fri, 12-07-2007 19:14 To: lml@lancaironline.net Subject: [LML] Computing TAS from GPS tracks =20 I've been doing some homework on how to calibrate airspeed indications and get the TAS of a plane. Given 3 GPS tracks taken at the same airspeed you can compute a complete solution for the heading on each track and the TAS. =20 Folks might be interested in my spreadsheet which contains real data from my plane at low altitude. I will gather some more data over time. =20 You can find my spreadsheet via my Soaring and Flying page at: http://www.dragonnorth.com/soaring.html scroll down a bit there is discussion a link to a reference document and a link to the spreadsheet itself. =20 My true airspeed as computed from my airspeed indicator is about 14 knots faster that the measured result. =20 ________________________________ Michael Newman Dragonnorth Group 319 Dean Rd. Brookline, MA 02445 Cell: 617 821-4608 Home: 617 566-7975 Fax: 617 566-7975 www.dragonnorth.com =20 mnewman@dragonnorth.com =20 ------_=_NextPart_001_01C839E2.EE62DDB5 Content-Type: text/html; charset="us-ascii" Content-Transfer-Encoding: quoted-printable

Mike – you have the right idea. This website = also does the calc: http://www.csgnetwork.= com/tasgpscalc.html

Or you can just find the wind direction and fly into the = wind and then turn 180 and fly out of the wind and just average your = groundspeeds. This is also TAS. But it’s tricky finding the wind = direction. You need to line up your heading and your track to find = it.

My GRT in my Legacy was computing a TAS that is 5 knots = too high for instance. GRT lets you calibrate this so now its more = accurate!

Dave T.

Legacy RG

From:= Lancair = Mailing List [mailto:lml@lancaironline.net] On Behalf Of Michael = Newman
Sent: Fri, 12-07-2007 19:14
To: lml@lancaironline.net
Subject: [LML] Computing TAS from GPS = tracks

I've been doing some homework on how to calibrate airspeed indications and = get the TAS of a plane. Given 3 GPS tracks taken at the same airspeed you can = compute a complete solution for the heading on each track and the = TAS.

Folks might be interested in my spreadsheet which contains real data from = my plane at low altitude. I will gather some more data over = time.

You can find my spreadsheet via my Soaring and Flying page at: http://www.dragonnorth.c= om/soaring.html scroll down a bit there is discussion a link to a reference document and a link = to the spreadsheet itself.

My true airspeed as computed from my airspeed indicator is about 14 knots = faster that the measured result.

Michael Newman	Dragonnorth Group
319 Dean Rd. Brookline, MA 02445	Cell: 617 821-4608 Home: 617 566-7975 Fax: 617 566-7975
www.dragonnorth.com	mnewman@dragonnorth.com<= /o:p>

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