Return-Path: Sender: "Marvin Kaye" To: lml@lancaironline.net Date: Sat, 16 Apr 2005 08:13:46 -0400 Message-ID: X-Original-Return-Path: Received: from imo-m17.mx.aol.com ([64.12.138.207] verified) by logan.com (CommuniGate Pro SMTP 4.3c3) with ESMTP id 880119 for lml@lancaironline.net; Sat, 16 Apr 2005 07:59:18 -0400 Received-SPF: pass receiver=logan.com; client-ip=64.12.138.207; envelope-from=MikeEasley@aol.com Received: from MikeEasley@aol.com by imo-m17.mx.aol.com (mail_out_v38.7.) id r.1fa.6ac61cf (3988); Sat, 16 Apr 2005 07:58:25 -0400 (EDT) From: MikeEasley@aol.com X-Original-Message-ID: <1fa.6ac61cf.2f9257e1@aol.com> X-Original-Date: Sat, 16 Apr 2005 07:58:25 EDT Subject: TruTrak and GPSV X-Original-To: Lancair_ES@yahoogroups.com, lml@lancaironline.net MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="-----------------------------1113652705" X-Mailer: 9.0 Security Edition for Windows sub 1200 -------------------------------1113652705 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit Fellow TruTrak Owners, I had an interesting conversation with Chuck Bilbe at TruTrak yesterday at SNF about the new Sorcerer and GPSV. I have a CNX80 (Garmin GNS480) which will fly all the GPS approaches with all the vertical guidance. But my TruTrak DFC 250 isn't compatible with GPSV. But the new Sorcerer is, sort of, according to TruTrak. I got a crash course (not the best name, I guess) is autopilots yesterday. GPSS, which is the horizontal guidance that allows an autopilot to fly courses very accurately, do things like turn anticipation, and on my unit, fly holding patterns, is driven by a 32 bit data stream that gives a huge amount of information like distance from the fix on the approach (important if you want to adjust the autopilot's gain as you get closer to the fix), rate of closure on the course, etc. Far more than a CDI "needle" gives you, so you can accurately fly a fast airplane without zig-zagging back and forth across the course. Apparently the GPSV (vertical signal) coming from my UPSAT/Garmin unit is simple "needle" information. TruTrak says that was they really need is 32 bit data for the vertical axis so it can keep from ballooning up-and-down across the vertical course. TruTrak says that the Sorcerer will fly just fine when the GPSV signal is a 3 degree glideslope course, but when you have a step down type of approach it can't hold the vertical as well. Apparently, Stec claims to be stable, but they only have the "needle" information too, and they aren't very stable either in fast airplanes. My contact at Garmin, a former UPSAT guy, said that they are aware of the issue, but resources aren't available right now to write the software to drive the 32 bit GPSV signal. I'm not sure weather I should upgrade to the Sorcerer or not, even though TruTrak would update my unit when the new 32 bit data is available from Garmin. I'm curious why the "standard" data format wasn't established by the ARINC people, or whoever decides this stuff. More to come when I dig a little deeper. Mike Easley Colorado Springs ES -------------------------------1113652705 Content-Type: text/html; charset="US-ASCII" Content-Transfer-Encoding: quoted-printable
Fellow TruTrak Owners,
 
I had an interesting conversation with Chuck Bilbe at TruTrak yesterday= at=20 SNF about the new Sorcerer and GPSV.  I have a CNX80 (Garmin GNS480) wh= ich=20 will fly all the GPS approaches with all the vertical guidance.  But my= =20 TruTrak DFC 250 isn't compatible with GPSV.  But the new Sorcerer is, s= ort=20 of, according to TruTrak.
 
I got a crash course (not the best name, I guess) is autopilots=20 yesterday.  GPSS, which is the horizontal guidance that allows an autop= ilot=20 to fly courses very accurately, do things like turn anticipation, and on my=20 unit, fly holding patterns, is driven by a 32 bit data stream that gives a h= uge=20 amount of information like distance from the fix on the approach (important=20= if=20 you want to adjust the autopilot's gain as you get closer to the fix), rate=20= of=20 closure on the course, etc.  Far more than a CDI "needle" gives you, so= you=20 can accurately fly a fast airplane without zig-zagging back and forth across= the=20 course.
 
Apparently the GPSV (vertical signal) coming from my UPSAT/Garmin unit=20= is=20 simple "needle" information.  TruTrak says that was they really need is= 32=20 bit data for the vertical axis so it can keep from ballooning up-and-down ac= ross=20 the vertical course.  TruTrak says that the Sorcerer will fly just fine= =20 when the GPSV signal is a 3 degree glideslope course, but when you have a st= ep=20 down type of approach it can't hold the vertical as well.  Apparently,=20= Stec=20 claims to be stable, but they only have the "needle" information too, and th= ey=20 aren't very stable either in fast airplanes.
 
My contact at Garmin, a former UPSAT guy, said that they are aware of t= he=20 issue, but resources aren't available right now to write the software to dri= ve=20 the 32 bit GPSV signal.  I'm not sure weather I should upgrade to the=20 Sorcerer or not, even though TruTrak would update my unit when the new 32 bi= t=20 data is available from Garmin.  I'm curious why the "standard" data for= mat=20 wasn't established by the ARINC people, or whoever decides this stuff.
 
More to come when I dig a little deeper.
 
Mike Easley
Colorado Springs
ES
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