X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Thu, 10 Apr 2008 01:11:01 -0400 Message-ID: X-Original-Return-Path: Received: from smtp0.av-mx.com ([137.118.16.56] verified) by logan.com (CommuniGate Pro SMTP 5.2.1) with ESMTP id 2840964 for lml@lancaironline.net; Thu, 10 Apr 2008 00:41:35 -0400 Received-SPF: pass receiver=logan.com; client-ip=137.118.16.56; envelope-from=pinetownd@volcano.net Received: from DennisDell (63-170-119-110.dsl.volcano.net [63.170.119.110]) (Authenticated sender: pinetownd@volcano.net) by smtp0.av-mx.com (Postfix) with ESMTP id D774B1BF83B for ; Wed, 9 Apr 2008 23:40:54 -0400 (EDT) X-Original-Message-ID: <005501c89abc$ad1eb8a0$6501a8c0@DennisDell> From: "Dennis Johnson" X-Original-To: "Lancair Mailing List" Subject: TruTrak ADI Report X-Original-Date: Wed, 9 Apr 2008 20:40:51 -0700 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0052_01C89A82.00012480" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2900.3138 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.3198 This is a multi-part message in MIME format. ------=_NextPart_000_0052_01C89A82.00012480 Content-Type: text/plain; charset="Windows-1252" Content-Transfer-Encoding: quoted-printable Several months ago, there was good discussion on this newsgroup about = the TruTrak ADI attitude direction indicator and it's value as a backup = instrument. I gave mine a good workout today and want to share my = thoughts. I installed a Chelton system in my Legacy and the small (2.25") TruTrak = ADI for backup. I also have steam gauges for backup airspeed and = altitude and a handheld GPS and handheld comm radio. Today I went up = with a safety pilot and tried out my backup instruments while wearing a = "hood" with the Chelton displays blanked out. The ADI sort of acts like a conventional gyroscopic attitude indicator = in that it shows pitch and bank information. Instead of calibrations in = degrees nose up or down, its calibrations are in feet per minute climb = or descent. The roll information acts similar to the way a conventional = attitude indicator works, although it has only two bank calibration = marks. =20 This is a little hard to describe, so if you're not familiar with = it,here's a photo: http://www.trutrakflightsystems.com/instruments.htm However, the photo shows the full size 3.125" ADI; the small one I have = does not have the slip/skid ball, has only two roll index marks, and the = climb/dive marks are labeled in feet per minute. I do not have mine = hooked up to a GPS yet, so mine does not show track. I might add a GPS = to it later, but the TruTrak autopilot displays heading, so that's a low = priority for me. I was pleased at how easy it was to fly my Legacy under the hood with = only my backup instruments and a Garmin 196 handheld GPS. The ADI = doesn't respond exactly the way a conventional attitude indicator does, = but I seemed to quickly adjust to it. After a few minutes, I was = interpreting the ADI's input without thinking about it. The only thing = that wasn't intuitive was controlling a descent. The dive calibration = marks don't "bank" when the airplane rolls the way the climb calibration = marks do. This is hard to explain, but look at the photo from the link = above. The blue part of the display rotates as the airplane banks, but = the brown part is stationary. That's not a big deal, but sort of an = oddity in a descending turn that I'm sure I'll get used to with a little = more practice. Also, the dive calibrations are much closer together = than the climb calibrations, which makes them a little harder to = interpret. But that's a pretty minor complaint. On the plus side, it costs a fraction of what a conventional attitude = indicator costs. It's also lighter weight and, if connected to a GPS, = provides track information that conventional attitude indicators don't. = On the minus side, it doesn't respond in exactly the same way as a = conventional attitude indicator, which might be an issue for some = people. It also uses similar electronic technology as the = Chelton/Pinpoint and my hunch is that any electronic attack on the = system, such as from lightning, would take out the ADI long before the = Chelton/Pinpoint. Which brings up the need to define what risk you want to protect = against. For me, I'm protecting against the risk that the Pinpoint, = which is the single point of information for GPS and attitude = information, fails for some reason internal to itself, such as a = connector coming unplugged, etc. I'm not protecting against a lightning = strike or a total electrical failure, which would also take out the ADI. = I understand that other people will choose different risks to protect = against and will, therefore, have different equipment requirements. =20 In conclusion, I'm happy with the TruTrak ADI and believe it will fill = the mission I have assigned it. And the Garmin 196 handheld GPS is = amazing, what a value! But that's for another post. Dennis Johnson Legacy, 125 hours ------=_NextPart_000_0052_01C89A82.00012480 Content-Type: text/html; charset="Windows-1252" Content-Transfer-Encoding: quoted-printable
Several months ago, there was good discussion on this = newsgroup about=20 the TruTrak ADI attitude direction indicator and it's value as a backup=20 instrument.  I gave mine a good workout today and want to share my=20 thoughts.
 
I installed a Chelton system in my Legacy and the small (2.25") = TruTrak ADI=20 for backup.  I also have steam gauges for backup airspeed and = altitude and=20 a handheld GPS and handheld comm radio.  Today I went up with a = safety=20 pilot and tried out my backup instruments while wearing a "hood" with = the=20 Chelton displays blanked out.
 
The ADI sort of acts like a conventional gyroscopic attitude = indicator in=20 that it shows pitch and bank information.  Instead = of calibrations=20 in degrees nose up or down, its calibrations are in feet per = minute=20 climb or descent.  The roll information acts similar to = the way a=20 conventional attitude indicator works, although it has only two bank = calibration=20 marks. 
 
This is a little hard to describe, so if you're not familiar = with=20 it,here's a photo:
http://www.t= rutrakflightsystems.com/instruments.htm
 
However, the photo shows the full size 3.125" ADI; the small one I = have=20 does not have the slip/skid ball, has only two roll index = marks, and=20 the climb/dive marks are labeled in feet per minute.  I do not have = mine=20 hooked up to a GPS yet, so mine does not show track.  I = might add=20 a GPS to it later, but the TruTrak autopilot displays heading, = so=20 that's a low priority for me.
 
I was pleased at how easy it was to fly my Legacy under the hood = with only=20 my backup instruments and a Garmin 196 handheld GPS.  The ADI = doesn't=20 respond exactly the way a conventional attitude indicator does, but I = seemed to=20 quickly adjust to it.  After a few minutes, I was interpreting the = ADI's=20 input without thinking about it.  The only thing that wasn't = intuitive=20 was controlling a descent.  The dive calibration marks don't "bank" = when=20 the airplane rolls the way the climb calibration marks do.  = This is=20 hard to explain, but look at the photo from the link above.  The = blue part=20 of the display rotates as the airplane banks, but the brown part is=20 stationary.  That's not a big deal, but sort of an oddity in a = descending=20 turn that I'm sure I'll get used to with a little more practice.  = Also, the=20 dive calibrations are much closer together than the climb calibrations, = which=20 makes them a little harder to interpret.  But that's a pretty minor = complaint.
 
On the plus side, it costs a fraction of what a conventional = attitude=20 indicator costs.  It's also lighter weight and, if connected to a = GPS,=20 provides track information that conventional attitude indicators = don't. =20
 
On the minus side, it doesn't respond in exactly the same way as a=20 conventional attitude indicator, which might be an issue for some = people. =20 It also uses similar electronic technology as the Chelton/Pinpoint = and my=20 hunch is that any electronic attack on the system, such as from = lightning, would=20 take out the ADI long before the Chelton/Pinpoint.
 
Which brings up the need to define what risk you want to protect=20 against.  For me, I'm protecting against the risk that the = Pinpoint, which=20 is the single point of information for GPS and attitude information, = fails for=20 some reason internal to itself, such as a connector coming unplugged, = etc. =20 I'm not protecting against a lightning strike or a total electrical = failure, which would also take out the ADI.  I understand that = other=20 people will choose different risks to protect against and will,=20 therefore, have different equipment requirements. 
 
In conclusion, I'm happy with the TruTrak ADI and believe it will = fill the=20 mission I have assigned it.  And the Garmin 196 handheld GPS = is=20 amazing, what a value!  But that's for another post.
 
Dennis Johnson
Legacy, 125 hours 
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