Message-ID: <004a01c32e28$80362ef0$663b3690@logan.com>
From: "Rob Logan" <Rob@Logan.com>
To: "Lancair Mailing List" <lml@lancaironline.net>
References: <list-2407867@logan.com>
Subject: Re: [LML] Over the line
Date: Sun, 8 Jun 2003 21:43:16 -0400
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> buy all the sensors for an AHRS for about $400. or spend a lot more. This Crossbow 500 sells for $15,000. and is worth
it.

I've only had two AHRS in the legacy..

http://www.icarusinstruments.com/microEFIS.html  at least it used kalman filers, but was useless
in the legacy as any acceleration was registered as pitch.

http://www.xbow.com/Products/Product_pdf_files/Inertial_pdf/6020-0032-01_A_AHRS500GA.pdf
works, and I've been hard IFR with it several times. its issues are:

1) one can't move the aircraft for 90 seconds after power on to fill its  kalman pipeline.

2) if the AHRS breaker is cycled, flying on AP is a good idea for #1 but it does recover
as long as you have some other reference where "straight" (not necessarily level) is

3) I have seen Jim's landing tilt error a few times.

that said, turning off the GPS reference and making it a real inertial navigation unit, works!
http://rob.com/lancair/flights/2003/graph/gps.shtml?2003-Mar-25-Tue-23.07.04
that's amazing!