Message-ID: <39BCE021.79449CB8@regandesigns.com>
Date: Mon, 11 Sep 2000 08:37:37 -0500
From: Brent Regan <brent@regandesigns.com>
To: Lancair List <lancair.list@olsusa.com>
Subject: RE: Sierra Flight Systems Gyros
Reply-To: lancair.list@olsusa.com
Mime-Version: 1.0

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Sierra Flight Systems flight tested the Crossbow AHRS and found that there
were two problems that made it unacceptable. First, it's maximum bandwidth
is only 10Hz, causing the attitude and heading display to be jerky. A higher
bandwidth is required for a smooth display. Second, the Crossbow system does
not have centripetal compensation. The result of this is that if you are in
a coordinated turn and then roll out to wings level, the Crossbow AHRS will
indicate a bank in the opposite direction of the turn. My inner ear already
has this feature, so I don't need it displayed.

It was my understanding at OSH that Meggit had dropped Crossbow and were now
using the same vendor at SFS. Gordon was frustrated that the two years of
flight testing and improvements that had gone into their AHRS were now
available to their competition.

You can always tell the pioneers, they have arrows in their backs.

The SFS certification efforts are going well. The hardware you can buy today
from them is virtually identical to the certified hardware with the
following exceptions. The certified hardware will have a minimum of two
IDUs, it will not have engine management and it will have a certified GPS
and Air Data system.

Regards
Brent

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