Message-ID: <39B7B9DE.1646E9AE@regandesigns.com>
Date: Thu, 07 Sep 2000 10:53:03 -0500
From: Brent Regan <brent@regandesigns.com>
To: Lancair List <lancair.list@olsusa.com>
Subject: RE: Sierra Flight Systems
Reply-To: lancair.list@olsusa.com
Mime-Version: 1.0

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Ahhh, the double edge sword of beta systems. You want to test hardware in
actual conditions but, if you do, any flaw is exposed to everyone. In this
case, it isn't even a flaw.

Charlie rode to SnF with Tony Durizzi. Tony's plane has Version 2 hardware
installed. Currently SFS is shipping Version 5 hardware. The changes from 2
and 5 include; elimination of the separate processor box, implementation of
the voice warning system, improved display optics, multiport IO, armored IO
and more. Tony's voice warning system "wasn't working" because it is not
supported in his version of the hardware. The heading was off by 20 degrees
because Tony did not have the opportunity to calibrate the heading sensor in
his AHRS.

AHRS calibration takes only about ten minutes but it requires a compass
rose. Before calibration my system was off by 18 degrees, after calibration
it is right on (less than 2 degrees). I understand that Tony's system is now
calibrated and is accurate as well.

Actual flight testing is essential to uncover unexpected interactions
between the airplane in flight and the system under test. Just last weekend
I discovered that in a 28 volt airplane, with a solid state voltage
regulator and tired GR batteries, the IDU's input protection circuitry can
interpret the avionics on power surge as an over voltage condition and shut
down the IDU power supply (protecting the rest of the system). Once the
problem was identified, a fix was tested and implemented and will be
incorporated in any system that may be affected. An interaction like this
would NEVER have been found in the lab. Naturally it reveled itself at the
worst possible time, just before my demo flight with Filidauro.

All products have problems. Any company that tells you otherwise is either
lying or hasn't done enough testing. The measure of a company is how it
reacts when a problem is discovered. I think you will find that SFS excels
in their problem remediation. Since installing the system in my airplane,
just before OSH, I have uncovered several minor squawks, all have been
corrected.

Regarding Megget, why would you pay more to get less? Do yourself a favor
and put the two systems side by side before you buy.

Regarding the comparison to Darkangel, that is just rude. Darkangel was
designed by a PhD college professor (Those who can, learn. Those who can't,
teach). SFS was designed by IFR rated pilots who fly behind the hardware in
their own planes. If one part of a Darkangel system fails the whole system
comes to it's knees. If one part of the SFS system fails the other parts
step up and pick up the slack. If an IDU fails, the other IDU takes over. If
the GPS fails, the inertial system takes over. If the AHRS fails you still
have moving map. If your aircraft electrical system fails, the optional UPS
will power the system for 45 minutes.

Whatever you do, don't believe me or anybody else. Do what Filidauro did and
go see first hand. Be warned though, if you don't have the cash for the SFS
don't even look or you will be trying to rationalize a second mortgage on
the homestead. My company designed the hardware for the SFS IDU (under
contract) so anything I say should suspect and independently verified before
taken as a fact.

Regarding 12 or 28 volt systems, I chose 28 volt because the big wires are
smaller (lighter) and a 60 amp 28 volt alternator produces twice the energy
of a 60 amp 12 volt alternator. Also, since current flows are less, voltage
drops through switches and contactors are less as well. Some argue that 12
volt components are easier to source but in my experience this is only true
if you plan to use automotive components. I had no difficulty finding 28
volt components for my plane. Check the archives for more on this topic.

Regarding the fly in, there were a lot more 2 place planes there than 4
place because there are a lot more 2 place planes out there. The light
turnout was probably because the weather Saturday was perfect for ice and
nobody likes ice. I even picked up some rime on Sunday. While it is true
that you can fly over most weather in a IV, you still have to get up there
and get back down.

Regards
Brent Regan


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