REFLECTOR: Load distrib

[Brett Ferrell]

Terrence,


1) I'm going with the BMA E/1 as primary, and a BMA Sport as my backup, and they
are completely independent/redudant from the AHRS and all primary flight modes,
including autopilot and radio control (and engine instrumentation with an
optional add-in).

2)  My Sport will not be on my essential bus, I consider E/1 death and primary
power loss as separate failure modes, and I can shed load manually without
having to fall back on my essential bus

What you're suggesting seems like belt, suspenders, and overalls to me.  I've
weighed the reliability of that kind of setup versus the risk I'm mitigating
and decided that this setup gives me the right balance.  Everybody needs to
make those choices for themselves, but Nuckoll's book is a good resource for
evaluating what makes sense to you.

Brett

Quoting Terrence Miles <knightflyr at sbcglobal.net>:

> Y'all,
>
> Great posts!!   Geez I am going to have to get and get trained in speed
> reading!  Several have mentioned dual screen GRT's, but I didn't see mention
> of dual AHRS.  So here's my two part question:
>
> Q #1.  What are you guys doing for attitude/airspeed indicator back up when
> AHRS goes bad?
>
> Q #2.  Craig, I am not familiar with the Blue Mt guts very much.  If you
> have a dual, independent central air data computers (CADC) will you have
> both your CADCs wired to your Essential bus?  Could you talk some more?
>
> My thinking at present is to create dual electrical power and distrib
> sytems:   DC1 and DC2.  Alt1 and Alt2.  Batt1 and Batt2...with each system
> having it's own main bus and each with it's own essential/critical bus.
> What causes this thinking is how to distribute power to these backed-up
> multi function EFIS rascals if I go w/o vacuum driven round dial stuff.
>
> Where's everybody mounting their EIS 6000's.  In pilot's eye view or
> elsewhere?
>
> Terry
>
>
>
>
>
>
>  : reflector-bounces at tvbf.org [mailto:reflector-bounces at tvbf.org] On Behalf
> Of Craig and/or Denise Woolston
> Sent: Friday, February 25, 2005 10:30 AM
> To: 'Velocity Aircraft Owners and Builders list'
> Subject: RE: REFLECTOR: electrical sys design
>
>
>
> John and I are going with a dual alternator/dual battery system also.  We
> are going the dual screen GRT also.  Add to that the Blue Mountain G3 with
> autopilot and we basically have dual everything except the engine.  My plan
> is the 70amp alternator that came with our IO-550 and either the 7 or 20 amp
> vacuum pump pad B&C.  The essential bus will have the radio, transponder, BM
> EFIS, EIS.  The main bus everything else.  I want to know that both my
> alternators are working before launching into the soup so both will be
> "active" all the time.  We plan to use Bob's Low Voltage Module to auto
> connect the Essential to the Main if the Essential alternator goes down.  We
> will have a crossfeed switch OFF/AUTO/ON.  The AUTO will be Normal Ops so
> there is no pilot work load during a failure.  If the ESSENTIAL does down,
> then it will auto switch to the MAIN.  If the MAIN alternator goes down then
> we get the Low Volt on MAIN and can when pilot work load dictates go to
> forced XFEED.  The Low Volt Module will then flash if the load is too great,
> so we can shed what we need to as appropriate.
>
>
>
> Currently I'm thinking a 24ah for starting and the main bus and a 17ah or
> smaller for the essential bus.  My thought is to always start on the 24 and
> then 17 is only seeing starting operations on those cold mornings or hot
> starts that go bad???  Plus there will be no voltage sag on the 17 under
> normal start so the EIS will be available immediately.
>
>
>
> My solution for the below is three annunciator, a LOW VOLT and then under it
> a MAIN and ESTL, which will light as described above.  Plus the EIS is on
> the ESSENTIAL bus so it will read that voltage and the GRT EFIS is on the
> MAIN bus so it will read that one.  Which should trigger my other
> annunciators a ENGINE and a EFIS.  I'll be looking at a fricking XMAS tree
> which will be hard to miss.
>
>
>
>
>
> Craig
>
> XL-5FG in Palmdale,CA
>
>
>
>
>   _____
>
>
> From: reflector-bounces at tvbf.org [mailto:reflector-bounces at tvbf.org] On
> Behalf Of Terrence Miles
> Sent: Thursday, February 24, 2005 6:14 PM
> To: 'Velocity Aircraft Owners and Builders list'
> Subject: RE: REFLECTOR: electrical sys design
>
>
>
> If it works out that way then I'll drop to a motorcycle batt with an ammeter
> and voltmeter on the primary system  Then I understand that there is an aux
> plug on the GRT EIS audio warning I could steal and/or maybe set abnormal
> range gauge readings  to a master caution.   One problem w/ electrical
> abnormals is you don't see 'em until the lights go out.
>
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