REFLECTOR: Major Outline

[Terrence Miles]

Guys,  (and Gals)
 
Thanks for all the suggestions on the spider valve.  I am putting a
heftier heat shield on the wheel brakes and maybe I can use the left
overs for a heat shield.  That was a good idea.  
 
Ken, I will probably take your advice and hold on Lasars after all.  I
have written twice to the Emag-air guys and received quick replies even
tho I a not a customer.  They are working on it, but no dates to offer
despite my pleadings.
 
It's too bad my Dad's not with us anymore.  He was an electrician, by
trade, and would have loved this stuff.did radio work in WWII.  So I do
plan to tackle it all including the panel.at least for now.I just can't
get myself passed the endless research vacuum!!   Thanks for the
cautions on ordering anything prematurely.  I know I can't claim the
same as y'all who work at this alone.  After one week, I am amazed at
how much was accomplished over me alone going at this in a two car
garage with a construction manual and list of phone numbers.  
 
Terry
 
-----Original Message-----
From: reflector-bounces at tvbf.org [mailto:reflector-bounces at tvbf.org] On
Behalf Of Jim Sower
Sent: Saturday, April 30, 2005 12:50 PM
To: Velocity Aircraft Owners and Builders list
Subject: Re: REFLECTOR: Major Outline
 
michalk wrote:



Figure out your reliability requirements.  And temper those with reality
and complexity.  I did a failure analysis of a dual battery system,
single alternator.  This is essentially three power sources.  One could
argue that if both batteries go, so does the alternator. 
Makes sense.  Haven't heard of it ever happening, but it makes sense.



If you figure a battery will unpredictably utterly completely fail in
100 flight hours, that's a chance of .01 in one hour.  
I would guess the number is more like 500 or more hrs (unpredictably
being a key word here).


If two batteries, that's a chance of both failing simultaneously of
.0001 per hour, or one failure every 10000 flight hours.  Of course,
this could happen on your first flight.  Damn statistics. 
Or 250,000 hrs using the 500-hr probability.  Change one battery every
annual (and put it in your car for a few more years) and you can easily
achieve a 500-hr (or better) probability on batteries.



Compare this to vacuum pumps.
Definitely.  Cost $300 - $500, have an [advertised] 800 hr life
expectancy, regularly fail early.


  Weigh your risks on the probability statistics.  DO NOT ACCEPT
ANECDOTAL ADVICE.
Now where you're gonna' get advice that's NOT anecdotal is unclear.


  Get good hard facts and verifiable data.  
Gathered by the guy to whose anecdotes you attach the most credibility


If you are not afraid of electricity, go with electric gyros. 
If you ARE afraid of electricity, take a bus :o) ... Jim S.






Bus structure:  Work in progress. 

Sounds like you have a good start.  With dual batts, I assume you can
separate critical/non-critical busses, and feed critical from either
battery. 

I'm not convinced of the argument that a person needs to be able to tie
the two batteries together for extra starting current.  If this is the
case, I would suggest that perhaps your batteries are getting old and
need to be replaced.  My critical bus/battery can't connect to the
starter, and with a battery isolator, that means my avionics and
computers remain up and running without power glitches through an engine
start. 



And now for a bit of humor from the new guy on the block.I hope to be in
the air by Christmas.  Thank you all very very much for the warm welcome


Bwahahaha!!! 
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