Today's Message Index:
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1. 07:29 AM - Re: Alternator part number? (Robert L. Nuckolls, III)
2. 11:38 AM - Re: Article from AOPA on Glass EFIS failures (Robert L. Nuckolls, III)
3. 05:13 PM - Re: Alternator part number? (Ken)
4. 05:28 PM - Re: I-Phone Inclinometer (rampil)
5. 10:40 PM - Re: Re: I-Phone Inclinometer (Etienne Phillips)
Message 1
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Subject: | Re: Alternator part number? |
> Followup: Another member on the List has turned me on to
> the following website:
>
>http://www.motorcarparts.com/catalog.htm
>
<snip>
Followup to the followup. I may have an opportunity
to examine failure analysis data for various automotive
alternators that would give us some insight as to
the smoothest way to integrate these devices into
OBAM aircraft.
Does anyone has a part number to share taken from
a label on their current installed alternator
or perhaps off a carton or invoice for having purchased
the alternator? I'd like to know what it is and perhaps
a little background on how you selected and acquired
the alternator.
We can plug the numbers into the big data-base-in-the-
sky and see what spits out. It may be significant,
it may not . . . but interesting in any case.
Bob . . .
Message 2
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Subject: | Re: Article from AOPA on Glass EFIS failures |
At 08:25 PM 8/6/2008 -0400, you wrote:
><echristley@nc.rr.com>
>
>Hinde, Frank George (Corvallis) wrote:
>>(Corvallis)" <frank.hinde@hp.com>
>>
>>Ahh yes...As I tell my engineers who want every cool gadget going on
>>their sysytems..."Every component is an expensive point of failure"
Yeah, I recall a gray-beard telling me 30 years ago about what he
called "the rule of tens". He was counseling me about specing
1% established reliability resistors even if the electrical
performance wasn't needed. He said it cost us 50 cents to bring
it in, $5 to find a bad one at the board level, $50 to find a bad
one at the ATP level, $500 to find it on the airplane, and a
whole lot more if somebody's airplane get's bent or people
get hurt (1975 prices!). The value of good parts goes beyond
the price of buying the part . . . more significant still was
the value of not having a part there in the first place. Parts
count reduction was a powerful tool for $risk$ reduction.
Lines of code, quantities of parts . . . it's good not to
have more than necessary to meet design goals..
<snip>
>Proper software engineering requires the same sort of methodical, tedious
>system review and modularity that we expect to put in our electrical
>design. In the end, that is exactly what it is, a lot of tiny electrical
>switches going off all over the place. The fault scenarios are often
>difficult to identify. Even people who should know better often forget this.
Yes, and the MBA/Regulatory solution to this is "standardize"
whether it's DO-xxx, ACzzz, ISO9xxx, FARxxxetc. The concept
is devilishly and deceptively simple. "Document the path to
Nirvana and anyone who can read will achieve the golden goal."
I've watched the production lines at local GA manufacturing
erode from experienced skill and pride of craftsmanship to
certificated ignorance and apathy. The same thing is happening
in engineering. Nobody designs anything any more, they write
specs (per the ISO approve P&P manual) and farm it out.
Problem is that the folks they farm it out to are just as
P&P driven as the folks who write the specs. When it doesn't
work quite right, everyone gets that deer-in-the-headlights
look while the customer of a $14M$ airplane is out in the lobby
tapping his toe awaiting delivery. "This can't be happening
. . . the specs say that it's supposed to work and yea verily,
it must be so!"
The poor sap who gets to write "real" code must follow the
top-down design document that was mandated to him irrespective
of his personal and perhaps accurate assessment of how bad it is.
Managers of "The Word According to ISO" may personally worship
individual abilities of a guy who can heard a tiny ball around
a big field better than anyone else, or the strange but obviously
talented inventor, the entertainer who enthralls thousands,
or the guy who can pick up a toolbox and 'scope and seems
to be able to fix anything. Yet if any individual working
under the "Gospel According to ISO" strays from the path of
documented excellence, he or she is promptly brought back in
line . . . if not fired.
If the likes of Edison, Kettering, Gates or Kay had been saddled
with modern business and product development dogma, the
technology we enjoy today would have a VERY different
appearance and utility.
The last two years of my tenure at H-B included an effort
to fund and execute a real IR&D activity intended to
produce a universal fuel gaging module. A device that could be
programmed to work in anything from a Bonanza to the
4000. Even had a team of capable and willing participants
lined up. "Nope, can't be messing with that kind of stuff.
It's not our core competency."
A year after I left, I participated in a response
to a request for proposal for development of just such a
gizmo. Eureka! I might get to work on this after all!
We put the proposal in about 10 weeks ago and everybody
was all smiles. It's been hung up in supply chain because
the P&P manual doesn't cover some of the unique features
of our proposal . . . (sigh)
If Frank Hedrick were still running the show, we'd
be flying our first-cut prototype by now and fine
tuning performance based on real-time feedback from
flight test pilots and instrumentation . . . not
waiting for the top-down writers to conjure up a new
route to Nirvana.
Bob . . .
Message 3
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Subject: | Re: Alternator part number? |
ND 100211-1680 which crosses to 612270 on the site.
An industrial 40 amp unit that is small, light, and relatively modern.
It was largely chosen for its low 40 amp output in case it ever ran away
and to allow loading it down if the voltage was high. Then I found out
about OVP protection. However all my lights and pitot heat can indeed
load it higher than 40 amps which I like. I think it was around $150
new. 212 hours on it so far and rock steady at 14.3 volts. Unlike some
newer units, it will draw field current anytime the IGN lead is powered,
even if the alternator is not rotating.
Ken
Robert L. Nuckolls, III wrote:
> <nuckolls.bob@cox.net>
>
>
>> Followup: Another member on the List has turned me on to
>> the following website:
>>
>> http://www.motorcarparts.com/catalog.htm
>>
>
> <snip>
>
> Followup to the followup. I may have an opportunity
> to examine failure analysis data for various automotive
> alternators that would give us some insight as to
> the smoothest way to integrate these devices into
> OBAM aircraft.
>
> Does anyone has a part number to share taken from
> a label on their current installed alternator
> or perhaps off a carton or invoice for having purchased
> the alternator? I'd like to know what it is and perhaps
> a little background on how you selected and acquired
> the alternator.
>
> We can plug the numbers into the big data-base-in-the-
> sky and see what spits out. It may be significant,
> it may not . . . but interesting in any case.
>
> Bob . . .
>
Message 4
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Subject: | Re: I-Phone Inclinometer |
Actually Ron has a reasonable question.
All of the modern inertial platforms use MEMS-based accelerometers
not gyros as sensors. The problem with MEMS chips is that they drift
and require correction or compensation. Often the drift correction
can be done with a GPS ala BlueMountain, etc.
So... some enterprising programmer could, with the new GPS
capabilities in the development software now in beta, create an
emergent AI, better in theory that the GPS only system like in the
Garmin 496.
I'm not an engineer, but I played one in grad school for 4 years
--------
Ira N224XS
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=197792#197792
Message 5
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Subject: | Re: I-Phone Inclinometer |
On 11 Aug 2008, at 2:25 AM, rampil wrote:
>
> All of the modern inertial platforms use MEMS-based accelerometers
> not gyros as sensors. The problem with MEMS chips is that they drift
> and require correction or compensation. Often the drift correction
> can be done with a GPS ala BlueMountain, etc.
>
All the electronic systems I've come across (MGL and Dynon in
particular) use both accelerometers and "solid-state" gyros, and some
even use an electronic compass and airspeed. The SS gyros only output
the rate of change of direction whereas the accelerometers, compass
and airspeed measurements give an absolute value at any time. If the
gyros have even a very slight offset error, this will be integrated
over time to be a constant change in direction, which is compared
Etienne
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