Today's Message Index:
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1. 12:08 PM - History of the E-Bus (Robert L. Nuckolls, III)
2. 12:10 PM - List subscription problems? (Robert L. Nuckolls, III)
3. 01:19 PM - Re: List subscription problems? (Christopher Cee Stone)
4. 07:17 PM - Buy [5Pieces] Samsung Galaxy New S10/S10+ 128GB $3,495CAD (trptioip)
Message 1
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| Subject: | History of the E-Bus |
One dark and quiet night, a long time ago, I got
a call from one of my California seminar attendees
wrestling with a Load Analysis/FMEA for his
Long-Ez project.
He cited a seminar discussion about the value
of Plan-B protocols for dealing with single
failure of a really important component
of the electrical system. A plan that would
prevent a failure from becoming the source
of his personal 'dark-n-stormy-night' story
. . . or worse yet . . . root cause of events
that produced an NTSB accident report on
his demise.
His airplane was fitted with an SD-8. 8+
Amps in cruise rpm. He was interested in long
endurance flights over unfriendly terrain limited
to daytime only. No lights on the aircraft.
After some discussion we settled on a design
goal for powering a minimally useful list of
electro-whizzies, battery only for duration
of fuel aboard.
I forget the exact numbers but one of the
sticking points of our study was the battery
contactor . . . 0.8A of constant draw while
energized . . . enough energy to operate two
solid state radios . . . just sitting there
using that energy to do nothing more than
get warm.
During that discussion, we concocted the idea
of an ENDURANCE bus to (1) power a
minimally useful equipment list, (2) power
additional items easily turned off to shed
load and (3) have a battery energy path
around a de-energized battery contactor.
I think it was Figure Z-1 back in those days
but the outcome of the conversation added a
bus structure diode fed from the main bus
and switched feed from the battery bus. As
I recall, we crafted a plan-B for his
project that would offer 5+ hours of
battery only operations with a battery
offering only 80% of nameplate capacity.
I made a mistake in calling it the ESSENTIAL
bus. Others wanted to call it the EMERGENCY
bus. Later I reasoned that the sole purpose
for installing the E-Bus was to prevent loss
of alternator or battery contactor from
becoming an emergency.
Easily switched gizmos of lesser utility
might also be driven from this bus;
easily managed by performing a check-list
driven transition to Plan-B.
Over the years, some builders have opted
to add switches to 'protect' avionics.
Some persist in the EMERGENCY/ESSENTIAL
nomenclature . . . which is fine. But
understand that the E-Bus has roots in
a design goal to maximize the utility of
a very limited electrical system while
reducing risk.
The E-bus is still practical for architectures
like Z13/8 where the second engine driven
power source is small (cheap and light too!).
Z13/8 offers an unlimited duration for en route
energy supplied by the SD8 and practically
unlimited energy for descent and approach
to landing by taping battery reserves
to augment the alternator.
As larger, pad-driven alternators became
available, the TC aircraft world readily
embraced the notion of simply adding the
second, smaller alternator in tandem
with the main alternator but with no
significant changes to original architecture
(See Z12). The larger pad-driven machine reduced
concerns for parasitic loads like battery
contactors. It also simplified crafting
plan-B requirements for load-shedding.
The value of an E-bus goes down.
This narrative is intended to encourage
well considered decisions for 'enhancing'
a Z-figure. We have an opportunity here on
the List to advance the state of our art
and science with tools the TC aircraft
world has largely abandoned.
In no way do I suggest that enhancements are
not useful . . . to be sure, Z-figs have
evolved considerably over 31 years of
collective consideration by what must now
include several thousand observers/
contributors.
Let us continue to refine old or advance
new ideas . . . but let's do it by the
numbers and with diligent respect for
lessons learned.
Bob . . .
Message 2
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| Subject: | List subscription problems? |
I've had some reports of subscribers to the
List being 'dropped' for reasons unknown.
In each case, the victim was able to renew
their membership through the /subscribe page
on matronics.com
Has anyone else experienced this difficulty?
Bob . . .
Message 3
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| Subject: | Re: List subscription problems? |
Bob...
Yes, was dropped and unable to log in to re-subscribe. Contacted Matt and
the issue was resolved.
-Chris Stone
On Tue, Feb 26, 2019 at 12:14 PM Robert L. Nuckolls, III <
nuckolls.bob@aeroelectric.com> wrote:
> nuckolls.bob@aeroelectric.com>
>
> I've had some reports of subscribers to the
> List being 'dropped' for reasons unknown.
>
> In each case, the victim was able to renew
> their membership through the /subscribe page
> on matronics.com
>
> Has anyone else experienced this difficulty?
>
>
> Bob . . .
>
>
Message 4
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