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Too many Circuit breakers....
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Ceengland



Joined: 11 Oct 2020
Posts: 378
Location: MS

PostPosted: Sat May 14, 2022 12:54 pm    Post subject: Too many Circuit breakers.... Reply with quote

On 5/14/2022 12:56 PM, andymeyer wrote:
Quote:


Bob,

Thanks! I've got other builders watching our learnings here closely so... Smile

I added the appropriate loads to where they need to go.
Main bus: (breaker size)
Pitot: 20A
Lighting: 10A
Boost pump: 5A
Starter Relay

Avionics Bus is:
Garmin stuff is 15 A (incl Audio panel)
AXP 322 + Stratux = 5A
ELT 1A

E Bus:
AV30E - 2A
Engine Monitor - 2A
IFD - 17.5A (GPX+Comm)

No need for brown-out boosting if I put the Avionics master in, Yes, if I don't. The Garmin items that I'd want brownout protection on all have internal diode or'd inputs so I can put the brownout booster on power #2 and it'll keep it awake. Same with the Avidyne IFD. AV30 will stay awake with it's internal battery. Engine monitor runs down to ~4.5 volts on the input. Okay, you just talked me into brownout boosting - booster + a few wires - simple. (Fuse to the booster, then do I also fuse each output line of the booster?

I modified the diagram to two versions - one dual alternator, one dual battery.
I was wondering why all of the relays - can we not get good switches to handle these loads, or is the relay + small switch + connections(7) more reliable than a higher power switch + connections (2)?

Dual Alt Preflight:
Pre-flight... EBus on - check that the AV30 wakes up. Master on, EBus off.
Run up... Eng Bus Alt feed on, Master off - make sure engine keeps running. But, everything else goes dark for this check???
Aux Alt to middle position, master off, make sure things don't go dark, check voltage, Aux alt up, check voltage rise (>13, but need higher RPM with SD8), aux alt to middle, Main alt on, Aux alt off, recheck voltage > 13.0

Annually, load test battery.

Major electrical failure: (failed master, shorted master bus, loose wire to master...)
Everything goes dark and quiet except battery bus and AV30.
Aux Alt on. E Bus wakes up and starts powering up.
Mixture - cut-off. Eng Aux bus on. Mixture rich. things get noisy again.
Dual Batt pre-flight
Pre-flight... EBus on - check that the AV30 wakes up. Master on, EBus off.
Run-up... Ignition - test #2 on both normal and standby power. Voltage > 13.0

Annually, load test both batteries.

Major electrical failure:
Everything goes dark except battery bus and AV30.
EBus alt on, IFD comes back up. monitor voltage on main battery. AV30, IFD and engine monitoring remains.
When main battery is < 6V, then move ignition #2 to middle position - #2 battery. 5Ah, ~2 hours of flight time with AV30 battery and engine monitoring. Engine monitoring dies around 4.5 volts.[/b]
On loads: wire should be sized to the mfgr spec, and protection sized to

wire. But if doing a load chart to size the alternator(s) and
battery(ies), it's worthwhile to measure actual consumption, and then
categorize each load by actual use. ex: flaps might draw 8 amps, but
would be so intermittent  (a few seconds at the end of the flight) that
they could be on the endurance bus if desired.

Brownout boost: not *needed* even without an avionics master; just a
possibility of an extra couple of minutes of reboot time. No risk of
damage, but the reboot and possible reloading of flight plan, etc can be
a pain. Booster wiring protection: If all the wires are the same size
(feeder to booster, and booster to loads), and the booster has built-in
overcurrent protection (likely it will), then fusing the feeder should
be adequate.

Relays: Like Joe said, two reasons; big loads, or remote control. If the
buses are physically close to the switch location, a big switch works
fine. If they're far from the switch, a relay mounted at the buses can
keep 'fat' wires short & may weigh less than a long run of fat wire. I
agree with the 'fewer failure points', of course.

"Master off - make sure engine keeps running. But, everything else goes
dark for this check???"
Depending on architecture, activating  the bus-tie switch prior to
'master off' would verify tie operation, and keep everything 'up'.

Charlie

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PostPosted: Sat May 14, 2022 4:39 pm    Post subject: Too many Circuit breakers.... Reply with quote

Quote:
Another reason for using relays is for remote control.

Note that the relays shown control wires with (*) notations.
This means make as SHORT as practical. These are bus feeders
that should not be switched on the panel by extended wires.



Bob . . .

Un impeachable logic: George Carlin asked, "If black boxes
survive crashes, why don't they make the whole airplane
out of that stuff?"


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Eric Page



Joined: 15 Feb 2017
Posts: 241

PostPosted: Sat May 14, 2022 5:05 pm    Post subject: Re: Too many Circuit breakers.... Reply with quote

Ceengland wrote:
Brownout boost: not *needed* even without an avionics master; just a possibility of an extra couple of minutes of reboot time. No risk of damage, but the reboot and possible reloading of flight plan, etc can be a pain. Booster wiring protection: If all the wires are the same size (feeder to booster, and booster to loads), and the booster has built-in overcurrent protection (likely it will), then fusing the feeder should be adequate.

Following up on Charlie's comment, I would add the following regarding brown-out boosters. Remember that they're constant-power devices. If the output is set at 12V and the load is 5A, power output is 60W. As input voltage falls (eg. during engine start), input current must rise to maintain constant output power. For example, powering that 60W load from an input voltage of 9V will require an input current of 6.7A (plus a little for losses in the boost circuit). Feed wires -- and, if it's fused separately, circuit protection -- should be sized with this in mind, but calculated for your specific load and booster efficiency.


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andymeyer



Joined: 31 Mar 2015
Posts: 54
Location: SW MI

PostPosted: Sun May 15, 2022 7:16 am    Post subject: Re: Too many Circuit breakers.... Reply with quote

This is continuing to be a really good journey.

My philosophy is shifting from how I've flown for years based on what I'm learning here towards what's in Z101. I am likely going to go dual battery to support the secondary ignition, but have the ability to add the secondary alternator at a later time. The weight won't hurt me in the nose as I'm on the back of the CG envelope right now - the second alternator will, if it will fit at all. (Long EZ...)

Clearance/Aux bus will get the brownout booster. Very light loads on that bus. (AV30E (.5A operational) + Engine Monitor (~.3 A) + IFD (4.4A + 6.5A (xmit'ing) operational). I shouldn't be transmitting when cranking. I may just take the connections from the brownout booster to PWR2 on both the IFD and Garmin GDU (this keeps the brownout from carrying the comm).

Why is the wire from the Main power bus to the master switch 20FLW, to 16 AWG, to 20AWG?

On the engine bus - if I'm feeding a single ignition at < 5A, Do I need the relay and all, or can I just switch and fuse it?

I do understand the push for the second alternator... I may do it if I can fit it in due time.

Bob, Great work in converting another pilot/builder (and maybe a few more) and to your years of great work and service to us builders and pilots... Thank you!


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PostPosted: Mon May 16, 2022 8:41 am    Post subject: Too many Circuit breakers.... Reply with quote

Quote:
the second alternator will, if it will fit at all. (Long EZ...)

The SD-8 was B&C's first product for OBAM aviation. Bill
Bainbridge began studying ways to put a lightweight
alternator on the vacuum pump pad of an engine at the
request of Burt Rutan. Bill's early explorations
brought him to Electro-Mech where I was employed as
a design engineer. Bill asked if he could purchase
raw, front end bell castings we were using on our
own AND20000 drive pad product; a standby generator
for Bonanzas (Boy, did that turn out to be a clunker
project . . . we should have taken a hint from Bill's
work with PM machines. It would have served
our customers as well. Best yet, we would have got
the concept qualified onto TC aircraft!)

I was surprised when boss Fred agreed to sell castings
to Bill. Bill later approached me for assistance in
evaluating performance tweaks . . . this began
my association with B&C back about 1985.

In any case, the SD-8 should fit your LongEz . . .

Quote:
Why is the wire from the Main power bus to the master switch 20FLW, to 16 AWG, to 20AWG?

The segment between the main bus and the alternator
field circuit breaker is an EXTENSION of a bus
out to the remotely located breaker on the
panel. If you're going with breakers on the
panel, then that segment can be deleted and your
alternator field breaker driven directly from
the bus with other breakers.

Quote:
On the engine bus - if I'm feeding a single ignition at < 5A, Do I need the relay and all, or can I just switch and fuse it?

Eliminate the engine bus. Drive ignition from
battery bus via 5A fuse . . . also any electric
fuel pumps can have their own fuses driven directly
from the battery.

Quote:
I do understand the push for the second alternator... I may do it if I can fit it in due time.

I think it's physically possible and practically
valuable.


Quote:
Bob, Great work in converting another pilot/builder (and maybe a few more) and to your years of great work and service to us builders and pilots... Thank you!

You're welcome.

Speaking of pad driven power sources, I found
an exemplar Electro-Mech standby generator for
sale on eBay. Pictures . . .

https://tinyurl.com/y5j3gjbl

That regulator was a project that prompted boss
Fred to ask me back to EM about 1978 (long story).
A variation was crafted for the generator project
a year or so later. First engine driven power
machine we ever attempted. Sold a boat-load
of the things. Very unpopular in the field.
Brush life was terrible.

I wasn't much into rotating machines back then
being pre-occupied with herding electrons. But
I participated in the program with a variation
on the family of regulators we'd already
qualified onto Beech piston products.

In retrospect, a variation of the B&C SD-8
would have filled the bill nicely in the
Bonanzas with an essentially zero failure
rate!

Too soon we get old . . . to late we get smart?


Bob . . .

Un impeachable logic: George Carlin asked, "If black boxes
survive crashes, why don't they make the whole airplane
out of that stuff?"


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andymeyer



Joined: 31 Mar 2015
Posts: 54
Location: SW MI

PostPosted: Sun Aug 21, 2022 6:48 am    Post subject: Re: Too many Circuit breakers.... Reply with quote

Bob, et al.,

Finally have all of the parts and pieces for the upgrade - new panel wiring is almost complete and ready to haul out to the airport for the install. Decided to bite the bullet and do the SD-8 right away - need to order this week. It will be a backup only per Z101B.

Question, as the wiring diagrams I'm seeing from BandC doesn't answer some questions... Basic SD-8 with the PMR1C-14... Just two wires coming of the SD-8 - connect to the two blue wires on the PMR1C-14. Black wire on the PMR1C-14 to engine case ground? Red wire via the Aux Alt switch (Carling 2GG51-73 15 Amp switch) to the fat wire tie point with a fusible link at the fat wire tie point?

Any need for crowbar / overvoltage protection with the SD-8 against a PC680 battery when used for emergency use only?

Do you consider having the battery and both alternators per the Z101B configuration sufficient redundancy for a dual electronic ignition aircraft? (ignition optionally fed from either side of the master.)

I am considering running the SD-8 output also to one of my ignitions (third switch position on the ignition - EMER) such that if there's a hard short and I lose the entire electrical system, the SD-8 can feed one ignition. Dark and stormy night - electrical system goes dark along with the engine - flip Ign2 to EMER.


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PostPosted: Wed Aug 24, 2022 7:47 am    Post subject: Too many Circuit breakers.... Reply with quote

At 09:48 AM 8/21/2022, you wrote:
Quote:
--> AeroElectric-List message posted by: "andymeyer" <meyerkc135(at)gmail.com>

Bob, et al.,

Finally have all of the parts and pieces for the upgrade - new panel wiring is almost complete and ready to haul out to the airport for the install. Decided to bite the bullet and do the SD-8 right away - need to order this week. It will be a backup only per Z101B.

good move


Quote:
Question, as the wiring diagrams I'm seeing from BandC doesn't answer some questions... Basic SD-8 with the PMR1C-14... Just two wires coming of the SD-8 - connect to the two blue wires on the PMR1C-14.

yes

Quote:
Black wire on the PMR1C-14 to engine case ground?

System ground . . . forest of tabs on firewall?

Quote:
Red wire via the Aux Alt switch (Carling 2GG51-73 15 Amp switch)
to the fat wire tie point with a fusible link at the fat wire tie
point?

yes


Quote:
Any need for crowbar / overvoltage protection with the SD-8 against a PC680 battery when used for emergency use only?

Probably not


Quote:
Do you consider having the battery and both alternators per the Z101B configuration sufficient redundancy for a dual electronic ignition aircraft? (ignition optionally fed from either side of the master.)

I would wire per z101 wherein engine bus enjoys
two, independent feed paths.


Quote:
I am considering running the SD-8 output also to one of my ignitions (third switch position on the ignition - EMER) such that if there's a hard short and I lose the entire electrical system, the SD-8 can feed one ignition. Dark and stormy night - electrical system goes dark along with the engine - flip Ign2 to EMER.

How are you going to get a 'hard fault' on the engine bus?

Hard faults in electrical systems are invariably results
of (1) poor craftsmanship or (2) really catastrophic
distortions of the airplane (like flying into mountainside).

Pay attention to wire security and clearance from
moving parts . . . don't worry about that dark-n-stormy
night scenario.


Bob . . .

Un impeachable logic: George Carlin asked, "If black boxes
survive crashes, why don't they make the whole airplane
out of that stuff?"


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andymeyer



Joined: 31 Mar 2015
Posts: 54
Location: SW MI

PostPosted: Tue Sep 27, 2022 5:21 pm    Post subject: Re: Too many Circuit breakers.... Reply with quote

Bob, and the rest of the AeroElectric crew,

Thank you for all of the guidance. About to install this fun in the next week or two - just need to take a couple days away from work and a long weekend.

Any final thoughts on this configuration?

My only lingering question - to get rid of the diode drop (NTE53016), do I pose any risk in running a wire from the Master Relay (out) to the NC connection on the E Bus Relay(Blue)? (Redundant wire paths, diode keeps the Aux Bus Relay from being a single point of failure, but during normal operation, diode doesn't flow any current - it all goes through the added wire.)

Andy


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user9253



Joined: 28 Mar 2008
Posts: 1907
Location: Riley TWP Michigan

PostPosted: Tue Sep 27, 2022 6:18 pm    Post subject: Re: Too many Circuit breakers.... Reply with quote

During normal operation, the diode should be conducting current.
It doesn't matter if the diode does drop a volt. The alternator output is 14 volts.
That still leaves 13 volts for the loads. That is plenty.
An additional wire does nothing except adds more possible failure points.
The voltage drop could be cut in half by using a Schottky diode. STPS24045TV
But it will cost 5 times as much.


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PostPosted: Wed Sep 28, 2022 8:09 am    Post subject: Too many Circuit breakers.... Reply with quote

At 08:21 PM 9/27/2022, you wrote:
Quote:
--> AeroElectric-List message posted by: "andymeyer" <meyerkc135(at)gmail.com>

Bob, and the rest of the AeroElectric crew,

Thank you for all of the guidance. About to install this fun in the next week or two - just need to take a couple days away from work and a long weekend.

Any final thoughts on this configuration?

Why the monkey motion in powering ignitions? What
are the anticipated failure modes that call for
those operational features. Multiple failures
during one tank of gas?

Recommend the ENGINE BUS as originally depicted.
One fuse/switch driving each ignition.

Why boost pump not on engine bus?

You've got a lot of 'stuff' on the e-bus.
Will the SD8 support everything on the
ebus? The e-bus is an ENDURANCE bus
crafted to be your 'plan-b' . . . ticket
to airport of intended destination in case of
main alternator failure.

Originally supported only by a well maintained
battery, a design goal was to power up only
those devices that get you home with
more electrical endurance than fuel.
Of course, this assumes that the builder
selects and maintains a battery such that
the design goal is met.

When supported by a s/b alternator, e-bus
loads can be greater but still, the idea
is to position the minimum number of switches
to re-configure for Plan-B. Have you done
those calculations?


Quote:
My only lingering question - to get rid of the diode drop (NTE53016), do I pose any risk in running a wire from the Master Relay (out) to the NC connection on the E Bus Relay(Blue)? (Redundant wire paths, diode keeps the Aux Bus Relay from being a single point of failure, but during normal operation, diode doesn't flow any current - it all goes through the added wire.)

The diode drop does not degrade performance
in any way. The diode is more reliable than
any relay or switch.

You show a mix of breakers/fuses. How come?




Bob . . .

Un impeachable logic: George Carlin asked, "If black boxes
survive crashes, why don't they make the whole airplane
out of that stuff?"


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PostPosted: Wed Sep 28, 2022 12:09 pm    Post subject: Too many Circuit breakers.... Reply with quote

At 08:21 PM 9/27/2022, you wrote:
Quote:
--> AeroElectric-List message posted by: "andymeyer" <meyerkc135(at)gmail.com>

Bob, and the rest of the AeroElectric crew,

Thank you for all of the guidance. About to install this fun in the next week or two - just need to take a couple days away from work and a long weekend.

Any final thoughts on this configuration?

P.S. you show the voltage sense lead to the LR3
tied to the battery. This puts a small but continuous
load on the battery even while parked. Suggest you
follow manufacturer's recommendations.


Bob . . .

Un impeachable logic: George Carlin asked, "If black boxes
survive crashes, why don't they make the whole airplane
out of that stuff?"


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andymeyer



Joined: 31 Mar 2015
Posts: 54
Location: SW MI

PostPosted: Thu Sep 29, 2022 6:51 am    Post subject: Re: Too many Circuit breakers.... Reply with quote

Bob,

Great find on the LR3 voltage sense. I need to double check where I have that installed right now.

Ignitions: No real monkey motion... primary is dual feed (battery and main alternator.) Main alt dies, flip on the SD8 and turn off the master to load shed... No rush.
Master dies, flip on SD8 and master off.
Fan ever stops: Ign#2 to EMER. (Boldface)

Major electrical issue (had an electrical fire in the F16). Shut master off and ignition 2 to EMER. Fan keeps running - everything else is off.

Lightspeed design recommendation is to have the ignitions wired to the battery side of the master. Help me understand what wiring the ignitions to the alternator side of the master buys? I'm getting rid of a relay, switch, and a few connections (and with the 3 position switch, get an isolated power source to keep the fan running).

Power on EBus: 2.6 amps for two ignitions. 1.45A for GDU/GSU, AV30 is .5A, Eng Mon ~.5A, IFD can and will be shut off as it pulls 4.9A, but is there to get me in crappy IFR conditions onto the ground - turn it on for the approach. Landing light only on short final. What do you suggest as a target for draw on the EBus with an SD8?

I'm still one fuse, one switch for each ignition direct to the battery. One switch has an additional position for an additional power source.

Boost pump - Multiple failures in one flight? I'm carbureted. Maybe I'm missing something and should move this to the EBus.
Flight endurance - It's a Long EZ - 13 hours isn't abnormal.

I have mostly fuses, but pullable breakers for the things I want to be able to hard shut off... A/P (obvious), audio panel(failed / squealing, etc...), transponder (formation), and my home built engine monitor (to be able to reset it in case).

I have some legacy W31 breakers for landing light, boost pump, exterior lights and pitot heat. Am I better replacing those with a good carling switch and a fuse?

Thanks!

Andy


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Ceengland



Joined: 11 Oct 2020
Posts: 378
Location: MS

PostPosted: Thu Sep 29, 2022 8:42 am    Post subject: Too many Circuit breakers.... Reply with quote

I have a 'FWIW' general observation about electrical systems design
discussions that we have on this list/forum. (Some of us get email;
others use the forum, and stuff often doesn't 'translate' well between
the two formats.)

The rise of multiple variations of electronic ignition and/or computer
controlled, high pressure fuel delivery, the replacement of steam gauges
with glass, and the increase in the number of people flying homebuilts
in the IFR environment, has made these discussions much more difficult.

Examples:
VFR & 'traditional' engine & panel? minimal effect on electrical system
design
electronic ignition only (carb/mech injection fuel delivery)? minimal
effect on electrical system design
high pressure electronic fuel injection? HUGE effect
IFR? quite serious effect, especially with a glass panel
And I've probably forgotten other factors that significantly influence
electrical system design.

I constantly see people post a question without a complete listing of
what will be installed, and how the plane will be operated. I also
frequently see answers that overlook one or more of the above qualifiers
even though it had been mentioned earlier.

I wonder if it would help to have a list of installed appliances &
intended mission requirements at the top of every post when we're
discussing 'best practices'.

Last, for 'switchology', some stuff has to change, especially with
electronic injection, etc, but I tried to keep it as close as possible
to operating like a traditional a/c setup. It's bad enough for me to
reprogram myself, but if someone else ever needs to fly my plane, I fear
that a completely alien switching process would make it unsafe for them
to operate it, especially in an emergency.

Charlie

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PostPosted: Thu Oct 06, 2022 9:57 am    Post subject: Too many Circuit breakers.... Reply with quote

At 11:43 AM 9/29/2022, you wrote:
Quote:
--> AeroElectric-List message posted by: Charlie England <ceengland7(at)gmail.com>

I have a 'FWIW' general observation about electrical systems design discussions that we have on this list/forum. (Some of us get email; others use the forum, and stuff often doesn't 'translate' well between the two formats.)

The rise of multiple variations of electronic ignition and/or computer controlled, high pressure fuel delivery, the replacement of steam gauges with glass, and the increase in the number of people flying homebuilts in the IFR environment, has made these discussions much more difficult.

Examples:
VFR & 'traditional' engine & panel? minimal effect on electrical system design
electronic ignition only (carb/mech injection fuel delivery)? minimal effect on electrical system design
high pressure electronic fuel injection? HUGE effect
IFR? quite serious effect, especially with a glass panel
And I've probably forgotten other factors that significantly influence electrical system design.

I constantly see people post a question without a complete listing of what will be installed, and how the plane will be operated. I also frequently see answers that overlook one or more of the above qualifiers even though it had been mentioned earlier.

I wonder if it would help to have a list of installed appliances & intended mission requirements at the top of every post when we're discussing 'best practices'.

Points well taken sir. I've received many a direct request for
comment and analysis on a builder's proposed architecture
and without fail, I have to start with asking about a load analysis
(are your battery/alternator choices adequate to design goals?) and
the request for recitation on what equipment is to be installed and how
will the airplane be used (is there any single appliance the
loss of which puts your airframe at-risk?).

List EVERY device that will need ship's power.
I.e. Pick a bus, feeder and protection size for each
device. The important thing is to get every electrical
load defined and down on paper.

Then, come to the AEList and get some insights
about how and under what flight condition might some
'critical' component become inoperative.

For more than 50 years I've read the 'Dark-n-
Stormy Night' stories in the journals. It wasn't
until late in those years and well in to my
aviation career did I come to understand how
those stories sold a bill of goods to an under
informed readership. Virtually all such stories
focused on pilot awareness (or worry) about how
to deal with a similar situation in the future.
I can't recall reading any stories that spoke
to root causes and reducing risk for that
situation happening again.

Of course, fixes to reduce risk in a TC aircraft
require dispensation from On High. We are not
so encumbered in OBAM Aviation Land.

In 30+ years of rubbing elbows with the OBAM aviation
community, EVERY sad tale of an aviator's demise due
to electrical system issues will had root cause
in errors of craftsmanship, maintenance and/or
understanding.

You're dead-on for asking that every load
on the ship's busses be identified for demand,
function and necessity for putting wheels
on the ground with CONFIDENCE.

I suggest that one print out some pages . . .

https://tinyurl.com/2zxe4jsr

with one page for each proposed bus. Get every
load accounted for. Then share with as many
individuals who are willing to brainstorm
(here on the List would be good).

Then deduce how each of those busses
will be powered with a goal of achieving
dual sources for mission critical items.

Consider proposed pilot controls
with a goal of minimizing numbers of switches
and reducing risks for undesired events
arising from mis-placement of switches.

This philosophy drove the evolution of
the library of z-figures not the least
of which is what might become the "Mother
of all Z-Figures", Z101. Z101 is 'modular'
with a mix/match array of busses that cover
the vast majority of powered flight projects.

Should Z101 be found lacking in the service
of some design goal, then let's thrash
it out here on the List. This is how
shortcomings are (1) identified and
fixed or (2) dismissed as a trip down the
rabbit hole.




Bob . . .

Un impeachable logic: George Carlin asked, "If black boxes
survive crashes, why don't they make the whole airplane
out of that stuff?"


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