Today's Message Index:
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1. 12:54 AM - Re: Final Elect. System Review (Peter Pengilly)
2. 05:08 AM - Re: Final Elect. System Review (Ken Ryan)
3. 06:49 AM - Re: Final Elect. System Review (user9253)
4. 12:48 PM - Re: Re: Final Elect. System Review (Robert L. Nuckolls, III)
5. 02:37 PM - Re: Re: Final Elect. System Review (Robert L. Nuckolls, III)
6. 02:37 PM - Re: Final Elect. System Review (bcone1381)
7. 08:36 PM - Re: Re: Final Elect. System Review (Robert L. Nuckolls, III)
Message 1
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| Subject: | Final Elect. System Review |
Dear Brooks,
As you are VFR only, and I guess your G5 has a back-up battery, do you need more
than one alternator and one bus? Its only more cost, weight and complexity that
won't buy you much in terms of continued flight after a failure as the battery
will do that with the simple system you are planning.
If the alternator fails figure out what must be switched off to extend battery
endurance.
The G5 will provide 4 hours and the portable navigation must have an internal battery,
so not that much left.
A typical 15Ah battery will keep your airplane flying until you are out of gas.
Keep everything as simple, and as low parts count, as possible. No point in adding
solenoids if a switch can handle the expected load.
Your diagram came over fairly low res, with the text indistinct, but if you really
want to cater for loss of the battery connector use the switch you already
have to bypass directly to all the busses. If a DPDT switch is used disable the
start button circuit so starter loads cannot be put through the switch.
Is circuit protection required on a 12G wire? Perhaps, if you have a large fuse
it may be worth adding, the risk is low.
I would delete the always hot (endurance) bus on a simple VFR aircraft - it only
runs down the battery. The load analysis always says it is good for several
months but my experience is when you haven't made it out to the airport in a month
or 6 weeks and have made an hour or two for a quick flight that plan will
be sunk by a flat battery.
Is the Surefly on the battery bus and aux bus? Would have thought it should be
shut down on the master?
Check the wire gauges you have specified and go for the lightest possible, copper
wire adds a lot of weight.
Regards, Peter
-----Original Message-----
From: owner-aeroelectric-list-server@matronics.com <owner-aeroelectric-list-server@matronics.com>
On Behalf Of bcone1381
Sent: 18 November 2022 16:53
Subject: ****SPAM**** AeroElectric-List: Final Elect. System Review
--> <bcone1964@gmail.com>
Please help me finalize my electrical system. It based off Bobs Z101 and taylored
to meet rather meager demands. I am moving from the conceptual phase to
the fuselage as we speak, installing components today.
My Bearhawk Patrol, like a Supercub, is VFR, with merely a Garmin G5, Engine Monitoring
System, Surefly ignition, Comm, and Xpndr, and portable navigation.
I have done my load analysis, drawn all schematics for individual circuits. My
diagram is attached. I transformed Bobs Z101 Engine Bus to my Aux Bus (Essential
Bus). Continuous draw is 1.5A (2.3A intermittent) plus a single USB charger
max of 2.5A. Please criticize me if the simple switch (Aux Bus - Aux Alt)
is a risk that should fixed with a solenoid.
The left side of the Battery Contactor has 12 AWG wire powering the Aux Bus through
a switch (AUX BUS - AUX ALT) that is not protected. Should I add protection
to that circuit? The length of the circuit is about 30 inches. I have a
B & C slow acting 23A midi fuse that might go well there.
Any other feedback? Bob?
--------
Brooks Cone
Bearhawk Patrol Kit Build
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=508934#508934
Attachments:
http://forums.matronics.com//files/screen_shot_2022_11_18_at_114320_am_149.png
Message 2
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| Subject: | Re: Final Elect. System Review |
Different path, but Viking Aircraft Engines, which supplies engines based
on the Honda Fit, recommends an electrical system that utilizes one
alternator and 2 batteries. They switch which battery gets charged each
flight. Has Bob designed an architecture using one alternator and 2
batteries?
On Sat, Nov 19, 2022 at 11:56 PM Peter Pengilly <Peter@sportingaero.com>
wrote:
> Peter@sportingaero.com>
>
> Dear Brooks,
>
> As you are VFR only, and I guess your G5 has a back-up battery, do you
> need more than one alternator and one bus? Its only more cost, weight and
> complexity that won't buy you much in terms of continued flight after a
> failure as the battery will do that with the simple system you are planni
ng.
> If the alternator fails figure out what must be switched off to extend
> battery endurance.
> The G5 will provide 4 hours and the portable navigation must have an
> internal battery, so not that much left.
> A typical 15Ah battery will keep your airplane flying until you are out o
f
> gas.
> Keep everything as simple, and as low parts count, as possible. No point
> in adding solenoids if a switch can handle the expected load.
> Your diagram came over fairly low res, with the text indistinct, but if
> you really want to cater for loss of the battery connector use the switch
> you already have to bypass directly to all the busses. If a DPDT switch i
s
> used disable the start button circuit so starter loads cannot be put
> through the switch.
> Is circuit protection required on a 12G wire? Perhaps, if you have a larg
e
> fuse it may be worth adding, the risk is low.
> I would delete the always hot (endurance) bus on a simple VFR aircraft -
> it only runs down the battery. The load analysis always says it is good f
or
> several months but my experience is when you haven't made it out to the
> airport in a month or 6 weeks and have made an hour or two for a quick
> flight that plan will be sunk by a flat battery.
> Is the Surefly on the battery bus and aux bus? Would have thought it
> should be shut down on the master?
> Check the wire gauges you have specified and go for the lightest possible
,
> copper wire adds a lot of weight.
>
> Regards, Peter
>
>
> -----Original Message-----
> From: owner-aeroelectric-list-server@matronics.com <
> owner-aeroelectric-list-server@matronics.com> On Behalf Of bcone1381
> Sent: 18 November 2022 16:53
> To: aeroelectric-list@matronics.com
> Subject: ****SPAM**** AeroElectric-List: Final Elect. System Review
>
> --> <bcone1964@gmail.com>
>
> Please help me finalize my electrical system. It based off Bob=C3=A2
=82=AC=84=A2s Z101
> and taylored to meet rather meager demands. I am moving from the
> conceptual phase to the fuselage as we speak, installing components
> today.
>
> My Bearhawk Patrol, like a Supercub, is VFR, with merely a Garmin G5,
> Engine Monitoring System, Surefly ignition, Comm, and Xpndr, and portable
> navigation.
>
> I have done my load analysis, drawn all schematics for individual
> circuits. =C3=A2=82=AC=C2=A8My diagram is attached. I transformed Bo
b=C3=A2=82=AC=84=A2s Z101 Engine
> Bus to my Aux Bus (Essential Bus). Continuous draw is 1.5A (2.3A
> intermittent) plus a single USB charger max of 2.5A. Please criticize me
> if the simple switch (Aux Bus - Aux Alt) is a risk that should fixed with
a
> solenoid.
>
> The left side of the Battery Contactor has 12 AWG wire powering the Aux
> Bus through a switch (AUX BUS - AUX ALT) that is not protected. Should I
> add protection to that circuit? The length of the circuit is about 30
> inches. I have a B & C slow acting 23A midi fuse that might go well ther
e.
>
> Any other feedback? Bob?
>
> --------
> Brooks Cone
> Bearhawk Patrol Kit Build
>
>
> Read this topic online here:
>
> http://forums.matronics.com/viewtopic.php?p=508934#508934
>
>
> Attachments:
>
>
> http://forums.matronics.com//files/screen_shot_2022_11_18_at_114320_am_14
9.png
>
>
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>
>
Message 3
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| Subject: | Re: Final Elect. System Review |
There was another discussion in 2014 on the AeroElectric list about aircraft electrical
architecture which includes a schematic by me.
http://forum.matronics.com/viewtopic.php?p=416668
--------
Joe Gores
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=508954#508954
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| Subject: | Re: Final Elect. System Review |
>What is best practice, a relay controlled by a small switch or just a switch?
There is a train of thought to resolving this question.
Generally speaking, relays are used to carry larger
currents than one wishes to bring to the panel on
a switch. Good examples include starter and battery
contactors (although the Piper Pacer had battery
under seat and both circuits were manual switches
on the panel under occupants legs!). Minimizing length
of the high current power path can be an important
consideration. One might also choose to use relays
to centrally locate power management tasks and simplify
control wiring. For example: Z101 suggests only 2 relays
which are best located adjacent to the busses
and fat-wires they control. Pilot management of those
relays is through two switches and itty-bitty wires
remotely located on the panel.
>Consider the advantages and disadvantages. If the relay fails, can
>you continue to fly safely?
This is called FAILURE MODE EFFECTS ANALYSIS (FMEA
for short). It's a process that should be artfully applied
to everything you do to configure and install your
electrical system. Everything from bolting a
Garmin G10000 to the panel down to crimping a
terminal on a wire.
(1) What are the ways this feature can fail?
(2) How will that failure affect ability of
the FLIGHT SYSTEM (pilot, airframe, circumstance)
ability to comfortably terminate the flight?
(3) How will I know failure has occurred?
(4) Is that failure pre-flight detectable?
(if so, put it on the check-list).
(5) If loss of that feature has a deleterious
effect under (2), what is your Plan-B
for mitigating the loss and having an exciting
tale to tell the grandchildren?
I have often referred readers to my personal
vaccination against the dreaded Dark Panel Syndrome:
https://tinyurl.com/4xjhgly
As a consistent renter of airplanes from a
relatively diverse fleet, taking a personal approach
to FMEA and preventative maintenance was a
bit impractical. But with those three items
in my flight bag (along with an AFD), my
chances of getting on the ground comfortably
even assuming total electrical system failure were
pretty good.
Your own recipe to comfortable arrivals with
the earth need not be so Spartan. But they
can be quite simple and BUILT IN to your
ship's architecture. Z101 offers multiple-source,
dual-path conduits of energy to various classes
of appliance. The likelihood of total loss
of any appliance is driven more by craftsmanship
than failure of a component . . . near zero.
Z101 switching philosophy covers all
keep-it-lit-and-turning options with
at most 3 and possibly 2 toggle switches.
The only radical in flight risk is to
switch them all OFF . . . and having them
all ON represents no particular hazard.
Bob . . .
Un impeachable logic: George Carlin asked, "If black boxes
survive crashes, why don't they make the whole airplane
out of that stuff?"
Message 5
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| Subject: | Re: Final Elect. System Review |
>Ref FAR 23.1361 "Master Switch Arrangement". FAR 23.1361 calls for
>protective device of 5A or less
That goes to crash-safety. The rational is that an
always hot wire soft-faulted as a result of mashing your
airplane into a wad is less likely to start
a fire if it's protected at 5A or less. This
idea is a bit specios . . . give me a cup of
gasoline, a battery, a 5a breaker and a hunk
of wire and I can start fires all day.
That 5A number was pulled from somewhere the sun
don't shine . . . but when you think about it,
there ARE certain needs for always hot wires
that HAD to be protected as SOME level . . . okay,
how about 5A?
But that assertion doesn't speak to the huge
differences in performance between fuses and
circuit breakers. Fuses are MUCH faster than
fuses. See:
https://tinyurl.com/muefe6s4
The demo only loaded the protective devices to
2 times rated. Presumably, a hard-fault to a
battery fed wire will be much stronger causing
faster operation. The likelihood of a dribbling
of fuel in the same time frame as the hard-fault
is very low if not impossible. A soft-fault is
another matter. The worry is for a dangling
remnant of a protected but always hot circuit making
intermittent contact with 'ground' for significant
periods of time. Time that allows compromised
fuel containment to spread about.
But as you saw in the video above, a soft-fault
(intermittent sparking) cannot be guaranteed
'fire safe' at any size of protective device
. . . so fooey, let's call it 5A and
forge ahead.
>Bob Nuckolls' advice is to allow 7-1/2 A fuses since fuses are faster than
>breakers, that's why the largest fuse you see on the battery bus in
>Z schematics is 7-1/2A.
Yeah, but if you really, Really, REALLY needed
a 10A always-hot circuit, go ahead with the
fuse.
>BTW, fuses are normally sized (max load) / (0.75) = fuse rating.
>Max load on a 7-1/2A fuse should be 5.6A.
Excellent point . . . but that assumes a 'gentle'
load (mostly resistive, little or no inrush).
The disadvantage of fuses is that they can be
'hammered' by short but repetitive transient
above their nameplate rating. The N811HB
accident
https://tinyurl.com/3h8vb3aj
was the result of fuse operations delayed for
HOURS of normal operations sprinkled
with transient excursions into a range
of currents that 'soften' the fuse element.
This hammering causes a slow DEPRESSION
of the fuse's operating current. N811HB had
to hammer TWO fuses events where the second
precipitating rough arrival with the rocks.
>As you can see, a 23A MIDI fuse does not meet FAR23.1361. Also it is
>considered bad practice to put two fuses in series even though the 10A
>fuses on your aux bus are smaller than a MIDI 23.
I sort wish that there was a different symbol
for fusible links vs. fuses. Fusible links are
so very slow that they can be reliably incorporated
to protect fat-wire feeders to bus bars that
distribute power to downstream arrays of breakers or
fuses.
The MIDI devices are not generally used as
protection to appliance feeders. They are
robust and slow like the legacy ANL current
limiters. See:
https://tinyurl.com/pm54y2ye
Note that a MIDI30 will carry 40 amps almost
forever, 60A for about 8 seconds, 200A for
200 mS. This device could be used to protect
the fat-wire supplying a bus with a 5A breaker
feeding a crowbar ov management module. Typical
crowbar currents are on the order of 200A. A
5A breaker opens in about 10 mS, 20x faster than
any MIDI device protecting that bus upstream.
But then, MIDI devices are kinda clumsy in that
they need holders and hardware to mount them.
a 10AWG feeder with a 14AWG fusible link wire
would be a fine alternative to a MIDI30 limiter.
>As mentioned, FAR 23.1361 is for fire-in-the-cockpit and
>off-field landing scenarios but it's also for service scenario,
>that's why auto service manuals say first thing disconnect
>the battery negative terminal.
Good idea . . . watched a very well done youtube
presentation by a fellow that was taking lots
of wires loose and laying tools on top of his
battery with all the fat-wires still hooked up.
I'm assuming he edited out the scene with
sparks and smoke . . .
Bob . . .
Un impeachable logic: George Carlin asked, "If black boxes
survive crashes, why don't they make the whole airplane
out of that stuff?"
Message 6
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| Subject: | Re: Final Elect. System Review |
Thanks for your input on multiple back up batteries.
I am installing one main battery with no backups. Z101 has good FMEA that will
minimize risk and cost of ownership. Backup Batteries have risk that rise over
time and cost. The SD-8 alternator is light weight, reliable, requires no
annual maintenance and is in my inventory.
--------
Brooks Cone
Bearhawk Patrol Kit Build
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=508963#508963
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| Subject: | Re: Final Elect. System Review |
At 04:37 PM 11/20/2022, you wrote:
>
>Thanks for your input on multiple back up batteries.
>
>I am installing one main battery with no backups.
Tell us also that you plan periodic capacity
checks along with a "replace at less-than-xx-percent"
maintenance philosophy.
Most light aircraft batteries get replaced
when they don't crank the engine any more.
By this time, capacity is probably much
smaller than a practical, battery-only endurance
mark.
In 50+ years of reading 'dark-n-stormy-night'
tales in the aviation rags, I cannot recall
a single narrative where the writer cites
battery failure in spite of satisfactory,
periodic maintenance tests.
Batteries are a commodity. Like tires,
oil, fuel, alternator belts, etc. they
are CONSUMED starting at hour-one. Avoid
your own dark-n-stormy night story by
not consuming past hour-too-many.
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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