Today's Message Index:
----------------------
1. 05:59 AM - Re: Proposed new Z diagram? (Thomas E Blejwas)
2. 06:13 AM - Re: Proposed new Z diagram? (Robert L. Nuckolls, III)
3. 06:19 AM - Re: Re: Proposed new Z diagram? (Robert L. Nuckolls, III)
4. 07:02 AM - Re: Proposed new Z diagram? (Dj Merrill)
5. 08:58 AM - Re: Re: Proposed new Z diagram? (Dj Merrill)
6. 09:07 AM - DIY Marker beacon antenna (Roger & Jean)
7. 10:08 AM - Re: DIY Marker beacon antenna (R. curtis)
8. 10:21 AM - Thoughts on a few electrical system configurations? (digidocs)
9. 10:52 AM - Re: DIY Marker beacon antenna (Tim Andres)
10. 11:54 AM - Re: Re: Proposed new Z diagram? (Dj Merrill)
11. 11:55 AM - Re: DIY Marker beacon antenna (BobsV35B@aol.com)
12. 01:40 PM - Re: Thoughts on a few electrical system configurations? (Bill Watson)
13. 01:57 PM - Re: Re: Proposed new Z diagram? (John W Livingston)
14. 02:28 PM - Re: Re: Proposed new Z diagram? (Robert L. Nuckolls, III)
15. 02:38 PM - Re: Thoughts on a few electrical system configurations? (Jim Berry)
16. 03:23 PM - Re: DIY Marker beacon antenna (Roger & Jean)
17. 05:16 PM - Re: Re: Proposed new Z diagram? (Dj Merrill)
18. 06:10 PM - Re: Re: Proposed new Z diagram? (Jeff Luckey)
19. 06:17 PM - Re: Re: Proposed new Z diagram? (Dj Merrill)
20. 06:18 PM - Re: Re: Proposed new Z diagram? (Dj Merrill)
Message 1
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Subject: | Re: Proposed new Z diagram? |
Bob,
You wrote:
> Assuming that the Viking engine with the as-
> proposed alternator does run gracefully in
> an alternator only mode, then the whole inter-linked
> switch philsosopy for battery and alternator is
> moot. This figure illustrates the opptions for
> being relieved of that constraint . . .
>
> http://tinyurl.com/mhblorq
The split of the "master" switch also allows the engine to be operated from the
aux battery and alternator. Why would you? I can imagine my battery monitor
on the main battery indicating very high charging current and low voltage. I
would interpret this as something wrong with the main and switch to the aux.
Because the alternator for the Viking is an internally regulated ND, I would use
a contactor with a "crow bar" for a disconnect, in the event of an o.v. runaway.
I would also connect the alternator sense wire without a switch to the "motive"
bus, so it can't be accidentally shut down while the engine is running
and destroy the permanent-magnet alternator. I would still be able to pull the
alternator CB in the event of an emergency.
Hope these make sense.
Tom
Sent from my iPad
> On Jan 6, 2014, at 8:01 PM, "Robert L. Nuckolls, III" <nuckolls.bob@aeroelectric.com>
wrote:
>
>
>
>
>> the alternator will always be turned off first
>> before the main battery contactor is turned off (ie, no alternator-only
>> mode). With either the aux or main contactors on, both power buses will
>> be enabled and there is no independent control to turn each bus off
>> individually.
>
> Assuming that the Viking engine with the as-
> proposed alternator does run gracefully in
> an alternator only mode, then the whole inter-linked
> switch philsosopy for battery and alternator is
> moot. This figure illustrates the opptions for
> being relieved of that constraint . . .
>
> http://tinyurl.com/mhblorq
>
>
>> Dual-Bat Z-7 requires two switches to shut down all power, and mine
>> requires three, as you indicate. I could replace the alternator and
>> main switches with a combined switch similar to Z-7, removing the
>> alternator-only mode, which may be a good thing to do and simplifies the
>> user experience, as well as allowing for each power bus to be separated
>> and powered independently. I think the chances of both batteries
>> failing and requiring an alternator-only mode are so remote that it is
>> not worth worrying about.
>
> How does a battery fail? If such a failure occurs
> in flight, how do you know it has happened? What
> light comes on to say, "Battery X Fail"?
>
> You have articulated some goals for addressing
> a constellation of failures as yet not clearly
> defined.
>
> When conducting an FMEA on a system or product
> the following questions are posed and answers
> sought:
>
> How might this part fail?
>
> How will I know that it failed? Can the effects
> of the failure be immediately known and
> dealt with in a simple, prescribed manner?
>
> Is the failure pre-flight detectable? If not can
> it be made detectable. I that's not possible/
> practical . . . what sort of testing is called
> for and at what intervals?
>
> How does any particular failure impact probability
> of comfortable termination of a flight?
>
> (a) Will any identified failure produce an immediate
> risk to ship's systems?
>
> (b) Will any identified failure over-tax my abilities
> to manage the event while maintaining competent
> control of the airplane?
>
> I have split the DC POWER MASTER into two switches
> which increases the number of power management controls
> to a total of 6. That gives you 36 possible combinations
> of switch positions some small number of which will
> result in the engine stopping . . . so those are
> easy to eliminate. Of the remaining combinations,
> what are the criteria for selecting/rejecting any
> combination that keeps the engine running and at least
> some stuff lit on the panel?
>
> At some point, after all the colors are laid down
> with the favorite brush strokes, you need to craft
> the pilot's operating handbook for how the switches
> are used. Do all those options serve a predictable,
> useful purpose?
>
> It's one thing to have so many options and control
> over those options . . . consider that each option
> should be deduced and prescribed in advance. Lots
> of options can work against you should one become reduced
> to a game of "flipping switches until things work better"
> while distracting concentration from your duties as a
> pilot.
>
>
>
> Bob . . .
>
>
>
>
Message 2
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Subject: | Re: Proposed new Z diagram? |
At 07:57 AM 1/8/2014, you wrote:
><tomblejwas@yahoo.com>
>
>Bob,
>
>You wrote:
> > Assuming that the Viking engine with the as-
> > proposed alternator does run gracefully in
> > an alternator only mode, then the whole inter-linked
> > switch philsosopy for battery and alternator is
> > moot. This figure illustrates the opptions for
> > being relieved of that constraint . . .
> >
> > http://tinyurl.com/mhblorq
>
>The split of the "master" switch also allows the engine to be
>operated from the aux battery and alternator. Why would you? I can
>imagine my battery monitor on the main battery indicating very high
>charging current and low voltage. I would interpret this as
>something wrong with the main and switch to the aux.
I'm not suggesting ANY particular mode of operation
. . . yet. DJ has proposed an architecture for which
he requested a considered critical review.
My input to this discussion goes toward understanding
the rationale for each proposed feature that states,
"when this happens, do this." At the same time, there is
idea that alternator-only ops MIGHT be a good thing
to review. Our current paradigm is rooted in the 1960's.
The drill for crafting any system is to do the FMEA
and then add/adjust features to minimize workloads
and risks for the catalog of failures.
Without such debate, we can only assess DJ's
efforts from the standpoint of being a work of
art or a photograph that is pleasant to look at . . .
but of unknown value for a pilot that is wrestling
with what could become a bad day in the cockpit.
Bob . . .
Message 3
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Subject: | Re: Proposed new Z diagram? |
At 07:16 PM 1/6/2014, you wrote:
>
>Attached is one more recipe to help fill the 1000 page cookbook of
>electrical architectures. :-)
>To keep it simple, this schematic has only one bus which is fed from
>both ends. The failure of any one wire or terminal or switch or
>relay will not interrupt power to the bus. In the event of low
>voltage, the pilot should shut off master switch #1. Doing so will
>shut off power to the alternator field and master contactor coil,
>thus conserving battery energy. It is up to the pilot to shut off
>any other unnecessary loads.
> Although this architecture is intended for a simple aircraft, the
> single bus could supply power to an IFR instrument panel or to an
> electrically dependent engine without danger of power loss due to
> the failure of any one component.
>Joe
>
>--------
>Joe Gores
What you have offered my friend is certainly appropriate
to say Figure Z-0 . . . a base line from which
our systems have evolved since the first battery/
generator system was installed in an airplane.
A boat-load of airplanes were successfully flown
for millions of hours with this architecture which
was unchanged until that pesky germanium transistor
showed up for work and scared the pants off of
too many system integrators who were happy with
the status quo . . . the avionics master switch
was born and things took off from there.
It has evolved from there in many ways . . . some
good . . . some not so good. But your suggestion
is an excellent reminder of the idea that the
best systems are crafted on a solid foundation
that's 99% golden . . . adding only those features
which address a tiny but risky fraction of the
rest.
Thanks!
Bob . . .
Message 4
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Subject: | Re: Proposed new Z diagram? |
On 01/08/2014 09:12 AM, Robert L. Nuckolls, III wrote:
> The drill for crafting any system is to do the FMEA
> and then add/adjust features to minimize workloads
> and risks for the catalog of failures.
>
> Without such debate, we can only assess DJ's
> efforts from the standpoint of being a work of
> art or a photograph that is pleasant to look at . . .
> but of unknown value for a pilot that is wrestling
> with what could become a bad day in the cockpit.
I apologize for not getting back to you on this and your other
questions. This thing called "work" keeps getting in the way... :-)
I will work on refining and clarifying my "feature" list and we can
definitely discuss! :-)
-Dj
--
Dj Merrill - N1JOV - VP EAA Chapter 87
Sportsman 2+2 Builder #7118 N421DJ - http://deej.net/sportsman/
Glastar Flyer N866RH - http://deej.net/glastar/
Message 5
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Subject: | Re: Proposed new Z diagram? |
Bob, I think I am getting a glimmer of understanding of the underlying
message you've been trying to communicate. I've been looking at this as
a top-down approach, and I presented a draft in roughly step 3 of my
design process and you've been asking about things back in step 1 that
I've attempted to communicate, but have failed to do so successfully.
You've also been asking about things in step 5, but we aren't there
yet... :-)
In rough terms, my "steps" are along the lines of:
1) List features and design goals.
2) Draft a circuit to reflect step 1. Note this is to illustrate a
functional representation, and is not intended as a implementation
diagram, thus specific values for components are not indicated at this time.
3) Review the circuit and verify functionality, checking for undesired
behaviour, etc. (This is where I submitted my first post to the mailing
list asking for peer review)
4) Spec each individual load and determine the appropriate location for
each load in the circuit. Examples would be to finalize the list of
which devices would be on the redundant bus, which would be on the main
bus, etc.
5) Fill in specific values for components in the circuit diagram and
draft an implementation diagram.
6) Review, verify, finalize.
7) Build the circuit and test, test, test.
Here is my list of features and design goals:
1) There are devices that are considered critical to the safe operation
of the aircraft. These devices should be able to draw power from two
completely independent power buses and battery sources. This shall be
known as the "redundant" bus.
2) When everything is on, devices on the redundant bus should be able to
automatically draw power from either source, with no user intervention
required. Ie, if one of the bus/batteries fails or is turned off, the
devices on the redundant bus will remain powered on using the other source.
3) Bonus feature if alternator-only mode can be optionally supported.
4) Minimize "always-hot" wires.
5) No parasitic loads on the battery when everything is "off" (ie,
clocks, etc.).
6) Each battery and associated bus should be able to be switched "off"
and isolated from the rest of the circuit.
7) With special regard to the engine ignition, the ability to switch off
independently of the other devices for pre-flight equivalent of "mag
checks".
Notes:
The EFIS has three built-in diode isolated power inputs. This implies
that it can be wired directly to the primary and secondary power buses
directly using two of those inputs.
Devices having only one power input and that are considered critical are
wired to the redundant bus. Other non-critical devices will be wired to
the primary bus.
The aircraft will initially have one mag and one Electronic Ignition
(EI). Eventually the second mag will likely be replaced with a second
Electronic Ignition. Based on discussions that we've had so far on the
list, I've already realized a change to be made from my initial drawing
with regards to how the ECU is connected. There will be one switch for
the mag, and one switch for the EI (versus the two switches for the
single EI as shown currently). When the mag is swapped for the second
EI, the switch will be swapped as well, leaving one switch for each EI,
allowing them to be switched on and off independently.
Physical layout:
My panel is laid out such that the engine switches are separate from the
rest. The three will be laid out as Mag (or 1st EI), 2nd EI, Starter.
Electrical would be Primary Power, Alternator, Secondary Power, followed
by the switches for the lights, etc.
Operations:
Normal operations are Primary, Alternator, and Secondary switches in the
on position before engine start, and until engine shutdown.
In the event of "smoke", Primary and Alternator would be turned off by
hitting the two leftmost switches. This cuts power to all but the
flight critical devices and has the highest chance of cutting power to
whatever is "smoking". If "smoke" continues, turn on Primary power and
turn off Secondary. If "smoke" still continues, get on the ground ASAP
- one or the other power bus must remain on to power the engine and EFIS.
Note there is a good argument to be made to replace the two separate
Alternator and Primary power switches with a combined three position
switch. This would reduce the total DC power switch count to 2, and
slightly reduce operations complexity while only giving up
alternator-only mode, which has dubious value in a two redundant bus
arrangement. After further thought, I am going to make this change in
my diagram.
-Dj
--
Dj Merrill - N1JOV - VP EAA Chapter 87
Sportsman 2+2 Builder #7118 N421DJ - http://deej.net/sportsman/
Glastar Flyer N866RH - http://deej.net/glastar/
Message 6
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Subject: | DIY Marker beacon antenna |
I have a wooden airplane in which I will be installing a Marker beacon
receiver.
My question is: Is it relatively simple to fabricate an antenna, or should
I consider purchasing one?
I assume it can be put on the inside of the airframe without a significant
loss of signal strength.
Roger
Message 7
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Subject: | Re: DIY Marker beacon antenna |
> I have a wooden airplane in which I will be installing a Marker beacon
> receiver.
>
> My question is: Is it relatively simple to fabricate an antenna, or
> should I consider purchasing one?
>
> I assume it can be put on the inside of the airframe without a significant
> loss of signal strength.
After posting the above, I searched the archives and found lots of
info
to answer my question.
Looks like I will run a coax to a convenient place and then a 40"
piece of wire for the antenna, or just strip the braid off the last
40"
of the coax and attach it inside the fuselage.
Marker beacons will most likely disappear in the near future anyway.
Just thought that since I already have the receiver, there is no
reason
not to put it to use.
Roger
--
Do you have a slow PC? Try a Free scan http://www.spamfighter.com/SLOW-PCfighter?cid=sigen
Message 8
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Subject: | Thoughts on a few electrical system configurations? |
I'm nearing the point in my RV-10 build where I need to make some decisions about
the electrical system architecture. Also, like any good engineer, I've got
a serious case of analysis paralysis going. In an effort to help clear the logjam,
would the list share its collective thoughts?
Background
- I fly in IMC fairly regularly.
- The engine doesn't require power to keep running, but the attitude instruments
are all electrically powered. Thus keeping at least some power running is important.
(i.e.: AI, GPS, COM)
- The planned avionics configuration is such that in a split bus design, one set/bus
of units could be depowered without loss of overall functionality. (i.e.:
EFIS, GPS1, COM1 on Bus A; AI, GPS2, COM2 on Bus B)
- Any LiFePO4 batteries mounted firewall forward in stainless steel enclosures
for fire containment (included in weight estimates).
System objectives
- Provide 4.5A of power for at least 4 hours in the event of any component failure
(unless we can point to a *very* established track record of performance for
that component)
- Minimize weight
- Minimize complexity and component count
Configuration options and my thoughts:
(weights given are nominal relative to configuration 1)
1. 60A alternator, 27Ah lead acid battery, e-bus. +0 lbs.
Standard configuration on this type of aircraft. According to Bob, complete battery
failure is very rare. Even fairly degraded battery has capacity to provide
sufficient reserve power. E-bus protects against wiring faults. Simple architecture
is a plus. Configuration is (relatively) heavy.
2. 60A alternator, 8A alternator, 17Ah lead acid battery, e-bus. -9 lbs.
Addition of backup alternator allows battery to be reduced in size, saves some
weight.
3. 60A alternator, 12Ah LiFePO4 primary battery, 12Ah LiFePO4 backup battery, split
bus. -18lbs.
Alternator charges primary battery and, through diode, secondary battery. Split
bus design because LiFePO4 batteries have low reliability compared to lead acid.
Cost/availability limits backup battery to 12Ah which falls short of endurance
requirement, may be possible to reduce power consumption. Relatively simple
architecture. Lightest configuration.
4. 60A alternator, 8A alternator, 12Ah LiFePO4 primary battery, 2Ah lead acid secondary
battery, split bus. -17lbs.
60A alternator + 12Ah LiFePO4 power Bus A. 8A alternator + 2Ah lead acid power
Bus B. Busses are not interconnected. May be safe to mount 2Ah lead acid under
panel to reduce firewall penetrations and wiring complexity. Dual alternator,
dual battery, split bus provides high availability and unlimited endurance.
Medium/high complexity. Relatively light.
5. Same as configuration 4, except with 4Ah LiFePO4 secondary battery. -16lbs.
Presented in case there are issues with using/charging such small lead acid batteries
with 8A alternator.
Thanks for your thoughts,
David
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=416700#416700
Message 9
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Subject: | Re: DIY Marker beacon antenna |
Yeah I started to answer your question but I'm not an avionics expert, but have
a bit of experience. So my input is a marker beacon will work off a wet noodle,
you can actually just put a rubber duck or length of wire out the back and
it will receive.
They are rather large if made resonant, but if you want I can get you the dimension
for a foil antenna if that will work.
And your right, already an approach certified GPS will serve for those approaches
that use a MB for a fix.
Tim
> On Jan 8, 2014, at 10:06 AM, "R. curtis" <mrspudandcompany@verizon.net> wrote:
>
>
>> I have a wooden airplane in which I will be installing a Marker beacon receiver.
>>
>> My question is: Is it relatively simple to fabricate an antenna, or should
I consider purchasing one?
>>
>> I assume it can be put on the inside of the airframe without a significant loss
of signal strength.
>
>
> After posting the above, I searched the archives and found lots of info
> to answer my question.
>
> Looks like I will run a coax to a convenient place and then a 40"
> piece of wire for the antenna, or just strip the braid off the last 40"
> of the coax and attach it inside the fuselage.
>
> Marker beacons will most likely disappear in the near future anyway.
> Just thought that since I already have the receiver, there is no reason
> not to put it to use.
>
> Roger
>
> --
>
> Do you have a slow PC? Try a Free scan http://www.spamfighter.com/SLOW-PCfighter?cid=sigen
>
>
>
>
>
>
Message 10
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Subject: | Re: Proposed new Z diagram? |
Updated "Z-redundant-B" diagram at
http://deej.net/glastar/pics/electrical/Z-redundant-B.jpg
Changes:
Removed alternator-only operation by combining the separate Alt and
Primary bus switches into a single three position switch (Off, Bat,
Bat+Alt).
Reduced operational complexity by removing separate Alt switch. Now has
2 DC power switches (Primary/Alt and Secondary) versus 3. In the event
of "smoke", turn the left most switch (Primary/Alt) off. This cuts
power to all but the flight critical devices and has the highest chance
of cutting power to whatever is "smoking".
Reflects two EI ECUs with independent switching to allow pre-flight
equivalent of "mag checks"
-Dj
--
Dj Merrill - N1JOV - VP EAA Chapter 87
Sportsman 2+2 Builder #7118 N421DJ - http://deej.net/sportsman/
Glastar Flyer N866RH - http://deej.net/glastar/
Message 11
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Subject: | Re: DIY Marker beacon antenna |
Good Afternoon Tim,
If I may be so bold, are you sure you wish to go to the trouble of
installing a Marker Beacon receiver and an Antenna?
The Marker Beacon is no longer a required piece of equipment for an ILS
approach. There are a few marker beacons that are still used as step down
fixes for a few Non Precision Approaches, but they are disappearing rapidly. A
very few Category II and Category III approaches are still using them, but
that is about it. Those that are still in service are rapidly being
replaced with other style fixes. I would imagine that if you are planning IFR
flight, you will have an IFR approved GPS installed. I know of no marker beacon
sites other than the ones for Category II and II that are not also a
designated waypoint. For those, the GPS can be used in lieu of the Marker Beacon.
No big deal, but you could save fraction of an ounce or so and little bit
of labor by not installing the Marker Beacon at all.
Happy Skies,
Old Bob
Do Not Archive
In a message dated 1/8/2014 1:20:07 P.M. Central Standard Time,
tim2542@sbcglobal.net writes:
--> AeroElectric-List message posted by: Tim Andres
<tim2542@sbcglobal.net>
Yeah I started to answer your question but I'm not an avionics expert, but
have a bit of experience. So my input is a marker beacon will work off a
wet noodle, you can actually just put a rubber duck or length of wire out
the back and it will receive.
>
Message 12
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Subject: | Re: Thoughts on a few electrical system configurations? |
David, I'm attaching the main power distribution diagram and
Fuse/Breaker diagram for my RV10 (2.3 years and 350+ hours).
It is an Aeroelectric Z-14 design with (2) 17aH Odysseys, 2
alternators, and dual buses. The panel, designed around 2008, includes
3 GRT/HX EFIS with dual AHRS, a G430w, SL30, PM audio panel, and TT AP.
I like the whole setup. I would be glad to answer any questions about it.
Bill "the electrical and avionics design & build was the most fun part
of the project" Watson
On 1/8/2014 1:19 PM, digidocs wrote:
>
> I'm nearing the point in my RV-10 build where I need to make some decisions about
the electrical system architecture. Also, like any good engineer, I've got
a serious case of analysis paralysis going. In an effort to help clear the
logjam, would the list share its collective thoughts?
>
> Background
> - I fly in IMC fairly regularly.
> - The engine doesn't require power to keep running, but the attitude instruments
are all electrically powered. Thus keeping at least some power running is
important. (i.e.: AI, GPS, COM)
> - The planned avionics configuration is such that in a split bus design, one
set/bus of units could be depowered without loss of overall functionality. (i.e.:
EFIS, GPS1, COM1 on Bus A; AI, GPS2, COM2 on Bus B)
> - Any LiFePO4 batteries mounted firewall forward in stainless steel enclosures
for fire containment (included in weight estimates).
>
> System objectives
> - Provide 4.5A of power for at least 4 hours in the event of any component failure
(unless we can point to a *very* established track record of performance
for that component)
> - Minimize weight
> - Minimize complexity and component count
>
> Configuration options and my thoughts:
> (weights given are nominal relative to configuration 1)
>
> 1. 60A alternator, 27Ah lead acid battery, e-bus. +0 lbs.
> Standard configuration on this type of aircraft. According to Bob, complete
battery failure is very rare. Even fairly degraded battery has capacity to provide
sufficient reserve power. E-bus protects against wiring faults. Simple
architecture is a plus. Configuration is (relatively) heavy.
>
> 2. 60A alternator, 8A alternator, 17Ah lead acid battery, e-bus. -9 lbs.
> Addition of backup alternator allows battery to be reduced in size, saves some
weight.
>
> 3. 60A alternator, 12Ah LiFePO4 primary battery, 12Ah LiFePO4 backup battery,
split bus. -18lbs.
> Alternator charges primary battery and, through diode, secondary battery. Split
bus design because LiFePO4 batteries have low reliability compared to lead
acid. Cost/availability limits backup battery to 12Ah which falls short of endurance
requirement, may be possible to reduce power consumption. Relatively
simple architecture. Lightest configuration.
>
> 4. 60A alternator, 8A alternator, 12Ah LiFePO4 primary battery, 2Ah lead acid
secondary battery, split bus. -17lbs.
> 60A alternator + 12Ah LiFePO4 power Bus A. 8A alternator + 2Ah lead acid power
Bus B. Busses are not interconnected. May be safe to mount 2Ah lead acid
under panel to reduce firewall penetrations and wiring complexity. Dual alternator,
dual battery, split bus provides high availability and unlimited endurance.
Medium/high complexity. Relatively light.
>
> 5. Same as configuration 4, except with 4Ah LiFePO4 secondary battery. -16lbs.
> Presented in case there are issues with using/charging such small lead acid batteries
with 8A alternator.
>
> Thanks for your thoughts,
> David
>
>
> Read this topic online here:
>
> http://forums.matronics.com/viewtopic.php?p=416700#416700
>
>
> -----
> No virus found in this message.
> Checked by AVG - www.avg.com
>
>
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Subject: | Re: Proposed new Z diagram? |
How do you know that each feed going into your diodes is working?
On 1/8/2014 2:53 PM, Dj Merrill wrote:
>
> Updated "Z-redundant-B" diagram at
>
> http://deej.net/glastar/pics/electrical/Z-redundant-B.jpg
>
>
> Changes:
>
> Removed alternator-only operation by combining the separate Alt and
> Primary bus switches into a single three position switch (Off, Bat,
> Bat+Alt).
>
> Reduced operational complexity by removing separate Alt switch. Now has
> 2 DC power switches (Primary/Alt and Secondary) versus 3. In the event
> of "smoke", turn the left most switch (Primary/Alt) off. This cuts
> power to all but the flight critical devices and has the highest chance
> of cutting power to whatever is "smoking".
>
> Reflects two EI ECUs with independent switching to allow pre-flight
> equivalent of "mag checks"
>
>
> -Dj
>
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Subject: | Re: Proposed new Z diagram? |
>
>
>In rough terms, my "steps" are along the lines of:
>
>1) List features and design goals.
Let's concentrate on this step. Take the Z-figure
that comes closest to what you want. Describe which
features do not address a design goal and articulate
what you would do different . . . speak to the design
goal either in terms of (1) a perceived risk that is
mitigated by a proposed change or (2) "just because."
There is no wrong motivation . . . but features
in the 1-bucket can be evaluated against legacy
lessons-learned and technical/economic trade-offs;
stuff in the 2-bucket are not technically debatable.
The feature offers functionality that is easily confirmed
by looking at the diagram and no sifting of
simple-ideas is needed. The change is justified
"just because".
This is an important exercise . . . if there are
compelling revelations of shortcoming in any of
the Z-figures, I'm intently interested in knowing
what they are. At the same time I am reluctant
to publish pretty-variations-on-a-theme that offer
no demonstrable increase in utility or reduction
of risk.
I just received a drawing from another reader
who has crafted a one-battery, two-alternator
configuration loosely based on Z-12 but with a
avionics master switch and some errors in
functionality. My question to him will be similar,
"How does Z-12 fall short of your expectations
for risk management and what information do you
have indicating that an avionics master is useful/
necessary?"
Bob . . .
Message 15
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Subject: | Re: Thoughts on a few electrical system configurations? |
David,
Suggest you also consider 60A primary alt. and 20A secondary alt. Set the regulator
on the secondary 0.5V lower than primary regulator. I have this in my all
glass RV10. After 3 years, I had a primary alt. failure due to spun bearing shorting
out the winding. Bus voltage dropped 0.5V as expected; the secondary alt.
picked up the slack and we completed our flight at our leisure. With 20A I
can keep everything lit up indefinitely except my heated pitot and landing lights.
No bus switching or load shedding necessary.
Jim Berry
RV-10
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=416712#416712
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Subject: | Re: DIY Marker beacon antenna |
If I may be so bold, are you sure you wish to go to the trouble of
installing a Marker Beacon receiver and an Antenna?
The trouble of installing the Marker Beacon Receiver is minimal. It
is already installed in my audio panel, so the only effort is to add the
antenna. Bob N. in an old post said a "wet string" would work as an
antenna, but I discarded that as too much trouble to keep the string
moist on an approach.
I am only installing it because it is there and can be activated
with very little effort and could possibly be used as a backup
indicator. If it wasn't there, I would NOT go out and purchase one.
Roger
Message 17
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Subject: | Re: Proposed new Z diagram? |
On 1/8/2014 4:56 PM, John W Livingston wrote:
> <livingjw@earthlink.net>
>
> How do you know that each feed going into your diodes is working?
Hi John,
Excellent question. The GRT HX EFIS monitors each power input, and
will notify you if either of the two power inputs lose power. This will
verify that the Primary and Secondary buses are getting power.
I do not have any monitoring in the diagram to tell if each of the
diodes is working, however, a pre-flight check turning off each of the
buses before enabling the alternator could be an option. If any of the
critical devices power down, one of the diodes has failed (or some other
issue).
-Dj
--
Dj Merrill - N1JOV - VP EAA Chapter 87
Sportsman 2+2 Builder #7118 N421DJ - http://deej.net/sportsman/
Glastar Flyer N866RH - http://deej.net/glastar/
Message 18
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Subject: | Re: Proposed new Z diagram? |
Dj, I cannot find your latest drawing.- Can you send a link or attach it?
=0A=0Athx=0A=0A=0A=0A________________________________=0A From: Dj Merrill <
deej@deej.net>=0ATo: aeroelectric-list@matronics.com =0ASent: Wednesday, Ja
nuary 8, 2014 5:15 PM=0ASubject: Re: AeroElectric-List: Re: Proposed new Z
@deej.net>=0A=0AOn 1/8/2014 4:56 PM, John W Livingston wrote:=0A> --> AeroE
lectric-List message posted by: John W Livingston <livingjw@earthlink.net>
=0A> =0A> How do you know that each feed going into your diodes is working?
=0A=0AHi John,=0A- - Excellent question.- The GRT HX EFIS monitors ea
ch power input, and will notify you if either of the two power inputs lose
power. This will verify that the Primary and Secondary buses are getting po
wer.=0A=0A- - I do not have any monitoring in the diagram to tell if ea
ch of the diodes is working, however, a pre-flight check turning off each o
f the buses before enabling the alternator could be an option.- If any of
the critical devices power down, one of the diodes has failed (or some oth
er issue).=0A=0A-Dj=0A=0A-- Dj Merrill - N1JOV - VP EAA Chapter 87=0ASports
man 2+2 Builder #7118 N421DJ - http://deej.net/sportsman/=0AGlastar Flyer N
=========================0A
- - - - - - - - - - - - - -Matt Dralle, List Admi
=======================
Message 19
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Subject: | Re: Proposed new Z diagram? |
On 1/8/2014 3:11 PM, Robert L. Nuckolls, III wrote:
>> 1) List features and design goals.
>
> Let's concentrate on this step. Take the Z-figure
> that comes closest to what you want. Describe which
> features do not address a design goal and articulate
> what you would do different . . . speak to the design
> goal either in terms of (1) a perceived risk that is
> mitigated by a proposed change or (2) "just because."
The closest from the Connection is Z-19.
Using my list of features/design goals from the previous email (for
reference they are included at the end of this email) and comparing to Z-19:
1) For avionics, Z-19 offers power from two separate batteries, but it
does not offer it from two independent power buses. However, it DOES
have both of these features in the engine section of the circuit.
(Because if we can do it with the critical EI, it makes sense to also do
it with other equally critical devices. Non-critical devices in
Z-redundant-B are on the Primary bus just like Z-19)
2) Z-19 offers this feature with regards to the batteries.
3) No alternator-only mode, but since I've also removed this from
Z-redundant-B this is a null.
4) Z-19 does not minimize "always hot" wiring. (Because I don't like it,
and it is easy to create a circuit that does minimize "always hot"
wiring. I have nothing in my plane that requires "always hot" power
other than the contactors.)
5) Z-19 has parasitic loads. (Because I don't like my battery being
drained between flights, and I have nothing in the plane that requires a
constant power source. The GRT EFIS will sync its time via the GPS
signal after power-up.)
6) Z-19 does not offer this feature. (This is a cross between "just
because I want to" and safety. In general bus wiring is "safe", with
the common cause of failure being installation error as we've discussed
on the list. I'm not perfect, and could inadvertently crimp a bad
connection or make a bad solder joint. Additionally, being able to
switch off and isolate the two separate buses allows me to easily turn
off all non-critical devices with a single switch if there are issues in
flight)
7) As written, Z-19 supports a single EI which can be turned off, but
requires modification to support two EIs that can be turned off
independently. (This is a safety feature to ensure both ignitions are
working correctly during the pre-flight checks)
What I would do different (ie, what I did) was take the features
that I liked from the Z-19 diagram and use it as a basis to create
Z-redundant-B. You can see many of the features of Z-19 in the
Z-redundant diagram, with emphasis on the redundant engine bus concept
in Z-19 extended to support flight critical devices.
As an exercise, let's flip this around. Suppose hypothetically
Z-redundant-B had been around for awhile, and someone proposed Z-19.
Why would you choose to use Z-19 over Z-redundant-B? What
features/design goals exist in Z-19 that you desire compared to
Z-redundant-B? :-)
-Dj
> Here is my list of features and design goals:
>
> 1) There are devices that are considered critical to the safe operation
> of the aircraft. These devices should be able to draw power from two
> completely independent power buses and battery sources. This shall be
> known as the "redundant" bus.
>
> 2) When everything is on, devices on the redundant bus should be able to
> automatically draw power from either source, with no user intervention
> required. Ie, if one of the bus/batteries fails or is turned off, the
> devices on the redundant bus will remain powered on using the other source.
>
> 3) Bonus feature if alternator-only mode can be optionally supported.
>
> 4) Minimize "always-hot" wires.
>
> 5) No parasitic loads on the battery when everything is "off" (ie,
> clocks, etc.).
>
> 6) Each battery and associated bus should be able to be switched "off"
> and isolated from the rest of the circuit.
>
> 7) With special regard to the engine ignition, the ability to switch off
> independently of the other devices for pre-flight equivalent of "mag
> checks".
--
Dj Merrill - N1JOV - VP EAA Chapter 87
Sportsman 2+2 Builder #7118 N421DJ - http://deej.net/sportsman/
Glastar Flyer N866RH - http://deej.net/glastar/
Message 20
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Subject: | Re: Proposed new Z diagram? |
On 1/8/2014 9:09 PM, Jeff Luckey wrote:
> Dj, I cannot find your latest drawing. Can you send a link or attach it?
>
>
Hi Jeff,
It can be found at:
http://deej.net/glastar/pics/electrical/Z-redundant-B.jpg
-Dj
--
Dj Merrill - N1JOV - VP EAA Chapter 87
Sportsman 2+2 Builder #7118 N421DJ - http://deej.net/sportsman/
Glastar Flyer N866RH - http://deej.net/glastar/
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