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deej(at)deej.net
Guest

Posted: Sat Jan 04, 2014 3:23 pm Post subject: Proposed new Z diagram?

I'd like to start off by saying please be gentle.  I'm not an expert and 

this could be completely boneheaded.



I've been looking through the various Z diagrams, and although there are 

parts of some that I like, I could not find one that is exactly what I 

am (or think I am) looking for.



 From being on this list for a decade or more, I know that Bob's first 

question will be along the lines of "What are you looking for" followed 

by "What elements do you want that aren't addressed by the current  

diagrams".  It is hard to put into words, but I'm going to try.



My aircraft will have an electrically dependent engine (electronic 

ignition, gravity feed so no fuel pump) and an electrically dependent 

panel (GRT HX EFIS and EIS).  It will be used for IFR.



I know recently that we have been talking about how statistically 

reliable alternators and batteries are, and have been considering a Z-7 

based on a single alt and battery.  Physics and statistics aside,  I am 

just not comfortable with this, and I want a dual battery 

configuration.  This is a personal choice.  That led me to Z-19.



What I do not like about Z-19 is that it has two always hot power 

buses.  I want a system that when the contactor is off, the battery is 

isolated except for the wires going to the contactor.  Again, physics 

and logic aside, this what I "want".



What I like about Z-19 is the redundancy providing power to the ECU and 

Fuel Pump, and that it is an automatic redundancy.  Both power buses are 

providing power to the ECU at the same time from independent sources.  

This led me to realize that I really do not care about having an 

"endurance" bus, but what I really care about is having a "redundant" 

bus, in other words there are a few devices in my setup that I want to 

have the same automatic redundant power as offered by the engine part of 

Z-19.



Taking parts of Z-19 that I like, and leaving parts out, I've attempted 

to create a "redundant bus" diagram.  It also incorporates an 

"alternator only" operation simply by the fact of isolating the two 

charging circuits and having the alternator on its own switch, although 

I can't picture running in this mode.



Please excuse the crudeness of the drawing.  I did it by hand, and just 

took a picture of the paper afterwards.



Some parts I am not even sure are feasible, such as the diodes that 

separate the two charging circuits (located just above the primary bus 

in the drawing).  I don't even know if diodes exist that will be able to 

handle those loads, but I am sure that some sort of electro-whizzy would 

probably do it.



Some notes:

I will be using a Fly EFII electronic ignition.  Manufacturer 

recommendation is a 10 amp CB/fuse for the coil charging circuit, and 5 

amp for the ECU.  I am told that overall the ignition draws 1.2 amps on 

average for power usage purposes, but the coil charging currents can be 

up to 10 amps. This current only flows for a few milliseconds.



Gravity feed for the fuel, so no fuel pump.



The GRT HX EFIS and the GRT EIS have multiple, internal diode isolated 

power feeds built in which is why there are Pow "A" and Pow "B" feeds 

for each of these devices.



This is a first pass, but I am thinking that I want GPS, NAV, COM, and 

the Intercom to also have redundant power.  I want enough to make an 

instrument approach if needed, so usage and/or recommendations may 

change this list.



Everything else is wired to the primary bus only (no access to the 

secondary bus).



Not completely sure yet, but I anticipate the Aux battery to be smaller, 

and mounted under the panel.  It will be sized appropriately to offer at 

least an hour of battery-only operation for items on the redundant bus 

and to support the ignition.  The main battery will be larger and 

mounted in the tail for CG purposes.



Please critique, but be nice!  



Small version: http://deej.net/glastar/pics/electrical/redundant.jpg



Larger picture: http://deej.net/glastar/pics/electrical/redundant-large.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/

nuckolls.bob(at)aeroelect
Guest

Posted: Sat Jan 04, 2014 4:03 pm Post subject: Proposed new Z diagram?

My aircraft will have an electrically dependent engine (electronic 

ignition, gravity feed so no fuel pump) and an electrically dependent 

panel (GRT HX EFIS and EIS).  It will be used for IFR.



    How is the engine dependent? Ignition? Fuel Injection?

    Do you have the energy requirement numbers?



I know recently that we have been talking about how statistically 

reliable alternators and batteries are, and have been considering a 

Z-7 based on a single alt and battery.  Physics and statistics 

aside,  I am just not comfortable with this, and I want a dual 

battery configuration.  This is a personal choice.  That led me to Z-19.



    One can ALWAYS add a second battery. Our builders

    have been doing this for decades and the techniques

    have been discussed at length on the List.



What I do not like about Z-19 is that it has two always hot power 

buses.  I want a system that when the contactor is off, the battery 

is isolated except for the wires going to the contactor.  Again, 

physics and logic aside, this what I "want".



    Any always hot busses are battery busses and they're

    part and parcel of a considered FEMA and meeting

    design goals. It's my wish that we can assist with

    the crafting of your design goals based more on

    understanding and planning and not so much on worries

    that drive your discomfort.



What I like about Z-19 is the redundancy providing power to the ECU 

and Fuel Pump, and that it is an automatic redundancy.  Both power 

buses are providing power to the ECU at the same time from 

independent sources.

This led me to realize that I really do not care about having an 

"endurance" bus, but what I really care about is having a "redundant" 

bus, in other words there are a few devices in my setup that I want 

to have the same automatic redundant power as offered by the engine 

part of Z-19.



    Redundant to meet what failure event. There's nothing

    that prevents one from having as many batteries, alternators,

    busses and switches as their creativity and physical space

    allows . . . but in the TC aircraft world, the first goal

    is to minimize weight, parts count, system complexity

    and cost of ownership. At the same time, risk assessment

    must necessarily drive all the above goals in the wrong

    direction. The elegant design adds just enough but no more.

Taking parts of Z-19 that I like, and leaving parts out, I've 

attempted to create a "redundant bus" diagram.  It also incorporates 

an "alternator only" operation simply by the fact of isolating the 

two charging circuits and having the alternator on its own switch, 

although I can't picture running in this mode.



Please excuse the crudeness of the drawing.  I did it by hand, and 

just took a picture of the paper afterwards.



Some parts I am not even sure are feasible, such as the diodes that 

separate the two charging circuits (located just above the primary 

bus in the drawing).  I don't even know if diodes exist that will be 

able to handle those loads, but I am sure that some sort of 

electro-whizzy would probably do it.



Some notes:

I will be using a Fly EFII electronic ignition.  Manufacturer 

recommendation is a 10 amp CB/fuse for the coil charging circuit, and 

5 amp for the ECU.  I am told that overall the ignition draws 1.2 

amps on average for power usage purposes, but the coil charging 

currents can be up to 10 amps. This current only flows for a few milliseconds.



    So have you arrived at a ball-park number

    for total electrical system energy requirements?

    You speak to a 60 minute battery-only ops goal

    but can/should it be longer?

Gravity feed for the fuel, so no fuel pump.



The GRT HX EFIS and the GRT EIS have multiple, internal diode 

isolated power feeds built in which is why there are Pow "A" and Pow 

"B" feeds for each of these devices.



This is a first pass, but I am thinking that I want GPS, NAV, COM, 

and the Intercom to also have redundant power.  I want enough to make 

an instrument approach if needed, so usage and/or recommendations may 

change this list.



Everything else is wired to the primary bus only (no access to the 

secondary bus).



Not completely sure yet, but I anticipate the Aux battery to be 

smaller, and mounted under the panel.  It will be sized appropriately 

to offer at least an hour of battery-only operation for items on the 

redundant bus and to support the ignition.  The main battery will be 

larger and mounted in the tail for CG purposes.



Please critique, but be nice!

    You have described adjustments to an architecture

    but it's not clear as to the reasoning behind those

    moves. It seems as if you don't want any single failure

    to cause to you drop to an energy efficient, endurance

    mode . . . are you trying to keep everything lit up

    no matter what?



    You speak of a large main battery and a smaller

    auxiliary battery. What's the physics behind these

    sizing decisions?



Larger picture: http://deej.net/glastar/pics/electrical/redundant-large.jpg



    Z-7 elects to drive a single engine bus

    through diodes from two power paths. What in

    your knowledge or experience suggests that

    charging batteries through diodes offers

    more attractive options?



   Bob . . .

deej(at)deej.net
Guest

Posted: Sat Jan 04, 2014 8:03 pm Post subject: Proposed new Z diagram?

Hi Bob,

     Thank you for your comments.  Based on your response and questions 

asked, I think you may have missed some points that I presented in my 

initial post.  I will try to elaborate and present my thoughts more clearly.



     You ask several questions concerning the "why".  As I mentioned, 

ultimately, it is because I "want", not solely based on any particular 

design based on physics, simple ideas, or statistical likelihood of any 

component failing.  When building or modifying an OBAM aircraft, "want" 

is an important factor.  This is why most of us build/fly experimental 

aircraft versus spam cans, and as with most experimental aircraft, one 

size does not necessarily fit all.



     I want dual batteries and am not comfortable with just one. This is 

not physics, these are those messy human "wants" and "feelings", which 

can't be quantified easily, if at all.



     I do not want an always hot power bus.  I want a system that when 

the contactor is off, the battery is isolated except for the wires going 

to the contactor.



     I want automatic redundancy to certain devices similar to that 

offered in the engine section of Z-19.



     Essentially, the "why" of the above doesn't really matter. These 

are things that I "want" in my aircraft, and I'm trying to figure out 

the best way to accomplish these goals safely.  I am hoping that you and 

others on the list are willing to help me to achieve this.  The diagram 

I presented is my first draft towards this goal, and is my first ever 

attempt at an electrical design. It might be total felgercarb, which is 

why I am asking for help.



     I do have a few guidellines in my thinking.  One is that from 

others' experience, we know that in a one battery situation, the EFIS 

and EIS can "brown out" and reboot when cranking the engine. I desire to 

have the EFIS and EIS up and running before cranking the engine, thus a 

second power source is required at least for these two items, which is 

one small part of the design goals.



 	  Quote: 	
		      How is the engine dependent? Ignition? Fuel Injection?

    Do you have the energy requirement numbers? 


	


     As mentioned, the engine is electrically dependent upon the 

ignition system, comprised of the ECU and coil circuits.  There is no 

fuel pump (and no fuel injection).  In particular, it is a Lycoming 

O-320 in a Glastar, using gravity for fuel feed into a Rotec TBI 

(Throttle Body Injector), which uses no electrical power.  As outlined 

in the initial post, the energy requirements are 1.2 amps to keep the 

ignition running, but simply keeping the engine running is only part of 

the goal.



 	  Quote: 	
		      Any always hot busses are battery busses and they're

    part and parcel of a considered FEMA and meeting

    design goals. It's my wish that we can assist with

    the crafting of your design goals based more on

    understanding and planning and not so much on worries

    that drive your discomfort. 


	


     I have no desire or need for an always hot battery bus.  When power 

is turned off, I do not wish to have any parasitic load that can drain 

the battery between flights, and I do not want to have any live buses.  

These are design goals that I consider important for my electrical 

system, but I fully agree that others may not share these same goals.  

That's okay.  

 	  Quote: 	
		      Redundant to meet what failure event. There's nothing

    that prevents one from having as many batteries, alternators,

    busses and switches as their creativity and physical space

    allows . . . but in the TC aircraft world, the first goal

    is to minimize weight, parts count, system complexity

    and cost of ownership. At the same time, risk assessment

    must necessarily drive all the above goals in the wrong

    direction. The elegant design adds just enough but no more. 


	


     All that is true, however, the most elegant design from an 

engineering perspective may not be the most desired design from a user 

perspective.  I've stated up front that parts of the design are based on 

what I "want", not just what is the most practical design based on 

physics or simple ideas.  As long as the engineering can support it, 

including the "wants" can be just as important in meeting a design goal 

as "elegance".



     I am sitting here with Z-19 in one hand, and my proposed drawing in 

the other, and to me my drawing looks much simpler than Z-19 with less 

parts count, and in my mind seems to offer similar yet slightly 

different functionality to incorporate my "wants" versus the Z-19 

boilerplate.  As I said, this is my first attempt ever at a design, so I 

might be way off on this, and please, do not take this as an attack on 

Z-19.  I am simply using it as a comparison to your comment about parts 

count and system complexity, especially since my diagram was based off 

Z-19 initially.



 	  Quote: 	
		  

    So have you arrived at a ball-park number

    for total electrical system energy requirements?

    You speak to a 60 minute battery-only ops goal

    but can/should it be longer? 


	


     The hour was picked as my personal comfort level.  An hour should 

be adequate to get the plane safely on the ground even in IFR 

conditions.  I do not have the exact numbers on all of the installed 

equipment in the entire airplane, however, the total load on the 

redundant bus is about 6 amps including the electronic ignition (COM not 

transmitting).  Unless I am missing something, I don't believe that 

having those exact numbers at this time will change the basic design of 

the electrical system.  It will have an impact on the size of the 

batteries chosen, and the values of fuses/CBs, though.  Would you agree, 

or have I misunderstood something?



     Bear in mind that if the alternator fails, I have two separate 

batteries that can provide power, so the total time should actually be 

much longer than an hour especially if I turn off "extra" loads on the 

main bus, but should be at least an hour from the aux battery if I don't 

turn off anything.  If one or the other battery or associated wiring and 

circuitry should fail, the alternator and single battery remaining 

should be able to run everything until the completion of the flight, 

although more than likely I would make a precautionary landing in the 

event of any type of problem.

 	  Quote: 	
		      You have described adjustments to an architecture

    but it's not clear as to the reasoning behind those

    moves. It seems as if you don't want any single failure

    to cause to you drop to an energy efficient, endurance

    mode . . . are you trying to keep everything lit up

    no matter what? 


	


     I thought I described this clearly, but apparently I've not 

communicated well.  I'm trying to keep everything on the redundant bus 

lit up as those are what I consider the critical items, and I mentioned 

that this list of items may change as I use the system and/or receive 

recommendations from others.  In particular, in my initial email I 

listed the electronic ignition, GPS, NAV, COM, and the Intercom to have 

redundant power.  At the moment, these are what I would consider minimum 

to get the airplane safely on the ground in IFR conditions.

 	  Quote: 	
		      You speak of a large main battery and a smaller

    auxiliary battery. What's the physics behind these

    sizing decisions? 


	


     Partly because I am rewiring an existing electrical system on an 

already flying airplane.  The main battery is located just behind the 

baggage area, and I do not desire to relocate this.



     The aux battery only needs to be large enough to run the redundant 

bus for an hour, and will be mounted under the panel for CG reasons, so 

it is helpful to have it be as small as practical from a physical 

perspective.



     As stated earlier, the electrical sizing of the batteries will be 

made after all of the electrical loads are calculated, and are located 

on either the main or redundant buses.  Again, I'm not sure how the size 

of the batteries will have any impact on the basic design of the 

electrical system.  Will selecting a 10ah versus a 12ah battery for the 

aux, for example, have any effect at all on the basic electrical design 

as depicted in the diagram?

 	  Quote: 	
		      Z-7 elects to drive a single engine bus

    through diodes from two power paths. What in

    your knowledge or experience suggests that

    charging batteries through diodes offers

    more attractive options? 


	


None, which is why I indicated diodes in the initial design.   As I 

stated, "I don't even know if diodes exist that will be able to handle 

those loads".  If they will, excellent, I chose correctly the first time 

and I really have learned some things from following this list for the 

past decade or so.  If not, I was sure someone on here would point that 

out and offer an alternative. Bear in mind that I'm still learning...

So we've gone through a couple of pages of questions and answers, but I 

feel like I haven't really gotten any feedback at all on the diagram 

itself as presented.



Will it work?



Are there any obvious or not so obvious flaws?



What are your concerns, if any, in the diagram as presented?



Have I communicated the basic design goals clearly enough to follow, 

taking in to account the end-user "wants" in addition to ensuring that 

the basic design will function properly?



http://deej.net/glastar/pics/electrical/redundant-large.jpg



Thanks,



-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/

nuckolls.bob(at)aeroelect
Guest

Posted: Sun Jan 05, 2014 10:34 am Post subject: Proposed new Z diagram?

So we've gone through a couple of pages of questions and answers, but 

I feel like I haven't really gotten any feedback at all on the 

diagram itself as presented.



   Clearly, your design goals are substantially different than

   those which drive the z-figures . . . which is not a bad

   thing . . . just different.



Will it work?



   I've never encountered an alternative approach that did

   not function as intended . . . where function is defined

   as, "flip that switch and expect this action to follow."

   You can easily confirm functionality with some judicious

   ground tests. Get an ac mains power supply to emulate

   the alternator and do the electrical system 'Walter Mitty'

   thing with the wheels on the ground.



Are there any obvious or not so obvious flaws?



   The z-figures are evolutionary . . . they form a

   kind of pyramid that spans the simplest to most

   complex, each tailored to a combination of aircraft/

   mission/pilot. When useful 'tweaks' were identified

   the figures evolved independently as well.



What are your concerns, if any, in the diagram as presented?



   As with any new adventure in design, some 'gotchas' may

   be discovered by analysis and comparison with lessons

   learned . . . others may not bubble up until the system

   is operated either as laboratory mock up (which we do

   in TC aircraft) or fly on the test-bed aircraft (like

   Burt Rutan does it).



   Those-who-know-more-about-airplanes-than-we-do are

   fond of the 75-hour test stand runs for engines

   and 40-hour fly-offs for airframes. But BOTH protocols

   presume that the person conducting the test isn't

   just along for the ride but is also getting answers

   to questions.



   The risks associated with discovery of glitches are low.

   Only a the smallest fraction of sad days in aviation

   have roots in failure of a component of the electrical

   system. Your development process will be refined on

   the flying test-bed . . . so flight into marginal

   environment for the first hundred hours or so is

   discouraged . . . with experiments conducted to

   validate every design goal.



   The highest risks will arise not from design and

   selection of components but from craftsmanship

    . . . as illustrated by numerous NTSB narratives

   on unhappy events. These were not based on the massaging

   of a 'z-figure' but more for lack of understanding of

   processes.



Have I communicated the basic design goals clearly enough to follow, 

taking in to account the end-user "wants" in addition to ensuring 

that the basic design will function properly?



   Based on inspection of your work-product and review of

   your design goals I have no particular concerns with

   respect to either risk or functionality.



   You've embarked on a new "z-figure" with a design philosophy

   based not so much on economies of energy, weight, functionality

   and risk but on decisions and desires personal to you. This

   makes your project more a one-of-a-kind work of art as

   opposed to a competitively merchantable collection of

   ideas. There is nothing 'golden' about either . . .

   they just need to satisfy the end-user's perceptions for

   return on investment.



   As with any such endeavor, cautious and introspective

   experimentation is the key to your success.

   Bob . . .

jluckey(at)pacbell.net
Guest

Posted: Sun Jan 05, 2014 3:03 pm Post subject: Proposed new Z diagram?

... cautious and introspective experimentation is the key to your success...



sounds like something you'd find in a fortune cookie, grasshopper   





        From: "Robert L. Nuckolls, III" <nuckolls.bob(at)aeroelectric.com>

 To: aeroelectric-list(at)matronics.com 

 Sent: Sunday, January 5, 2014 10:33 AM

 Subject: Re: Proposed new Z diagram?

  

  

 --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <nuckolls.bob(at)aeroelectric.com (nuckolls.bob(at)aeroelectric.com)>

So we've gone through a couple of pages of questions and answers, but I feel like I haven't really gotten any feedback at all on the diagram itself as presented.



  Clearly, your design goals are substantially different than

  those which drive the z-figures . . . which is not a bad

  thing . . . just different.



Will it work?



  I've never encountered an alternative approach that did

  not function as intended . . . where function is defined

  as, "flip that switch and expect this action to follow."

  You can easily confirm functionality with some judicious

  ground tests. Get an ac mains power supply to emulate

  the alternator and do the electrical system  'Walter Mitty'

  thing with the wheels on the ground.



Are there any obvious or not so obvious flaws?



  The z-figures are evolutionary . . . they form a

  kind of pyramid that spans the simplest to most

  complex, each tailored to a combination of aircraft/

  mission/pilot. When useful 'tweaks' were identified

  the figures evolved independently as well.



What are your concerns, if any, in the diagram as presented?



  As with any new adventure in design, some 'gotchas' may

  be discovered by analysis and comparison with lessons

  learned . . . others may not bubble up until the system

  is operated either as laboratory mock up (which we do

  in TC aircraft) or fly on the test-bed aircraft (like

  Burt Rutan does it).



  Those-who-know-more-about-airplanes-than-we-do are

  fond of the 75-hour test stand runs for  engines

  and 40-hour fly-offs for airframes. But BOTH protocols

  presume that the person conducting the test isn't

  just along for the ride but is also getting answers

  to questions.



  The risks associated with discovery of glitches are low.

  Only a the smallest fraction of sad days in aviation

  have roots in failure of a component of the electrical

  system. Your development process will be refined on

  the flying test-bed . . . so flight into marginal

  environment for the first hundred hours or so is

  discouraged . . . with experiments conducted to

  validate every design goal.



  The highest risks will arise not from design and

  selection of components but from craftsmanship

   . . . as illustrated by numerous NTSB narratives

  on unhappy events. These were not based on the massaging

  of a 'z-figure'  but more for lack of understanding of

  processes.



Have I communicated the basic design goals clearly enough to follow, taking in to account the end-user "wants" in addition to ensuring that the basic design will function properly?



  Based on inspection of your work-product and review of

  your design goals I have no particular concerns with

  respect to either risk or functionality.



  You've embarked on a new "z-figure" with a design philosophy

  based not so much on economies of energy, weight, functionality

  and risk but on decisions and desires personal to you. This

  makes your project more a one-of-a-kind work of art as

  opposed to a competitively merchantable collection of

  ideas. There is nothing 'golden' about either . . .

  they just need to satisfy the end-user's perceptions for

  return on investment.



  As with any  such endeavor, cautious and introspective

  experimentation is thep;  * AeroElectric www.buildersbnbsp;    * My Pilot Store www.mrrace.com</                     &nbsd much .com/Navigator?AeroElectric-List" target="_blank">http://www.matronics.co======

nuckolls.bob(at)aeroelect
Guest

Posted: Sun Jan 05, 2014 3:15 pm Post subject: Proposed new Z diagram?

At 04:59 PM 1/5/2014, you wrote:

 	  Quote: 	
		  ... cautious and introspective experimentation is the key to your success...



sounds like something you'd find in a fortune cookie, grasshopper   


	


    That would be a good one for the cookie . . . but

    in fact a simple reality taught and practiced by

    every competent practitioner of both the arts and

    sciences. It's the hammer-n-tongs for implementation of

    spontaneous order, a concept that has been around

    for better than 2300 years . . .



   Bob . . .

deej(at)deej.net
Guest

Posted: Sun Jan 05, 2014 5:56 pm Post subject: Proposed new Z diagram?

When I decided to post my draft diagram on the list, my hope was to 

get a peer review from others, and an independent verification that the 

circuit design would function properly and as desired.  In a basic 

sense, I would really like to have someone with far more experience than 

I to go over the diagram, and reply with a clear "YES, it will work as 

you expect", or "NO, you missed (blah), or you will smoke the circuit 

because of (blah)."  I believe I have learned a lot on this list over 

the years, enough to feel confident to post a circuit diagram, but I am 

far from an expert and am still learning.  A "look over the shoulder" 

from a guru now and then is a great help to a student to tell if they 

are on the right track, or not, much the same as constructing a wing or 

installing critical flight controls.  In other words, I am pleading for 

a technical review if there are people out there willing to do so.



     Bob, I've read through your recent response several times, and it 

is not clear to me if you did a review of the circuit diagram, or are 

simply telling me in a sense, "good luck" in far more elegant and 

lengthy prose (which I do appreciate!   ).  Based on one sentence, I 

think you have looked it over, ie "Based on inspection of your 

work-product and review of your design goals I have no particular 

concerns with respect to either risk or functionality."  I think what 

you are saying here is that yes, the circuit should work as desired, but 

I'm not certain (You could simply be saying that you have no concerns 

about it working, which is not quite the same thing).  Would you be 

willing to answer the question with a simple "yes" or "no", will this 

circuit diagram work properly and as desired given the guidelines and 

design goals that we've talked about over the past few messages?



     An interesting and unexpected side effect - I've received emails 

direct from others that say they are also interested in this type of 

architecture, specifically the automatic "redundant" bus feature for 

critical devices to get power from either the primary or secondary power 

buses.  Since this appears to have an interest going beyond my personal 

implementation, I'd be honored if you would consider pursuing this 

further, and possibly entertaining the idea of including something like 

this as a Z diagram in a future version of the Connection.



Thank you,



-Dj

On 1/5/2014 1:33 PM, Robert L. Nuckolls, III wrote:

 	  Quote: 	
		   

 <nuckolls.bob(at)aeroelectric.com>

 So we've gone through a couple of pages of questions and answers, but 

 I feel like I haven't really gotten any feedback at all on the diagram 

 itself as presented.



   Clearly, your design goals are substantially different than

   those which drive the z-figures . . . which is not a bad

   thing . . . just different.



 Will it work?



   I've never encountered an alternative approach that did

   not function as intended . . . where function is defined

   as, "flip that switch and expect this action to follow."

   You can easily confirm functionality with some judicious

   ground tests. Get an ac mains power supply to emulate

   the alternator and do the electrical system 'Walter Mitty'

   thing with the wheels on the ground.



 Are there any obvious or not so obvious flaws?



   The z-figures are evolutionary . . . they form a

   kind of pyramid that spans the simplest to most

   complex, each tailored to a combination of aircraft/

   mission/pilot. When useful 'tweaks' were identified

   the figures evolved independently as well.



 What are your concerns, if any, in the diagram as presented?



   As with any new adventure in design, some 'gotchas' may

   be discovered by analysis and comparison with lessons

   learned . . . others may not bubble up until the system

   is operated either as laboratory mock up (which we do

   in TC aircraft) or fly on the test-bed aircraft (like

   Burt Rutan does it).



   Those-who-know-more-about-airplanes-than-we-do are

   fond of the 75-hour test stand runs for engines

   and 40-hour fly-offs for airframes. But BOTH protocols

   presume that the person conducting the test isn't

   just along for the ride but is also getting answers

   to questions.



   The risks associated with discovery of glitches are low.

   Only a the smallest fraction of sad days in aviation

   have roots in failure of a component of the electrical

   system. Your development process will be refined on

   the flying test-bed . . . so flight into marginal

   environment for the first hundred hours or so is

   discouraged . . . with experiments conducted to

   validate every design goal.



   The highest risks will arise not from design and

   selection of components but from craftsmanship

    . . . as illustrated by numerous NTSB narratives

   on unhappy events. These were not based on the massaging

   of a 'z-figure' but more for lack of understanding of

   processes.



 Have I communicated the basic design goals clearly enough to follow, 

 taking in to account the end-user "wants" in addition to ensuring that 

 the basic design will function properly?



   Based on inspection of your work-product and review of

   your design goals I have no particular concerns with

   respect to either risk or functionality.



   You've embarked on a new "z-figure" with a design philosophy

   based not so much on economies of energy, weight, functionality

   and risk but on decisions and desires personal to you. This

   makes your project more a one-of-a-kind work of art as

   opposed to a competitively merchantable collection of

   ideas. There is nothing 'golden' about either . . .

   they just need to satisfy the end-user's perceptions for

   return on investment.



   As with any such endeavor, cautious and introspective

   experimentation is the key to your success.

   Bob . . .




	




-- 

Dj Merrill - N1JOV - VP EAA Chapter 87

Sportsman 2+2 Builder #7118 N421DJ - http://deej.net/sportsman/

Glastar Flyer N866RH - http://deej.net/glastar/

Bob McC

Joined: 09 Jan 2006
Posts: 258
Location: Toronto, ON

Posted: Sun Jan 05, 2014 7:08 pm Post subject: Proposed new Z diagram?

First; it would appear that what you have drawn will function.



Is that function what you intend?? Or expect?? I'm not sure. It will power

the components you mention from either of two sources redundantly, but is it

what you want?? My second point below may be the gotcha you're alluding to

and may not have considered but I don't know.



Second; turning off either the primary or secondary power (master?) switch,

as the circuit is drawn, will not turn off the respective primary or

secondary buss so long as the alternator is functioning. The alternator will

support the buss directly without benefit of the corresponding battery. The

master switches only serve to disconnect the batteries not turn off the

buss. If this is your desired goal then it will work.

This is not necessarily any sort of functional problem, just that you may

turn off one of these two master switches expecting the corresponding buss

to shut down and it won't. As long as you know that this is "normal" for the

way you've wired the circuit and are expecting this result then all is well.

Is there any conceivable instance when you would wish to shut down a buss

utilizing the corresponding master switch?? I so, then you need to be aware

that for this to happen you must also shut down the alternator.



The down side is that in the case (heaven forbid) of a "crash" or "accident"

turning off the master switches does not "kill all power" as the electrical

system is still kept alive by the alternator if it is functioning and the

engine is turning. (even wind milling). Your wiring requires the

manipulation of three switches to fully shut down electrical power.



Bob McC

[quote] --

_________________
Bob McC
Falco #908
(just starting)

nuckolls.bob(at)aeroelect
Guest

Posted: Sun Jan 05, 2014 10:01 pm Post subject: Proposed new Z diagram?

Bob, I've read through your recent response several times, and 

it is not clear to me if you did a review of the circuit diagram, or 

are simply telling me in a sense, "good luck" in far more elegant and 

lengthy prose (which I do appreciate!   ).  Based on one sentence, 

I think you have looked it over, ie "Based on inspection of your 

work-product and review of your design goals I have no particular 

concerns with respect to either risk or functionality."



     DJ, what you ask is not unlike somebody laying a recipe

     in front of an experienced chef and asking, will this

     accomplish what I want? But without articulating exactly

     what it is you want and why.



     When we produced system designs for the military we

     first offered a proposal . . . followed by a preliminary

     design review . . . followed by a critical design

     review. I had to stand in front of a team of sharp reviewers

     and defend my work product twice.



   I think what you are saying here is that yes, the circuit should 

work as desired, but I'm not certain (You could simply be saying that 

you have no concerns about it working, which is not quite the same 

thing).  Would you be willing to answer the question with a simple 

"yes" or "no", will this circuit diagram work properly and as desired 

given the guidelines and design goals that we've talked about over 

the past few messages?



     Define "properly" . . . I believe your drawing accurately

     illustrates the goals you've cited .



     I'm looking at your drawing without benefit of knowing

     the foundation for your design goals which becomes

     a task not unlike reverse-engineering . . . attempt

     to deduce original intent from a document . . . we

     can all sit around and talk about it, like visitors

     to an art gallery and hypothesize about the mind-set,

     tools and techniques of the artist . . . who has

     probably been dead for a few hundred years.



     You've said you don't want any always hot busses . . .

     in spite of the fact that a quarter million airplanes

     were built with the benefit of always hot busses.

     Okay, defend the design goal. You've got some power

     diodes for which I can deduce no value . . . defend

     the decision to put them in. Trade off the pros and cons

     of your proposal with the features of other proven

     philosophies, mine or anyone else.



     Do you have a reason to be different or just want

     to be different?



     An interesting and unexpected side effect - I've received emails 

direct from others that say they are also interested in this type of 

architecture, specifically the automatic "redundant" bus feature for 

critical devices to get power from either the primary or secondary 

power buses.  Since this appears to have an interest going beyond my 

personal implementation, I'd be honored if you would consider 

pursuing this further, and possibly entertaining the idea of 

including something like this as a Z diagram in a future version of 

the Connection.



     I had a builder reject a proposal for a

     system on his proposed light jet because "it

     didn't have a big enough circuit breaker panel."

     I was a bit stunned . . . the most I could offer

     was the idea that he could make the panel as

     large as he wanted, nobody would demand that

     all the breakers were hooked up to do anything.

     He got p(at)#$Sd off and fired me . . . for which

     I was thankful. If others are finding value

     in your proposal, then perhaps they can defend

     its features . . . or perhaps they are captivated

     by colors and brush strokes . . . I don't know.



     We're not producing works of art or recipes

     for gourmet meals . . . I'm always interested

     in ideas that advance the state of our art and

     science but it shouldn't be just one more page

     in a 1000-page cookbook.



     Bob . . .

nuckolls.bob(at)aeroelect
Guest

Posted: Mon Jan 06, 2014 6:02 am Post subject: Proposed new Z diagram?

 	  Quote: 	
		       An interesting and unexpected side effect - I've received 

 emails direct from others that say they are also interested in this 

 type of architecture, specifically the automatic "redundant" bus 

 feature for critical devices to get power from either the primary 

 or secondary power buses.


	




    Not sure what the term "automatic redundant" feature is all

    about . . . for what kind of failure is there value in

    offering an 'automatic' response?



    Let's try another tack . . .



    You said you wanted dual batteries and no always

    hot busses. Okay. Consider this variant on the

    Z07 work-in-process . . .



http://tinyurl.com/mevf3n8



    What failures in this architecture pose any

    unacceptable/unmanageable risks? In what way

    are your design goals yet to be realized?



   Bob . . .

deej(at)deej.net
Guest

Posted: Mon Jan 06, 2014 9:16 am Post subject: Proposed new Z diagram?

Hi Bob McC,

	Thank you for looking things over and offering feedback.  You make a

very good point, and I'll have to think about this for a bit.  The

original intent was to have a system that could run specific critical

equipment from either of two completely redundant power buses and

battery power sources, and that both batteries would be charging when

the alternator is enabled.  Recently on the list we've been talking

about running in an alternator-only mode, and I thought it a nice

feature that my proposed architecture would allow this.  However, I

missed the fact that in doing so I now had no way to disable each of the

separate buses if the alternator were running.  Thank you for

highlighting that!  



	Bob M offered a new dual battery Z-7 diagram this morning that offers

more food for thought.  I haven't had time to look at it with any

detail, but I look forward to doing so later.  If I am reading it

correctly, at first glance it also seems to share a similar

characteristic whereas both the main power bus and the endurance bus are

always powered if the alternator is powered, with no way to individually

remove power from each bus separately.  A difference is that there is a

single switch that controls the alternator and main battery contactor,

and is wired such that 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.



	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.



Thank you!



-Dj



On 01/05/2014 10:06 PM, Bob McCallum wrote:

 	  Quote: 	
		   

 

 First; it would appear that what you have drawn will function.

 

 Is that function what you intend?? Or expect?? I'm not sure. It will power

 the components you mention from either of two sources redundantly, but is it

 what you want?? My second point below may be the gotcha you're alluding to

 and may not have considered but I don't know.

 

 Second; turning off either the primary or secondary power (master?) switch,

 as the circuit is drawn, will not turn off the respective primary or

 secondary buss so long as the alternator is functioning. The alternator will

 support the buss directly without benefit of the corresponding battery. The

 master switches only serve to disconnect the batteries not turn off the

 buss. If this is your desired goal then it will work.

 This is not necessarily any sort of functional problem, just that you may

 turn off one of these two master switches expecting the corresponding buss

 to shut down and it won't. As long as you know that this is "normal" for the

 way you've wired the circuit and are expecting this result then all is well.

 Is there any conceivable instance when you would wish to shut down a buss

 utilizing the corresponding master switch?? I so, then you need to be aware

 that for this to happen you must also shut down the alternator.

 

 The down side is that in the case (heaven forbid) of a "crash" or "accident"

 turning off the master switches does not "kill all power" as the electrical

 system is still kept alive by the alternator if it is functioning and the

 engine is turning. (even wind milling). Your wiring requires the

 manipulation of three switches to fully shut down electrical power.

 

 Bob McC


	




-- 

Dj Merrill - N1JOV - VP EAA Chapter 87

Sportsman 2+2 Builder #7118 N421DJ - http://deej.net/sportsman/

Glastar Flyer N866RH - http://deej.net/glastar/

user9253

Joined: 28 Mar 2008
Posts: 1921
Location: Riley TWP Michigan

Posted: Mon Jan 06, 2014 5:16 pm Post subject: Re: Proposed new Z diagram?

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

Simple Elect System.pdf

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_________________
Joe Gores

nuckolls.bob(at)aeroelect
Guest

Posted: Mon Jan 06, 2014 7:01 pm Post subject: Proposed new Z diagram?

 	  Quote: 	
		    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

 	  Quote: 	
		           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 . . .

nuckolls.bob(at)aeroelect
Guest

Posted: Tue Jan 07, 2014 6:49 am Post subject: Proposed new Z diagram?

At 09:01 PM 1/6/2014, you wrote:

 	  Quote: 	
		  

<nuckolls.bob(at)aeroelectric.com>


	


   While considering the size and utilization

   of batteries, add the following into your

   deliberations:



   If the batteries are of different size, will

   the smaller be capable of cranking the engine?

   I.e. 17 a.h. or larger?  If so, then you can

   alternate between batteries for starting the

   engine. This philosophy offers a pre-flight test

   of battery health and integrity of associated

   wiring (contactors etc.)



   If it's never used to crank the engine, then

   consider the philosophy for assurance of continued

   airworthiness.



   If the batteries are the same size, then one has

   the option of simply rotating a new battery into

   the more strenuous/critical slot (probably supporting

   the motive power bus) and moving the original battery

   into the other slot. This alleviates any need to

   accomplish more introspective testing. All you need

   is to craft a change-out philosophy tailored for

   the most economical outcome.



   Perhaps a yearly rotation of a low cost battery

   as opposed to a premium device.



   I noticed a suggestion in the Viking drawings

   for using lithium batteries. Obviously NOT

   low cost and probably not candidates for periodic

   rotation . . . now you'll need a more introspective

   protocol for assuring continued air worthiness.



   If rotation is not a viable option, then periodic

   inspection for quantifying capacity is indicated.

   System reliability and failure tolerance is built

   on KNOWING limits . . .



   Something to factor into crafting and implementing

   the grand-plan . . .



   Bob . . .



   Bob . . .

nuckolls.bob(at)aeroelect
Guest

Posted: Tue Jan 07, 2014 11:45 am Post subject: Proposed new Z diagram?

At 09:01 PM 1/6/2014, you wrote:

 	  Quote: 	
		  

<nuckolls.bob(at)aeroelectric.com>


	


   Discussions about the Viking installation have

   raised heretofore unconsidered questions. Since

   the earliest days of the change-over from generators

   to alternators, the GENERAL consensus and design

   philosophies have held that alternators should be

   only operated with a battery on line.



   There have been the odd exception . . . Bonanzas

   and Barons have always offered alternator operation

   independently of batteries . . . there may be others

   about which I have no knowledge.



   If Viking has officially asserted that their product

   will function alternator-only, then there are

   interesting questions to be explored for crafting

   a new design philosophy.



   Obviously, the engine driven power source is at

   the foundation of energy pyramid. IF the current

   generation of alternators and system loads

   are amenable to alternator-only operations, then

   the legacy design goal for taking an alternator

   off line before the battery (split rocker philosophy)

   forces a waste of a potentially valuable resource.



   I'm going to noodle out some experiments to be

   conducted, probably at B&C on their test stand,

   to gather data on the quality and integrity

   of energy available from an alternator running

   barefoot. No doubt inquiring minds would like

   to KNOW . . .



   In the mean time, you Viking customers have

   solid justification for asking the supplier,

   "Are alternator-only operations 'approved' under

   your design goals? Are there risks to alternator-

   only operations. If I hit the system with a

   hydraulic pump motor or 250 watt landing light,

   can the alternator be stalled? What tests have

   been conducted to support your assertions?"

   Bob . . .

Tundra10

Joined: 14 Jun 2010
Posts: 102
Location: Scarborough, Ontario

Posted: Tue Jan 07, 2014 1:06 pm Post subject: Proposed new Z diagram?

I did have a car-sized battery in my boat explode once.  It was happy  

with the current draw to tilt the motor, but the starter current draw  

did something to it.  It had responded normally to the battery charger  

and had normal voltage before I put it in the boat in the spring.  It  

was a heck of a mess to clean up.  A fully enclosed battery box is  

recommended !



I agree the switches will be complex to operate in the air when a  

failure occurs.  For my design, I had to write out the checklist  

sequence for various scenarios before I greatly simplified my design  

(not electrically dependent engine).



For this proposed Z diagram, I suggest considering using a progressive  

switch to combine the main battery and alternator into a single  

switch.  In the event of a fire, shutting off the two battery switches  

will take away all power from the main bus.



The engine switches are not symmetrical in operation.  That is, the  

Normal switch works without the main battery switch on.  The Aux  

switch does not provide power to the engine unless the Aux Battery  

switch is also on.  This could be confusing while handling a failure  

in flight.  Although a diode could be connected to the Endurance bus,  

my preference would be to have the Aux engine independent of the  

Endurance bus switch as well, which means adding another relay.



Jeff Page

Dream Aircraft Tundra #10

 	  Quote: 	
		   Time: 07:01:58 PM PST US

 From: "Robert L. Nuckolls, III" <nuckolls.bob(at)aeroelectric.com>

 Subject: Re: Proposed new Z diagram?



>  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 . . .

teblejw

Joined: 19 Nov 2013
Posts: 14

Posted: Wed Jan 08, 2014 5:59 am Post subject: Proposed new Z diagram?

Bob,

You wrote:

 	  Quote: 	
		   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

 	  Quote: 	
		   On Jan 6, 2014, at 8:01 PM, "Robert L. Nuckolls, III" <nuckolls.bob(at)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 . . .

nuckolls.bob(at)aeroelect
Guest

Posted: Wed Jan 08, 2014 6:13 am Post subject: Proposed new Z diagram?

At 07:57 AM 1/8/2014, you wrote:

 	  Quote: 	

<tomblejwas(at)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 . . .

nuckolls.bob(at)aeroelect
Guest

Posted: Wed Jan 08, 2014 6:19 am Post subject: Proposed new Z diagram?

At 07:16 PM 1/6/2014, you wrote:

 	  Quote: 	
		  



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 . . .

deej(at)deej.net
Guest

Posted: Wed Jan 08, 2014 7:02 am Post subject: Proposed new Z diagram?

On 01/08/2014 09:12 AM, Robert L. Nuckolls, III wrote:

 	  Quote: 	
		     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/

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