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andrewbutler(at)ireland.c
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 Posted: Mon Sep 24, 2007 6:23 am Post subject: Dual Electronic Ignition |
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Hello,
I am an RV7 builder in Ireland and plan to install dual electronic ignition. I was eyeing up a Split Bus config, but I think that is overkill for a VFR machine. So I was looking to vary the Z14 design for (40A main, 20A aux alts and 16AH main, 7.2AH aux batteries.
Then I saw the Z13/20 variant, All Electric Aeroplane with 20Amp eBus. This looks perfect, albeit it has one battery. Is it feasible to add a small battery to this design? If so where is the best to point to connect?
What is the normal mode of Operation of this design and what is the main alt out mode? Why is the eBus Alt Master a three position switch?
How would each Alt be tested during the pre-flight check listed?
Thanks for your help,
Andrew Butler.
[quote][b]
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nuckolls.bob(at)cox.net
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| Posted: Mon Sep 24, 2007 7:02 am Post subject: Dual Electronic Ignition |
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At 02:22 PM 9/24/2007 +0000, you wrote:
| Quote: | Hello,
I am an RV7 builder in Ireland and plan to install dual electronic
ignition. I was eyeing up a Split Bus config, but I think that is overkill
for a VFR machine. So I was looking to vary the Z14 design for (40A main,
20A aux alts and 16AH main, 7.2AH aux batteries.
|
Also overkill.
| Quote: | Then I saw the Z13/20 variant, All Electric Aeroplane with 20Amp eBus.
This looks perfect, albeit it has one battery. Is it feasible to add a
small battery to this design? If so where is the best to point to connect?
|
Why?
| Quote: | What is the normal mode of Operation of this design and what is the main
alt out mode?
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Take a look at Z-13/8 and tell us where it falls short of
accommodating your plan-b for any single failure of the
electrical system.
| Quote: | Why is the eBus Alt Master a three position switch?
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OFF/BAT ONLY/BAT+ALT just like the split rocker switch
in the majority of TC single engine aircraft.
| Quote: | How would each Alt be tested during the pre-flight check listed?
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Run each alternator by itself and watch the bus voltage and/or
loadmeter.
The Z-13/20 was not well thought out when I crafted it
and it's going to be removed from future publications.
If Z-13/8 doesn't cut it for you (and it should for 95%
or more of all SE OBAM aircraft flying) then Z-14 is the
next step.
In fact, I just pulled that drawing from the Appendix Z
posting on the website. I cannot imagine a situation where
Z-13/8 won't cut it for you.
Bob . . .
----------------------------------------
( "Problems are the price of progress. )
( Don't bring me anything but trouble. )
( Good news weakens me." )
( -Charles F. Kettering- )
----------------------------------------
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trigo(at)mail.telepac.pt
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| Posted: Mon Sep 24, 2007 8:48 am Post subject: Dual Electronic Ignition |
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Hi Andrew
Sorry for not answering your questions, but I chimed him just to greet you and to know about your engine.
After giving up the Subaru, with which engine did you go?
Carlos
From: owner-aeroelectric-list-server(at)matronics.com [mailto:owner-aeroelectric-list-server(at)matronics.com] On Behalf Of Andrew Butler
Sent: segunda-feira, 24 de Setembro de 2007 15:22
To: aeroelectric-list(at)matronics.com
Subject: Dual Electronic Ignition
Hello,
I am an RV7 builder in Ireland and plan to install dual electronic ignition. I was eyeing up a Split Bus config, but I think that is overkill for a VFR machine. So I was looking to vary the Z14 design for (40A main, 20A aux alts and 16AH main, 7.2AH aux batteries.
Then I saw the Z13/20 variant, All Electric Aeroplane with 20Amp eBus. This looks perfect, albeit it has one battery. Is it feasible to add a small battery to this design? If so where is the best to point to connect?
What is the normal mode of Operation of this design and what is the main alt out mode? Why is the eBus Alt Master a three position switch?
How would each Alt be tested during the pre-flight check listed?
Thanks for your help,
Andrew Butler.
| Quote: | | http://www.matronics.com/Navigator?AeroElectric-List |
01234
[quote][b]
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andrewbutler(at)ireland.c
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| Posted: Mon Sep 24, 2007 6:20 pm Post subject: Dual Electronic Ignition |
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Thanks Bob, appreciate the feedback.
Lets assume I go for the Z13/8, but replace the generic Ford regulator with an LR3 regulator. This gives me my Low Volts/OV warning and tells me when to switch to main Alt out mode.
I assume this involves opening the DC Master and closing the E-Bus Alternate Feed. In this mode, how would I install a low voltage warning light? Would repositioning the AEC9005 module to the Endurance Bus do it? Do you supply these, as I couldn't find it on yours or BandC's website?
If I was compelled to add a second small battery for an aux battery bus for the second ignition, where would I put it?
The reason I am veering towards overkill is because I need to get approval from my engineer to install dual electonic ignition before order my engine and this will be based on the "perceived" reliability of my electical system. If I do dual e-ignition, I will be the first in Ireland to do so on an IO360 homebuild. In fact, just over the Irish sea in the UK, dual electronic ignition is not permitted on homebuilts at all. All G registered homebuilts must keep at least one mag................
Andrew.
[quote]---
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mlas(at)cox.net
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| Posted: Wed Sep 26, 2007 7:05 am Post subject: Dual Electronic Ignition |
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Maybe I’m over stating the obvious, but what does split bus / dual electronic ignitions (DEI) and VFR have to do with each other? An engine failure is an engine failure! Yes it may be easier to deal with a failed engine VFR on a good day vs. low IFR. But isn’t the idea here to make the two ignition systems independent of each other. I have several friends flying airplanes with DEI on the same electrical bus. To me that is a single point failure on many levels If the bus shorts or opens, the end result is you’re a glider! In my world of high speed race planes, I have seen more then one land out without ignition. For me the only acceptable way to deal with DEI is to have two separate independent electrical sources and none of them an alternator as the primary source of power. My minim system requirements are two batteries on a separate bus with more than a simple gauge to show system state and at least one preferably two charging sources.
Mike
--
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nuckolls.bob(at)cox.net
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| Posted: Wed Sep 26, 2007 10:39 am Post subject: Dual Electronic Ignition |
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At 08:04 AM 9/26/2007 -0700, you wrote:
| Quote: | Maybe I'm over stating the obvious, but what does split bus / dual
electronic ignitions (DEI) and VFR have to do with each other?
|
absolutely nothing
| Quote: | An engine failure is an engine failure! Yes it may be easier to deal
with a failed engine VFR on a good day vs. low IFR. But isn't the idea
here to make the two ignition systems independent of each other. I have
several friends flying airplanes with DEI on the same electrical
bus. To me that is a single point failure on many levels If the bus
shorts or opens, the end result is you're a glider!
|
But these things don't happen in an artfully crafted
system. For example, you don't fly around expecting to
loose a prop or a wing . . . why is this?
| Quote: | In my world of high speed race planes, I have seen more then one land
out without ignition.
|
Probably because the designer was a go-fast expert and
not a fail-passive system designer. Fail passive says that
we can tolerate any single failure of a piece of hardware
and not suffer an uncomfortable landing.
| Quote: | For me the only acceptable way to deal with DEI is to have two separate
independent electrical sources and none of them an alternator as the
primary source of power. My minim system requirements are two batteries
on a separate bus with more than a simple gauge to show system state and
at least one preferably two charging sources.
|
You're mired down in the notions that probability of
comfortable termination of flight is maximized by
having back-ups to back-ups. It doesn't need to be
that difficult. There's a simple process called the
failure mode effects analysis backed up by the
notion that you are exceedingly unlikely to experience
TWO failures of really useful items on any one tank
full of fuel.
Check out chapter 17 in the 'Connection and let's talk
about your proposed system with the idea of crafting
a logical, minimum parts count approach to a fail-passive
system.
Bob . . .
----------------------------------------
( "Problems are the price of progress. )
( Don't bring me anything but trouble. )
( Good news weakens me." )
( -Charles F. Kettering- )
----------------------------------------
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mprather(at)spro.net
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| Posted: Wed Sep 26, 2007 12:19 pm Post subject: Dual Electronic Ignition |
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I agree with everything you said Bob.. I would add that many race planes
are in a constant state of systems redesign. In the quest for speed,
racers are always modifying one thing or other. Experimenting happens.
In a perfect world, that new "lightning strike ten thousand" ignition
system would be tried out one set of spark plugs at a time, and preferably
on an Ag Cat or Supercub (but using the same installation methods) where
the consequences of total failure might be lower than on one of the nearly
wingless wonders that they run at Reno. As it is, racers are pulling all
nighters gluing together systems for race week when they really should
have been snoozing for safety (IMO)..
Regards,
Matt-
| Quote: |
<nuckolls.bob(at)cox.net>
At 08:04 AM 9/26/2007 -0700, you wrote:
>Maybe I'm over stating the obvious, but what does split bus / dual
>electronic ignitions (DEI) and VFR have to do with each other?
absolutely nothing
> An engine failure is an engine failure! Yes it may be easier to deal
> with a failed engine VFR on a good day vs. low IFR. But isn't the idea
> here to make the two ignition systems independent of each other. I have
> several friends flying airplanes with DEI on the same electrical
> bus. To me that is a single point failure on many levels If the bus
> shorts or opens, the end result is you're a glider!
But these things don't happen in an artfully crafted
system. For example, you don't fly around expecting to
loose a prop or a wing . . . why is this?
> In my world of high speed race planes, I have seen more then one land
> out without ignition.
Probably because the designer was a go-fast expert and
not a fail-passive system designer. Fail passive says that
we can tolerate any single failure of a piece of hardware
and not suffer an uncomfortable landing.
> For me the only acceptable way to deal with DEI is to have two
> separate
> independent electrical sources and none of them an alternator as the
> primary source of power. My minim system requirements are two batteries
> on a separate bus with more than a simple gauge to show system state and
> at least one preferably two charging sources.
You're mired down in the notions that probability of
comfortable termination of flight is maximized by
having back-ups to back-ups. It doesn't need to be
that difficult. There's a simple process called the
failure mode effects analysis backed up by the
notion that you are exceedingly unlikely to experience
TWO failures of really useful items on any one tank
full of fuel.
Check out chapter 17 in the 'Connection and let's talk
about your proposed system with the idea of crafting
a logical, minimum parts count approach to a fail-passive
system.
Bob . . .
----------------------------------------
( "Problems are the price of progress. )
( Don't bring me anything but trouble. )
( Good news weakens me." )
( -Charles F. Kettering- )
----------------------------------------
|
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Peter H
Joined: 20 Mar 2007
Posts: 197
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| Posted: Wed Sep 26, 2007 12:55 pm Post subject: Dual Electronic Ignition |
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Mike,
Why not use the alternator as a separate source of power?
< For me the only acceptable way to deal with DEI is to have two separate independent electrical sources and none of them an alternator as the primary source of power. >
Mike >
Peter H
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nuckolls.bob(at)cox.net
Guest
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| Posted: Wed Sep 26, 2007 2:58 pm Post subject: Dual Electronic Ignition |
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At 02:17 PM 9/26/2007 -0600, you wrote:
| Quote: |
I agree with everything you said Bob.. I would add that many race planes
are in a constant state of systems redesign. In the quest for speed,
racers are always modifying one thing or other. Experimenting happens.
In a perfect world, that new "lightning strike ten thousand" ignition
system would be tried out one set of spark plugs at a time, and preferably
on an Ag Cat or Supercub (but using the same installation methods) where
the consequences of total failure might be lower than on one of the nearly
wingless wonders that they run at Reno. As it is, racers are pulling all
nighters gluing together systems for race week when they really should
have been snoozing for safety (IMO)..
|
Yup . . . a few years ago I was pasted here on the List
for being critical of a system design wherein the airplane
was forced into an expensive off-airport landing because
the alternator failed. I was considered "insensitive" to
the poor guy who suffered the expense and injury. The point
of my assertions had nothing to do with the individuals
involved or the outcome of their experience but the lack of
knowledge and forethought for preventing it in the first place.
I've participated in all manner of railway, automotive and
aviation accidents over the years and the focus is always
on the physics and/or shortcomings in design or procedure.
Lessons-learned is one of the more powerful teachers and sometimes
folks pay dearly for the education. All too often, individuals
with a particular expertise find themselves blind-sided by
relatively simple conditions . . . that reside outside their
particular areas of interest or expertise.
The most elegant system designs are always a team effort.
Bob . . .
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