Today's Message Index:
----------------------
1. 07:41 AM - Re: EXP 2 Bus workaround (Robert L. Nuckolls, III)
2. 10:47 AM - Re: iPad charger? (Eric M. Jones)
3. 11:31 AM - Re: EXP 2 Bus workaround (Robert L. Nuckolls, III)
4. 11:44 AM - Re: Re: iPad charger? (Robert L. Nuckolls, III)
5. 11:54 AM - Re: EXP 2 Bus workaround (Fred Klein)
6. 12:26 PM - Re: EXP 2 Bus workaround (Fred Klein)
7. 02:51 PM - Re: EXP 2 Bus workaround (Robert L. Nuckolls, III)
8. 03:11 PM - Re: EXP 2 Bus workaround (Robert L. Nuckolls, III)
9. 03:19 PM - Re: EXP 2 Bus workaround (Peter Pengilly)
10. 03:20 PM - Re: EXP 2 Bus workaround (Fred Klein)
11. 03:30 PM - Re: EXP 2 Bus workaround (Robert L. Nuckolls, III)
12. 03:31 PM - Re: EXP 2 Bus workaround (Robert L. Nuckolls, III)
13. 03:53 PM - Re: EXP 2 Bus workaround (Fred Klein)
14. 04:07 PM - Re: EXP 2 Bus workaround (Fred Klein)
Message 1
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Subject: | Re: EXP 2 Bus workaround |
>
>Bob...my reasoning behind the individual little back up batteries
>for Skyview EFIS and my back up GPS was not to address an immediate
>concern for main battery life, but rather to provide continued
>operation independent of the aircraft electrical system, be it
>powered by the "main bus" or the "endurance bus".
Yes, that's what backup batteries do . . .
>On the other hand, I thought that given the degree of my engine's
>dependence on electricity, it would be a good thing to lessen the
>load going thru the endurance bus...I've yet to quantify
>the implications of this, but conceptually, I thought it was a good move.
In a two-battery system, the engine never sees
the endurance bus; in a one-battery system, ditto.
The engine should run from a battery bus, preferably
one dedicated to the task.
>No question in my mind that I want to incorporate a robust endurance
>bus...a couple of years ago, a Europa pal, Paul McCallister, was
>struck by lightning, and continued flying for 90 minutes to your
>design which he'd followed which included an endurance bus as part
>of your Rotax 9XX diagram.
90 minutes . . . that's the first NUMBER that
has popped up in this discussion. Last week we had
some conversation here on the List with a fellow
who was going through much of the same questions
you are now . . . but with no answers based on
analysis and preventative maintenance as opposed
to "good moves".
The point being that the elegant system design
starts with energy budgets . . . we had some
discussion here on the List about the Dreaded
Downwind Turn and I promised to finish an
article on the topic. That problem also yields
to an analysis that identifies, quantifies and
then distributes a finite amount of energy to
a series of activities that produce the desired
end goal.
The outcome of that analysis promises to dispel
useless if not dangerous myths and gives us
opportunity to be better pilots based on the
numbers.
I used to occupy a booth at OSH right across
the isle from the guy selling EXP-Bus . . . or
something similar . . . I don't recall now. That
was 20 years ago. But I could hear his 'pitch'.
Even at that stage of advancement in my career,
I had to cringe at some of the superlatives
he used first to hook then reel in a prospective
customer. The word "emergency" was used with some
frequency along with claims for automation, labor
reduction, cost reduction, etc. etc. . . . all
GOOD things. But not once did he speak to sizing
batteries, alternators and particularly ARCHITECTURE
to a task, then knowing what the limits were for
expecting that task to terminate comfortably.
After all, he didn't sell alternators or batteries
(we were doing that across the isle). He was selling
architecture . . . and if he had any notion of how
is cookie-cutter architecture would tie the hands
of his customer's design process . . . that was not
part of the 'pitch.'
When we learn to fly, we're encourage to know, use
and respect numbers for Vx, Vy, Best Glide, Vne,
Stall Clean, Stall Dirty, Flap and gear extension
speeds, C.G., weight, mixture, manifold pressures,
increased drag in a turn, . . . all those numbers spread out
across the panel. But my instructor never mentioned
the value of KNOWING just how long I could fly
battery only and MAINTAINING that capability through
design and preventative maintenance.
For my instructor, the BEST notion for detecting
alternator failure was to pick up on the ammeter
reading . . . yeah, we all scan that thing, right?
For him, first notice that the alternator was dead
triggered an emergency situation . . . because he
wasn't sure how long it had been dead and he had
not the foggiest notion of how many minutes of
battery-only endurance was available. The best he
could hope for is to extend an unknown number by
turning off switches and pulling breakers . . .
in-flight systems analysis when the pilot SHOULD be
flying and navigating. It's the stuff from which
really good dark-n-stormy-night stories are
made.
I'll suggest that the EXP-Bus offers at most
a challenge for working around some relatively
minor architecture issues. But like the guy
who sits down to design a new airplane, we're
wrestling with the same quest for setting
design goals and then meeting them based on
the numbers.
The first number that would be of interest to
me in your airplane is how long can I run this
engine on a battery that who's service life is
25% used up? The next number is to deduce the
time you can run a minimalist list of electro-
whizzies that will get you to a comfortable
arrival . . . if not at your original destination
at least some place with convenient maintenance
services . . . not at Dead Cow International
50 miles from everywhere else.
The guy who sold you the engine should KNOW
how much energy it takes to run his product.
Not recommended wire or breaker size but WATTS
of total power consumption at full throttle . . .
and if draw is RPM dependent, then current
demands at throttle settings for maximum
endurance as well. Knowing those numbers at
both normal (14.6v) and end of battery life
(10.5v) would be required if I were designing
a TC aircraft . . . but no less important in
the OBAM aircraft.
These are the functional equivalents of "Vx, Vy
and Best Glide" numbers for your engine . . .
numbers a flight instructor would never be
expected to know but of intense interest to
somebody in your position.
A backup battery is a band-aid for not KNOWING
the capabilities of and demands on the main
battery. This is a kind of confession for saying
that while we can FLY the airplane with due
diligence to Vx, Vy and Best Glide . . . but
ignorant of battery-only endurance for the
engine or other accessories. Features necessary
us to demonstrate our skills as pilots.
My suggestion is to see how we can do a minimalist
effort to incorporate the EXP-Bus into something
like Z-19. Those are things we can discuss here
on the List because they deal with the architecture.
But whether or not you can toss out the notion of
'backup batteries' depends on your acquiring good
numbers and then folding those numbers into your
POH with as much confidence as you have for putting
the wheels down when and where you wanted them every
time.
QUESTION: Is there any value in having separate,
independent controls for ECU, Pumps and/or Ignition
in planning the partition between normal flight and
Plan-B? In other words, could Plan-A and Plan-B
configurations be controlled by a single switch?
In other words, let us consider switches. Under what
conditions would you want to turn any one thing ON
or OFF independently of other switches . . . or can
we combine functionality much like that which happens
when you turn the key in your car?
Bob . . .
Message 2
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Subject: | Re: iPad charger? |
Google: " How to make your own iPad 2 USB charger ". Looks straightforward, but
common to many chargers is the current limit which leads to fairly slow battery
charge. Still, it's pretty easy to do.
Rox Cox's post of http://www.amazon.com/gp/product/B0082CXEI8/ref=oh_details_o01_s00_i02?ie=UTF8&psc=1
Seems pretty good and carries good reviews.
Beware if you are years away from flying. USB-3 will be common soon (looks like
USB-2 with a blue insert tongue.
--------
Eric M. Jones
www.PerihelionDesign.com
113 Brentwood Drive
Southbridge, MA 01550
(508) 764-2072
emjones(at)charter.net
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=410425#410425
Message 3
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Subject: | Re: EXP 2 Bus workaround |
>90 minutes . . . that's the first NUMBER that
>has popped up in this discussion. Last week we had
>some conversation here on the List with a fellow
>who was going through much of the same questions
>you are now . . . but with no answers based on
>analysis and preventative maintenance as opposed
>to "good moves".
Some bullet points to touch on in the quest
for an elegant solution:
(1) See if the present avionics bus and it's associated
master switch can be re-configured for the master switch
to become an e-bus alternate feed switch by taking
the upstream-end of that switch to a fuse on the main
battery bus. Then jeep some flying leads onto the EXP-Bus
assembly to add a diode feed from the Main bus to the
new E-Bus.
(2) Explore the value of an Engine Bus Option A
and an Engine Bus Option B . . . an organization
of normal and standby engine loads that can be
controlled by a switch dedicated to each option.
(a) Determine whether or not it is unhealthy
or dangerous for both busses to be powered at the
same time.
(b) If so, what kind of mechanism would allowing
either option to be selected OFF or ON indiviudally
but never simultaneously.
(c) Conduct a failure modes effects analysis to
deduce the single point failure items for engine
operation.
(3) Get real life numbers on the power required to
power either of these options.
(4) Consider bringing the alternator B-Lead to a stud on
a fire wall mounted contactor.
Answer to (2) will drive further suggestions for
eliminating a number of switches and improving on
the probability for smooth conversion of a failure
event to be no-big-deal.
Bob . . .
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Subject: | Re: iPad charger? |
At 12:46 PM 10/13/2013, you wrote:
>
>Google: " How to make your own iPad 2 USB charger ". Looks
>straightforward, but common to many chargers is the current limit
>which leads to fairly slow battery charge. Still, it's pretty easy to do.
>
>Rox Cox's post of
>http://www.amazon.com/gp/product/B0082CXEI8/ref=oh_details_o01_s00_i02?ie=UTF8&psc=1
>
There is a link to a Wikipedia article in the
comments for this device. See:
http://tinyurl.com/l3krbv7
The article clears up some of the questions
about why some devices balk at being conneted
to just any ol' USB charger and others do not
seem to care. There's further discussion about
a device having a conversation with the USB
host to see if and when a high power mode of
charging can be negotiated.
Interesting stuff. I've archived the article
for further study.
Bob . . .
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Subject: | Re: EXP 2 Bus workaround |
Bob...thank you so much for your continued assistance in sorting out my ship's
electrical issues...I have some unrelated things to do today, but will continue
this conversation tomorrow after I've been able to quantify at least some of
the considerations you've raised...and if it makes sense to throw the EXP Bus
under the bus, I'm certainly willing to do so.
Cheers,
Fred
>> 90 minutes . . . that's the first NUMBER that
>> has popped up in this discussion. Last week we had
>> some conversation here on the List with a fellow
>> who was going through much of the same questions
>> you are now . . . but with no answers based on
>> analysis and preventative maintenance as opposed
>> to "good moves".
>
> Some bullet points to touch on in the quest
> for an elegant solution:
>
Message 6
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Subject: | Re: EXP 2 Bus workaround |
On Oct 13, 2013, at 7:40 AM, Robert L. Nuckolls, III wrote:
> The engine should run from a battery bus, preferably
> one dedicated to the task.
Bob...I accept this without reservation...and I regret that in my
attempts to work out a scheme which put my EPS Bus to good use and
honored the concepts embedded in your Z-19 resulted in a circuit diagram
which led me so far astray from this concept.
As I study Z-19, I'm noting the multiple busses fed from the two battery
contactors and the nominal sizing of the wires (12 AWG, w/ the caveat
that they be no longer than 6 inches) to the 2 battery busses.
I will determine the connected load on each of 2 battery busses which
would be devoted to keeping the engine running...(fuel pumps, ECU, fuel
injectors, coils) and the required size of their feeders.
Feeding these multiple busses w/ my 2 batteries in the tailcone seems
problematic if the contactors are adjacent to the batteries. I'd queried
you a while back about the implications of mounting the contactors on
the fire wall w/ the batteries in the rear...about 10 feet away...you
mentioned this is not common practice and (I believe you said that) it
poses unwanted risks.
Can those risks be mitigated by some kind of fusible links back at the
batteries?...or is it just plainly a dumb idea to separate bat from
contactor?
Would not the feeders to the (hot) battery busses carry the same risks?
Fred
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Subject: | Re: EXP 2 Bus workaround |
At 01:53 PM 10/13/2013, you wrote:
>
>Bob...thank you so much for your continued assistance in sorting out
>my ship's electrical issues...I have some unrelated things to do
>today, but will continue this conversation tomorrow after I've been
>able to quantify at least some of the considerations you've
>raised...and if it makes sense to throw the EXP Bus under the bus,
>I'm certainly willing to do so.
Let's not get too carried away . . . as
far as I know, the EXP-Bus performs as
advertised.
Many of its features could not be qualified
onto TC aircraft. Other features are just
plain awkward from a cost of ownership
perspective.
However, unlike other 'flashes in the
pan' of OBAM aviation history, the EXP-Bus is
still with us . . . and to my knowledge, it's not
set anyone's airplane on fire or played the
staring character in a dark-n-stormy night story.
The exercise for sifting of FMEA bits and
adding up all the numbers is 90% common to
any other suite of hardware. So before we
abandon the $time$ you already have invested,
let's consider ways to round off the rough
edges without pushing your fly-date out
unnecessarily.
By the way, does anyone on the List have an
EXP-Bus 2 that is un-installed that they
could photograph from all perspectives to
share with the List? Don't need pictures
of the remote boxes . . . just the power
distribution and switching assembly.
Fred, your lighting and image quality was
excellent but this view . . .
Emacs!
is a bit cluttered in the foreground. I'd liked to see
how this puppy is assembled and wired . . . If anyone
is taking new pictures, avoid flash and/or direct lighting,
sky-light shaded from direct sun provides excellent, shadow
and high-light free illumination for illustrating the deeper
secrets.
No hurry, we don't have a dragon to slay. I need to
spend some time on Carlos' V-Power system integration
questions.
Bob . . .
Message 8
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Subject: | Re: EXP 2 Bus workaround |
At 02:26 PM 10/13/2013, you wrote:
On Oct 13, 2013, at 7:40 AM, Robert L. Nuckolls, III wrote:
The engine should run from a battery bus, preferably
one dedicated to the task.
Bob...I accept this without reservation...and I regret that in my
attempts to work out a scheme which put my EPS Bus to good use and
honored the concepts embedded in your Z-19 resulted in a circuit
diagram which led me so far astray from this concept.
Lets turn this into an inconvenience as opposed to
a $time$ disaster . . .
As I study Z-19, I'm noting the multiple busses fed from the two
battery contactors and the nominal sizing of the wires (12 AWG, w/
the caveat that they be no longer than 6 inches) to the 2 battery busses.
I will determine the connected load on each of 2 battery busses which
would be devoted to keeping the engine running...(fuel pumps, ECU,
fuel injectors, coils) and the required size of their feeders.
Feeding these multiple busses w/ my 2 batteries in the tailcone seems
problematic if the contactors are adjacent to the batteries. I'd
queried you a while back about the implications of mounting the
contactors on the fire wall w/ the batteries in the rear...about 10
feet away...you mentioned this is not common practice and (I believe
you said that) it poses unwanted risks.
Can those risks be mitigated by some kind of fusible links back at
the batteries?...or is it just plainly a dumb idea to separate bat
from contactor?
Would not the feeders to the (hot) battery busses carry the same risks?
Let's get the numbers and all the players identified
first. I'm not so sure that you're rear-mounted batteries
pose much of a design problem.
How many pumps? Dual fuel injectors? Seems unlikely.
You said you have one plug per cylinder . . . but
if you have a distributor-less system, then you have
coil-paks that do not lend themselves neatly to
combining dual ignition through high voltage diodes
like the Corvair guys do.
So draw a box with a propeller on it and identify
each device that consumes power in order to keep
the engine running. Differentiate which items are
use in 'normal mode', which are used in 'backup mode'
and which are used in both modes.
This part of the task is like assembling an arithmetic
logic unit from a handful of gates . . . I need to
have a handle on the logic before we start stringing
wire and punching holes for switches.
Bob . . .
Message 9
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Subject: | Re: EXP 2 Bus workaround |
Yeah - I can do that tomorrow - its a little butchered from the removal
process, but I think it will provide the information you require.
Peter
On 13/10/2013 22:50, Robert L. Nuckolls, III wrote:
> By the way, does anyone on the List have an
> EXP-Bus 2 that is un-installed that they
> could photograph from all perspectives to
> share with the List? Don't need pictures
> of the remote boxes . . . just the power
> distribution and switching assembly.
Message 10
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Subject: | Re: EXP 2 Bus workaround |
On Oct 13, 2013, at 2:50 PM, Robert L. Nuckolls, III wrote:
> By the way, does anyone on the List have an
> EXP-Bus 2 that is un-installed that they
> could photograph from all perspectives to
> share with the List?
Bob...I can have mine out in a jif...Fred
Message 11
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Subject: | Re: EXP 2 Bus workaround |
At 05:19 PM 10/13/2013, you wrote:
><peter@sportingaero.com>
>
>Yeah - I can do that tomorrow - its a little butchered from the
>removal process, but I think it will provide the information you require.
>
>Peter
Super!
Bob . . .
Message 12
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Subject: | Re: EXP 2 Bus workaround |
At 05:20 PM 10/13/2013, you wrote:
>On Oct 13, 2013, at 2:50 PM, Robert L. Nuckolls, III wrote:
>
>>By the way, does anyone on the List have an
>> EXP-Bus 2 that is un-installed that they
>> could photograph from all perspectives to
>> share with the List?
>
>Bob...I can have mine out in a jif...Fred
Okay! Lets have your pix too. Top, bottom,
angles . . .
Does the mfgr provide anything in the way
of a printed schematic?
Bob . . .
Message 13
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Subject: | Re: EXP 2 Bus workaround |
Bob...will these photos serve?...have I missed anything?
The smaller item w/ the ribbon is the companion Indicator Module...Peter
sez it has an excellent dimmer...
Yes...a printed schematic is available:
http://support.anywheremap.net/pdfs/EXP2-C.pdf
Fred
DSCN7164.JPG
DSCN7166.JPG
DSCN7168.JPG
DSCN7169.JPG
DSCN7170.JPG
DSCN7171.JPG
Message 14
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Subject: | Re: EXP 2 Bus workaround |
Bob...I wrote,
Yes...a printed schematic is available:
http://support.anywheremap.net/pdfs/EXP2-C.pdf
I've been referring to the diagram labeled "Typical Installation;
External Solenoid"
Also, there is a diagram depicting a Subaru installation w/ 2 circuits
set up for a back up battery connection; however, I've given scant
attention to it because I have no reason to believe that it addresses
is:sues related to fuel injection:
http://support.anywheremap.net/pdfs/expsub.PDF
...hope this is useful to your anlysis...
Fred
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