Today's Message Index:
----------------------
1. 03:21 AM - Re: Re: AutoPilot Disconnect Brain Teaser - 05/12/03 (M.J. Gregory)
2. 04:32 AM - Noise ()
3. 04:40 AM - Re: OV circuit breaker tripping (Cy Galley)
4. 05:44 AM - Re: Dual electronic ignition - revisited again (John Schroeder)
5. 06:19 AM - non-Microprocessor based Fuel Gauge Linearizer (Eric M. Jones)
6. 06:37 AM - Re: AutoPilot Disconnect Brain Teaser - (Eric M. Jones)
7. 06:52 AM - Cheap blind encoder. (Ian Scott)
8. 07:06 AM - Re: Noise (Robert L. Nuckolls, III)
9. 07:15 AM - Re: non-Microprocessor based Fuel Gauge (Robert L. Nuckolls, III)
10. 07:17 AM - Re: Re: AutoPilot Disconnect Brain Teaser - (Robert L. Nuckolls, III)
11. 07:19 AM - Radio Noise Redux (William Yamokoski)
12. 07:52 AM - Diode failures and "Reliable Systems" [ was Re: Radio Noise Redux] (David Carter)
13. 07:58 AM - Re: Dual electronic ignition - revisited (Robert L. Nuckolls, III)
14. 08:07 AM - Re: 100 % Solution (diode-fed supportbatt-was Avionics bus) (Eric M. Jones)
15. 08:41 AM - Interference (PTACKABURY@aol.com)
16. 08:51 AM - Re: Dual electronic ignition - revisited again (Jim Pack)
17. 09:02 AM - SD-8 Alternator Questions (Phil Birkelbach)
18. 09:14 AM - Re: Dual electronic ignition - revisited (Robert L. Nuckolls, III)
19. 09:14 AM - Re: Dual electronic ignition - revisited again (Geoff Evans)
20. 09:29 AM - Re: non-Microprocessor based Fuel Gauge Linearizer (Jerzy Krasinski)
21. 09:35 AM - Re: Re: AutoPilot Disconnect Brain Teaser - (Rob Housman)
22. 09:38 AM - Re: AutoPilot Disconnect Brain Teaser - (Eric M. Jones)
23. 10:45 AM - non-Microprocessor based Fuel Gauge Linearizer (Eric M. Jones)
24. 10:51 AM - Static when Refuelling re Braid (Fergus Kyle)
25. 11:18 AM - Re: Diode failures and "Reliable Systems" (Robert L. Nuckolls, III)
26. 11:28 AM - Re: SD-8 Alternator Questions (Robert L. Nuckolls, III)
27. 11:32 AM - Re: Cheap blind encoder. (Robert L. Nuckolls, III)
28. 11:50 AM - Wig wag (Bob Kuc)
29. 12:24 PM - Re: Cheap blind encoder. (DHPHKH@aol.com)
30. 12:32 PM - Re: Re: Flap system failure modes (Was circuit protection issues) (Gilles.Thesee)
31. 01:11 PM - Re: OV circuit breaker tripping (John Karnes)
32. 01:32 PM - Re: SD-8 Alternator Questions (Phil Birkelbach)
33. 02:21 PM - Re: Flap system failure modes (Was circuit protection issues) (Robert L. Nuckolls, III)
34. 02:24 PM - Re: Wig wag (Robert L. Nuckolls, III)
35. 02:53 PM - Re: Wig wag (Bob Kuc)
36. 04:16 PM - Re: Cheap blind encoder. (Greg Young)
37. 04:26 PM - Re: Static when Refuelling re Braid (Kent Ashton)
38. 04:31 PM - Re: Wig wag (Robert L. Nuckolls, III)
39. 04:44 PM - Re: SD-8 Alternator Questions (Robert L. Nuckolls, III)
40. 05:08 PM - Re: SD-8 Alternator Questions (Rob Housman)
41. 05:21 PM - Re: Static when Refuelling re Braid (Charlie & Tupper England)
42. 06:23 PM - Re: Avogadro's Number (Robert L. Nuckolls, III)
43. 06:51 PM - encoder wiring (Dave Ford)
44. 07:02 PM - Re: encoder wiring (BobsV35B@aol.com)
45. 07:34 PM - Re: Re: Avogadro's Number (Don Boardman)
46. 07:42 PM - Re: Re: Avogadro's Number (Rob Housman)
47. 08:48 PM - Re: OV circuit breaker tripping (Robert L. Nuckolls, III)
48. 09:25 PM - Re: Cheap blind encoder. (Robert L. Nuckolls, III)
49. 09:27 PM - Re: encoder wiring (Robert L. Nuckolls, III)
50. 10:05 PM - Re: non-Microprocessor based Fuel Gauge (Robert L. Nuckolls, III)
51. 10:14 PM - Re: AutoPilot Disconnect (Robert L. Nuckolls, III)
52. 10:47 PM - Re: non-Microprocessor based Fuel Gauge Linearizer (John Rourke)
Message 1
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| Subject: | Re: AutoPilot Disconnect Brain Teaser - 05/12/03 |
--> AeroElectric-List message posted by: "M.J. Gregory" <m.j.gregory@talk21.com>
Bob
I was waiting for you to shake the cube and let all those one billion balls
settle so that you could add some more. I understand that stacking balls
pyramid-style can fill some 74 percent of the volume. This compares with
the 52.3 percent you have by stacking them in one-million-ball layers. The
ratio of these figures is approximately sq root 2, but I don't know if this
is the mathematically precise relationship.
I therefore calculate that you should be able to get some 1,410,000,000
balls into your cube, increasing their surface area to 4,430 sq in.
While there would be only a very little direct see-through area round the
sides with this arrangement, I shall leave it to others to calculate the
reduction in cross sectional area for your liquid flowing through from one
face to another. I suspect it would again be a factor of approximately sq
root 2.
Happy calculations.
Mike
m.j.gregory@cranfield.ac.uk
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III"
<bob.nuckolls@cox.net>
At 03:10 PM 5/13/2003 -0500, you wrote:
>--> AeroElectric-List message posted by: "Phil Birkelbach"
><phil@petrasoft.net>
>
> > Take an array of steel balls 0.001" in diameter
> > and stack them into 1 cubic inch of volume. How
> > many balls does it take to fill the cube? What
> > is the total surface area of all balls contained
> > in the cube? What is the open (see-through) area
> > of the space between the balls for any liquid
> > that passes into one face and out the opposite face?
> >
> > Bob . . .
> >
>You'll need 1,000
3 steel balls or...
>
>1,000,000,000 balls
>
>The surface area of a sphere is... 4*pi*r
2
>
>So the area of one ball... 3.141592E-6 sq in
>So the area of a billion balls... 3,141.5 sq in or 21.8166 sq ft
>which is about 2/3 the area of a piece of plywood.
That's the part that really surprises folks . . . that
a 1" cube could have that much surface area contained
within.
>Now for the second part the wetted area...
>
>It would be 1 sq in - the area of a million circles...
>
>area of a circle = pi * r
2
>
>Area of a 0.001" diameter circle = 7.85398E-7 sq in
>Area of a million of them would be... 0.785398 sq in
>so the see through area would be... 0.214602 sq in
yup . . .
>Of course this all assumes that we stack the balls in a rectangular pattern
>1,000 balls to an edge, and the 1 cubic inch volume is a 1" x 1" x 1" cube,
>if it is anything more sinister than that then I don't have time to look it
>up. :-)
yeah, getting all those balls to set in there un-nested
takes some REAL patience.
Bob . . .
Message 2
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--> AeroElectric-List message posted by: <danobrien@cox.net>
Slightly off topic, but if analogies exist for noise in aircraft, perhaps the answer
will be instructive nonetheless. I am finishing a new room in my house
where I want to run a cable connection for a cable modem. The preferred route
runs the cable wire along a 240 volt circuit for an air conditioner/heat pump
unit. Is there any issue with the 240 volt wire creating interference in the
cable line?
Thanks,
Dan
Message 3
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| Subject: | Re: OV circuit breaker tripping |
--> AeroElectric-List message posted by: "Cy Galley" <cgalley@qcbc.org>
How about high temps melting or softening some wire insulation so it the
wire is rubbing some metal. I would check down stream from the CB with an
ohm meter.
Cy Galley - Bellanca Champion Club
Newsletter Editor & EAA TC
www.bellanca-championclub.com
Actively supporting Aeroncas
----- Original Message -----
From: "Robert L. Nuckolls, III" <bob.nuckolls@cox.net>
Subject: Re: AeroElectric-List: OV circuit breaker tripping
> --> AeroElectric-List message posted by: "Robert L. Nuckolls, III"
<bob.nuckolls@cox.net>
>
> At 09:10 PM 5/13/2003 -0700, you wrote:
> >--> AeroElectric-List message posted by: "John Karnes"
<jpkarnes@charter.net>
> >
> > > >Sounds like a dead short.
> > > >It would pull down the voltage and the excess amperage would trip the
> > > >breaker.
> > >
> > > I agree . . . check to make sure your diode on
> > > the b-lead contactor isn't hooked up backwards
> > > or shorted.
> >
> >How do I check to see if the diode is shorted? I know it's not backwards
as
> >I haven't changed it and it was working fine before.
>
> Use your ohmmeter to check the resistance across the diode.
> If it (or something else on the line is shorted) it will
> read very low (less than 1 ohm) no matter which way you
> attach the leads.
>
> > Could the high heat in
> >the engine compartment have caused this? (I'm talking HIGH heat!)
>
> Not likely.
>
> Bob . . .
>
> --------------------------------------------
> ( Knowing about a thing is different than )
> ( understanding it. One can know a lot )
> ( and still understand nothing. )
> ( C.F. Kettering )
> --------------------------------------------
>
>
Message 4
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| Subject: | Re: Dual electronic ignition - revisited again |
--> AeroElectric-List message posted by: John Schroeder <jschroeder@perigee.net>
Geoff -
IMHO, look at the Z-14 with two 17 AH batteries. No question as to
suitability for dual electronic ignition systems.
> I'm trying to avoid the added weight of two full-size batteries, and I
> really
> like the idea of having the SD-8 as a backup alternator instead. I'm also
> trying to avoid the complexity of having a backup battery just for half
> of a
> dual ignition system -- if that's even a logical position to take.
>
> Can you put an end to the ambiguity (read: my confusion) one and for all?
>
> Thanks much!
> -Geoff
>
Message 5
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| Subject: | non-Microprocessor based Fuel Gauge Linearizer |
--> AeroElectric-List message posted by: "Eric M. Jones" <emjones@charter.net>
There has been some discussion of this, and I have not gotten very far on my plans
to build one. Since I have no shortage of stuff to make (Hey Bob, Re: Other
Life, just use you wife's washing machine for the 30G centrifuge. The spin cycle
should do 30Gs and you won't hit anybody when the thing comes apart. Paint
it gray, stick a NASA label over the Kenmore label, and you're all set! Total
cost--Old Washer, Paint, Logo....let's see.).
Here's the non-microprocessor plan for the linearizer: (As they say in school,
the exercise is left up to the reader).
1) Know the true final volume of the tank.
1) Assume the graph of Fuel Volume (Y) and Fuel Gauge Reading (x) is everywhere
a negative slope. (Not necessarily true in all cases, but then it's hopeless.)
Draw yourself a sample graph. It looks like a downhill ski run. Remember--all
negative slopes!
2) Let's assume that a four-segment straight-line approximation is adequate for
the job, divide up the X-axis into four parts and using the intersections of
the divisions with the downhill ski run, connect the dots to make four line segments.
3)---A small pause here---The purpose of the four line segments is to model the
ski-run curve of declining fuel volume versus fuel gauge reading (note that the
linearity of the sender AND the panel meter can be included as one variable).
The SLOPE (deltaX/deltaY) of these segments is going to be the voltage amplification
of four teeny little op amps that will read these parts of the curve.
It is useful to note that the way the x-axis is divided up should reflect the
geometry of the tank and the linearity of the gauge and sender. That is, in
a smoothly arcing curve, maybe simply quartering the x-axis is fine, but when
the reading error is mostly in one place, the line segments that model it should
be concentrated there. This make the job simpler, but you can make this basic
technique as complicated as you want.
4) Now having the four teeny little op amps (Quad Op Amp LM324), you add four teeny
little adjustment pots to set the slopes (gains), and a quad comparator LM339
to tell the output which one of the Op Amps is valid. There are some other
parts in this mix---
--An I-V converter chip for the input and a V-I converter chip for the output.
Is there a way to avoid this?
--A good averaging anti-slosh filter on the input. Easy...
--Low fuel setpoint alarm?
Now if someone wants to work on this. The total BOM should be less than $20. The
entire assembly in surface mount will be 1" X 1.5" X 3/8", it will weight <1
ounce, it will operate up to 30 VDC.
Here's my offer: If someone wants to build this on a proto board, design the schematic,
and do some work on it--I will build her two samples of the real thing
in surface mount. The reality of the internet is that we can design things with
world-wide brains and resources in a cooperative venture. Let's get together
on this!
Regards,
Eric M. Jones
"When dealing with the enemy, it helps if he thinks you're a little bit crazy."
--Gen. Curtis LeMay
Message 6
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| Subject: | Re: AutoPilot Disconnect Brain Teaser - |
--> AeroElectric-List message posted by: "Eric M. Jones" <emjones@charter.net>
The packing fraction for face-centered cubic packing is rho0.7405. Adjust results
accordingly.
Eric
Message 7
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| Subject: | Cheap blind encoder. |
--> AeroElectric-List message posted by: "Ian Scott" <jabiru22@yahoo.com.au>
HI All,
I a getting a Micro air transponder, and was wondering what I should do
for encoder and antenna, in a glass plane
Ian
Message 8
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--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <bob.nuckolls@cox.net>
At 07:31 AM 5/14/2003 -0400, you wrote:
>--> AeroElectric-List message posted by: <danobrien@cox.net>
>
>Slightly off topic, but if analogies exist for noise in aircraft, perhaps
>the answer will be instructive nonetheless. I am finishing a new room in
>my house where I want to run a cable connection for a cable modem. The
>preferred route runs the cable wire along a 240 volt circuit for an air
>conditioner/heat pump unit. Is there any issue with the 240 volt wire
>creating interference in the cable line?
>
>Thanks,
>Dan
No, "noises" from the power wiring in a house are relatively low
frequency (60 hz and harmonics plus noises generated by appliances)
while your cable modem works at hundreds of megahertz inbound traffic
and tens of megahertz outbound. Further, house wiring is carried
on parallel pairs . . . for every electron going one way there is
a companion headed the other way in close proximity . . . net result
is that magnetic fields (strongest noise coupling mode) cancel
each other.
Bob . . .
--------------------------------------------
( Knowing about a thing is different than )
( understanding it. One can know a lot )
( and still understand nothing. )
( C.F. Kettering )
--------------------------------------------
Message 9
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| Subject: | Re: non-Microprocessor based Fuel Gauge |
Linearizer
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <bob.nuckolls@cox.net>
At 09:21 AM 5/14/2003 -0400, you wrote:
>--> AeroElectric-List message posted by: "Eric M. Jones" <emjones@charter.net>
>
>There has been some discussion of this, and I have not gotten very far on
>my plans to build one. Since I have no shortage of stuff to make (Hey Bob,
>Re: Other Life, just use you wife's washing machine for the 30G
>centrifuge. The spin cycle should do 30Gs and you won't hit anybody when
>the thing comes apart. Paint it gray, stick a NASA label over the Kenmore
>label, and you're all set! Total cost--Old Washer, Paint, Logo....let's see.).
>
>Here's the non-microprocessor plan for the linearizer: (As they say in
>school, the exercise is left up to the reader).
>1) Know the true final volume of the tank.
>1) Assume the graph of Fuel Volume (Y) and Fuel Gauge Reading (x) is
>everywhere a negative slope. (Not necessarily true in all cases, but then
>it's hopeless.) Draw yourself a sample graph. It looks like a downhill ski
>run. Remember--all negative slopes!
>2) Let's assume that a four-segment straight-line approximation is
>adequate for the job, divide up the X-axis into four parts and using the
>intersections of the divisions with the downhill ski run, connect the dots
>to make four line segments.
>3)---A small pause here---The purpose of the four line segments is to
>model the ski-run curve of declining fuel volume versus fuel gauge reading
>(note that the linearity of the sender AND the panel meter can be included
>as one variable). The SLOPE (deltaX/deltaY) of these segments is going to
>be the voltage amplification of four teeny little op amps that will read
>these parts of the curve. It is useful to note that the way the x-axis is
>divided up should reflect the geometry of the tank and the linearity of
>the gauge and sender. That is, in a smoothly arcing curve, maybe simply
>quartering the x-axis is fine, but when the reading error is mostly in one
>place, the line segments that model it should be concentrated there. This
>make the job simpler, but you can make this basic technique as complicated
>as you want.
>4) Now having the four teeny little op amps (Quad Op Amp LM324), you add
>four teeny little adjustment pots to set the slopes (gains), and a quad
>comparator LM339 to tell the output which one of the Op Amps is valid.
>There are some other parts in this mix---
>--An I-V converter chip for the input and a V-I converter chip for the
>output. Is there a way to avoid this?
>--A good averaging anti-slosh filter on the input. Easy...
>--Low fuel setpoint alarm?
>
>Now if someone wants to work on this. The total BOM should be less than
>$20. The entire assembly in surface mount will be 1" X 1.5" X 3/8", it
>will weight <1 ounce, it will operate up to 30 VDC.
>
>Here's my offer: If someone wants to build this on a proto board, design
>the schematic, and do some work on it--I will build her two samples of the
>real thing in surface mount. The reality of the internet is that we can
>design things with world-wide brains and resources in a cooperative
>venture. Let's get together on this!
I've built multi-slope analog systems like this. Did
a feel-spring actuator controller for some model of a Cessna
way back when that needed to adjust compression on a spring
cartridge based on IAS and a second order transfer function.
I think we did it with three op amps (two breaks in the curve).
That was the best we COULD do then, can't recommend it today.
There are microcontrollers for under $5 with built in D/A
and enough memory to hold program and scratch pad for
this kind of task. The HARDest part is building a user
i/o interface so that the end user can plug in a laptop
and adjust the lookup table to fit his airplane.
If there are enough folks really interested in this,
I have some byte-wienies out at RAC that could make this
play in software. The board layouts are rudimentary.
Bob . . .
>Regards,
>Eric M. Jones
>
>"When dealing with the enemy, it helps if he thinks you're a little bit
>crazy."
>--Gen. Curtis LeMay
>
>
Bob . . .
--------------------------------------------
( Knowing about a thing is different than )
( understanding it. One can know a lot )
( and still understand nothing. )
( C.F. Kettering )
--------------------------------------------
Message 10
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| Subject: | Re: AutoPilot Disconnect Brain Teaser - |
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <bob.nuckolls@cox.net>
At 09:38 AM 5/14/2003 -0400, you wrote:
>--> AeroElectric-List message posted by: "Eric M. Jones" <emjones@charter.net>
>
>The packing fraction for face-centered cubic packing is rho0.7405. Adjust
>results accordingly.
>
>Eric
You threw me a new one there Eric. Care to describe "packing fraction"
in 25 words or less? ;-)
Bob . . .
--------------------------------------------
( Knowing about a thing is different than )
( understanding it. One can know a lot )
( and still understand nothing. )
( C.F. Kettering )
--------------------------------------------
Message 11
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| Subject: | Radio Noise Redux |
--> AeroElectric-List message posted by: "William Yamokoski" <yamokosk@lmc.cc.mi.us>
Hi Folks,
I've made a bit of progress on the noises I was hearing in my headsets. My
main problem continues to be on the transmission side...sometimes fine, sometimes
unintelligable. The intermittent nature of the beast is the most frustrating
part. I've never been able to hear what people are reporting, but i think
I've been able to duplicate what they tell me they hear.
The MicroAir is powered from the essential bus, which in turn gets its power
from the main bus via a diode as per Bob's drawings. With engine off, main
contactors on, pushing the PTT results in a normal feedback in the headsets.
When I start adding to the current load (e.g., Naviad, GPS, transponder) things
get a little dicey. I start hearing terrible noises in the headset, but only
very intermittently. When I then turn on one of the big current loads
like the pitot heat or strobes, pushing the PTT switch switch gives me continuous
loud growling sounds....voice can barely be made out. At this point the
Grand Rapids EIS is showing 11.9 v or thereabouts.
This at least seems logical. The radio doesn't get enough electrons, I guess,
to tranmit properly. The problem is, why might this be happening with the
engine on in flight? Yesterday in flight someone reported my transmission
as unreadble, with loud background noise. At that time the EIS read 14.5 v.
Twenty minutes earlier I got a report that my transmission was clear, with a
small amount of background static.
Could there be a problem with the diode? I'm not sure if they fail in an all-or-nothing
way or if you can see a "partial." failure. I've used Bob's idea
of hooking two 6 volt batteries together to power the radio separately from
the busses. That helped me in isolating some of the the odd noises I was getting
in the headset. However, I've never used those batteries to power the
radio in flight. It seems like it would be easy enough to test-out this diode
theory...just by-pass the thing and power the essential bus with a simple wire
from the main bus for a while. But am I barking up the wrong tree here?
Another Glastar/Subaru owner has replaced his diode due to a failure. Any
thoughts appreciated.
Thanks
Bill Yamokoski
Message 12
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Noise Redux]
--> AeroElectric-List message posted by: "David Carter" <dcarter@datarecall.net>
----- Original Message -----
From: "William Yamokoski" <yamokosk@lmc.cc.mi.us>
Subject: AeroElectric-List: Radio Noise Redux
> --> AeroElectric-List message posted by: "William Yamokoski"
<yamokosk@lmc.cc.mi.us>
>
> Hi Folks,
<snip> The MicroAir is powered from the essential bus, which in turn gets
its power from the main bus via a diode as per Bob's drawings. <snip>
> Could there be a problem with the diode? I'm not sure if they fail in
an all-or-nothing way or if you can see a "partial." failure <snip> It seems
like it would be easy enough to test-out this diode theory...just by-pass
the thing and power the essential bus with a simple wire from the main bus
for a while. But am I barking up the wrong tree here? Another
Glastar/Subaru owner has replaced his diode due to a failure. Any thoughts
appreciated.
> Thanks
> Bill Yamokoski
Diodes. . . . . I get a little excited when I hear stories of diodes
failing.
I've quoted the relevant parts above.
Now, my anecdote, prior to asking a ques: Anecdote: While Avionics Officer
for an A-7D unit, one of the Big Eight test stations (each of the eight
costing about $1 million each) suffered a diode "short" on a circuit card.
This simple 2 cent piece failed - resulting in high current flow in that
circuit, which was not protected - designers didn't consider the diode
failure mechanism. Well, the high current cascaded throughout the test
station and resulted in something like a lightning strike on the entire test
station. We spent months and LOTS of unit funds repairing that test
station.
Now, I'm in the role of home builder-designer of my RV-6 electrical system.
And we've been talking many months about an Endurance Bus, with a diode
allowing power to flow to the E-bus from the main bus, and to prevent
battery drain from the E-bus to the main bus when main bus is shut down for
alternator failure.
A diode.
I'll bet those who work in this field have other stories about diode
failures.
Are there some diodes that are better (more durable, longer lasting) than
other diodes?
What level of "diode spec" ought to be sufficient to avoid "typical" diode
failures? Is "bigger" better?
What are diodes most sensitive to? (that would cause them to fail)
If I can't "rely" on the diode between Main & E busses, then I might
consider "adding parts count" to detect failure of this critter; or special
pilot operating procedures to use voltmeter wired to specific, switch
selectable places, with opening and closing of e-bus switch or other means
of verifying, on every flight, that the diode is function correctly. (Do I
smell my own paranoia oozing out?)
David Carter
Message 13
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| Subject: | Re: Dual electronic ignition - revisited |
again
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <bob.nuckolls@cox.net>
At 09:55 PM 5/13/2003 -0700, you wrote:
>--> AeroElectric-List message posted by: Geoff Evans
><hellothaimassage@yahoo.com>
>
>Hi Bob.
>
>I thought I was all squared away after our message exchange of a few months
>ago, but some recent postings of yours on the list have rekindled my
>confusion.
>
>Our prior conversations were about using the Z-13 architecture for dual
>electronic ignitions, and whether the Z-13 system was any more likely to
>result in an electrically-caused engine failure (with dual electronic
>ignitions) than a something like a Z-11 system with an aux battery. At the
>time, I was confused by some prior postings and some seemingly conflicting
>language in your book.
>
<snip>
>"We at Aeroelectric Connection do not advocate using the Z-13 architecture
>for an aircraft with dual electronic ignitions. We prefer dual batteries
>instead."
>
>or...
>
>"We at the Aeroelectric Connection believe that the Z-13 architecture does
>not have any greater chance of total electrical failure than a Z-11 system
>with an aux battery. In fact, we think it's a better option, and it's
>perfectly viable for use with dual electronic ignitions."
Let's review some simple-ideas which you need to
ponder to answer the question for yourself:
(1) If a system has but one battery and no alternators
proven to be stand-alone providers of electrical energy
then there IS risk of loosing the whole system should the
one battery become unavailable.
(2) If you have an electrically dependent engine with stand-alone
backups (like dual ignition) then to preserve as much of the
independent qualities of the dual systems, then two power
sources capable of operation independent of each other are
indicated.
(3) If one of those power sources cannot be an alternator, the
two batteries are indicated.
(4) Obviously, if one of the batteries is tasked only with
supporting one ignition system, then it's capacity could
be sized to some value that supports ignition for duration
of fuel aboard.
(5) If a second, small battery is part of your planning,
it need not be tied to the system with a heavy contactor.
The original Aux Battery Management Module article spoke
of an "Ignition" Battery Management Module and suggested
a hefty power relay making connection with the main bus
to keep a small battery charged. This relay was NOT closed
during cranking to assist the main battery in getting the
engine started.
(6) If the light weight and low cost of the SD-8 as a
second engine drive power source is attractive to you
then there's no reason why you couldn't take advantage of
it using Figure Z-13 but it has little relevance to the
reliability considerations for the dual electronic ignitions.
It would be handy if it worked when the main alternator
quits but it's not NECESSARY for comfortable completion
of flight and would assure power to at least one
ignition in the face of multiple failures (very
unlikely).
(7) You might consider a Z-13 system with the aux battery
connected so as to parallel with the main battery for
normal ops and battery charging. If the aux battery management
module is attractive to you, I might drive it from the
e-bus so that during main alternator out operations,
it would allow the second battery to stay connected to
the main battery only if the SD-8 were working and
not overloaded because too much stuff is turned on.
(8) Now, likelihood of finding yourself without enough
engine driven power to keep necessary goodies running
is on same order as wing or propeller falling off.
Even if you loose the battery contactor or wiring
to the main battery, you've still got a small battery
that would stabilize the SD-8 for unlimited endurance
operations from the e-bus.
Now, sort through these ideas and see if you have any
disagreement or question as to their validity. Once
the suite of ideas is validated, do you see a way to
assemble them into a solution suited to your needs?
>If you'd rather not make either of those statements (for liability reasons,
>or whatever), I totally understand. I'm just trying to get a feel for your
>opinion on the matter. Would you personally have any problem getting in an
>airplane that uses the Z-13 architecture with dual electronic ignitions?
Liability? Let's not make this a decision based on anyone's
opinion but your own. The whole universe runs on physics and
each basic fact of physics is stone simple . . . a simple-idea.
The task is for you to sort through a basket of simple-ideas
and make a considered decision based on your own understanding . . .
not upon anyone else's opinion.
>I'm trying to avoid the added weight of two full-size batteries, and I really
>like the idea of having the SD-8 as a backup alternator instead. I'm also
>trying to avoid the complexity of having a backup battery just for half of a
>dual ignition system -- if that's even a logical position to take.
>
>Can you put an end to the ambiguity (read: my confusion) one and for all?
I can't "put an end" to it, that's not part of my magic wand's
bag of tricks. I can put out some simple-ideas for you or
anyone else to critique, correct or amplify so that
you and others can gather them into a system that
offers the comfort of understanding and the utility
of system reliability.
So, given what's been outlined above, I encourage further
discussion to see if those things can satisfy your
needs. This is the first time I've considered the
architecture described in (7) . . . does anyone have
something to contribute there?
Bob . . .
Message 14
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| Subject: | Re: 100 % Solution (diode-fed supportbatt-was Avionics |
bus)
--> AeroElectric-List message posted by: "Eric M. Jones" <emjones@charter.net>
What Bob says about Mallory (and other) supercaps seems to be true. I looked at
putting some supercaps near the starter, but the technology has fallen out of
favor for the reasons Bob mentions. For situation where the rate of charging
or discharging is important, they still have some use.
I do wonder--In a power-limited situation, would it make sense to have greater
energy available for the first couple seconds of radio transmission or reception?
Would the availability of 15 Volts in the first second extend the low voltage
operation? I think this seems reasonable.
For anyone interested in battery power, the advances in Lithium-Ion makes the use
of anything else questionable, especially if you don't need to fly for a while.
Batteries are heavy and Lithium-Ion is CERTAINLY going to supplant everything
else, even the much vaunted micro-fuelcells have fallen behind the curve.
Li-Ion advantages--
Li-Ion cells weigh around half that of a NiCd or NiMH cell of the same capacity.
In addition Li-Ion cells are 40 to 50% volumetrically smaller than NiCd cells,
and 20-30% smaller than NiMH cells.The average voltage of a Li-Ion cell (3.6-3.7V)
is equivalent to three NiCd or NiMH cells (each 1.2V). Li-Ion cells can
typically be discharged at rates up to 1.5C continuous. Very safe environmentally.
No Lithium metal, other electrode is carbon. Shapes....any shape and flexible
too. When fully charged and fully discharged under normal conditions, the
life of a Li-Ion cell is between 300 and 500 cycles (RG batteries are half
this). No "memory effect" Fast charge capable, wide operating temperature range,
enormous charge retentions, trickle charging is rarely needed. Many batteries
are "smart"; that is--they have a computer doing tricks inside of it.
Regards
Eric M. Jones
www.PerihelionDesign.com
113 Brentwood Drive
Southbridge MA 01550-2705
Phone (508) 764-2072
Email: emjones@charter.net
Message 15
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--> AeroElectric-List message posted by: PTACKABURY@aol.com
Bob et al: First background one: I built a LongEZ some 20 years ago and
have learned to live with some quirks with the electrical system. For
example when I transmit the fuel low lites come on and the Navaid autopilot
rolls into a 30 degree bank. I gave up trying to find these uninvited bugs
and have learned to enjoy them as part of life's little surprises.
Background two: a friend has just completed a beautiful Lancair IVP with a
very professional wiring job. When he transmits his SFS fuel indicators go
to zero (while using the bottom, externally mounted antenna, not when using
the antenna mounted inside the tail). He has been trouble shooting for a few
weeks but so far no luck. Now to the point: I am just about ready to string
wires and add an external com antenna to my Lancair IV and would like to
avoid repeating these interference problems (EMI??). Advice? Does and
don'ts? Are these quirks just part of life with a plastic airplane? Are
they the result of multiple grounds, insufficient wire shielding, bad antenna
installation, com coax too close to other wires, or too few chicken bones
tossed during the build process? all help is appreciated--paul
Message 16
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| Subject: | Re: Dual electronic ignition - revisited again |
--> AeroElectric-List message posted by: "Jim Pack" <jpack@igs3.com>
With all the talk of a 20 am standby alt & a second battery, why not z14
(dual alt, dual bat)? If it were my plane with dual EI's, I'd want to make
sure that at least one was always running (no single point failures in the
electrical system will stop the engine).
- jim
> . . . does anyone have
> something to contribute there?
>
Message 17
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| Subject: | SD-8 Alternator Questions |
--> AeroElectric-List message posted by: "Phil Birkelbach" <phil@petrasoft.net>
This recent discussion on dual batteries vs. dual alternators had me
thinking about the system that I am planning. I'll be using the "All
Electric on a Budget" except with an internally regulated alternator (with
OVM and another big contactor), but my question is about the SD-8. I have
assumed that the SD-8 is a true permanent magent alternator which means that
if you spin it, it will make juice. Is this true?
I have heard bits and pieces of debate on this list about the SD-8 requiring
power to get started but then the battery can go away after the unit is
running and assuming a good filter it will produce decent power. I assume
that these concerns are due to the fact that the relay will need some
external source of power to get it closed, but once it is closed there is no
further need of the battery. I guess I am challenging my own assumptions
and want to understand this little alternator a little better.
I also read here once that it was not a good idea to start this little
alternator during the pre-flight checks because then it will sit there and
make power the whole flight and that this was somehow bad for it. I would
really like to be able to check this little guy during the pre-taxi check
list and would like to better understand what is going on inside it before I
plunk down the money.
Although my engine will not totaly rely on electrical power my panel does.
I'll be blind as the proverbial bat if I lose my electrical system.
Oh BTW what was the answer to the water molecule ping pong ball question? I
would guess they would be a few inches deep, but I barely passed Chemistry
so I can't remember all that mole stuff.
Godspeed,
Phil Birkelbach - Houston Texas
RV-7 N727WB (Reserved) - Fuselage
http://www.myrv7.com
Message 18
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| Subject: | Re: Dual electronic ignition - revisited |
again
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <bob.nuckolls@cox.net>
At 09:51 AM 5/14/2003 -0600, you wrote:
>--> AeroElectric-List message posted by: "Jim Pack" <jpack@igs3.com>
>
>With all the talk of a 20 am standby alt & a second battery, why not z14
>(dual alt, dual bat)? If it were my plane with dual EI's, I'd want to make
>sure that at least one was always running (no single point failures in the
>electrical system will stop the engine).
>
>- jim
I think he was talking about the 4# SD-8 as a standby and
further interested in downsizing the #2 battery to serve
the need of a #2 ignition and then only if BOTH alternators
have failed.
With two engine driven power sources, the need for e-bus
capacity in the main battery goes away. If one can find
low capacity batteries with the ability to dump starting
current, a Z-13 configured as I described has tremendous
potential for weight and volume savings. The biggest
gotcha is cost of low capacity batteries that will
also crank . . . but again, you can run this battery
until it croaks if you have two engine driven power sources.
Bob . . .
Message 19
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| Subject: | Re: Dual electronic ignition - revisited again |
--> AeroElectric-List message posted by: Geoff Evans <hellothaimassage@yahoo.com>
Bob. Thank you so much for that elegant and concise response. It definitely
adds some perspective.
Bob wrote:
(7) You might consider a Z-13 system with the aux battery
connected so as to parallel with the main battery for
normal ops and battery charging. If the aux battery management
module is attractive to you, I might drive it from the
e-bus so that during main alternator out operations,
it would allow the second battery to stay connected to
the main battery only if the SD-8 were working and
not overloaded because too much stuff is turned on.
So, given what's been outlined above, I encourage further
discussion to see if those things can satisfy your
needs. This is the first time I've considered the
architecture described in (7) . . . does anyone have
something to contribute there?
That was going to be my next question... In regard to (7) above, would the
small aux battery actually need to be "driven" from the e-bus, or could it be
connected to the main battery side of the main battery contactor where the
the SD-8 hooks up? It seems to me that if we connected it here, in the
unlikely event that the aux battery was deeply discharged, it would prevent
high charging currents flowing through the main battery bus and the e-bus.
Also, would you recommed the hefty power relay to connect the small aux
battery in lieu of the shottky diode that is shown on the drawings that come
with the Lighspeed ignition? Personally, I don't know anything about shottky
diodes, so I guess this question is more of a request for a "compare and
contrast" between a relay connection method and a shottky diode connection
method.
Thanks again!
-Geoff
__________________________________
http://search.yahoo.com
Message 20
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| Subject: | Re: non-Microprocessor based Fuel Gauge Linearizer |
--> AeroElectric-List message posted by: Jerzy Krasinski <krasinski@direcway.com>
Eric M. Jones wrote:
>.....Now having the four teeny little op amps (Quad Op Amp LM324), you add four
teeny little adjustment pots to set the slopes (gains), and a quad comparator
LM339 to tell the output which one of the Op Amps is valid.....
>
>......An I-V converter chip for the input and a V-I converter chip for the output.
Is there a way to avoid this?......
>
Why would you need these converters? The input and output are voltage
signals.
An unpleasant feature of this solution is that each segment of the curve
has TWO parameters to set. These include the slope and the offset. For
a four segment curve one would have to mess around with eight adjusting
potentiometers. Any correction of gain or offset in any of the opamps
would change alignment of the corresponding curve sector in respect to
both neighbouring sectors. That means that if settings for any segment
were changed one would have to readjust all other segments, in order
to get a curve without kinks at the switching points. And to check if
adjustment is done correctly one would have to scan the input over the
whole range, and see if there are no output jumps at the op amp change
points, and if the slopes are as expected. It can be done but it is
rather messy
A microcontroller solution has that advantage that one can input
separately several slope parameters for the sectors of the curve, or
input the data points in a process of adding a gallon to the tank and
depressing a button, and leave the whole messy curve generation process
to the controller.
Jerzy
Jerzy
Message 21
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| Subject: | Re: AutoPilot Disconnect Brain Teaser - |
--> AeroElectric-List message posted by: "Rob Housman" <RobH@hyperion-ef.com>
Better than words is an illustration:
http://www.jwave.vt.edu/crcd/farkas/lectures/structure/tsld002.htm.
Although this is illustration shows how atoms are arranged in a crystalline
lattice it is the same concept as solid spheres being closely packed. In
FCC each of the six sides of the cube contains 1/2 of a sphere for a total
of three, and the eight corners contribute eight eighths of a sphere for
another whole one. Calculate the volume occupied by the four spheres and
compare it to the volume of the cube and you get the 74.05% number.
Best regards,
Rob Housman
Europa XS Tri-Gear A070
Airfarame complete
Irvine, CA
-----Original Message-----
From: owner-aeroelectric-list-server@matronics.com
[mailto:owner-aeroelectric-list-server@matronics.com]On Behalf Of Robert L.
Nuckolls, III
Subject: Re: AeroElectric-List: Re: AutoPilot Disconnect Brain Teaser -
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III"
<bob.nuckolls@cox.net>
At 09:38 AM 5/14/2003 -0400, you wrote:
>--> AeroElectric-List message posted by: "Eric M. Jones"
<emjones@charter.net>
>
>The packing fraction for face-centered cubic packing is rho0.7405. Adjust
>results accordingly.
>
>Eric
You threw me a new one there Eric. Care to describe "packing fraction"
in 25 words or less? ;-)
Bob . . .
--------------------------------------------
( Knowing about a thing is different than )
( understanding it. One can know a lot )
( and still understand nothing. )
( C.F. Kettering )
--------------------------------------------
Message 22
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| Subject: | Re: AutoPilot Disconnect Brain Teaser - |
--> AeroElectric-List message posted by: "Eric M. Jones" <emjones@charter.net>
>At 09:38 AM 5/14/2003 -0400, you wrote:
>>--> AeroElectric-List message posted by: "Eric M. Jones" <emjones@charter.net>
>>
>>The packing fraction for face-centered cubic packing is rho0.7405. Adjust
>>results accordingly.
>>
>>Eric
>You threw me a new one there Eric. Care to describe "packing fraction"
>in 25 words or less? ;-)
>Bob . . .
Sure:
Well, If you put a bunch of balls in a box, they achieve a packing that is better
than all-lined-up in straight rows and columns. (25 words.)
There are an infinite number of way to do this, but pure hexagonal packing is best
(hard to prove but easy to measure). When the cubic constraint is applied,
a face-centered cubic packing is most efficient (arranged like a diamond's carbon
atoms).
Illustrative brain teaser-- A cubic box holds a bowling ball. The bowling ball
is removed, melted down into very tiny spheres and the tiny balls poured back
into the box. To what level is the box filled ? Answer--That's easy! 74.05 percent
of the original volume.
Any "thought experiment" that arranges balls in purely cubic rows and column misses
the fact that the true number is 1/rho (where rho is the packing fraction)
times the rows-and-columns-result. Thus there are (1 / 0.7405) X 1 X 10
9 balls in the 1" cube.
Regards,
Eric M. Jones
Message 23
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| Subject: | non-Microprocessor based Fuel Gauge Linearizer |
--> AeroElectric-List message posted by: "Eric M. Jones" <emjones@charter.net>
Jerzy--Of course you are right. I was hoping this detail would fall into place,
since there are some issues yet to be resolved.
Bob and Jerzy and others. You would be right to guess I am more comfortable with
op amps than with microprocessors. I returned to using discrete chips after
receiving the source code for a device of similar complexity....and it is 25 pages
of assembler. The notion that using a microprocessor instead of a couple
of chips should best be argued upon the completion of parallel projects. Believe
me, I am wholeheartedly a microprocessor fan, but not in this design.
Besides....analog input, analog output, and don't a few op amps and comparators
make an analog "computer"?
Regards,
Eric M. Jones
"The natural progress of things is for liberty to yield and government to gain
ground."
-- Thomas Jefferson
Message 24
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| Subject: | Static when Refuelling re Braid |
--> AeroElectric-List message posted by: "Fergus Kyle" <VE3LVO@rac.ca>
" Any help is kindly > appreciated, but I did buy the tinned copper braid today,
and
> after reading your message I don't know what to do with it. >
> Reg
> Tony Renshaw
That would be braid dangling inside the tank, wired to electrical ground? It won't
do anything during refueling to suppress static charges, since fuel is essentially
nonconductive.
Fred F"
This byplay brings to mind the accident report of the glider over S England hit
by lightning well clear of cloud. Basically it blew up. Admittedly, the strike
was a big one electrically, but the composition glider came to bits because
the bolt fllowed the control rods from aileron to cockpit (sound familiar?), burnt
the instructor's jacket collar and blew both occupants into the air. The
craft came down in bits and the boys in 'chutes - but the message was 'you don't
need fuel to blow it to bits, but you might need a 'chute".
I've got a printed version of the report here somewhere.
Ferg
Message 25
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| Subject: | Re: Diode failures and "Reliable Systems" |
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <bob.nuckolls@cox.net>
>Diodes. . . . . I get a little excited when I hear stories of diodes
>failing.
>
>I've quoted the relevant parts above.
>
>Now, my anecdote, prior to asking a ques: Anecdote: While Avionics Officer
>for an A-7D unit, one of the Big Eight test stations (each of the eight
>costing about $1 million each) suffered a diode "short" on a circuit card.
>This simple 2 cent piece failed - resulting in high current flow in that
>circuit, which was not protected - designers didn't consider the diode
>failure mechanism. Well, the high current cascaded throughout the test
>station and resulted in something like a lightning strike on the entire test
>station. We spent months and LOTS of unit funds repairing that test
>station.
>
>Now, I'm in the role of home builder-designer of my RV-6 electrical system.
>And we've been talking many months about an Endurance Bus, with a diode
>allowing power to flow to the E-bus from the main bus, and to prevent
>battery drain from the E-bus to the main bus when main bus is shut down for
>alternator failure.
>
>A diode.
>
>I'll bet those who work in this field have other stories about diode
>failures.
>
>Are there some diodes that are better (more durable, longer lasting) than
>other diodes?
>
>What level of "diode spec" ought to be sufficient to avoid "typical" diode
>failures? Is "bigger" better?
>
>What are diodes most sensitive to? (that would cause them to fail)
>
>If I can't "rely" on the diode between Main & E busses, then I might
>consider "adding parts count" to detect failure of this critter; or special
>pilot operating procedures to use voltmeter wired to specific, switch
>selectable places, with opening and closing of e-bus switch or other means
>of verifying, on every flight, that the diode is function correctly. (Do I
>smell my own paranoia oozing out?)
>
>David Carter
It's always useful to critique anecdotal data if only to
discover that there is no useful data contained therein.
Looking at the above I would offer the following observations
and perhaps folks out there can cite others:
We've all heard about the nation that was lost for want
of a nail in a horseshoe . . . a classic analogy of
cascaded failures. There is always potential and even
probability that one failure will propagate to the
destruction of other components of a system. If any
single failure can take the system down, our consideration
as flight-system designers is to build firewalls between
the failed system and the rest of the aircraft. For
most instances, a fuse or circuit breaker is all that's
needed to prevent the worst kind of failure in any one
system from having a deleterious effect on other systems.
As soon as you run a wire from one system to another,
then a degree of interdependency has been created
that must be considered in your failure mode effects
analysis. For example: if the GPS receiver goes down, will
my wing-leveler retain any degree of usefulness as
an aid to operating this airplane . . . or does it
become useless too?
So, what can we learn about a 2-cent diode that
caused so much grief in the anecdote cited above:
We don't know the details of how this "nail" failure
propagated across the host system or ancillary
systems . . . but if the cost to fix included months
of repair time and lost-of-use time, it's reasonable
to conclude that damage was extensive. It raises
a further question about whether or not the design
flaw was corrected to make it more tolerant of such
failures . . . or were the failed systems simply
repaired leaving a potential for the same failure
to happen again?
Given that the anecdote cites a diode as the
first event in this cascade failure, is this
a rational reason for extra-ordinary attention
to the use of diodes in our little airplanes?
Further, is there anything to suggest that
other components are not equally deserving
of similar attention. It's conceivable that
the very same story could be repeated with the
phrase "2-cent resistor" substituted for "2-cent
diode."
When we design systems for Part 25 and higher
duty service, were obligated by decree to consider
MULTIPLE failures weighed with each other in
reliability analysis . . . presumably to demonstrate
that in spite of any two failures, our design is
is robust enough to run 1,000,000 hours failure
free . . . any skeptics out there?
Sooo . . . rather than wrap ourselves around
the axles of reliability studies that take lots
of research, time and probably don't mean much
anyhow, the OBAM community has deduced that
it's easier to ASSUME that parts of our
system are going to fail and that the
goal is to configure for failure tolerance
as opposed to failure proof. Something
akin to breeding war horses that fight well
on three legs.
Yup, that diode between the main-bus and e-bus
is NOT IMMUNE FROM FAILURE. In what ways can
it fail? (OPEN or SHORT). How do we know it
has failed (E-BUS STUFF GOES DARK for open
and (E-BUS ALT FEED TEST IN PREFLIGHT POWERS
THE MAIN BUS - for shorted). What are the
consequences of either failure mode? (IF
SHORTED WHILE AIRBORNE - probably not
noticed . . . but we'll catch it at next
preflight) (IF OPEN WHILE AIRBORNE - e-bus
goodies go dark and we have to close the
alternate feedpath switch for continued
operation).
Okay, assuming you can deduce no errors
of reasoning in the analysis above, how does
this affect your concerns about diode
reliability in this particular case?
If failure concerns are adequately addressed
we can turn our attention to reducing likelihood
of failure as a sort of icing-on-the-cake . . .
i.e. were not trying to improve reliability
with an eye on flight comfort but more as
a reduced maintenance issue.
The smallest diode array that comes in the
package I suggest is rated at 25A . . . you can
buy these rectifier arrays in ratings up to
35A. Sooo . . . unless you have everything
but the kitchen sink powered from the e-bus,
our diode is very adequately de-rated.
The lowest voltage offered by any diode manufacturer
is 50V . . . plenty of headroom for our 14V
application. These critters have a voltage drop
so they dissipate heat. Can't hang 'em out in
the air . . . so bolt it down to a metallic
surface.
Wrap-up: We've made a considered selection of
the component and its installation with a
eye toward robustness. Further, we've
deduced that failure of the component
is no more than a nuisance.
Going back to the 2-cent diode bringing
down $millions$ worth of equipment. How is
this anecdote relevant to how a $5 diode
is bolted to your airplane?
Bob . . .
Message 26
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| Subject: | Re: SD-8 Alternator Questions |
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <bob.nuckolls@cox.net>
At 11:02 AM 5/14/2003 -0500, you wrote:
>--> AeroElectric-List message posted by: "Phil Birkelbach"
><phil@petrasoft.net>
>
>This recent discussion on dual batteries vs. dual alternators had me
>thinking about the system that I am planning. I'll be using the "All
>Electric on a Budget" except with an internally regulated alternator (with
>OVM and another big contactor), but my question is about the SD-8. I have
>assumed that the SD-8 is a true permanent magent alternator which means that
>if you spin it, it will make juice. Is this true?
yes . . . but it's regulator senses the bus-side . . .
>I have heard bits and pieces of debate on this list about the SD-8 requiring
>power to get started but then the battery can go away after the unit is
>running and assuming a good filter it will produce decent power. I assume
>that these concerns are due to the fact that the relay will need some
>external source of power to get it closed, but once it is closed there is no
>further need of the battery. I guess I am challenging my own assumptions
>and want to understand this little alternator a little better.
. . . and doesn't bring the SD-8 on line unless there
is a battery present.
>I also read here once that it was not a good idea to start this little
>alternator during the pre-flight checks because then it will sit there and
>make power the whole flight and that this was somehow bad for it. I would
>really like to be able to check this little guy during the pre-taxi check
>list and would like to better understand what is going on inside it before I
>plunk down the money.
Not true . . . test it and run it any way you like.
>Although my engine will not totaly rely on electrical power my panel does.
>I'll be blind as the proverbial bat if I lose my electrical system.
>
>Oh BTW what was the answer to the water molecule ping pong ball question? I
>would guess they would be a few inches deep, but I barely passed Chemistry
>so I can't remember all that mole stuff.
I purposely left out one piece of data to see if anyone
remembered their chemistry. There is a physical constant
called Avagadro's number (Na = 6.022 times ten to the
23rd power) that defines the number of molecules in a gram-mole
of a substance. For example, oxygen molecules have an atomic
mass of 32. Therefore, an Avagadro's number of oxygen
molecules will have a mass of 32g. H20 has an atomic mass
of 16+1+1 or 18. So, an Avagadro's number of water molecules
is 18g. 1 cc of water is 1 gram so the cc of water has 1/18th of
an Avagadro's number of water molecules.
The rest is setting up the calculations to figure out the
total volume this number of ping-pong balls (Stacked in
planar rows - not nested) and dividing that volume by
the surface area of the US . . . give it a try. Trust me,
you'll be amazed by the number.
Bob . . .
Message 27
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| Subject: | Re: Cheap blind encoder. |
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <bob.nuckolls@cox.net>
At 11:52 PM 5/14/2003 +1000, you wrote:
>--> AeroElectric-List message posted by: "Ian Scott" <jabiru22@yahoo.com.au>
>
>
>HI All,
>
>I a getting a Micro air transponder, and was wondering what I should do
>for encoder and antenna, in a glass plane
Look at the ACK model A-30. The street price on these is
about $175. Don't know of anything less expensive.
Bob . . .
Message 28
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--> AeroElectric-List message posted by: "Bob Kuc" <bkuc1@tampabay.rr.com>
Bob ...
Did you ever receive my Wig Wag package for you to check? It has been a few weeks.
Thanks
Bob K
Message 29
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| Subject: | Re: Cheap blind encoder. |
--> AeroElectric-List message posted by: DHPHKH@aol.com
Companion encoder question: Panel will have a transponder and a GNS430. Both require
input from an encoder. Can the two units be paralleled to the same encoder
(two wires from each encoder pin) or does the typical installation have two
encoders?
Dan
Message 30
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| Subject: | Re: Flap system failure modes (Was circuit protection |
issues)
--> AeroElectric-List message posted by: "Gilles.Thesee" <Gilles.Thesee@ac-grenoble.fr>
Bob,
Thanks for your help and your advice.
>
> Okay. I'm not sure you need to have an on-purpose limitation
> to the flaps as long as your pilots are aware how to use
> them safely. Benefits of flaps happen at touchdown. More
> flaps just makes you come down faster and leaves you with
> less energy to squander in the flare. If I were a flight
> instructor, I'd not let a student use flaps at all until
> they were proficient without them.
>
> In the older C-150's, you could get the best of both
> worlds by hanging out no more drag than you can tolerate
> at full throttle to arrest your descent. When you're
> sure you have the landing made, put out the rest of
> the flaps.
>
That's the way we use them in this country.
We intend to use the full flap position only for particular landing
conditions.
> >
> >I guess you and I know too well....
>
> Okay, let's see what we can do to make failures as tolerant
> as possible. I think I'd simply wire all four motors in
> parallel with each other. Treat them as a single motor.
> Drive the system through a single, 20A breaker at the bus.
> The idea of protecting each motor in any way is scary. You
> don't want the system to continue to run in any way if one
> motor has decided to mis-behave.
>
Yes of course. Indeed my intention to wire them in parallel.
My question was about the sizing of the fuse and the wires, considering
fuses are faster than breakers ("the others" are using a breaker)
> My sense is that this little airplane simply cannot need
> as much snort as a 20A breaker would suggest. Wire with
> 14AWG wire and put a 20A breaker in for now. During flight
> testing, let's put an ammeter in and see what the system
> REALLY needs.I wouldn't be surprised to see that we can
> drop the breaker size down to 15 or even 10 amps. An
> RV actuator runs at under 5A.
Will do.
You don't need to size the
> breaker for inrush currents.
Is it the same for fuses ? I'm using fuseblocks, and the only breaker on
board is for the alterrnator OV protection. Or do I need to use a breaker
for the flaps ?
>
> If one wanted to reduce the hazards of single motor
> failure, we could design some fancy circuitry to sense
> abnormal operation and shut the whole system down
> when it was detected.
>
> Single point protection combined with judicious use
> of flaps in approach-to-landing should let you make the
> best of a rather un-thoughtful design. This wouldn't be
> the only airplane flying around with idiosyncrasies
> capable of embarrassing you or driving your pucker
> factor up. Take a checkout in a Tri-Pacer or a AA-1
> Yankee and have the check pilot show you how easy it
> is to get tense in these airplanes. They ain't your
> grandfather's C-172.
>
> If this system has a satisfactory history . . . meaning
> that gear-boxes aren't shelling out and motors are
> hanging in there, then you're not facing gross design
> limits or high rates of infant mortality. This suggests
> that until a motor or gearbox reaches wear-out,
> you won't have to shoulder duties as a failure modes
> test-pilot soon. Maybe this won't happen until after you've
> sold the airplane.
>
Let's hope so !
Thank you,
Gilles
Message 31
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| Subject: | Re: OV circuit breaker tripping |
--> AeroElectric-List message posted by: "John Karnes" <jpkarnes@charter.net>
Bob and Cy-
Today I bypassed the B-load contactor and went directly to the starter
contactor from the alternator. I got about 14 volts without any circuit
breaker tripping. My problems appear to be centered around the B-load
contactor. The diode was about 100 ohms, so I don't think that is the
problem. Maybe the contactor itself or the 80 amp fuse???
John Karnes
Message 32
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| Subject: | Re: SD-8 Alternator Questions |
--> AeroElectric-List message posted by: "Phil Birkelbach" <phil@petrasoft.net>
>
>. . . but it's regulator senses the bus-side . . .
>
>
> . . . and doesn't bring the SD-8 on line unless there
> is a battery present.
>
>
> Bob . . .
Yep that is the piece that I was missing. I didn't think about the
regulator. Why would the regulator be built to inhibit the alternator
unless there was bus voltage? I must be missing something because it looks
like if the regulator saw zero volts it's 'brain' would tell it to do what
it took to bring the volts up to setpoint.
Does the "All Electric on a Budget" circuit have a single point of failure
in the fat wires coming off of the battery? Not that there is much chance
of either of those wires failing, but I am curious. I guess if the battery
ground wire came loose then the primary alternator would still yield some
volts but how ugly would running the main alternator without the battery be?
Godspeed,
Phil Birkelbach - Houston Texas
RV-7 N727WB (Reserved) - Fuselage
http://www.myrv7.com
Message 33
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| Subject: | Re: Flap system failure modes (Was circuit protection |
issues)
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <bob.nuckolls@cox.net>
> > My sense is that this little airplane simply cannot need
> > as much snort as a 20A breaker would suggest. Wire with
> > 14AWG wire and put a 20A breaker in for now. During flight
> > testing, let's put an ammeter in and see what the system
> > REALLY needs.I wouldn't be surprised to see that we can
> > drop the breaker size down to 15 or even 10 amps. An
> > RV actuator runs at under 5A.
>
>Will do.
>
>You don't need to size the
> > breaker for inrush currents.
>
>Is it the same for fuses ? I'm using fuseblocks, and the only breaker on
>board is for the alterrnator OV protection. Or do I need to use a breaker
>for the flaps ?
Hmmmm . . . Without specific measurements on your
group of 4 motors, I'm reluctant to offer an
opinion. With the right gear ratio, ONE of those
motors will run the flaps. In fact, the actuator
popular with RV builders uses a ball-screw that
is so efficient that a motor about the same size
runs the flaps with very little current compared
to ANYTHING with worm or acme drive components.
Problem is that inrush is 4x that of a single
motor. They're small motors and will accelerate
right smartly but the inrush IS going to be
higher even if it is relatively short.
Let's go the 20A fuse. This will be easy to test
before you fly. Run flaps to mid position. Then
do a series of flap drive operations for just a
second or so each direction. Delay long enough
between pulses to let the motors come to a stop.
If the fuse stays in place with a couple dozen
short term reversals over a period of a minute
or so, then it's going to be okay with respect
to in-flight operations.
Once the ground test is complete, we can go after
the flight data to see if we have a justification
for scaling the fuse to any lower value.
Bob . . .
Message 34
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--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <bob.nuckolls@cox.net>
At 02:49 PM 5/14/2003 -0400, you wrote:
>--> AeroElectric-List message posted by: "Bob Kuc" <bkuc1@tampabay.rr.com>
>
>Bob ...
>
>Did you ever receive my Wig Wag package for you to check? It has been a
>few weeks.
>
>Thanks
>
>Bob K
Yes. I can wasn't able to get your assembly to mis-behave.
Poked around on it a bit but no change. It's still on the
bench. I'd like to keep it here for further investigation.
I'm sending you one I built that's about 1/6th the size
and potted for ruggedness. It's the prototype for an article
on w/w module I started a few months ago before I found the
electronically driven relays.
The new module and your original relays will go out this
evening.
Bob . . .
Message 35
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--> AeroElectric-List message posted by: "Bob Kuc" <bkuc1@tampabay.rr.com>
Thanks Bob, Onething that I did notice after I sent this out was that I was
only supply 10 Volts throught it. Since I am still building and not engine
yet, I am stuck at battery power. However, my batery is perty weak, Maybe
the low volts is through more amps through there and causin the
mis-behaving.
Bob
----- Original Message -----
From: "Robert L. Nuckolls, III" <bob.nuckolls@cox.net>
Subject: Re: AeroElectric-List: Wig wag
> --> AeroElectric-List message posted by: "Robert L. Nuckolls, III"
<bob.nuckolls@cox.net>
>
> At 02:49 PM 5/14/2003 -0400, you wrote:
> >--> AeroElectric-List message posted by: "Bob Kuc"
<bkuc1@tampabay.rr.com>
> >
> >Bob ...
> >
> >Did you ever receive my Wig Wag package for you to check? It has been a
> >few weeks.
> >
> >Thanks
> >
> >Bob K
>
> Yes. I can wasn't able to get your assembly to mis-behave.
> Poked around on it a bit but no change. It's still on the
> bench. I'd like to keep it here for further investigation.
> I'm sending you one I built that's about 1/6th the size
> and potted for ruggedness. It's the prototype for an article
> on w/w module I started a few months ago before I found the
> electronically driven relays.
>
> The new module and your original relays will go out this
> evening.
>
> Bob . . .
>
>
Message 36
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| Subject: | Cheap blind encoder. |
--> AeroElectric-List message posted by: "Greg Young" <gyoung@cs-sol.com>
What inputs does your transponder and GNS430 accept, Gray code, serial or
both? I just installed UPS gear in my Navion and the SL70 transponder will
accept either Gray code or serial encoder input and output a serial signal
to the GX60 GPS/Com (it only accepts serial). That let me use my existing
(and cheap) Ameriking AK-350 encoder instead of an expensive serial encoder
or serial converter and still have the altitude input needed for IFR
approval. I suspect Garmin may have similar capability. It's an option to
explore.
Regards,
Greg Young - Houston (DWH)
RV-6 N6GY ...project Phoenix
Navion N5221K - just an XXL RV-6A
> --> AeroElectric-List message posted by: DHPHKH@aol.com
>
> Companion encoder question: Panel will have a transponder and
> a GNS430. Both require input from an encoder. Can the two
> units be paralleled to the same encoder (two wires from each
> encoder pin) or does the typical installation have two encoders?
>
> Dan
>
Message 37
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| Subject: | Re: Static when Refuelling re Braid |
--> AeroElectric-List message posted by: Kent Ashton <kjashton@vnet.net>
>
>
>" Any help is kindly > appreciated, but I did buy the tinned copper braid today,
and
> > after reading your message I don't know what to do with it. >
> > Reg
> > Tony Renshaw
>
For fiberglass airplanes, If you rivet the braid, or any wire, to
the fuel cap ring and bring it down to some central point, like in the
cockpit strake area or the external step, you can at least ground the
fuel cap to prevent static sparking between the refueling nozzle and the
cap ring. Should help some.
--Kent A.
Message 38
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--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <bob.nuckolls@cox.net>
At 05:52 PM 5/14/2003 -0400, you wrote:
>--> AeroElectric-List message posted by: "Bob Kuc" <bkuc1@tampabay.rr.com>
>
>Thanks Bob, Onething that I did notice after I sent this out was that I was
>only supply 10 Volts throught it. Since I am still building and not engine
>yet, I am stuck at battery power. However, my batery is perty weak, Maybe
>the low volts is through more amps through there and causin the
>mis-behaving.
Hmmm . . I'll try that and see what happens.
. . . in any case, the other flasher went out
a few minutes ago.
Bob . . .
Message 39
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| Subject: | Re: SD-8 Alternator Questions |
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <bob.nuckolls@cox.net>
At 03:32 PM 5/14/2003 -0500, you wrote:
>--> AeroElectric-List message posted by: "Phil Birkelbach"
><phil@petrasoft.net>
>
> >
> >. . . but it's regulator senses the bus-side . . .
> >
> >
> > . . . and doesn't bring the SD-8 on line unless there
> > is a battery present.
> >
> >
> > Bob . . .
>
>Yep that is the piece that I was missing. I didn't think about the
>regulator. Why would the regulator be built to inhibit the alternator
>unless there was bus voltage? I must be missing something because it looks
>like if the regulator saw zero volts it's 'brain' would tell it to do what
>it took to bring the volts up to setpoint.
That's what they did. It's a purchased regulator Bill gets
from some outfit in Kansas City as I recall. Perhaps the rational
for the design was to make sure that any time the alternator
was delivering useful power, the presence of a battery
made sure it was as clean as practical.
I've got some ideas about how to get a few more watts out of
and SD-8 with a regulator that would provide quite smooth
power sans battery. I'll keep that on the back burner as
a potential product.
>Does the "All Electric on a Budget" circuit have a single point of failure
>in the fat wires coming off of the battery? Not that there is much chance
>of either of those wires failing, but I am curious.
There is that risk. I've never had or seen a wire come loose
but a list member broke a post off a 17 a.h. RG battery and
reported on it here a few weeks ago. Obviously, the chances
are not zero. If it were my airplane, I'd use 4AWG welding
wire battery jumpers to get soft, flexible leads.
> I guess if the battery
>ground wire came loose then the primary alternator would still yield some
>volts but how ugly would running the main alternator without the battery be?
Hard to quantify. You can certainly run the experiment
after the airplane is built and see. If you don't
like what you see, you can always add the tiny aux
battery to accommodate that condition.
Keep in mind that about 100,000 S.E. aircraft are
flying around out there now with one altenrator, one
battery and the same risk for loss of system due to
battery coming unhooked. It's much more likely that
you'll get alternator or contactor failure than
failure of wires on the battery. So an all-electric-
on-a-budget architecture is waaaaayyyyyy more reliable
than anything flying around in spam-can-land.
Consider too that for most of the way we use our
airplanes, TOTAL loss of electrical system can be
tolerated. I normally use hand-held GPS to navigate
and I carry a hand-held VOR/COM. When I walk up to
a rental airplane, there's no practical way for me
to assess the condition or history of that ship's
electrical system. If I can fly a J-3 somewhere
with no electrical system, I can fly an A-36
too.
Bob . . .
Message 40
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| Subject: | SD-8 Alternator Questions |
--> AeroElectric-List message posted by: "Rob Housman" <RobH@hyperion-ef.com>
When I took P. Chem Avagadro's number was 6.0238 X 10 E 23
Best regards,
Rob Housman
Europa XS Tri-Gear A070
Airfarame complete
Irvine, CA
-----Original Message-----
From: owner-aeroelectric-list-server@matronics.com
[mailto:owner-aeroelectric-list-server@matronics.com]On Behalf Of Robert L.
Nuckolls, III
Subject: Re: AeroElectric-List: SD-8 Alternator Questions
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III"
<bob.nuckolls@cox.net>
SNIP
I purposely left out one piece of data to see if anyone
remembered their chemistry. There is a physical constant
called Avagadro's number (Na = 6.022 times ten to the
23rd power) that defines the number of molecules in a gram-mole
of a substance.
SNIP
Bob . . .
Message 41
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| Subject: | Re: Static when Refuelling re Braid |
--> AeroElectric-List message posted by: Charlie & Tupper England <cengland@netdoor.com>
Fergus Kyle wrote:
>--> AeroElectric-List message posted by: "Fergus Kyle" <VE3LVO@rac.ca>
>
>" Any help is kindly > appreciated, but I did buy the tinned copper braid today,
and
> > after reading your message I don't know what to do with it. >
> > Reg
> > Tony Renshaw
>
>That would be braid dangling inside the tank, wired to electrical ground? It
won't do anything during refueling to suppress static charges, since fuel is essentially
nonconductive.
>Fred F"
>
snipped
I haven't followed this thread, but this caught my eye. The static
discharge problem is *caused* by the fact that fuel is basically non
conductive. A glass rod is non conductive, but we've all seen the
effects after rubbing one through a cat's fur.
Either the fuel or the plane can have a static charge. If they are at a
different voltage potential, the chance of a spark exists as the nozzle
approaches the tank. The fuel can acquire a charge as it moves through a
hose, just like the glass rod through fur.
If you don't bring the fuel delivery system & the plane to the same
voltage potential before beginning the refueling process, you can get a
spark. That's why the line boy grounds the truck and grounds the plane
before fueling begins.
Charlie
Message 42
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|
| Subject: | RE: Avogadro's Number |
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <bob.nuckolls@cox.net>
At 05:08 PM 5/14/2003 -0700, you wrote:
>--> AeroElectric-List message posted by: "Rob Housman" <RobH@hyperion-ef.com>
>
>When I took P. Chem Avagadro's number was 6.0238 X 10 E 23
>
>
>Best regards,
A check of my 41st edition (1960) edition of the
CRC Handbook calls it 6.0247*10E23 . . . and I
seem to recall using 6.025*10E23 in class.
. . . but a search on the 'net yields
6.022136736*10E23
http://education.jlab.org/glossary/avogrado.html
http://www.britannica.com/ebc/article?eu=381538
You know how those guys are. There are folks who can
spend a lifetime refining a single idea. Avogadro's
idea seems to have moved a tad. Does the value
of Na we carved into the gray matter date when we
all took chemistry?
Bob . . .
Message 43
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--> AeroElectric-List message posted by: "Dave Ford" <dford@michweb.net>
I am at the stage of integrating wiring of instruments and have noticed I have
three instruments requesting encoded altitude information from the encoder.
Can the encoder output be daisy-chained or paralleled to each instrument needing
that information? Is isolation required via resistors? Is an altitude
encoder capable of its information going to more than one device without loading
its output?
Dave Ford
Message 44
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| Subject: | Re: encoder wiring |
--> AeroElectric-List message posted by: BobsV35B@aol.com
In a message dated 5/14/03 8:52:41 PM Central Daylight Time,
dford@michweb.net writes:
> I am at the stage of integrating wiring of instruments and have noticed I
> have three instruments requesting encoded altitude information from the
> encoder. Can the encoder output be daisy-chained or paralleled to each
> instrument needing that information? Is isolation required via resistors?
> Is an altitude encoder capable of its information going to more than one
> device without loading its output?
>
> Dave Ford
>
Good Evening Dave,
I know nothing about wiring problems, but I have been involved with that
problem in the past. You can feed them all by using parallel wiring. My
recollection is that it takes about eleven wires to each device. Just double
up on the pins and take it on to the next device. One caution, there are
some transponders that tend to have a back feed interference of some sort.
Specifically, the King KT-76 series. For those, it is advisable to put
diodes in the input lines to the transponder so that the data can only go
into the transponder and not flow back out. Eleven little 1N4001s will do
the job just fine. Anything up to 1N4009s is supposedly OK.
Maybe one of those who know what is happening will comment further.
Happy Skies,
Old Bob
Message 45
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| Subject: | Re: RE: Avogadro's Number |
--> AeroElectric-List message posted by: Don Boardman <dboardm3@twcny.rr.com>
> seem to recall using 6.025*10E23 in class.
> . . . but a search on the 'net yields
> 6.022136736*10E23
> You know how those guys are. There are folks who can
> spend a lifetime refining a single idea. Avogadro's
> idea seems to have moved a tad. Does the value
> of Na we carved into the gray matter date when we
> all took chemistry?
>
> Bob . . .
Tomorrow I will enjoy telling my 33rd. group of chemistry students that
Avogadro's number is alive and well on the Internet list serve circuit!
I tell them all the time that it is a number they better remember for life,
and that if I run into them when they are older I will expect them to rattle
it off in style.
5 weeks to retirement.
Regards,
Don Boardman
Murphy Moose #130 M-14PF 400HP, MT-prop, Aerocet 3500 amphibs,
AeroElectric Wired, Rome, NY
Message 46
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| Subject: | RE: Avogadro's Number |
--> AeroElectric-List message posted by: "Rob Housman" <RobH@hyperion-ef.com>
My P. Chem. text shows a copyright date of 1961 (and shows only four decimal
places). I knew a lot of the practical stuff I learned is outdated but I
thought the basic stuff should have remained constant. Oh well.
Best regards,
Rob Housman
Europa XS Tri-Gear A070
Airfarame complete
Irvine, CA
-----Original Message-----
From: owner-aeroelectric-list-server@matronics.com
[mailto:owner-aeroelectric-list-server@matronics.com]On Behalf Of Robert L.
Nuckolls, III
Subject: AeroElectric-List: RE: Avogadro's Number
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III"
<bob.nuckolls@cox.net>
At 05:08 PM 5/14/2003 -0700, you wrote:
>--> AeroElectric-List message posted by: "Rob Housman"
<RobH@hyperion-ef.com>
>
>When I took P. Chem Avagadro's number was 6.0238 X 10 E 23
>
>
>Best regards,
A check of my 41st edition (1960) edition of the
CRC Handbook calls it 6.0247*10E23 . . . and I
seem to recall using 6.025*10E23 in class.
. . . but a search on the 'net yields
6.022136736*10E23
http://education.jlab.org/glossary/avogrado.html
http://www.britannica.com/ebc/article?eu=381538
You know how those guys are. There are folks who can
spend a lifetime refining a single idea. Avogadro's
idea seems to have moved a tad. Does the value
of Na we carved into the gray matter date when we
all took chemistry?
Bob . . .
Message 47
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| Subject: | Re: OV circuit breaker tripping |
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <bob.nuckolls@cox.net>
At 01:09 PM 5/14/2003 -0700, you wrote:
>--> AeroElectric-List message posted by: "John Karnes" <jpkarnes@charter.net>
>
>Bob and Cy-
>
>Today I bypassed the B-load contactor and went directly to the starter
>contactor from the alternator. I got about 14 volts without any circuit
>breaker tripping. My problems appear to be centered around the B-load
>contactor. The diode was about 100 ohms, so I don't think that is the
>problem. Maybe the contactor itself or the 80 amp fuse???
Hmmm . . . perhaps there's a short inside the contactor.
I've heard of such things but never seen them. Disconnect
all the wires from the small terminals of the contactor
and measure the resistance between the two terminals and then
from each terminal to the contactor case and tell us what you
find.
Bob . . .
Message 48
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| Subject: | Re: Cheap blind encoder. |
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <bob.nuckolls@cox.net>
At 03:23 PM 5/14/2003 -0400, you wrote:
>--> AeroElectric-List message posted by: DHPHKH@aol.com
>
>Companion encoder question: Panel will have a transponder and a
>GNS430. Both require input from an encoder. Can the two units be
>paralleled to the same encoder (two wires from each encoder pin) or does
>the typical installation have two encoders?
You can drive multiple loads with one encoder but you need an array of
diodes to avoid cross-coupled problems between loads. I don't
recall now exactly how the diodes are oriented. I searched the
net and found some encoder loads (transponders) that claim
to have isolation diodes installed.
I'll call around and see if an avionics wienie can tell me
of the top of his head which way the diodes have to go . . .
Opps, just found an overhaul manual for an encoder on the
'net at:
http://www.trans-cal.com/7421%20B.pdf
on page 2 it speaks of open collector outputs which
are active pull down only devices and that the pull-up
for logic "hi" is expected to come from the transponder
(signal load). This means that isolation diodes would
have to be included in the data lines for each device
that expects to get altitude data with the cathode
facing the encoder.
These diodes prevent the data lines from being pulled
to ground by a transponder or GPS that is powered down.
I've published an exemplar diagram at
http://216.55.140.222/temp/Encoder.pdf
The neatest way to install this raft of diodes
is to lay out a simple etched circuit board with
d-sub connector to bring wires onto and off the
board. For driving two loads, there's a total
27 wires . . . a single 37-pin D-sub would
do it.
I've seen some "professional" installations
where the diodes were simply butt-sliced
into the wire bundles and covered with heat-
shrink. I guess some DER signed off on this
somewhere.
Be sure to check if the devices that need
altitude data for built in diodes. If they're
already present, then you can simply eliminate
the diodes show in the drawing and wire direct.
Bob . . .
>Dan
>
>
Bob . . .
--------------------------------------------
( Knowing about a thing is different than )
( understanding it. One can know a lot )
( and still understand nothing. )
( C.F. Kettering )
--------------------------------------------
Message 49
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| Subject: | Re: encoder wiring |
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <bob.nuckolls@cox.net>
At 09:51 PM 5/14/2003 -0400, you wrote:
>--> AeroElectric-List message posted by: "Dave Ford" <dford@michweb.net>
>
> I am at the stage of integrating wiring of instruments and have
> noticed I have three instruments requesting encoded altitude information
> from the encoder. Can the encoder output be daisy-chained or paralleled
> to each instrument needing that information? Is isolation required via
> resistors? Is an altitude encoder capable of its information going to
> more than one device without loading its output?
See my earlier on this subject. If your device needing
altitude has isolation diodes already installed, it
can be simply paralleled with the other devices. Otherwise
you need to add them per the example at:
http://216.55.140.222/temp/Encoder.pdf
Bob . . .
Message 50
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| Subject: | Re: non-Microprocessor based Fuel Gauge |
Linearizer
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <bob.nuckolls@cox.net>
At 01:47 PM 5/14/2003 -0400, you wrote:
>--> AeroElectric-List message posted by: "Eric M. Jones" <emjones@charter.net>
>
>Jerzy--Of course you are right. I was hoping this detail would fall into
>place, since there are some issues yet to be resolved.
>
>Bob and Jerzy and others. You would be right to guess I am more
>comfortable with op amps than with microprocessors. I returned to using
>discrete chips after receiving the source code for a device of similar
>complexity....and it is 25 pages of assembler. The notion that using a
>microprocessor instead of a couple of chips should best be argued upon the
>completion of parallel projects. Believe me, I am wholeheartedly a
>microprocessor fan, but not in this design.
Hmmm . . . I'll bet the code to read an a/d, get the first
lookup table values above and below the reading and average
them for output to a d/a wouldn't fill one page.
>Besides....analog input, analog output, and don't a few op amps and
>comparators make an analog "computer"?
There are some single chip processors with an a/d and
d/a built in that would do this. Check out the PIC12F675
data sheet at
http://www.microchip.com/download/lit/pline/picmicro/families/12f6xx/41190c.pdf
and application tips at:
http://www.microchip.com/download/lit/pline/picmicro/families/12f6xx/40040b.pdf
This device sells for under $3 from Digikey and will do about
everything you need to do in one chip . . . in fact, it
might be possible to do a DUAL linearizer in the same chip
so that both tanks can be calibrated on one assembly.
You can talk to the a/d directly from the tank sender
driven by a constant current source. A relatively simple
routine to drive a fet with a variable duty-cycle would
provide for analog i/o to drive the standard gage that
comes with the senders.
The hardest part would be to write the program to go into
a laptop for consumers to talk to the chip and modify its
lookup table. Visual Basic would probably help with a
user-friendly windows-like interface.
I'm finding it increasingly difficult to justify even
simple projects in analog and/or discrete logic parts
any more. The chips are just too cheap and getting
more powerful all the time.
Bob . . .
Message 51
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| Subject: | AutoPilot Disconnect |
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <bob.nuckolls@cox.net>
At 10:08 AM 5/13/2003 -0700, you wrote:
>--> AeroElectric-List message posted by: John Loram <johnl@loram.org>
>
<snip>
>This analysis makes some simplifying assumptions; most importantly that the
>switch and relay contacts have zero resistance, and that the only non-purely
>resistive component is the relay coil. The calculation of the effect of
>these tertiary elements are left to the student.... ;-)
>
>
> >(is there a prize????) ;-) -john-
>
> Sure, after you finish the test . . .
>
> Bob . . .
You got it. Do you have a copy of the CD we
sell?
Bob . . .
Message 52
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| Subject: | Re: non-Microprocessor based Fuel Gauge Linearizer |
--> AeroElectric-List message posted by: John Rourke <jrourke@allied-computer.com>
No need for a laptop... just a switch to put it in calibrate mode, and a
serial EEPROM... and some PICs even contain those I think. Switch to
"calibrate" mode, have it light each bar of a bar-mode display
sequentially, then add the desired amount of fuel to be represrented by
that display element, and push a button to "capture" that A/D value -
let it build it's own lookup table.
Hmmm, maybe I'll make one.
-John R.
Robert L. Nuckolls, III wrote:
>--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <bob.nuckolls@cox.net>
>
>At 01:47 PM 5/14/2003 -0400, you wrote:
>
>
>>--> AeroElectric-List message posted by: "Eric M. Jones" <emjones@charter.net>
>>
>>Jerzy--Of course you are right. I was hoping this detail would fall into
>>place, since there are some issues yet to be resolved.
>>
>>Bob and Jerzy and others. You would be right to guess I am more
>>comfortable with op amps than with microprocessors. I returned to using
>>discrete chips after receiving the source code for a device of similar
>>complexity....and it is 25 pages of assembler. The notion that using a
>>microprocessor instead of a couple of chips should best be argued upon the
>>completion of parallel projects. Believe me, I am wholeheartedly a
>>microprocessor fan, but not in this design.
>>
>>
>
> Hmmm . . . I'll bet the code to read an a/d, get the first
> lookup table values above and below the reading and average
> them for output to a d/a wouldn't fill one page.
>
>
>
>
>>Besides....analog input, analog output, and don't a few op amps and
>>comparators make an analog "computer"?
>>
>>
>
>
> There are some single chip processors with an a/d and
> d/a built in that would do this. Check out the PIC12F675
> data sheet at
> http://www.microchip.com/download/lit/pline/picmicro/families/12f6xx/41190c.pdf
>
> and application tips at:
>
> http://www.microchip.com/download/lit/pline/picmicro/families/12f6xx/40040b.pdf
>
> This device sells for under $3 from Digikey and will do about
> everything you need to do in one chip . . . in fact, it
> might be possible to do a DUAL linearizer in the same chip
> so that both tanks can be calibrated on one assembly.
> You can talk to the a/d directly from the tank sender
> driven by a constant current source. A relatively simple
> routine to drive a fet with a variable duty-cycle would
> provide for analog i/o to drive the standard gage that
> comes with the senders.
>
> The hardest part would be to write the program to go into
> a laptop for consumers to talk to the chip and modify its
> lookup table. Visual Basic would probably help with a
> user-friendly windows-like interface.
>
> I'm finding it increasingly difficult to justify even
> simple projects in analog and/or discrete logic parts
> any more. The chips are just too cheap and getting
> more powerful all the time.
>
> Bob . . .
>
>
>
>
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