Today's Message Index:
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1. 05:04 AM - Re: Stobes (stearman456)
2. 07:03 AM - Re: Stobes (Eric M. Jones)
3. 10:10 AM - Re: Expanded horizons for the List?Marketing suggestion (Terry Watson)
4. 11:32 AM - Re: Re: wingtip vor antenna (Mark Harris)
5. 06:43 PM - Re: Expanded horizons for the List?Marketing suggestion (nuckollsr)
6. 07:11 PM - Re: Re: Expanded horizons for the List?Marketing suggestion (Neal George)
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tperry(at)lvtofly.com wrote:
> Advantage is less noise from the high voltage lines running the length of your
airplane. Also your strobes are independent of one another, if you loose one
power supply your other strobes still work.
That makes sense - the kit with the three power supplies is slightly more expensive
but I can afford the weight of the extra units. Flying an airplane with noisy
strobes has always driven me nuts in the past.
Any advice on building the ultimate in quiet strobe installations (Whelen A 490A,TS,CF
Power Supplies) appreciated.
Dan
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=369286#369286
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Bob N. saiys:
> I would offer that centralized
> supplies are also qualified, i.e. have passed DO-160
> conducted and radiated emissions. So if installed with
> attention to good practice for treatment of shields,
> they should present no greater noise problem in an
> OBAM aircraft than they do in a TC aircraft.
I agree Bob, but the basic EMC rule of fixing the noise at its source is a good
one, and this points in the direction of putting the HV very close to the strobe
tubes. If a standard installation works well, that does not mean a global
shift in design is unwise, particularly if some particular design has problems.
Bob N. says:
> All the strobes on turbine aircraft have local power
> supplies but as you've noted, these are breathtakingly
> expensive.
This is interesting Bob. I wonder if there are some additional design forces at
work here?
> What kind of voltages/currents and duty cycles
> are involved? I've seen some LED anti-collision
> protects offered to HBC while I was still there but
> folks who showed them to me were unable or reluctant
> to discuss design details.
>
> What's the architecture for wiring up large arrays
> of LED's. The tail strobe I saw had about 36 leds
> in it. The guy thought it was 4 strings of 9 each.
> At 4 volts per led in an overdriven pulse mode,
> one comes to believe that a pulsed, 36 volt constant
> current supply is used. What approach has been most
> attractive in your experience?
Bob, I try to stay away from boosted switch-mode LED supplies of any sort. The
reason for these (one presumes) is that common lighting is often in strings that
make difficult parallel wiring, or that parallel lights demand higher currents,
which in some instances is difficult to achieve. But having only 12-28 voltage
"Luminaries" allows designs of large parallelism. But this is simple on
a PCB. My discontinued (but fabulous) LED position light was 4 strings of 3 (70
mA) LEDs. My LED tail light is a single beefy 1200 mA LED with a linear LM317
regulator. Totally EMC silent.*
> I've sold perhaps 50 filtered supplies over the past 4-5 years
> and perhaps half that number of filter boards for
> folks who already had supply modules.
> Bob . . .
*As an aside. These supplies were Luxdrive Power Pucks (I don't think Luxeon is
involved). You are to be congratulated on quieting these demons. I gave up and
dissolved away the potting to examine the PCB. The design was quite clearly
laid out by someone who had never taken a Kimmel Gerke course. I toyed with the
notion of redesigning the device, but finally sold my shelf full of them on
Ebay, converted all my designs to linears, and washed my hands of it.
Some data and comments:
The Whelen strobe anti-collision power supply output nominal is 550V. This fact
alone would make distributed supplies a good design choice. Separate supplies
at the tubes should theoretically weigh less if the supporting structure and
wiring is included, but the comparison is hard to glean from the published Whelen
data. Whelen has one spearate strobe supply that says "cannot be synchronized",
which is weird when you understand how little it takes to do so.
My "vapor-ware" design uses a parallel string of two RED leds. Oddly, the FAA has
had a long love affair with neon tubes since the 1930s, so red is a permissible
color and red LEDs have the highest efficiency. (But the human visual response
is best at 555 nm yellow green...the color under the African jungle canopy).
Xenon blue-white strobes are easy to make. (A side note for your kid's science
project...Radon should make great flash tubes..unfortunately all radon isotopes
are radioactive.)
But I digress.... My design uses an array of red LEDs for 12V, and a parallel array
of 4 for 28V. powered by small local supercaps (hey, why not?). Each LED
"strobe lamp" is basically pulsed on and off and synchronized by a central circuit
the size of a postage stamp. The power to the LED strobes is the same as
the position lights.
I would gladly publish the circuit but it is incomplete...as is my Glastar, which
I'd better start working on. My electro-whizzie work has slowed down since
I spend much of my time selling switch guards. NASCAR is also a big market. See
attached. (The Redbull team was so secret at first I thought they had to be
spooks!)
--------
Eric M. Jones
www.PerihelionDesign.com
113 Brentwood Drive
Southbridge, MA 01550
(508) 764-2072
emjones(at)charter.net
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Subject: | Re: Expanded horizons for the List?Marketing suggestion |
Bob, I was so pleased to see you mention the Khan Academy. It is a great example
- as is your aeroelectric list - of the extraordinary but becoming ordinary
benefits of modern information technology.
To you and those of your readers who might want to avoid being blind-sided by the
accelerating rate of change of our probable future, I want to recommend a new
book: "Abundance: The Future is Better Than You Think", by Peter Diamandis.
I don't think I have read anything in the 32 years since Alvin Toffler's "The
Third Wave" that made me more excited and optimistic about the near future.
To add a note of credibility to the Abundance book for aeroelectric list subscribers,
Peter Diamandis is the man who created the X prize that inspired Paul Allen
to finance Burt Rutan to put the first private astronauts into space. He
has gone on to create other X prizes which you will read about in the book. What's
so amazing is how rapidly the very high bar set for the prizes is being achieved.
Just Google "Abundance" and you will find links to the book's website and to Amazon
if you want to read reviews or buy it.
Terry
RV-8A stalled
Seattle
Message 4
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Subject: | Re: wingtip vor antenna |
Hi Bob
Just another quick question I fabricated the parts for the VOR antenna today.is
it ok to alocrom the parts before assembly and then would paint etch prime be
ok ,I would bear the connection points.
Thanks
Mark
Rent our beautiful 3 bedroom luxury villa in Orlando, Florida.
View our virtual tour but book direct with us. See the link below:-
http://www.florida1strentals.com/property.php?id=21
Contact Emma and Mark Harris 01582 529820
harrisfloridavilla@hotmail.com
On 21 Mar 2012, at 01:50, "Robert L. Nuckolls, III" <nuckolls.bob@aeroelectric.com>
wrote:
>
> At 02:18 PM 3/20/2012, you wrote:
>>
>> Cheers Bob
>>
>> Looks like a job for the weekend
>
> Do you have access to an antenna analyzer or
> at least an SWR meter?
>
>
> Bob . . .
>
>
>
>
>
Message 5
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Subject: | Re: Expanded horizons for the List?Marketing suggestion |
Thank you for the recommendation. I'll get it. Speaking of "abundance', I'm finding
it easy to be overwhelmed by the quantity and scope of good data available
off the 'net for the time and effort to download . . . THEN comes the investment
of time to absorb it.
I had seen some of Milton Friedman's work in 10 minute chunks . . . but somebody
turned me on to "Free to Choose" in 10 segments and downloadable from YouTube.
I captured all the videos and now need to get them watched. I think I may
strip off the audio so I can listen to them in the car. I do spend a lot of time
on the road these days.
Dr. Dee turned me onto Kahn. She too has an intense interest in the video mini-lecture
technique. There are a few important points in her statistics classes
that are common stumbling blocks for some students. While fully willing to explain
the material again, students who are already on board are not too happy about
'back tracking'. We've decided to do some mini-lectures on those sicking
points that can be accessible to any Bethany student 24/7.
The hope is that these productions will bring the lagging students up at their
own speed/convenience, provide good review for the rest, and make progress in
the class room match the syllabus. We have similar situations here on the List
in what has been called 'frequently asked questions'.
An exciting 'new' concept, at least for me. Once I'm comfortable with the mechanics
of production and we have Dr. Dee's most pressing needs addressed, I'll be
looking for suggestions from folks here on the List for topics to be 'canned'
in a similar fashion.
Thanks for the tip!
Bob . . .
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=369311#369311
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Subject: | Re: Expanded horizons for the List?Marketing suggestion |
Bob - care to share that link?
neal
-----Original Message-----
From: nuckollsr
I had seen some of Milton Friedman's work in 10 minute chunks . . . but
somebody turned me on to "Free to Choose" in 10 segments and downloadable
from YouTube.
Bob . . .
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