LED / Nav lights

[Scott Gettings]

Recently I posted some questions regarding this issue. After some
experimentation, it appears that LEDs and inexpensive strobes are indeed
a feasible option for experimental a/c.

Following a presentation at our recent EAA meeting, our most senior DAR
liked the mock-ups so well that he will install some LEDs on his own
plane! He has no problem approving an appropriate LED/nav installation
as long as the visibility geometry is appropriate.

To see an article on using LEDs and inexpensive strobes, feel free to
visit our EAA site, scroll down to the member news area and click on the
obvious link. http://www.eaa724.org/

Scott Gettings
Glass Goose

[Morgans]

"Scott Gettings" > wrote

> To see an article on using LEDs and inexpensive strobes, feel free to
> visit our EAA site, scroll down to the member news area and click on the
> obvious link. http://www.eaa724.org/
>
> Scott Gettings
> Glass Goose
>
It was not so obvious to me. How about a direct link, or a clue?
--
Jim in NC


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Outgoing mail is certified Virus Free.
Checked by AVG anti-virus system (http://www.grisoft.com).
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[Evan Carew]

-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1

Morgans wrote:
> "Scott Gettings" > wrote
>
>
>>To see an article on using LEDs and inexpensive strobes, feel free to
>>visit our EAA site, scroll down to the member news area and click on the
>>obvious link. http://www.eaa724.org/
>>
>>Scott Gettings
>>Glass Goose
>>
>
> It was not so obvious to me. How about a direct link, or a clue?
try:
http://www.eaa724.org/MeetingsEvents.html#anchorMeeting031004
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[Morgans]

"Evan Carew" > wrote
> try:
> http://www.eaa724.org/MeetingsEvents.html#anchorMeeting031004

Thanks. Good stuff.
--
Jim in NC


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Checked by AVG anti-virus system (http://www.grisoft.com).
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[COUGARNFW]

Scott...

That is the best eaa site I have visited.

Guessed which was the LED story and read it all.

Good job.

Last week, I attended the farcical FAA-sponsored maintenance seminar and the GE
lighting people were there for the first time.

I had a good discussion with them as to why the Q4509 bulbs burn up when used
continuously as so many do these days (not designed for continuous, and never
tested that way and a surprise that people use them as get out of my way
lights) and they were queried about LED's and the "blue lights" which are such
a pain when on cars.

LED lights are being "looked at".

The blue lights (high intensity discharge) are being evaluated but they have
found too few willing to pay the high prices for it to be a product for
them...yet.

Thanks for the site info and the lead to the article.

Neal

[Info]

We run LED lights on the Pipistrel Motorgliders,
http://www.pipistrel-usa.com they seem to work really well and are
lower power consumption which is important for gliding. They are made by
BW Avio in Italy www.bwavio.com and have a 4 year gaurantee.



COUGARNFW wrote:
> Scott...
>
> That is the best eaa site I have visited.
>
> Guessed which was the LED story and read it all.
>
> Good job.
>
> Last week, I attended the farcical FAA-sponsored maintenance seminar and the GE
> lighting people were there for the first time.
>
> I had a good discussion with them as to why the Q4509 bulbs burn up when used
> continuously as so many do these days (not designed for continuous, and never
> tested that way and a surprise that people use them as get out of my way
> lights) and they were queried about LED's and the "blue lights" which are such
> a pain when on cars.
>
> LED lights are being "looked at".
>
> The blue lights (high intensity discharge) are being evaluated but they have
> found too few willing to pay the high prices for it to be a product for
> them...yet.
>
> Thanks for the site info and the lead to the article.
>
> Neal

[Evan Carew]

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Hash: SHA1

For those of you trying to convert between Lumins & candel power, the
formula is as follows:
1 cd = 12.5664 lumen
1 Lumen = .001496 wats
1 lumen/sq ft = 1 ft. candel

Hope you find this useful

Evan
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=+4F5
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[Scott Gettings]

Glad you guys found this useful.

Our DAR says that they don't make specific demands regarding how something is
done, so LEDs are fine as long as they are bright enough and have the necessary
visibility pattern. He saw no problem whatsoever using LEDs for these lights.

I noted in one of my aviation mags that Whelen has a $700+ vertical stab. LED
strobe light! Probably doesn't include the power supply. This is obscene and
could easily be done with a set of Luxeon 5-watt white LEDs in a circular pattern.

Some 3-rd parties are trying to market various combinations, but unless you need
very special hardware, you can just make these yourself at a fraction of the cost.

Good luck.

Scott

COUGARNFW wrote:

> Scott...
>
> That is the best eaa site I have visited.
>
> Guessed which was the LED story and read it all.
>
> Good job.
>
> Last week, I attended the farcical FAA-sponsored maintenance seminar and the GE
> lighting people were there for the first time.
>
> I had a good discussion with them as to why the Q4509 bulbs burn up when used
> continuously as so many do these days (not designed for continuous, and never
> tested that way and a surprise that people use them as get out of my way
> lights) and they were queried about LED's and the "blue lights" which are such
> a pain when on cars.
>
> LED lights are being "looked at".
>
> The blue lights (high intensity discharge) are being evaluated but they have
> found too few willing to pay the high prices for it to be a product for
> them...yet.
>
> Thanks for the site info and the lead to the article.
>
> Neal

[Scott Gettings]

Sorry this was not so "obvious".

Scroll about 1/4 way down the page and click on the "more" beside the picture
of the nav/strobe light demonstration.

Scott

Morgans wrote:

> "Scott Gettings" > wrote
>
> > To see an article on using LEDs and inexpensive strobes, feel free to
> > visit our EAA site, scroll down to the member news area and click on the
> > obvious link. http://www.eaa724.org/
> >
> > Scott Gettings
> > Glass Goose
> >
> It was not so obvious to me. How about a direct link, or a clue?
> --
> Jim in NC
>
> ---
> Outgoing mail is certified Virus Free.
> Checked by AVG anti-virus system (http://www.grisoft.com).
> Version: 6.0.629 / Virus Database: 403 - Release Date: 3/17/2004

[Blueskies]

I like the idea of a 'rotating beacon' of white LEDs. Fire them off in sequence around and around. Would save power over
firing them off all at once...

--
Dan D.



..
"Scott Gettings" > wrote in message ...
> Glad you guys found this useful.
>
> Our DAR says that they don't make specific demands regarding how something is
> done, so LEDs are fine as long as they are bright enough and have the necessary
> visibility pattern. He saw no problem whatsoever using LEDs for these lights.
>
> I noted in one of my aviation mags that Whelen has a $700+ vertical stab. LED
> strobe light! Probably doesn't include the power supply. This is obscene and
> could easily be done with a set of Luxeon 5-watt white LEDs in a circular pattern.
>
> Some 3-rd parties are trying to market various combinations, but unless you need
> very special hardware, you can just make these yourself at a fraction of the cost.
>
> Good luck.
>
> Scott
>
> COUGARNFW wrote:
>
> > Scott...
> >
> > That is the best eaa site I have visited.
> >
> > Guessed which was the LED story and read it all.
> >
> > Good job.
> >
> > Last week, I attended the farcical FAA-sponsored maintenance seminar and the GE
> > lighting people were there for the first time.
> >
> > I had a good discussion with them as to why the Q4509 bulbs burn up when used
> > continuously as so many do these days (not designed for continuous, and never
> > tested that way and a surprise that people use them as get out of my way
> > lights) and they were queried about LED's and the "blue lights" which are such
> > a pain when on cars.
> >
> > LED lights are being "looked at".
> >
> > The blue lights (high intensity discharge) are being evaluated but they have
> > found too few willing to pay the high prices for it to be a product for
> > them...yet.
> >
> > Thanks for the site info and the lead to the article.
> >
> > Neal
>

[Ernest Christley]

Scott Gettings wrote:
> Glad you guys found this useful.
>
> Our DAR says that they don't make specific demands regarding how something is
> done, so LEDs are fine as long as they are bright enough and have the necessary
> visibility pattern. He saw no problem whatsoever using LEDs for these lights.
>
> I noted in one of my aviation mags that Whelen has a $700+ vertical stab. LED
> strobe light! Probably doesn't include the power supply. This is obscene and
> could easily be done with a set of Luxeon 5-watt white LEDs in a circular pattern.
>
> Some 3-rd parties are trying to market various combinations, but unless you need
> very special hardware, you can just make these yourself at a fraction of the cost.
>

You can actually make them much cheaper without the Luxeon and get the
pattern closer to the FAA spec. Buy the LED's from SuperBright LED
(sorry, can't remember the website). Their website will show the light
patter makes for each of the LED's and how much power they put out. The
FAR's specify how much light must shine where. Pick out the LED
combinations that will put the right amount of light in the right places.

Take a piece of 1/4" plexiglass. Drill holes that will be a tight fit
for the LEDs at angles that will point them where they should shine.
Push the LEDs into the holes, solder some resistors directly to the
leads, and pot the backside of the whole thing. You have a solid chunk
of plastic that will blind you at night if you put 12V across it.

--
http://www.ernest.isa-geek.org/
"Ignorance is mankinds normal state,
alleviated by information and experience."
Veeduber

[Scott Gettings]

Ernest Christley wrote:

> Scott Gettings wrote:
> > Glad you guys found this useful.
> >
> > Our DAR says that they don't make specific demands regarding how something is
> > done, so LEDs are fine as long as they are bright enough and have the necessary
> > visibility pattern. He saw no problem whatsoever using LEDs for these lights.
> >
> > I noted in one of my aviation mags that Whelen has a $700+ vertical stab. LED
> > strobe light! Probably doesn't include the power supply. This is obscene and
> > could easily be done with a set of Luxeon 5-watt white LEDs in a circular pattern.
> >
> > Some 3-rd parties are trying to market various combinations, but unless you need
> > very special hardware, you can just make these yourself at a fraction of the cost.
> >
>
> You can actually make them much cheaper without the Luxeon and get the
> pattern closer to the FAA spec. Buy the LED's from SuperBright LED
> (sorry, can't remember the website). Their website will show the light
> patter makes for each of the LED's and how much power they put out. The
> FAR's specify how much light must shine where. Pick out the LED
> combinations that will put the right amount of light in the right places.
>
> Take a piece of 1/4" plexiglass. Drill holes that will be a tight fit
> for the LEDs at angles that will point them where they should shine.
> Push the LEDs into the holes, solder some resistors directly to the
> leads, and pot the backside of the whole thing. You have a solid chunk
> of plastic that will blind you at night if you put 12V across it.
>
> --
> http://www.ernest.isa-geek.org/
> "Ignorance is mankinds normal state,
> alleviated by information and experience."
> Veeduber

Look at the specs for Superbright LEDs (http://www.superbrightleds.com/leds.htm).

These don't come close to the Luxeon. Superbrights are 3-13 candles (divide mcd by
1,000), while Luxeon can deliver up to 120 lumens (120 candles in 1 sq. foot at one
foot distance). That is the problem with most other LEDs: they just aren't bright
enough.

Scott Gettings

[Ernest Christley]

Scott Gettings wrote:
>
> Ernest Christley wrote:
>
>>
>>You can actually make them much cheaper without the Luxeon and get the
>>pattern closer to the FAA spec. Buy the LED's from SuperBright LED
>>(sorry, can't remember the website). Their website will show the light
>>patter makes for each of the LED's and how much power they put out. The
>>FAR's specify how much light must shine where. Pick out the LED
>>combinations that will put the right amount of light in the right places.
>>
>>Take a piece of 1/4" plexiglass. Drill holes that will be a tight fit
>>for the LEDs at angles that will point them where they should shine.
>>Push the LEDs into the holes, solder some resistors directly to the
>>leads, and pot the backside of the whole thing. You have a solid chunk
>>of plastic that will blind you at night if you put 12V across it.
>>
>>--
>>http://www.ernest.isa-geek.org/
>>"Ignorance is mankinds normal state,
>> alleviated by information and experience."
>> Veeduber
>
>
> Look at the specs for Superbright LEDs (http://www.superbrightleds.com/leds.htm).
>
> These don't come close to the Luxeon. Superbrights are 3-13 candles (divide mcd by
> 1,000), while Luxeon can deliver up to 120 lumens (120 candles in 1 sq. foot at one
> foot distance). That is the problem with most other LEDs: they just aren't bright
> enough.
>
> Scott Gettings
>

I used 10 of them, if I remember correctly. I've gotta get around to
taking pictures of that thing. It is much brighter than the taillights
I've compared it to. I can make it brighter by adding more. The
problem with the Luxeon is that the pattern is set already, and if you
check the FARs, the pattern is as important as the intensity (as it
should be...what do you do when you see the red, green and white light?)

BTW, all LED's can be 'overclocked' by pulsing them at a high freqency.
The current rating is limited by the heat it produces. The light is a
function of the voltage. Pulse the light and get more light, but don't
leave it on long enough to burn the LED.

--
http://www.ernest.isa-geek.org/
"Ignorance is mankinds normal state,
alleviated by information and experience."
Veeduber

[Greg Reid]

I'm surprised nobody has posted this website yet --
http://www.killacycle.com/Lights.htm -- where the guy offers a pretty
nice kit at a pretty reasonable price. It'll save you the time/hassle
of digging up all this stuff yourself. (I have no financial interest,
other than in buying a kit myself.)

Greg Reid

[Veeduber]

>That is the problem with most other LEDs: they just aren't bright
>enough.
>
>Scott Gettings

-------------------------------------------------------

So use more of them. Run them about 20% over-voltage and pulse them. So it
reduces your MTBF from 50,000 hours to 10,000... big deal.

As I understand it, Luxeon is simply multiple LED's on a single substrate.
Same physics but more output from a single package. Given the present-day cost
of ultrabrights from new/surplus retailers, anyone capable of making up a
simple circuit board and rolling their own pulse circuit can enjoy a
significant advantage over the high priced stuff.

Indeed, I think there are advantages other than price to using a larger number
of discrete LED's, one of which is the ability to pulse them in patterns, leave
a core of 'always-on' lamps as a running light and so forth.

-R.S.Hoover (KA6HZF)

[Blueskies]

The Luxeon LEDs have a special heat sink built in during construction of the chip which provides better heat dissipation
and therefore a single element can put off more light. The also have single element emmiters that can be arranged in
whatever pattern you like.

More details here: http://www.lumileds.com/products/family.cfm?familyId=1
and http://www.lumileds.com/pdfs/protected/AB07.PDF

--
Dan D.



..
"Veeduber" > wrote in message ...
> >That is the problem with most other LEDs: they just aren't bright
> >enough.
> >
> >Scott Gettings
>
> -------------------------------------------------------
>
> So use more of them. Run them about 20% over-voltage and pulse them. So it
> reduces your MTBF from 50,000 hours to 10,000... big deal.
>
> As I understand it, Luxeon is simply multiple LED's on a single substrate.
> Same physics but more output from a single package. Given the present-day cost
> of ultrabrights from new/surplus retailers, anyone capable of making up a
> simple circuit board and rolling their own pulse circuit can enjoy a
> significant advantage over the high priced stuff.
>
> Indeed, I think there are advantages other than price to using a larger number
> of discrete LED's, one of which is the ability to pulse them in patterns, leave
> a core of 'always-on' lamps as a running light and so forth.
>
> -R.S.Hoover (KA6HZF)

[Blueskies]

There is not a white kit there...

--
Dan D.



..
"Greg Reid" > wrote in message
om...
> I'm surprised nobody has posted this website yet --
> http://www.killacycle.com/Lights.htm -- where the guy offers a pretty
> nice kit at a pretty reasonable price. It'll save you the time/hassle
> of digging up all this stuff yourself. (I have no financial interest,
> other than in buying a kit myself.)
>
> Greg Reid

[Scott Gettings]

This site was noticed during my original research. $120 per position
light is not very reasonable in my opinion, when you can get a certified
light for not that much more.
On the other hand you can buy a pair of 1-watt red Luxeons for about $20,
and a single, 3-watt green one for about $15. Their 140-degree
"lambertian" pattern is easily wide enough for nav lights, especially if
you use two of them 90 degrees apart. Most other LEDs have very narrow
visibility geometry and have far less light output. Many trying to use
them have given up.

For strobes, surely you can solder together numerous white LEDs in a
360-degree or other geometry. If a "high-powered" LED produces 4
candlepower (4,000 mcd), you'll still need over 100 of them! Or you can
use a few, newer Luxeon LEDs that are still relatively inexpensive. I
calculated you'll spend about $75 for Luxeons that produce over 400 cp
and only have to assemble a small number of LEDs.

I have no financial interest in Luxeon or any other LED product. My
comments were solely to let builders know there is another viable option
and give them another possibility to save money by building it
themselves.

Scott Gettings

Greg Reid wrote:

> I'm surprised nobody has posted this website yet --
> http://www.killacycle.com/Lights.htm -- where the guy offers a pretty
> nice kit at a pretty reasonable price. It'll save you the time/hassle
> of digging up all this stuff yourself. (I have no financial interest,
> other than in buying a kit myself.)
>
> Greg Reid

[Jerry Springer]

Scott Gettings wrote:
> This site was noticed during my original research. $120 per position
> light is not very reasonable in my opinion, when you can get a certified
> light for not that much more.

Read it again, it is NOT per light it is for both of them. It really is pretty
reasonable when you consider all the enginering and boards are already done.

Jerry

[Ernest Christley]

Scott Gettings wrote:
> This site was noticed during my original research. $120 per position
> light is not very reasonable in my opinion, when you can get a certified
> light for not that much more.
> On the other hand you can buy a pair of 1-watt red Luxeons for about $20,
> and a single, 3-watt green one for about $15. Their 140-degree
> "lambertian" pattern is easily wide enough for nav lights, especially if
> you use two of them 90 degrees apart. Most other LEDs have very narrow
> visibility geometry and have far less light output. Many trying to use
> them have given up.
>
> For strobes, surely you can solder together numerous white LEDs in a
> 360-degree or other geometry. If a "high-powered" LED produces 4
> candlepower (4,000 mcd), you'll still need over 100 of them! Or you can
> use a few, newer Luxeon LEDs that are still relatively inexpensive. I
> calculated you'll spend about $75 for Luxeons that produce over 400 cp
> and only have to assemble a small number of LEDs.
>
> I have no financial interest in Luxeon or any other LED product. My
> comments were solely to let builders know there is another viable option
> and give them another possibility to save money by building it
> themselves.

I'll have to agree with you on the advantage of the Luxeon for strobes.

However, for postition lights, the red and green have to span 110
degrees, and the white taillight has to span 140 degrees. Each one's
light output is to taper in the vertical direction. The individual
LED's are much easier to arrange and aim properly, and 10 or so aren't
that difficult to solder together. My airframe is steel tube, so I
already have a rather large heat sink 8*).

--
http://www.ernest.isa-geek.org/
"Ignorance is mankinds normal state,
alleviated by information and experience."
Veeduber

[Roger Halstead]

On Sat, 20 Mar 2004 00:25:32 GMT, Scott Gettings
> wrote:

>Sorry this was not so "obvious".
>
>Scroll about 1/4 way down the page and click on the "more" beside the picture
>of the nav/strobe light demonstration.
>
Just went through the information on the page and it looks good as
well as interesting. However I'd like to offer a warning.

The math and resistor rating concern me a tad. I may have misread, or
mis-calculated, but...

It talks about using two LEDs and dropping 7 volts at 0.35 A or ( 350
ma) and using a half watt, 20 ohm resistor.

It mentions the resistor getting hot. It should, they are over rating
the resistor by over a factor of 4 and that is with no safety factor.
It's not uncommon for a resistor to get hot, but they should not get
so hot you have to be concerned about them except in the case of wire
wound power resistors which may actually run quite hot.

R does = E/I and in this case 7/0.35 = 20 ohms but it needs to be
carried one step farther and figure the power as well.

Two ways, the first is simply the voltage times the current. You are
dropping 7 volts at 0.35 A = 2.45 watts.
Another way is P = I^2*R, or current squared multiplied by the
resistance. or (0.35 * 0.35) = 0.1225 * 20 = 2.45 watts.

Normally, we double the rating for safety so you need a 5 Watt
resistor, not a half watt.

You are dissipating 2.45 watts in a half watt resistor.
You could get away with that if the lights were pulsed, but in this
case they are on all the time. That much heat will cause the
resistor value to change and is a definite fire hazard.

Normally the resistor gets too hot and breaks, but I have see the
things start glowing. When they do that the resistance can become
quite low, rather than high and you run the risk of shorting the LEDs
which would increase the current even more.

Roger Halstead (K8RI & ARRL life member)
(N833R, S# CD-2 Worlds oldest Debonair)
www.rogerhalstead.com

>Scott
>
>Morgans wrote:
>
>> "Scott Gettings" > wrote
>>
>> > To see an article on using LEDs and inexpensive strobes, feel free to
>> > visit our EAA site, scroll down to the member news area and click on the
>> > obvious link. http://www.eaa724.org/
>> >
>> > Scott Gettings
>> > Glass Goose
>> >
>> It was not so obvious to me. How about a direct link, or a clue?
>> --
>> Jim in NC
>>
>> ---
>> Outgoing mail is certified Virus Free.
>> Checked by AVG anti-virus system (http://www.grisoft.com).
>> Version: 6.0.629 / Virus Database: 403 - Release Date: 3/17/2004

[Scott Gettings]

Ernest Christley wrote:

> Scott Gettings wrote:
> > This site was noticed during my original research. $120 per position
> > light is not very reasonable in my opinion, when you can get a certified
> > light for not that much more.
> > On the other hand you can buy a pair of 1-watt red Luxeons for about $20,
> > and a single, 3-watt green one for about $15. Their 140-degree
> > "lambertian" pattern is easily wide enough for nav lights, especially if
> > you use two of them 90 degrees apart. Most other LEDs have very narrow
> > visibility geometry and have far less light output. Many trying to use
> > them have given up.
> >
> > For strobes, surely you can solder together numerous white LEDs in a
> > 360-degree or other geometry. If a "high-powered" LED produces 4
> > candlepower (4,000 mcd), you'll still need over 100 of them! Or you can
> > use a few, newer Luxeon LEDs that are still relatively inexpensive. I
> > calculated you'll spend about $75 for Luxeons that produce over 400 cp
> > and only have to assemble a small number of LEDs.
> >
> > I have no financial interest in Luxeon or any other LED product. My
> > comments were solely to let builders know there is another viable option
> > and give them another possibility to save money by building it
> > themselves.
>
> I'll have to agree with you on the advantage of the Luxeon for strobes.
>
> However, for postition lights, the red and green have to span 110
> degrees, and the white taillight has to span 140 degrees. Each one's
> light output is to taper in the vertical direction. The individual
> LED's are much easier to arrange and aim properly, and 10 or so aren't
> that difficult to solder together. My airframe is steel tube, so I
> already have a rather large heat sink 8*).
>
> --
> http://www.ernest.isa-geek.org/
> "Ignorance is mankinds normal state,
> alleviated by information and experience."
> Veeduber

Go for it. Remember that the Lambertian pattern Luxeons have a 140-degree
pattern.

Scott

[Scott Gettings]

Jerry Springer wrote:

> Scott Gettings wrote:
> > This site was noticed during my original research. $120 per position
> > light is not very reasonable in my opinion, when you can get a certified
> > light for not that much more.
>
> Read it again, it is NOT per light it is for both of them. It really is pretty
> reasonable when you consider all the enginering and boards are already done.
>
> Jerry

Go for it. I'm sure they are happy to have your money.

Scott

[Scott Gettings]

Roger Halstead wrote:

> On Sat, 20 Mar 2004 00:25:32 GMT, Scott Gettings
> > wrote:
>
> >Sorry this was not so "obvious".
> >
> >Scroll about 1/4 way down the page and click on the "more" beside the picture
> >of the nav/strobe light demonstration.
> >
> Just went through the information on the page and it looks good as
> well as interesting. However I'd like to offer a warning.
>
> The math and resistor rating concern me a tad. I may have misread, or
> mis-calculated, but...
>
> It talks about using two LEDs and dropping 7 volts at 0.35 A or ( 350
> ma) and using a half watt, 20 ohm resistor.
>
> It mentions the resistor getting hot. It should, they are over rating
> the resistor by over a factor of 4 and that is with no safety factor.
> It's not uncommon for a resistor to get hot, but they should not get
> so hot you have to be concerned about them except in the case of wire
> wound power resistors which may actually run quite hot.
>
> R does = E/I and in this case 7/0.35 = 20 ohms but it needs to be
> carried one step farther and figure the power as well.
>
> Two ways, the first is simply the voltage times the current. You are
> dropping 7 volts at 0.35 A = 2.45 watts.
> Another way is P = I^2*R, or current squared multiplied by the
> resistance. or (0.35 * 0.35) = 0.1225 * 20 = 2.45 watts.
>
> Normally, we double the rating for safety so you need a 5 Watt
> resistor, not a half watt.
>
> You are dissipating 2.45 watts in a half watt resistor.
> You could get away with that if the lights were pulsed, but in this
> case they are on all the time. That much heat will cause the
> resistor value to change and is a definite fire hazard.
>
> Normally the resistor gets too hot and breaks, but I have see the
> things start glowing. When they do that the resistance can become
> quite low, rather than high and you run the risk of shorting the LEDs
> which would increase the current even more.
>
> Roger Halstead (K8RI & ARRL life member)
> (N833R, S# CD-2 Worlds oldest Debonair)
> www.rogerhalstead.com
>

Sound like good advice. My calculations were based on all the sources I've
found, but the above makes sense with its safety margins.

A 1/2 watt resistor doesn't get scalding hot, but hot enough. Using a
larger-wattage resistor (such as going to 5-watt) is easy, safer and certainly
cheap!

Scott

[Jerry Springer]

Scott Gettings wrote:
>
> Jerry Springer wrote:
>
>
>>Scott Gettings wrote:
>>
>>>This site was noticed during my original research. $120 per position
>>>light is not very reasonable in my opinion, when you can get a certified
>>>light for not that much more.
>>
>>Read it again, it is NOT per light it is for both of them. It really is pretty
>>reasonable when you consider all the enginering and boards are already done.
>>
>>Jerry
>
>
> Go for it. I'm sure they are happy to have your money.
>
> Scott
>
I am sure they would, My point was you said per unit and I said it included both.
You can use up a $120 worth of time pretty fast trying to trying to hay wire
someting together.

Jerry

[Michael Crowder]

Scott,

Thanks for the great information. I really like the new luxeon LED's.
I did a internet search and found that Honeywell has a LED position
light for business jets ......

http://www.grimesaero.com/info/literature/Astreon_wingposition.pdf

Looks like they using one Luxeon Star with lambertian distribution and
two Luxeon emitters with side emitter domes. They report a total of 9
watts so I wonder if they are using 3 three watt Luxeon III's?

Thanks again for the useful inforation.

--Mike
Sonex #293

[Scott Gettings]

Michael Crowder wrote:

> Scott,
>
> Thanks for the great information. I really like the new luxeon LED's.
> I did a internet search and found that Honeywell has a LED position
> light for business jets ......
>
> http://www.grimesaero.com/info/literature/Astreon_wingposition.pdf
>
> Looks like they using one Luxeon Star with lambertian distribution and
> two Luxeon emitters with side emitter domes. They report a total of 9
> watts so I wonder if they are using 3 three watt Luxeon III's?
>
> Thanks again for the useful inforation.
>
> --Mike
> Sonex #293

You are welcome, and correct re: the Luxeon IIIs. I wonder how much
Honeywell is charging to put 3 LEDs in their fixture? The Luxeons are
worth about $45 retail.

Scott

[Michael Crowder]

Scott Gettings > wrote in news:406B6C00.75AB45C3
@cfl.rr.com:


> You are welcome, and correct re: the Luxeon IIIs. I wonder how much
> Honeywell is charging to put 3 LEDs in their fixture? The Luxeons are
> worth about $45 retail.
>
> Scott
>

I wonder what they are doing for the Red LED's? Lumiled doesn't seem to
have the Luxeon III emitter in Red or Red/Orange colors, although the 1W
parts are pretty bright. The Honeywell datasheet doesn't show a difference
in current requirements between the RED and Green lights. I wonder what
they are doing.

--Mike
Sonex #293

[Dean Wilkinson]

Ernest Christley > wrote in message news:<YE47c.1569

> BTW, all LED's can be 'overclocked' by pulsing them at a high freqency.
> The current rating is limited by the heat it produces. The light is a
> function of the voltage. Pulse the light and get more light, but don't
> leave it on long enough to burn the LED.

While it is true that you can pulse current to LEDs to achieve a
higher peak output, this does not make it appear brighter to your eye.
The human eye integrates the light output as a time average, so an
LED that pulses at twice the current for 1/2 half the time will look
no brighter than one that is running steady state. In fact, it may
actually be dimmer because LED efficiency can drop at higher currents
due to current saturation of the junction hole/electron pair
generation/recombination function. There is a range of operation at
around 5Hz where pulsed light can appear brighter than steady state,
but this frequency range is too low to be useful because of the
visible flickering of the light. This is due to the psychophysical
characteristics of the human visual system.

Also, the total power dissipated by the LED package is a function of
the average current. Pulsing at twice the current for half the time
dissipates the same power as steady state operation. Proper heat
sinking of the device is important to maintain quantum efficiency
which is highest at cold temperatures and drops as the device heats
up.

PWM of LEDs is really only useful for dimming. At full on, it
operates steady state, and to dim it you start chopping the current
for longer and longer periods of time at the PWM frequency to dim the
device.

Dean Wilkinson
B.S.E.E.
Former Boeing 777 AIMS Display System engineer

[Scott Gettings]

Michael Crowder wrote:

> Scott Gettings > wrote in news:406B6C00.75AB45C3
> @cfl.rr.com:
>
> > You are welcome, and correct re: the Luxeon IIIs. I wonder how much
> > Honeywell is charging to put 3 LEDs in their fixture? The Luxeons are
> > worth about $45 retail.
> >
> > Scott
> >
>
> I wonder what they are doing for the Red LED's? Lumiled doesn't seem to
> have the Luxeon III emitter in Red or Red/Orange colors, although the 1W
> parts are pretty bright. The Honeywell datasheet doesn't show a difference
> in current requirements between the RED and Green lights. I wonder what
> they are doing.
>
> --Mike
> Sonex #293

Must be using 1 watt Luxeons. These are pretty bright at about 44 lumens. I
used 2 ($20 worth) in my left wingtip, and they are so bright you can't look
at them.

Scott

[Greg Reid]

FYI, here's another site for pre-made LED position lights:
http://www.periheliondesign.com/ledlights.htm

He has a Luxeon Star Portable 5.6W white tail-light too. (Might be
prohibitively expensive for many, tho'. These Luxeon's aren't cheap!)

(Again, for the record, I have no financial interest, blah blah blah.)

Greg Reid http://www.DivorceMagazine.com/Vision132

[Scott Gettings]

Greg Reid wrote:

> FYI, here's another site for pre-made LED position lights:
> http://www.periheliondesign.com/ledlights.htm
>
> He has a Luxeon Star Portable 5.6W white tail-light too. (Might be
> prohibitively expensive for many, tho'. These Luxeon's aren't cheap!)
>
> (Again, for the record, I have no financial interest, blah blah blah.)
>
> Greg Reid http://www.DivorceMagazine.com/Vision132

Actually, a 3w luxeon is less than $20 -- more than enough for any tail
light. The other $130 goes to the guy. Get a surplus housing and drop
in an LED!

(Also no financial interest).

Scott Gettings

[Pete Schaefer]

"Ernest Christley" > wrote in message
m...
> Scott Gettings wrote:
> > Glad you guys found this useful.
> >
> > Our DAR says that they don't make specific demands regarding how
something is
> > done, so LEDs are fine as long as they are bright enough and have the
necessary
> > visibility pattern. He saw no problem whatsoever using LEDs for these
lights.
> >
> > I noted in one of my aviation mags that Whelen has a $700+ vertical
stab. LED
> > strobe light! Probably doesn't include the power supply. This is
obscene and
> > could easily be done with a set of Luxeon 5-watt white LEDs in a
circular pattern.
> >
> > Some 3-rd parties are trying to market various combinations, but unless
you need
> > very special hardware, you can just make these yourself at a fraction of
the cost.
> >
>
> You can actually make them much cheaper without the Luxeon and get the
> pattern closer to the FAA spec. Buy the LED's from SuperBright LED
> (sorry, can't remember the website). Their website will show the light
> patter makes for each of the LED's and how much power they put out. The
> FAR's specify how much light must shine where. Pick out the LED
> combinations that will put the right amount of light in the right places.
>
> Take a piece of 1/4" plexiglass. Drill holes that will be a tight fit
> for the LEDs at angles that will point them where they should shine.
> Push the LEDs into the holes, solder some resistors directly to the
> leads, and pot the backside of the whole thing. You have a solid chunk
> of plastic that will blind you at night if you put 12V across it.
>
> --
> http://www.ernest.isa-geek.org/
> "Ignorance is mankinds normal state,
> alleviated by information and experience."
> Veeduber