LED / Nav lights

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

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

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

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

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)

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 he 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)

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

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

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

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