1 watt and 5 watt LED for Nav lights?

To Jim Weir and Group

I am interested in using the new (to me) 1 watt and 5 watt LEDs for
nav lights.
Not having to worry about changing bulbs or the power requirements are
very attractive.

I have seen some posts about leds but would like to tie it all
together.
I know of two sites showing their versions and one is using 9 LEDs
while the other is using more.

What it boils down to is this: how many leds for the the right and
left wings, how many for the tail and can the leds be strobed or any
thing else I don't know?

Thanks
Bill

I'm not sure anybody really "knows". We've seen some subjective comments like
"boy they are really bright" and "gee, they sure are green", but I do not
believe anybody has quantitative data as to whether the actual FAR optical
specification has been met.

OTOH, I've seen some comments in here about the FAR specification being so
loosey-goosey that two birthday candles inside a wine bottle strapped to the
wingtip would be OK.

As you say, I'd like to see some hard photometric data taken with calibrated
equipment and a checklist of HOW this particular installation meets the FAR.

Jim



(Bill)
shared these priceless pearls of wisdom:

-To Jim Weir and Group
-
-I am interested in using the new (to me) 1 watt and 5 watt LEDs for
-nav lights.



Jim Weir (A&P/IA, CFI, & other good alphabet soup)
VP Eng RST Pres. Cyberchapter EAA Tech. Counselor
http://www.rst-engr.com

Jim Weir wrote:

I'm not sure anybody really "knows". We've seen some subjective comments
like "boy they are really bright" and "gee, they sure are green", but I do
not believe anybody has quantitative data as to whether the actual FAR
optical specification has been met.

OTOH, I've seen some comments in here about the FAR specification being so
loosey-goosey that two birthday candles inside a wine bottle strapped to
the wingtip would be OK.

As you say, I'd like to see some hard photometric data taken with
calibrated equipment and a checklist of HOW this particular installation
meets the FAR.

I'm just browsing (i.e. not building a plane) so I haven't got the FAR
regulations to hand. But I've played with Luxeons quite a lot so this
piqued my interest. What exactly are the FAR requirements?

Luxeon provide some good photometric data on their LEDs on their website.
http://www.lumileds.com/products/doc...ion_index.html
They give peak wavelengths, CIE chromaticity co-ordinates,
spectrophotometric measurements, deviation with temperature, luminous
efficiency...

IIRC the red-orange 1w LED gives out 55 Lumens of light output - which is an
order of magnitude better than a filtered lightbulb. Other colours give out
considerably less light - but even the green LED will be more efficient
than a green-filtered xenon-flash tube, for example.

Then there's the matter of making sure the right amount of light goes in the
right directions.

AC

Jim



(Bill)
shared these priceless pearls of wisdom:

-To Jim Weir and Group
-
-I am interested in using the new (to me) 1 watt and 5 watt LEDs for
-nav lights.



Jim Weir (A&P/IA, CFI, & other good alphabet soup)
VP Eng RST Pres. Cyberchapter EAA Tech. Counselor
http://www.rst-engr.com

anonymous coward wrote:
Jim Weir wrote:


I'm not sure anybody really "knows". We've seen some subjective comments
like "boy they are really bright" and "gee, they sure are green", but I do
not believe anybody has quantitative data as to whether the actual FAR
optical specification has been met.

OTOH, I've seen some comments in here about the FAR specification being so
loosey-goosey that two birthday candles inside a wine bottle strapped to
the wingtip would be OK.

As you say, I'd like to see some hard photometric data taken with
calibrated equipment and a checklist of HOW this particular installation
meets the FAR.


I'm just browsing (i.e. not building a plane) so I haven't got the FAR
regulations to hand. But I've played with Luxeons quite a lot so this
piqued my interest. What exactly are the FAR requirements?

Luxeon provide some good photometric data on their LEDs on their website.
http://www.lumileds.com/products/doc...ion_index.html
They give peak wavelengths, CIE chromaticity co-ordinates,
spectrophotometric measurements, deviation with temperature, luminous
efficiency...

IIRC the red-orange 1w LED gives out 55 Lumens of light output - which is an
order of magnitude better than a filtered lightbulb. Other colours give out
considerably less light - but even the green LED will be more efficient
than a green-filtered xenon-flash tube, for example.

Then there's the matter of making sure the right amount of light goes in the
right directions.

AC

Jim



(Bill)
shared these priceless pearls of wisdom:

-To Jim Weir and Group
-
-I am interested in using the new (to me) 1 watt and 5 watt LEDs for
-nav lights.



Jim Weir (A&P/IA, CFI, & other good alphabet soup)
VP Eng RST Pres. Cyberchapter EAA Tech. Counselor
http://www.rst-engr.com



The problem is that everyone uses a different yardstick to measure the
light output, and not all the yardsticks measure length.

Which would you rather have over your shop bench, one of those tiny LED
that are so bright you have to blink, or an 8ft flourescent that you can
stare at all day? Candles, watts, candella, lux, lumens...the terms go
on and on and what the FAA specifies may have more to do with
measurement convenience than they do safety. It's been a while, but the
FAA chose measurements that emphasize total light output, while all the
LED manufacturers use metrics that emphasize intensity.

Your tail light will cover the rear out to a 70* angle on each side, for
a 140* sweep. The marker light cover from directly ahead, back to the
70* mark.(Draw a circle and mark it off in 3 quadrants and you'll see
hwo this makes sense). Allmost all the ouput intensity is concentrated
on the level with it tapering to about 5% of the max at 85* up and down.
Note these are minimum values. More intensity is always a good thing.

I'm at work, but I'm thinking that it is all in FAR23-1490 (or within a
few paragraphs thereof).


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

Whelen is now selling LED nav lights.. green and red. I wonder if their
data (intensity, wavelenth) is readily available.. so they can show
proof of their compliance.

Dave

Ernest Christley wrote:
anonymous coward wrote:

Jim Weir wrote:


I'm not sure anybody really "knows". We've seen some subjective
comments
like "boy they are really bright" and "gee, they sure are green", but
I do
not believe anybody has quantitative data as to whether the actual FAR
optical specification has been met.

OTOH, I've seen some comments in here about the FAR specification
being so
loosey-goosey that two birthday candles inside a wine bottle strapped to
the wingtip would be OK.

As you say, I'd like to see some hard photometric data taken with
calibrated equipment and a checklist of HOW this particular installation
meets the FAR.



I'm just browsing (i.e. not building a plane) so I haven't got the FAR
regulations to hand. But I've played with Luxeons quite a lot so this
piqued my interest. What exactly are the FAR requirements?

Luxeon provide some good photometric data on their LEDs on their website.
http://www.lumileds.com/products/doc...ion_index.html
They give peak wavelengths, CIE chromaticity co-ordinates,
spectrophotometric measurements, deviation with temperature, luminous
efficiency...

IIRC the red-orange 1w LED gives out 55 Lumens of light output - which
is an
order of magnitude better than a filtered lightbulb. Other colours
give out
considerably less light - but even the green LED will be more efficient
than a green-filtered xenon-flash tube, for example.

Then there's the matter of making sure the right amount of light goes
in the
right directions.

AC

Jim



(Bill)
shared these priceless pearls of wisdom:

-To Jim Weir and Group
-
-I am interested in using the new (to me) 1 watt and 5 watt LEDs for
-nav lights.



Jim Weir (A&P/IA, CFI, & other good alphabet soup)
VP Eng RST Pres. Cyberchapter EAA Tech. Counselor
http://www.rst-engr.com




The problem is that everyone uses a different yardstick to measure the
light output, and not all the yardsticks measure length.

Which would you rather have over your shop bench, one of those tiny LED
that are so bright you have to blink, or an 8ft flourescent that you can
stare at all day? Candles, watts, candella, lux, lumens...the terms go
on and on and what the FAA specifies may have more to do with
measurement convenience than they do safety. It's been a while, but the
FAA chose measurements that emphasize total light output, while all the
LED manufacturers use metrics that emphasize intensity.

Your tail light will cover the rear out to a 70* angle on each side, for
a 140* sweep. The marker light cover from directly ahead, back to the
70* mark.(Draw a circle and mark it off in 3 quadrants and you'll see
hwo this makes sense). Allmost all the ouput intensity is concentrated
on the level with it tapering to about 5% of the max at 85* up and down.
Note these are minimum values. More intensity is always a good thing.

I'm at work, but I'm thinking that it is all in FAR23-1490 (or within a
few paragraphs thereof).

Just back from Sun-n-Fun and I saw Whelan has started to use LEDs. Picked up
there info but have not read it yet.

Dean
Cozy MK4
BKV FL

"Bill" wrote in message
om...
To Jim Weir and Group

I am interested in using the new (to me) 1 watt and 5 watt LEDs for
nav lights.
Not having to worry about changing bulbs or the power requirements are
very attractive.

I have seen some posts about leds but would like to tie it all
together.
I know of two sites showing their versions and one is using 9 LEDs
while the other is using more.

What it boils down to is this: how many leds for the the right and
left wings, how many for the tail and can the leds be strobed or any
thing else I don't know?

Thanks
Bill

Using the web, I found in part 23 section 23.1391 a list of the
intensity (candels) by angle required. From what it looks like,
someone measured the system that was already being made (a bulb and
filter) and put in in the book. So what this means is that you're
stuck emulating a technology inferior in almost every way using a new
technology. The spec emphasizes what light bulbs do well (high flux,
even illumination) and de-emphasizes what it doesn't (spectral purity,
reliability).

You could probably do the math from the minimum guaranteed intensity
and the beam shapes and meet the spec on paper, but it would be nice
to actually measure it. You can buy equipment to do this if you want
to add to your tool box yet another single purpose tool.

The other issue is that the manufacturer beam shapes are really a
little bogus because the high intensity LEDs use clear lenses and
actually project an image of the semiconductor chip inside. So
instead of a nice round shape, you get a picture of a little bright
chicklet and reflector cup.

So how many LEDs? Depends on if your using "typical" or minumum
guaranteed intensity. Depends on what direction you array them,
depends on what bin they came from, depends on a lot of things.




(Bill) wrote in message . com...
To Jim Weir and Group

I am interested in using the new (to me) 1 watt and 5 watt LEDs for
nav lights.
Not having to worry about changing bulbs or the power requirements are
very attractive.

I have seen some posts about leds but would like to tie it all
together.
I know of two sites showing their versions and one is using 9 LEDs
while the other is using more.

What it boils down to is this: how many leds for the the right and
left wings, how many for the tail and can the leds be strobed or any
thing else I don't know?

Thanks
Bill

Jay wrote:

Using the web, I found in part 23 section 23.1391 a list of the
intensity (candels) by angle required. From what it looks like,
someone measured the system that was already being made (a bulb and
filter) and put in in the book. So what this means is that you're
stuck emulating a technology inferior in almost every way using a new
technology. The spec emphasizes what light bulbs do well (high flux,
even illumination) and de-emphasizes what it doesn't (spectral purity,
reliability).

You could probably do the math from the minimum guaranteed intensity
and the beam shapes and meet the spec on paper, but it would be nice
to actually measure it. You can buy equipment to do this if you want
to add to your tool box yet another single purpose tool.

The other issue is that the manufacturer beam shapes are really a
little bogus because the high intensity LEDs use clear lenses and
actually project an image of the semiconductor chip inside. So
instead of a nice round shape, you get a picture of a little bright
chicklet and reflector cup.

This is very true for the LEDs with a very narrow beam (half angles down to
8-degrees or so) - but luxeons give a much broader beam and for whatever
reason this isn't the case in my experience (lambertian beam pattern only).
You can buy an optical widget that fits over the LED to make a narrower
beam again, and IMO your criticism is very valid for this case.

A solution is to shine the LEDs through some five or ten-degree holographic
diffusing filter from the POC (Physical Optics Corporation - if memory
serves). They're nice people to deal with, and were giving out free 1"
samples last time I asked.

AC

So how many LEDs? Depends on if your using "typical" or minumum
guaranteed intensity. Depends on what direction you array them,
depends on what bin they came from, depends on a lot of things.




(Bill) wrote in message
. com...
To Jim Weir and Group

I am interested in using the new (to me) 1 watt and 5 watt LEDs for
nav lights.
Not having to worry about changing bulbs or the power requirements are
very attractive.

I have seen some posts about leds but would like to tie it all
together.
I know of two sites showing their versions and one is using 9 LEDs
while the other is using more.

What it boils down to is this: how many leds for the the right and
left wings, how many for the tail and can the leds be strobed or any
thing else I don't know?

Thanks
Bill

Ok, Looked at the retro units at SNF and the associated specs. Red/green/
TSO'ed position lights. Contains 7 elements (appeared to be the Luxeon
style. 28 v @ .35 A for the total draw....looks like they are using the 1
watt style. Arrayed 2 rows 3 and 4 to a row. Don't see why we could not
build something similar from materials now available.

BTW, the list price is $460 each (WOW)

Dean
Cozy MK4
Bkv FL

"Bill" wrote in message
om...
To Jim Weir and Group

I am interested in using the new (to me) 1 watt and 5 watt LEDs for
nav lights.
Not having to worry about changing bulbs or the power requirements are
very attractive.

I have seen some posts about leds but would like to tie it all
together.
I know of two sites showing their versions and one is using 9 LEDs
while the other is using more.

What it boils down to is this: how many leds for the the right and
left wings, how many for the tail and can the leds be strobed or any
thing else I don't know?

Thanks
Bill

Dean Head wrote:
Ok, Looked at the retro units at SNF and the associated specs. Red/green/
TSO'ed position lights. Contains 7 elements (appeared to be the Luxeon
style. 28 v @ .35 A for the total draw....looks like they are using the 1
watt style. Arrayed 2 rows 3 and 4 to a row. Don't see why we could not
build something similar from materials now available.

BTW, the list price is $460 each (WOW)

Dean
Cozy MK4
Bkv FL


But you gotta remember, Dean, these are aircraft quality LEDs they're a
usin'. You can't get these LEDs from just any SuperBright LED supplier,
and you definitely won't get a paper trail that says they are in fact
"SuperBright LEDs". You get what you pay for.

(Now removing tongue from cheek)

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