LEDs with Strobe lights

[pekka1510]

Hello fellow aviators,

Does anyone has deeper knowledge of the following thing?
I have been thinking to modify Strobe/Nav.Light system. Halogen bulbs
will be replaced with ultra bright leds.
Benefits; low current draw, cheaper than incandenscent bulbs, long
life time.
Low points; narrow beam, mechanically challenging .... BUT....

Does semiconductor LEDs work near with strobe flashtubes (HIGH
VOLTAGE)??? I am looking ElectroMagneticCompatibility.

Anyone experiences or recommendations, please?

regards,
pekka, FL

[Juan E Jimenez]

I think you are going to have a hard time finding LED's that are bright
enough to do this and meet the FAA requirements for strobe lights.

Juan

"pekka1510" > wrote in message
om...
> Hello fellow aviators,
>
> Does anyone has deeper knowledge of the following thing?
> I have been thinking to modify Strobe/Nav.Light system. Halogen bulbs
> will be replaced with ultra bright leds.
> Benefits; low current draw, cheaper than incandenscent bulbs, long
> life time.
> Low points; narrow beam, mechanically challenging .... BUT....
>
> Does semiconductor LEDs work near with strobe flashtubes (HIGH
> VOLTAGE)??? I am looking ElectroMagneticCompatibility.
>
> Anyone experiences or recommendations, please?
>
> regards,
> pekka, FL

[Ron Natalie]

"Juan E Jimenez" > wrote in message news:2SP2b.268078$YN5.183108@sccrnsc01...
> I think you are going to have a hard time finding LED's that are bright
> enough to do this and meet the FAA requirements for strobe lights.
>
I believe he was only talking about replacing the NAV light part of the fixture.
He specifically asked if the LED's would survive near the flashtubes.

[Ron Natalie]

"pekka1510" > wrote in message
>
> Does semiconductor LEDs work near with strobe flashtubes (HIGH
> VOLTAGE)??? I am looking ElectroMagneticCompatibility.
>
> Anyone experiences or recommendations, please?
>
Can't answer the question about interoperability with flashtubes, but these
are starting to show up for marine use, however there's nowhere near
bright enough (at least the marine ones) to meet the Part 23 brightness
requirement for position lights.

You need up to 40 candela over 110 degrees horizontal and +/- 90
degrees vertical. Can be done I guess, but can't find anything canned
that has that kind of specs.

[Juan E Jimenez]

Absolutely correct. I misread.

"Ron Natalie" > wrote in message
m...
>
> "Juan E Jimenez" > wrote in message
news:2SP2b.268078$YN5.183108@sccrnsc01...
> > I think you are going to have a hard time finding LED's that are bright
> > enough to do this and meet the FAA requirements for strobe lights.
> >
> I believe he was only talking about replacing the NAV light part of the
fixture.
> He specifically asked if the LED's would survive near the flashtubes.
>
>

[Juan E Jimenez]

A while back Jim Weir said he was working on something like this -- at least
he was asking where to find the specs, then he asked if anyone had the
expertise and hardware to do the analysis of the output of the unit to see
if it met the specs. However, he did not say he was planning to put them
inside an assembly next to strobe flashtubes.

"Ron Natalie" > wrote in message
m...
>
> "pekka1510" > wrote in message
> >
> > Does semiconductor LEDs work near with strobe flashtubes (HIGH
> > VOLTAGE)??? I am looking ElectroMagneticCompatibility.
> >
> > Anyone experiences or recommendations, please?
> >
> Can't answer the question about interoperability with flashtubes, but
these
> are starting to show up for marine use, however there's nowhere near
> bright enough (at least the marine ones) to meet the Part 23 brightness
> requirement for position lights.
>
> You need up to 40 candela over 110 degrees horizontal and +/- 90
> degrees vertical. Can be done I guess, but can't find anything canned
> that has that kind of specs.
>
>

[Pete]

in assemblies they appear to be bright enough... see:

http://www.killacycle.com/Lights.htm

Or cert'd units from Whelen:
http://www.dallasavionics.com/whelen/

Cheers,
Pete
Europa Builder

"Ron Natalie" > wrote in message
m...
>
> "pekka1510" > wrote in message
> >
> > Does semiconductor LEDs work near with strobe flashtubes (HIGH
> > VOLTAGE)??? I am looking ElectroMagneticCompatibility.
> >
> > Anyone experiences or recommendations, please?
> >
> Can't answer the question about interoperability with flashtubes, but
these
> are starting to show up for marine use, however there's nowhere near
> bright enough (at least the marine ones) to meet the Part 23 brightness
> requirement for position lights.
>
> You need up to 40 candela over 110 degrees horizontal and +/- 90
> degrees vertical. Can be done I guess, but can't find anything canned
> that has that kind of specs.
>
>

[Dave S]

From my observations, I will say they are VERY compatible...

There are traffic signals on stretches of road that place white strobe
tubes across the red LED signals of the latest generation of stoplights,
as an attention-getter for the red light (I see it mostly on highways
that have a long stretch of nothing with a red light in the middle of
nowhere.. easy to get road hypnosis and ignore)...

Also, many of the latest generation emergency vehicle lighting signals
have both LED and Strobe tubes in close proximity.. and we are talking
LOTS of strobe tubes... not just one..

I do believe aviation tubes have a higher amount of joules than the
typical 10 joules used in public safety applications, but if
non-aviation applications are any indication, it should be workable.

Dave

Y
pekka1510 wrote:

> Hello fellow aviators,
>
> Does anyone has deeper knowledge of the following thing?
> I have been thinking to modify Strobe/Nav.Light system. Halogen bulbs
> will be replaced with ultra bright leds.
> Benefits; low current draw, cheaper than incandenscent bulbs, long
> life time.
> Low points; narrow beam, mechanically challenging .... BUT....
>
> Does semiconductor LEDs work near with strobe flashtubes (HIGH
> VOLTAGE)??? I am looking ElectroMagneticCompatibility.
>
> Anyone experiences or recommendations, please?
>
> regards,
> pekka, FL
>

[baltobernie]

The newest blue, white and green LEDs are static sensitive, and typical ESD
precautions are required during handling and assembly. Once installed as
part of a circuit, they should be resistant to damage. An interesting
question; lemme check with our engineers in Japan. I'll post when (if)
they respond. What is the voltage present at the tube?

Spatial distribution is going to be your greatest challenge, and you'll need
to design a multi-surfaced PCB to achieve the required viewing angle spec.

BTW, the newest LEDs have an intensity of 5 cd. New traffic signal designs
use only a few of these vs. hundreds of the "old" (last year's) ones.

I'm not well-versed in aviation lighting requirements, but I believe that
your green spec is a little towards the blue. Should not be a problem, you
can get "green" from 502 to 525 nm. Only one choice with one red, though,
at 625 nm dominant and 635 nm peak. Its the hue difference between
incandescent auto stoplamps and the LED center one. Perhaps OK for an
Experimental, but, again, I'm no expert.

Bernie
(remove my age to Reply)


> pekka1510 wrote:
>
> > Hello fellow aviators,
> >
> > Does anyone has deeper knowledge of the following thing?
> > I have been thinking to modify Strobe/Nav.Light system. Halogen bulbs
> > will be replaced with ultra bright leds.
> > Benefits; low current draw, cheaper than incandenscent bulbs, long
> > life time.
> > Low points; narrow beam, mechanically challenging .... BUT....
> >
> > Does semiconductor LEDs work near with strobe flashtubes (HIGH
> > VOLTAGE)??? I am looking ElectroMagneticCompatibility.
> >
> > Anyone experiences or recommendations, please?
> >
> > regards,
> > pekka, FL
> >
>

[baltobernie]

The new "high flux emitters" I referenced are packaged differently than the
conventional T-1 3/4 (5mm) LEDs. I haven't seen the design you describe
below, but LED leads are not designed to support the housing, particularly
in a wingtip environment. Also note that, while much more efficient than
incandescents, LEDs still have thermal management issues, particularly the
high power versions.

Bernie


Jay > wrote in message
om...
> "baltobernie" > wrote in message
et>...
> > Spatial distribution is going to be your greatest challenge, and you'll
need
> > to design a multi-surfaced PCB to achieve the required viewing angle
spec.
>
> At least one design bends the device leads at a variety of specific
> angles to attempt to get that distribution that's so natural for the
> incumbant incandescant bulb and color filter combination.
>
> As for color specs, the regular nav light color filters tend to bleach
> out after years in the sun. By comparison the LEDs should look pure.

[Ron Natalie]

"Ernest Christley" > wrote in message . com...

>
> There's an awful lot of cooling air out on those wingtips. Shoot, with
> a decent heatsink, something about the size of a wing maybe, I bet you
> wouldn't even need a fan.
>
Yep, ever touch an incadenscent nav light when the airplane is not moving?

[Matthew M. Jurotich]

FYI for those building the LED "Lights"


>Bill,
>
>I received the kits today, nice package!


Thanks! :
)



>I have several questions / comments:
>
>(1) Is the solder paste a no-wash paste, or should I clean the
> the board after soldering? If cleaning is needed, is it
> water based or should I use flux remover?


It is Kester "no clean" solder, but it does leave a residue. I
cleaned it off with 409 and it seemed to work.



>(2) Can I assume the 50, 80, and 85 degree LEDs bend away from
> the "Main Cluster" of LED's and the 70 degree bends toward
> the "Main Cluster"?


That is correct. You point the LEDs in the direction of the number
printed on the board. Notice that all the LEDs have their legs bent in the
same direction.


The reason I mounted the 70 degree upward and downward LEDs toward
the inside was to allow the zero degree LEDs to peek over and under a
strobe mounted in front of the board in the center of the wingtip.


You could, if you wanted to, bend the 70 degree LEDs towards the
middle of the board instead of towards the edge of the board as long as
you didn't mount the strobe flush against the board. If you think about it,
it will become obvious that the upper LEDs will do the job of the lower
LEDs, and vice versa. As long as two LEDs point down at a 70 degree angle,
it doesn't matter where they are mounted. The same is true for the
upward-pointing 70 degree LEDs.


Indecently, there is +/- 5 degrees of slop allowed in the angle of
the LEDs.


You can look at pictures of the assembly at:


http://www.killacycle.com/InstructionPictures.htm


I put this together after I sent the first few kits, so you didn't
get one. :
(


Be sure to check out the latest version of the instructions at:


http://www.killacycle.com/Instructions.htm



>(3) As I started to power up the green board (using an adjustable
> power supply) One of the LEDs came on "early". I thought there
> might be a problem, so I stopped, cut the wire on the resistor,
> and continued. All other LEDs worked great. Major bright!


Pictures don't do them justice, do they? Once you see then lit,
there is no question in anyone's mind that these will pass FAA and will
make your airplane very visible at night.


I've had folks ask me to just send them the boards and they would
get their own LEDs. They don't understand that these are nothing like the
LEDs they get at Radio Shack. The LEDs are the major fraction of the cost
of the kit. They are the hottest thing available. Note the large viewing
angle. These LEDs hump out some major photons.


> I then took a look at the board. All of the LEDs on the green
> are configured as pairs, except there are 27 (Odd Number) of
> LEDs.


The red ones are in threes. Red LEDs need less voltage than green
LEDs. I wanted to make the board be able to run full brightness at 10.5
volts, so I only put two green LEDs in series.


>It then hit me that the one comming on "early" was the
> single LED. So I re-soldered the resistor and slowly brought
> the unit back up to 12 volts. All is OK. I was just not
> expecting the single LED to come on first.


Good power-up procedure. Most folks just hook it up to a battery. ;
)


Cutting the wire was un cool. The resistor is a current sensing
feedback resistor. The regulator can go "full on" without it. The regulator
increases the current until it sees 1.2 volts across that resistor. This
could pop the LED.


Like the redundancy? I paired LEDs in a way that would allow
partial light in all directions if a part of the circuit failed. That is
why the traces on the board go every which ways.



>So far, so good. One green "light" assembly working.
>
>Feel free to post this to the internet if you think others might
>benefit from the answers.


Post it to the RV list if you like. It would be nice to have
someone that bought and assembled a kit give an independent revue.


Thanks for dropping me a note. Feel free to contact me if you have
any questions or comments.



Later, Jim Combs
Lexington, Ky
Waiting for Wings (RV-8A)

>