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)