LED Navigation Lights and Strobes
January 2nd, 2004:
Luxeon Releases new Emitter-III LEDs
Luxeon has released a new, lower cost
emitter that has resurrected the LED Nav Strobes
(at least for my interests!) The new emitters cost around $13 in Quantity
1 and can be
over-driven to some extent (necessary for cost-efficient strobes.
This started a re-engineering effort of the work that I did on this last
year, and I have
produced a set of PCB's for testing and evaluation (see pics below:)
In the picture above you can see (left to right) The Red Position Light
Assembly (with a sample
RED-LED Board and Driver in front of it), a White-LED Position Light Board and
Driver (Center),
and an Anti-collision Strobe Assembly (the triangular structure on the right)
and sample PCBs.
The coin in the center is a Quarter. Sorry for the fuzzy pictures; my
digital camera doesn't do
"close-focus" well.
So far, the tests are encouraging (especially for the position lights), but I
need to do some
comparative testing on the Strobe Assembly to gauge whether it will be accepted
by your
average FAA-Inspector.
For the Position Lights, the results are well within the FAR requirements.
The peak light output of the Red Position Light is 73.5fc with a steady state
output of 58fc
(the FARs require a minimum of 40fc). The difference between the peak and
steady state
numbers is due to the self-heating of the LEDs (LEDs produce LESS light output
as they
get hotter). Therefore, heat management will be important in the packaging
of the LED
boards. Typically, this should not be a problem if the packaging is done
right, since the
air-flow over the Position-Light in flight should keep the assembly much cooler
than my
ambient steady-state tests on my test bench.
Technical Details:
Red-Green Position Lights:
Light
Output:
58fc Minimum, >73fc peak
Voltage:
14V or 28V
RED
Current:
0.5A at 14V, 0.25A at 28V
GREEN Current: 1.4A
at 14V, 0.7A at 28V
LED Board Size: 1.3"
x 1.25"
Driver Board Size: 1.3" x
1.25"
(The Driver and LED Boards are designed to attach to opposite sides
of an aluminum
heat-spreader that can be formed into a leading edge recess with a
acrylic cover.)
White Position Lights:
Light
Output:
58fc Minimum, >73fc peak
Voltage:
14V or 28V
WHITE
Current: 0.7A at
14V, 0.35A at 28V
LED Board Size: 1.3"
x 0.62"
Driver Board Size: 1.3" x
0.62"
(The Driver and LED Boards are designed to attach to opposite sides
of an aluminum
heat-spreader that can be formed into a leading edge recess with a
acrylic cover.)
Anti-Collision Strobes:
Light
Output:
450fc Minimum, >530fc peak
Voltage:
14V or 28V
Peak
Current:
24A at 14V, 12A at 28V
Average
Current: 1.2A
at 14V, 0.6A at 28V
LED/Drvr Brd Size:
1.3" x 0.62"
Length:
4.5"
Width-Main:
1.1"
Width with Vert LEDs: 2.2"
Height:
2.8"
(The Driver and LEDs occupy the same Board and need reflectors to
achieve the required
light distribution of the FARs. The Vertical LEDs, two
per side, are required to meet the
20fc light distributions in the 30-75 degree range.)
(For a historical account of this experiment/effort, see NavStrobe History.)