At first I did not like the use of a fan either. However, the
alternative is to install heftier heatsinks (more weight and more
space). This is also why I installed a thermistor. If the fan fails,
the temperature will rise quite dramatically, and you will know
something is wrong. But you have a good point. The thermistor could
have been easily incorporated with the circuit to automatically scale
down the current with tempertaure rise.

karel wrote:
"Andrew Sarangan" schreef in bericht
oups.com...
Recently I designed and built a nav light system for my Europa aircraft
using the Luxeon LEDs with great results.

I also measured the radiation pattern (after fitting the LEDs to the
aircraft) and compared it to the FAR specs. It exceeds the requirements
by 3-5 times, and draw only 2 Amps total. It is bright enough to almost
use as a landing light.

Actually, I am surprised that most manufacturers do not provide a
measured radiation pattern. They just say that it complies with the
FAR. Well, meeting the specs is not the same as exceeding it. Since
LEDs lose power with age, this could be an important consideration.

Just in case someone might find this useful, I wrote it up as an
article:
http://www.sarangan.org/aviation/eur...tip-Lights.pdf

Let me know what you think.

Nice! The one thing I do not like about it
is the dependence on mechanical ventilators,
and nothing to check they are working OK.
A nice addition would be a temp sensor that
reduces LED current if things get hot.

The documentation you supply might serve
as an example to many: complete and clear.
My heartfelt compliment!
KA