Last year I built a night-flying TSII with a 90W (6000lumens) headlight.
It was quite a sucess, so I'm back this year bigger and better
Led technolgy is doing leaps and bounds, a 5mm square led can produce more light than a 60W halogen bulb. Last year I built a leds light using 12 CREE XP-G leds producing each little over 500lumens. This one use 16 of the new CREE XM-L capable of 1300lumens each.
These leds are SMD type, usualy reflowed onto a metalic PCB which is fixed on a heatsink. Even if very efficient, they still put out a decent amount of heat on a very small surface area. Instead of heat sinks, I built a water cooling system. The leds being so close together, a conventinal heat sink won't spread the heat fast enough, unless being very big and heavy.
I reflowed the led on 5/32" copper tubes with a flat spot to accept the led's heat pad:
The tube is 3 sections soldered in a "U" shape, tube solder is lead free while leds use leaded soder. This way, the tubes don't fall apart when reflowing the leds (20C windows)
The assemblies are glued to an aluminium plate to hold them inside the aircraft and provide some air-cooling from the air rushing inside the reflector area:
As I wanted the light to spread to the side but not much verticaly, I carved a parabolic reflector in the nose of my TSII:
The two 8 leds tubes are cooled by two water cooling circuit with independant pumps:
Two 6 feet coiled aluminium tube serve as radiator to shed heat into the air flowing around the fuse:
Details of the pumps and radiators, also the driver circuit needed to provide constant current to the leds array. Current is adjusted from 0 to 20A by a radio channel. It also start the pumps when the light is powered. Power come from a 4S lipo:
Here's a video of the light being tested on the bench:
Another one with the light installed and pumps working:
Temperature and current of the light is monitored ans diplayed on my OSD.
I glassed the nose to make-up for the carving. Quick shot of paint and voila!
I also made vent holes on the sides, air enter by the reflector and "nose" to come by those vents. A small ply separate the lamp area from the rest of the plane.