Experimental Aircraft Landing Light

[mn velocity pilot]

I completed my work (or at least for now)... here's a link to an Instructable documenting what I did:

http://www.instructables.com/id/LED-Landing-Light-for-Experimental-Aircraft/

At some point I start thinking about even more power...!

 

[TEEJ]

I completed my work (or at least for now)... here's a link to an Instructable documenting what I did:

http://www.instructables.com/id/LED-Landing-Light-for-Experimental-Aircraft/

At some point I start thinking about even more power...!

XML2 LED can be pushed a lot harder than the ~ 300 lumens you are getting from them. You could be getting up to 500-700 lumens from each LED for example, about doubling your output. When pushed hard, you can get up to ~ 1,200 L from each LED, instead of ~ 2k L for all of them combined, and so forth.

Heat management does become an issue of course as you up the performance.

It was hard to tell in your pics, but, does any part/enough of your exterior nose lens protrude enough to be visible in profile/from the side?


If so, a simple nose reflector that would reflect some light to the sides, and/or removing and/or re-aiming the optics from some of the LED (If any are forward enough to be visible from the side, etc...) to increase lateral dispersion, etc, could help with lighting to the sides.

It could be an artifact of the pics, but, in the pic at least, your light's cover appeared to be cloudy.

This can greatly reduce transparency and output....and, if it wasn't cloudy, and the apparent cloudiness was due to reflections, that typically means you could benefit from an AR coating (to reduce reflection and increase transparency/transmission).


For a nose reflector, think of a simple reflective strip aligned so that its thin edge faces the light, and the light passes along its reflective width on either side. That minimizes its shadow, and, maximizes the lateral visibility.

 

[mn velocity pilot]

Thanks, TEEJ!

Yes, for sure, I can drive the LEDs much harder. The issue became that to do so would really force the shift from a linear regulator to a switcher. Switcher's are more efficient, but are more complex and can create electrical noise (which can be an issue in an airplane)... so I took the easy way out (for now). The lamp assembly itself can handle much more power, so I'm all set for when I can get back to thinking about more power.

Yes, the plexiglass lens on the aircraft nose was cloudy when I took the picture. It was a very humid day, and there was condensation all over everything. Normally it's quite clear.

Some side dispersion would be OK, but it's really forward visibility that I'm after. At 200 mph it's what's pretty much directly in front of me that I worry about. The closure rate is very fast. Also, the light is set back far enough into the nose that it'd take more work than I'm up for right now to gain more side dispersion.

Anyway, thanks for taking a look. Any suggestions on a, say, 10amp switching regulator that can be controlled to create a programmable flashing mode?

Thanks again!

 

[mn velocity pilot]

Me again!

I've had the flashing landing light deployed in my airplane since this spring, and it seems to be working OK... but, as winter is coming, and I'll have time on my hands, I'd like to think about improvements.

I published an instructable on my implementation here: http://www.instructables.com/id/LED-Landing-Light-for-Experimental-Aircraft/

As winter is coming, and I'll have time on my hands, I'm starting to think about the next generation of this setup. My questions to the forum are:
- There are nowadays many "off the shelf" LED based aircraft strobe systems. The ones I've seen are incredibly bright, but don't have much circuitry at all, especially the big, bulky current limiters that I've got, and certainly don't seem to generate much heat. What gives? What are most manufacturers doing for flashing current limiters?
- I'm using 10W CREEs, with either 7 or 9 in parallel - i.e., in theory, I can drive it with between 70 and 90 watts, or between 21 to 27 amps of current. The linear regulator I'm using (an LM338) maxes out at 5 amps. How can I increase the current to get more brightness?
and
- I'm flashing these CREEs with 5 x 100ms pulses / second. The pulses are in a rapid burst: flashflashflashflashflash .... pause ... flashflashflashflashflash. One idea that's crossed my mind is to just, gulp, eliminate the current limiter and just plain flash 'em. My thinking is that what really kills the LEDs in an overcurrent situation is heat, and that because my average current, or average power, is low due to the flashing, and also because of the inherent current limiting effect of the flash circuit and all the wiring, the instantaneous power will be far less than the average power, and so the heat may not be an issue. Is just flashing the LEDs and hoping I don't fry them just plain dumb?

I'd be grateful for any input... in net, how are the other guys doing this???

THANKS!

Dave

 

[cujet]

Me again!

I've had the flashing landing light deployed in my airplane since this spring, and it seems to be working OK... but, as winter is coming, and I'll have time on my hands, I'd like to think about improvements.



Dave

I'm a pilot, A+P and engineer. I've installed the Whelen Parmetheus in both PAR 36 and PAR 46. I even recently purchased a Parmetheus plus (supposedly 40% brighter) Taxi light. All of them have been underwhelming. I'm not happy with the light output, of approx 1200-1700 lumens, depending on model.

So, with that in mind, I recently purchased some motorcycle aux lights made in China. They are truly amazing lights due to the very small size (about 2 inches in diameter) and outright power, claimed 3600 lumens. Each light contains 4ea Cree XM-L-T6 emitters, generally considered to be 1080 lumens each.

I've installed one on our Extra 300L experimental/exhibition stunt plane. That single "toy" of a light is worlds better than the Parmeteus and GE4509, both on at the same time, in my Cessna.