Lionclaw

Lionclaw

Well Known Member
I've been working on putting together my diy nav lights. So far so good. I CNCed the mirrored plexi parts. CAD template here if anyone wants it.

I'm using Pete's resistor-based LED schematic. I went with a 10W 5 ohm resistor and 4 K2 star LEDs. I ran them for a few hours and they get warm, but not too hot. The strobe cutouts are sized for the strobes n' more strobes.

Anyone have any ideas for mounting the LEDs to the back of the plexi? I've been thinking about proseal, RTV, JB weld...

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Hi Andy,

I just let them float, and use heat sink compound to thermally tie the stars to the aluminium backplate. RTV or hotmelt gule could be used to tie them to the plexi if you want.

Your setup looks great! That CNC is sharp.

600 hrs on mine now, and I run them day and night.
 
I used polished AL plates instead of mirrored plexi. I drill 2 #40 holes for each LED and used soft pull rivets to mount them. The AL plates act as heat sinks. I used 4 LED's for the nav and two white ones are flashing. Good reports from others.
 
Andy,
Like Brian said. Mount the Stars to an aluminum plate with thermal epoxy. Here is my plate with the Stars installed before wiring. I also included computer CPU heat sinks on the back of the plates to add in cooling. I also used 2 slightly different dropping resistor values to balance out the cyan and red led lights. Six of these were overkill but they look great even in broad daylight. I used some spacers between the aluminum and plexi on the attachment screws.





 
Where are the entrepreneurs?

I love the cool lights but electricity, solder irons, ohms, amp etc give me a headache.
There seem to be LOTS of pretty smart and talented electronic folks here that love to compare outputs, angles, diffusion, heat sinks etc that I find pretty much greek. Why dont one of you tweak what Jeff B, Pete H etc have come up with and do what Craig V did with the rudder stops. Punch out a few sets and make a few bucks. If someone wishes to sell these, let me know. The inputs seem cheap, seems like a good little side business?? Let me know.

There is no perfect solution but there are some nice set ups here, its experimental aviation and I would much rather a set up like this then to just go the old school whelan, or the big$$ factory led stuff.

I will be waiting by my in box for offers. :D
 
Looks Great!

Rocky,

Your lights look great. They are amazingly bright, aren't they?
 
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Thanks Pete! The lights are very bright. Everyone at my field has commented about them. They even impressed the DAR during my inspection.

A kit has been produced in the past. I'm not sure if Jeff is still doing these but here is a link.

http://www.jeffsrv-7a.com/LEDPROJECT1.htm

I know Chad at one time used one of Jeff's kits to do his lights and I pretty much "borrowed" his and Brian's ideas.

Just a note: I originally used power supplies that were so dirty they wiped out my VHF radio. After several attempts to clean up the RFI issues I went with the dropping resistors and they have worked great for 140 hours. I know Bob Nuckolls built a filter for the power supplies, but I'm not sure if anyone is aiborn using it yet.
 
The resistors work fine and are easy.

The drivers are a great way if you want to use constant current and you want to eliminate the wasted power you get with the resistors.

The noise filter Bob sells works great as far as I can tell on the ground. It totally eliminated any issues with the driver I was using.

I will let you know how it works in the air but for this issue it should work the same in the air as it works on the ground.
 
Another Option

I found these on the web and have been using one of these units in my wingtip for 200 hrs now to drive a P7 taxi light with no noise on the radio. No idea if it would be noisy closer to the cockpit. The price is right. They come in 350, 500, 700, 1000, and 1400ma constant current flavors. $9.95 each.

Yes they ship from Turkey! They take about 20 days to arrive. The people there have been great to deal with.
 
Lionclaw said:
I've been working on putting together my diy nav lights. So far so good. I CNCed the mirrored plexi parts. CAD template here if anyone wants it.
Click to expand...

As 9 has different wing as 7, the wing tips likely differ as well. Anyone has template for 7? :confused: BTW your work looked good and sure those templates will help many. I've sketched something from mine already but haven't truly tried to do good template yet.
 
Optics for K2 Stars?

Just purchased 6 red and 6 cyan k2 stars and the driver/filters from Bob. However I just noticed the "optics" offered by Led Supply. What do others use - any optics, if so which ones? Or do you leave LED as is? Thanks, Steve.

RV-9A
 
LED thermal details?

Rockyjs said:
Andy,
Like Brian said. Mount the Stars to an aluminum plate with thermal epoxy. Here is my plate with the Stars installed before wiring.
Click to expand...
Hi Rocky - thanks for posting. Did you (or anyone else) happen to measure the temperature rise of the aluminum plate?

I'm interested in doing some simple thermal analysis. If anyone has the data and can post it, that would be great. What I'm looking for is:
1) # and type of LEDs, and drive current through each
1a) attachment method LED to plate
2) thickness and size of thermal plate
3) room temperature when testing
4) temperature of plate after it is turned on and stabilizes (may take hours)
5) any other thermally important details (fins, heatsink, etc).

Also, where are you guys mounting the ballast resistors? They've got to get warm too.
 
Just FYI Jeff is still making the lights, I just ordered my set through him. Takes him 12 weeks to deliver.
-david
 
DIY navlights meeting DAR approval?

For all those like me who've done these DIY navlights (or bought them from Jeff) and who have also gone through the inspection process already...

Any problems with DARs signing off on them? I got an identical pass/fail inspection form from both a DAR and my FSDO in anticipation of my inspection (suggesting that this form is commonly used), one category of which deals with night flight equipment related to FAR91.205(c). It reads: "Approved position light." What does it mean by "approved." Even though mine are way brighter than most, and angles of coverage at least as good, any chance a DIY system would be rejected for not being "approved"? There's so many of these LED/mirrored DIY lights out there that obviously many have passed through no problem before, but I do want to be able to anticipate any potential issues before my DAR arrives.

Thanks.
 
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LEDs are meant to be driven with a constant current as has been previously mentioned. If you are just using a resistor in series the current is approximately constant, but it does vary as the battery voltage varies. For your navigation lights this may not be too much variation, I'm not sure. A actual constant current source driver would be better and it would be independent of the voltage. This type of driver may not be more effiecient. It can be visualized as a resistor that varies with the battery voltage.

If you decide to stay with the resistor arrangement the efficiency can be maximized by minimizing the voltage drop across the series resistor and selecting LEDs which have a total forward voltage drop that is lower than the minimum battery voltage. Make sure that you size the resistor for the max battery voltage.

One other thought. There is some high efficiency reflector material that 3M makes called ESR or Electro Specual Reflector. I think Digi-Key sells sheets of it. It is a thin flim and it reflects much more of the light than polished aluminum. Again it might not be worth the additional work. Most LEDs output a cone of light so I'm not sure how much light is actually being reflected off the surface. It would depend on the LED selected there are generally some lobes of light that would get reflected.

Just my two cents.
 
LED Nav Light service update...

My DIY LED nav lights are now 860 hours and 5 years old. They have run every one of those 860 hours and work great! While not ideal, the simple resistor works well for this setup and is passive(quiet).

Last Friday, late afternoon, King Air on final while I am in am holding short to take off @KCFE......he lands and asks "What is the deal with those nav lights - we saw them 3 miles out!" I told him they were LEDs - I made them in the garage with the rest of the plane.......
 
rapid_ascent said:
If you are just using a resistor in series the current is approximately constant, but it does vary as the battery voltage varies. For your navigation lights this may not be too much variation, I'm not sure.
Click to expand...
I wired up mine just like Pete did. His schematic is here in one of the old threads somewhere. The only difference is that I used different resistor sizes to deal with 4 K2 starts rather than the 4 Luxeons that he uses. I'm driving them mid range (resistor size controlling this) and have found that it's pretty hard to tell much of a brightness difference b/w about 10 and 14 volts. In any case, these things are so bright that even when the voltage is low they are still brighter than the nav lights on many store bought planes.

Constant current drivers are probably "better," but this is, I think, one of those issues where "theory" says one thing and our everyday requirements say something else. Plus, I think I spent about $80 total on my nav lights!

All that said, I don't have the 860 hours on mine that Pete does, so I'll report back next year when I do!:D Thanks again for your help last spring, Pete!
 
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K2 Star Leds

They are replaced by a new LED now the Rebel Endostar 7040-pw740-n which is brighter and cheaper by about $1.50 at Ledsupply.com. They have one with 3 Leds on the same 'star'.
 
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