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Cheap Complete Strobe System

RudiGreyling

RudiGreyling

Well Known Member
Hi Guys,

I was looking for strobes for a while and got a very good special which I think is worthwhile to pass on. I bought mine yesterday. Use the info if you like..

The special is on at the moment: $160 for a 60Watt, 4 head upgradable to 6, multipattern, 5 Year Guarentee. Normal price is $240. It looks like the unit is manufactured by Nova, cause it has the same form factor, product ID numbering etc. The talk is Nova was started by ex Whelen employees, so it should be good. Nova Reference Site: www.strobe.com.

What I like is that at 60W. That is the same as the Nova AVIPAK designed specifically for Aviation, but at a much cheaper price. For AVIPAK Reference: http://www.strobe.com/products.asp?id=60&view=product normal Avipak price is $400 !!! that equates to a $240 saving!

Now I hope they ship mine, before all you okes in the USA grab all the stock! :D

Do you own homework and decide if it will work for you...
Here's the direct link for the special, it is hidden deep in the www . strobesnmore. com website:
http://strobeguy.safeshopper.com/90/2277.htm?248
bv0slpdt.jpg

Strobes N' More Professional System 4
System includes:
1 - 60 Watt 6 Outlet Multipattern Strobe Power Supply
4 - 32 Watt Undercover Strobe Tubes
4 - 15 Foot Strobe Power Cables with connectors
2 - Power and Control Harnesses

Features:
*5 Year Warranty
*15 Flash Patterns
*2 Diagnostic Indicators, for trouble and normal operation at a glance.
*Simple 1 Wire Flash Pattern Control for easier wiring.
*Total output control allowing the maximum output available to installed strobe heads.

We will have these systems on sale for a limited time as an introductory special, so don't wait.
Click to expand...
 
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Thanks Rudi! I actually had that set on my list as a possibility but had missed the sale. I just ordered a set myself. :)
 
I e-mailed them about a month ago asking what, exactly, was different between the regular drivers and this super special aviation driver that makes the aviation one worth 2 or 3 times more (other than the fact it has an picture of an airplane on it). Their response: "The aviation driver was custom built to exacting specifications, blah blah blah, aviation, blah blah blah, airplane more money..."

There's also these guys:

www.gs-air.com

They also use "custom" Nova driver (the HR in the part number stand for Half Rate). Somehow, though, they manage to sell it at a reasonable price, not the ridiculous $300 that some peddle it for.

The one thing to watch out for is too high of a strobe rate. There's a spec for how fast the strobes must go and there's an upper limit.
 
John makes a good point about flash rate.

FAR 23.1401(c): Flashing characteristics. The arrangement of the system, that is, the number of light sources, beam width, speed of rotation, and other characteristics, must give an effective flash frequency of not less than 40, nor more than 100, cycles per minute. The effective flash frequency is the frequency at which the airplane's complete anticollision light system is observed from a distance, and applies to each sector of light including any overlaps that exist when the system consists of more than one light source. In overlaps, flash frequencies may exceed 100, but not 180, cycles per minute.

The NOVA Superpak606X, which seems to be the same as the Strobes 'n More Pro System 606, lists a flash rate of "4 flash bursts alternating, 140 quad flashes per minute" or 2 flash bursts alternating, 125 double flashes per minute".

The NOVA Avi-Pak lists 85 quad and 100 double flashes per minute.

At first glance it looks like the 606 systems have a flash rate that is too high, but perhaps not. Note the lines in 23.1401(c) regarding sectors, and then consider the 606 specification. Does "alternating" mean every bulb flashes 140 (or 125) times per minute, or that all bulbs together flash a total of 140 (or 125) times, each in turn? If they flash in turn, the 606 would be legal given that you can't see all three sectors (left,right,tail) at one time.
 
Jeff,
<<The X-Pak 604 is what I recommend for everyone using my LED Nav Lights.>>

So what do you observe about it's flash rate? Does every bulb flash 140 times per minute in the quad flash mode or 125 times in double flash?
 
From their installation mannual:


# Flash Pattern Description
1 Quad Flash 4 Flash bursts alternating, 140 Quad Flashes Per Minute.
2 Quintuple Flash 5 Flash bursts alternating, 140 Quintuple Flashes Per Minute.
3 Mega Flash 1 Flash burst alternating, 700 Flashes Per Minute.
4 Double Flash 2 Flash bursts alternating, 125 Double Flashes Per Minute.
5 Single Flash 1 Flash burst alternating, 200 Single Flashes Per Minute.
6 Twin Single Flash Two Single Flash bursts before alternating. 120 Twin Single Flashes Per Minute.
7 Twin Double Flash Two Double Flash bursts before alternating. 100 Twin Single Flashes Per Minute.
8 Triple Flash 3 Flash bursts alternating, 140 Triple Flashes Per Minute.
9 Twin Triple Flash Two Triple Flash bursts before alternating. 70 Twin Triple Flashes Per Minute.
10 Twin Mega Flash Two Mega flash bursts before alternating. 350 Twin Mega! Flashes Per Minute
11 Triple-Mega-Bang Three Flashes alternating then one Single Flash. 76 Flashes Per Minute.
12 Warble 6 Single flashes alternating at 450 FPM, 6 single flashes alternating at 860 FPM.
13 Phased Mega Flash 1 Flash burst alternating, Flash rate varies from 360 FPM to 860 FPM
14 Single-Quad Single Flash - Quad Flash combination pattern.
15 Cycle Flash Two warble flashes, Two Quad Flashes, Two Mega Flashes in a continuous cycle.
 
Here is where I got my info and compared. The wording is a little different however they both seem to meet the criteria.

NOVA X-PAK 604 Data Sheet

EX-AVI-PAK

I did note the X-PAK 604 provides only low power double flash mode as compared to the EX-AVI-PAK which does high power in double flash mode.

-Jeff
 
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I called Nova this AM and confirmed the flash rate. The stated flash rate in the spec sheets is the total for all sockets.

Odd numbered sockets flash together, as do even numbered sockets. If you connect the wingtip strobes to odd numbered sockets and the tail strobe to an even numbered socket, you should have a legal flash rate. Viewed from either side (in quad flash mode) you would see 140 total flashes, 70 from a wingtip alternating with 70 from the tail strobe. As I read FAR 23.1401(c), that is legal because the wing and tail are treated as two different overlapped sectors, and the max allowed is thus 180 flashes per minute.

Yeah, I ordered the Strobes 'N More kit. Rudi, thanks for the tip!

Anybody want to talk about Luxeon nav lights? Looks like 1, maybe 2 per side might be bright enough.
 
Luxeon LED nav lights

The FAA requires a minimum intensity of 40 candles straight ahead, reducing to lower values from the side. The Luxeon datasheets don't provide an intensity value, and I haven't found one published anywhere. The datasheet does provide values for luminous flux (measured in lumens), which is a completely different measurement. Intensity and luminous flux are related, but cannot easily be converted from one to the other.

I developed a spreadsheet model that uses the published flux and light distribution patterns to estimate values of the intensity of these LEDs. Based on the model, I believe the peak intensity of the red LEDs to be about 10 candles and the green LEDs to range from 13.6 to 18 candles. The intensity drops significantly with less than 350 mA of current and without an adequate heat sink.

I don't have any specific experience with light distribution modeling, so I could be way off base with this. I'd be glad to share my spreadsheet, especially if there is anyone with an engineering background in this type of modeling to review my approach.
 
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Now when you (DanH and Mike) get Lumileds (Luxeon) in to discussion, let's get on... ;) I've also planned to do LED navlights and stobos but not yet planned too much because the development is going so fast at this field that if building something now it is out-of-date in one year. Or waiting one year more you'll get a much better performance or you can do same with less LEDs.

Only hard thing I see also with LEDs is that also they will heat up in a long run. Even efficiency would be high, they are just so small that some kind of cooling will likely have to be considered. Assuming that they are driven at highest rated continous currents.

But I wish to see how you, Mike, have calculated those luminosity and Candelas... I would say that with LEDs we have now and what is coming out we should easily archieve any ancient specification. And I would also use more LEDs as Jeff has done and drive them with lower current if they will become too bright. Few K2s ain't cost much anyway.

Stobo part should be even easier: as the pulse lenght is so small compared to the pause between blinks the LED can be driven much higher currents than it is ment to. It usually breaks because it heats too much so therefore currents has limited somewhere but when driving:pause ratio is very low, it actually will handle high current pretty well (at least IR-leds does). However as specified "long" peak currents for Lumileds are already pretty high, don't know how wise it is to overdrive it anyway. At least good (=expensive) capacitor next to the LED should provide much better performance.

As driving voltage of Lumileds is quite high, it might be more wise to put only three of them in serie. Putting four in the serie may already limit the current as you need some serie resistor anyway. Also what can be seen from Jeff's LEDs is that there is plenty of space to put even more LEDs if needed. Space shouldn't be limiting factor here.

One more thing to consider, which is visible also at Jeff's LEDs is that visible intensity for eye for different colors vary and intensity what LEDs give out vary also between colors. So if we take a look Jeff's pictures taken at dark, do red and green look same to you? So IMHO circuit should be optimized to drive either red or green color as it ain't big deal.

Here is something which might get you somewhere: http://www.caves.org.uk/led/foot1.pdf I've also found one good calculator from web to calculate these things, but I'm now on a business trip and can't access my home favorites for few days. It's way over midnight here so I got to get some sleep now. :eek:
 
sslayden said:
Does anyone have any ideas about how to mount the strobe and the position light in the bottom rudder fairing? I've typically seen a combo strobe / position light in the tail such as:[...]
Also, has anyone seen a lense for the tail strobe?
Click to expand...
I can handle the electronics but this is the harder part. Wing tips are easy as something similar than Jeff has is at least what I'm looking for. But as you say the tail light is more tricky. I do have couple of plans how to do it:

a) Buy used (cheap) and remove bulp and replace it with leds. Propably some kind of reflectors might be good... could be aluminium as in wingtips. Would be defenitely easiest way but might cost a bit more than the B-alternative.

b) Build everything itself. I've feeling that the hardest thing would be clear covers (lense). Anyone familiar doing something like this?
 
The 606 kit from Strobes N" More arrived today, on time and as promised. Good tip, thanks Rudi.

Excellent question about a combo tail and strobe light. The obvious (but expensive) way is the Whelen tail light, which I hope to avoid.

Seems like everything comes down to "how many of which LED at what current?"

Gotta do some reading about lighting terms (candles, lumens, etc). I'm starting from zip on this subject, so education efforts are welcome.
 
Constant current for LEDs

Here's a good reference for building different circuits to deliver a constant current to LEDs:

Constant Current Circuit

My current thinking is to use the option in figure 2. Because I want to have 6 Luxeons in each wing, I plan to double this circuit in each wing with three lights in parallel for each. A 3.6 ohm resistor should deliver 350 mA. I think you need to allow for a drop across the regulator of about 2-3 volts in addition to the resistor and LEDs.
 
MTBehnke said:
I developed a spreadsheet model that uses the published flux and light distribution patterns to estimate values of the intensity of these LEDs. Based on the model, I believe the peak intensity of the red LEDs to be about 10 candles and the green LEDs to be about 12 candles. The intensity drops significantly with less than 350 mA of current and without an adequate heat sink.
Click to expand...

Nice job; this is pretty close to what I have measured experimentally, perhaps slightly higher. That's why I run 5 red and 4 green 1W lambertians. I tried to do a bunch of calculus myself to figure out the theoretical candle output and came up with something a bit higher than your numbers -- Initially I thought I could get by with 4 and 3.

As for cooling, I put them on a big piece of aluminum (use neutral-base luxeons or get some special noncondctive thermal epoxy), and my lens cover is not so tight so I figure there will be a nice breeze.
 
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MTBehnke said:
Here's a good reference for building different circuits to deliver a constant current to LEDs:

Constant Current Circuit

My current thinking is to use the option in figure 2. Because I want to have 6 Luxeons in each wing, I plan to double this circuit in each wing with three lights in parallel for each. A 3.6 ohm resistor should deliver 350 mA. I think you need to allow for a drop across the regulator of about 2-3 volts in addition to the resistor and LEDs.
Click to expand...

I used a similar design. One gotcha that may be an issue is that some of the LM317 parts I found are not rated for temps at ~freezing or below, so if you're putting this out on the wingtip you may want to search for the lower-temp part. They will warm up with use but will they start up below the rated temp? I don't know.

Also watch the power rating for your sense resistors, they will dissipate a lot of juice (and will get hot, as will the LM317 itself) at luxeon currents. Heatsinking the LM317s may be necessary; it was on mine.
 
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MTBehnke said:
My current thinking is to use the option in figure 2. Because I want to have 6 Luxeons in each wing, I plan to double this circuit in each wing with three lights in parallel for each. A 3.6 ohm resistor should deliver 350 mA. I think you need to allow for a drop across the regulator of about 2-3 volts in addition to the resistor and LEDs.
Click to expand...

This could work, but you will be generating some unnecessary heat through LM317 and the resistor, which equates to more current needed / less efficiency. Check into the LuxDrive constant current power supplies at http://www.theledlight.com/luxeonled_drivers.html . They have 350mA, 700mA and 1000mA ratings models.
 
Keep it up guys; the students are all ears.

Ok, looks like a max of six 1W per wingtip, red and green. Do I correctly understand that white (the taillight) will require fewer LEDs?

Dumb question time: A single 5W does not equal five 1W?
 
DanH said:
Keep it up guys; the students are all ears.

Ok, looks like a max of six 1W per wingtip, red and green. Do I correctly understand that white (the taillight) will require fewer LEDs?

Dumb question time: A single 5W does not equal five 1W?
Click to expand...

Luminosity aside, if you're concerned with coverage five 1W's are much easier to work with than a 5W. You can just bend the LED leads and aim them wherever you need.
 
DanH said:
Ok, looks like a max of six 1W per wingtip, red and green. Do I correctly understand that white (the taillight) will require fewer LEDs?
Click to expand...

Dan,

Check out FAR 27.1391: http://www.flightsimaviation.com/data/FARS/part_27-1391.html

The rear position light needs to be at least 20 candles, whereas the forward green and red position lights need to be at least 40 candles. Be aware that there is also maximun intensities of the lights, as dictated in FAR 27.1395 : http://www.flightsimaviation.com/data/FARS/part_27-1395.html.


Simple answer, yes, the tail light will require fewer LED's.
 
Alternate tail strobe position

Guys,
Would it be legal to mount your strobe on the top of the rudder and the position light at the bottom? I don't much care for the dual purpose sockets.

A few notes on LED's.
LEDs are current driven devices. Because you are controlling the current, the regulator's heat is directly related to voltage drop.
Put as many LED's in series as practical until you run out of voltage AT YOUR LOWEST EXPECTED BATTERY VOLTAGE (Plus regulator drop).
This will keep you from wasting power and generating unwanted heat.
Using more low power LEDs in several 'strings' addresses the reliability and heat issues.

Also keep in mind that different color LED's have differnt forward voltage drops. What works for red will not work for green and white!

LM317 regulators in parallel can also have stability problems. I have seen them Osc at 70MHZ! A small 1u capacitor across the supply right at the regulator is cheap insurance against Osc.
 
jdeas said:
Would it be legal to mount your strobe on the top of the rudder and the position light at the bottom? I don't much care for the dual purpose sockets.
Click to expand...


As far as I know, there is nothing in the FAR's that dictate where on the rudder the strobe should be mounted, but you must have proper coverage as defined in FAR 23.1401: http://www.flightsimaviation.com/data/FARS/part_23-1401.html?marked=anticollision

The only issue with mounting the strobe high would be there isn't much room on the aft end of the top rudder tip, so some fiberglass work would be needed. Also, you would be adding more weight to the tail by running an extra 3' or so of the heavy strobe wiring.

One idea would be to keep the strobe down low and put your LED tail position light up high, because most likely that will be a lower profile than the strobe. The other thing you could do is to do away with the strobes on the rudder and put them on the aft end of the wingtips.
 
Here's how I did it

Here's how I am doing the strobes and position lights...

I chose the NOVA REG4-80 strobe power supply. It supplies 20 watts to each strobe light regardless of how many are connected. In an unregulated supply the power to each strobe is determined by how many strobes are connected. In the unregulated designs if a single strobe is connected to one of the connector pairs (odd or even) it would receive 40 watts (in an 80 watt supply with four stobe outputs). Also, in an unregulated 4 strobe 80W supply, if you have two strobes connected to a connector pair each would normally receive 20 watts of power. But, if one strobe burns out the other would then receive the full 40 watts. This could quickly burn out the other strobe as most are not rated that high. The Whelen tail light/stobe will handle 40 watts, but my wingtip strobes are only rated at about 30 watts.

The 2 wingtip strobes flash synchronously at about 70 flash cycles per minute and the tail strobe flashes alternately with the wingtip strobes also about 70 flash cycles per minute, so the most flash cycles you can see is about 140 flash cycles per minute. This is within the FAR requirements.

Here are a couple of pictures...

(I've enclosed the wingtip strobes in cardboard tubes to protect my camera from the bright flashes)
img06561nd1.jpg


img06571xf0.jpg


I also designed LED nav lights but they're not done yet. They will have 6 Luxeon Star 1W LED's on each wingtip -- 3 facing forward and 3 facing outboard. The Luxeons are mounted on heat sinks (using Arctic Alumina thermal epoxy) that are then mount to an aluminum plate. The aluminum mounting plates will also house the wingtip landing lights and strobes and will be covered with plexiglass mirror material so that no screws will show and only the Labertian (sp?) lense of the Luxeons will protrute. I use constant current drivers called "Buck Toot" manufactured by LUXDRIVE to provide the 350 mA drive to each set of 3 LEDs. They look great, and should really look nice when finished. Here's what I've got so far...

BuckToot
img17081hj2.jpg


These images don't really do justice to the brightness of the Luxeons -- they are retina-burning bright when you look directly at them
img0942mediumrv6.jpg


img0943mediumht5.jpg
 
One thing my spreadsheet can help with is to overlay the light output of up to six Luxeons at different angles to see the overall output. In the case below, I have six of each, four angled 20 degrees outward to match the angle of the rear of the wingtip cutout, and two more angles out 40 or 60 degrees out.

luxeonnavintensityfc7.gif


Of course, meeting the minimum FAA requirements is the easy part. I'd be very surprised if most of the layouts conform with the maximum intensity limits beyond the normal 0 to 110 degree coverage zones.
 
Cut-off

MTBehnke said:
.....
Of course, meeting the minimum FAA requirements is the easy part. I'd be very surprised if most of the layouts conform with the maximum intensity limits beyond the normal 0 to 110 degree coverage zones.
Click to expand...

Mike,

This is were the geometry of the wing tip mount comes into play. A low, solid baffle an inch or two out from the LEDs should be able to provide a physical cut-off to prevent light spillage outside the 110 degrees mark...

Neat spreadsheet display!

What would happen if you added 2 more reds at 30 and 60 degrees?

gil in Tucson
 
This thread will soon have everything need to do LED lights. Not bad.

I had already earlier in my mind few links and now I can give them. I thought that this CandlePowerForums came from this site but couldn't find it with search tought. :confused: Anyway, I quess this (Candle Power) forum pretty much equals Van's Airforce if you want to know about LEDs and such. http://candlepowerforums.com/

This page has some basics about LEDs: http://led.linear1.org/ and the best part is Candela to Lumens conversion wizard http://led.linear1.org/lumen.wiz

And can't believe nobody yet didn't link Lumileds page here http://www.lumileds.com/ altought it is not too hard to find. However you easily notice that as I earlier said, the luminosity will increase fast in the future as there are a lot of suitable applications for high power LEDs. Check out Company Info > Press Room > January 23...

One thing which doesn't seem to be highlighted yet here is that stobos will use pretty high currents. Especially (simplified a bit) if you are using LED stobos where the luminosity is proportional to the current and current is proportional to the voltage, having a voltage drop will affect greatly to luminosity you are getting. Peak current driven to the strobing LED can be high and therefore also voltage drop across the wire is too. To calculate voltage drops I've found another good site: http://www.securityideas.com/howtocalvold.html To avoid problems with voltage drop, I would design system so that the supply voltage would go near the LEDs. This would require control line (one more wire) to the system if the timer is in the cockpit. This would allow to parallel some low ESR (yes, they do cost a lot more than regular capacitors) capacitors near the LEDs. As if driven just three LEDs in a serie that would allow also diode between supply and LEDs just in case.

Sparky: Have you measured how high temperatures you get with your LED positioning lights? You seem to have big cooling elements so I wish to know how much heat those LEDs really produce.

Edit: just typos
 
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Pirkka,

There is a thermal design guide available at the Luxeon site included amongst the links to the datasheets. Here's a direct link http://www.lumileds.com/pdfs/AB05.pdf . It includes proper heat sink sizing.

The datasheets (http://www.lumileds.com/pdfs/DS23.pdf) includes graphs that show the reduction in intensity to account for thermal effects. A summary is below:

Derating LED intesity to account for temperate:
Tjunction Green Red
25?C 100% 100%
40?C 95% 85%
60?C 86% 70%
80?C 78% 55%

Note: Tjunction = ambient temperature + temperature due to power consumption

If you assume Tambient = 22?C (72?F) as an outside air temp, and with very effective heat sinks, best case would be an 18?C increase, resulting in Tjunction = 40?C. So the 10 and 12 candle outputs I noted before should be reduced. If you assume a 38?C (100?F) air temp the reduction would be even greater.
 
Heat Sinks

Pirkka,

Although the heat sinks appear large, they are about the minimal requirement for 3 closely spaced 1 W LUXEON Stars. Total surface area is about 36 sq inches. I have not measured actual temperatures, but after having them on for several hours at room temperature in still air with the cooling fins oriented vertically the heat sinks are just warm to the touch.

The aluminum "backplate" of the LUXEON stars are not electrically isolated, so you can't just attach them to a electrically common point (aluminum heat sink) without providing isolation. The Arctic Alumina thermal epoxy provides this electrical isolation while acting as an excellent thermal conductor. And this epoxy is STRONG. These babies are attached permanently.

Here's a close-up of the Luxeon stars and heat sink assembly before wiring...
img08141kv1.jpg
 
az_gila said:
What would happen if you added 2 more reds at 30 and 60 degrees?
Click to expand...

The red and green luxeons have different intensity patterns. Here's a comparison of a single red and a single green:

luxeonnavintensity3yi5.gif


If I add one red LED, (5 at 20 degrees and 2 at 40 degrees) gives:

luxeonnavintensity2dl3.gif


I'd be glad to send anyone a copy of the spreadsheet and you can play with various configurations - just send me a PM with your email address.
 
It looks like everyone is using the Lux I drivers. In the little experimenting I've done and what I've read, the Lux III driver is a great choice. It can be driven at up to 1000mA and can deliver up to 100 lumens. Same size, nearly same price. You should be able to use 2x Lux IIIs for the nav lights.
 
Sparky said:
The aluminum "backplate" of the LUXEON stars are not electrically isolated, so you can't just attach them to a electrically common point (aluminum heat sink) without providing isolation.
Click to expand...

This is true of some luxeons but not all. My 1W red/green Stars are neutral (according to the data sheet and under test), so I was able to just screw them onto a piece of angle. This is probably not as easy as the epoxy though.

The "naked" emitters are all non-neutral on the back, I believe.
 
Luxeon intensity

I'll credit Paul Winkels (Sparky) with finding a bug in one of my spreadsheet formulas which caused it to underestimate the intensity of the green LED. Instead of a peak intensity of 12 candles, it looks like it's a range of 13.6 to 18 candles. The luxeon datasheet provides a range of values for the light distribution, resulting a range of intensities. Unfortunately the red still looks to peak at 10 candles.

For those I've sent my spreadsheet to, I'll resend a version with the corrected cell formula.
 
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Recognition lights

I have dual HID landing lights in my wings already, but you guys are getting me thinking about putting some white Luxeons in the wingtips to serve as pulsing recognition lights (since you can't wig-wag HID lamps). I think spam can recognition lights are usually in the 25W range... how many lumens worth of white Lambertian Luxeon stars do you suppose I'd have to use to get an equivalent amount of light?

thanks,
mcb (sucker for gadgets and shiny things, of which LEDs are both...)
 
Mike,
<< (green) looks like it's closer to 18 candles....the red still looks to peak at 10 candles.>>

Good work, very useful! What does the formula say for white?
 
mburch said:
I think spam can recognition lights are usually in the 25W range... how many lumens worth of white Lambertian Luxeon stars do you suppose I'd have to use to get an equivalent amount of light?
Click to expand...
If we assume that the LED's junction temperature is around NTP and 25 W bulb gives out about 17 lm/W which yields to 425 lumens. Typical luminosity for Luxeon Star Emitter is 45 but as said before if you are driving them as stobo and pulses are short (10 - 50 ms should be well enough) the total energy absorbed in LED ain't big (50/1000 = 5% of rated). For continous driving of those LEDs you would need 10 of them but I would try something like 3 or 6... Should be plenty when driven with currents ~3 times higher than rated.

As The Other Doug Reeves asks why do you wish to use ice age LEDs? I really don't know. K2-serie would give out 2.5 times more luminosity than Luxeon I -serie LEDs. 3 K2s would be plenty if driven with peak pulses... At least my plans for now would be use K2s for strobos and actually for everything else too.

Generally I would put more LEDs and drive them with smaller current. Also in positioning lights I don't like when greens LEDs seem to be superior compared to the red ones... in terms of luminous flux.


References:
http://hyperphysics.phy-astr.gsu.edu/hbase/vision/lumpow.html
Luxeon Star Technical Datasheet
LUXEON? K2 Emitter
 
Pirkka said:
As The Other Doug Reeves asks why do you wish to use ice age LEDs? I really don't know. K2-serie would give out 2.5 times more luminosity than Luxeon I -serie LEDs. 3 K2s would be plenty if driven with peak pulses... At least my plans for now would be use K2s for strobos and actually for everything else too.
Click to expand...
Sorry, I should have mentioned that I was thinking about using K2 stars for recognition lights. :)

I'm not really interested in LED nav lights at this time, since I'm not convinced the noncertified ones that are available today really meet the FARs for viewing angle, minimum light output, and maximum light output, though I don't begrudge those builders who're using them with good results. I also already have a set of Whelen nav and strobe lights so I'm covered there. My landing lights are HID and thus I can't wig-wag them, so what I'm thinking of using the LEDs for is a set of relatively narrowly focused, pulsing lights (50% duty cycle at low rate, not peak pulse operation as you mentioned) to increase visibilty for day and evening operations.

For that application, it looks like a few white K2's with 5x20 degree oval lenses with the beam aligned in the horizontal plane could possibly work. 130 lumens per LED with a lens to redirect some of the "wasted" upward/downward photons out horizontally sounds pretty good. I may end up buying a few to play with once I get around to working on the wingtips.

Of course, I may just end up putting some 25W halogens out there to serve the same purpose, as suggested in this post...

mcb
 
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mcb,

<<...I was thinking about using K2 stars... >>

I was just over at the Phillips Lumiled site and don't recall a listing for K2 stars, just emitters. Do they make them?

<<My landing lights are HID and thus I can't wig-wag them,..>>

Hmm, I was also leafing through the lighting section in the Spruce catalog this AM and came across the "Aviflash HID and Halogen Lamp Flasher". Went back and looked it up for you, PN 11-04412, $59.85
 
DanH said:
I was just over at the Phillips Lumiled site and don't recall a listing for K2 stars, just emitters. Do they make them?
Click to expand...
I think they are a third-party item, not made by Phillips, but you can get a K2 star in the same footprint here: http://www.luxeonstar.com/ The backplate is also electrically isolated, which is a nice bonus.

DanH said:
I was also leafing through the lighting section in the Spruce catalog this AM and came across the "Aviflash HID and Halogen Lamp Flasher".
Click to expand...
Yeah, I actually bought one of those as an impulse purchase a while back. However, I think I'm too chicken to actually hook it to my landing lights. I talked to Bill VonDane about it and he says he's had no problems on his airplane, but I want to be extra conservative about shortening the life of my expensive light bulbs!

mcb
 
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mburch said:
I may end up buying a few to play with once I get around to working on the wingtips.
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Go for it and let us know how you successed.

You said that you wanted visibility - to whom? If you want that others will see you I strongly suggest using very short pulses and overdriving LEDs. While you are doing your testing, just try it. Very short pulses doesn't heat up LEDs much but are more visible.

You actually don't need LEDs to do testing: get two similar lamps, one around 40W and one 100W. Put them side by side and try different timings -- do you ever get the feeling that 40W lamp would beat 100W even how long it would be on? And even 100W would be on just a fraction of a second. Comparison may not be fair because I'm not sure how fast bulbs turn on. LEDs turn on very quickly so therefore their pulses can be very short.

I don't see how Stars would be so superior... I would consider just emitters -- gives more flexibility how to arrange them and then they can be casted in epoxy if wanted.
 
Pirkka said:
I don't see how Stars would be so superior... I would consider just emitters -- gives more flexibility how to arrange them and then they can be casted in epoxy if wanted.
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Stars are, IMHO, easier to mount than emitters. Emitters look better when mounted properly. Stars are easily mounted to existing aluminum surfaces using the thermal adhesive.
 
DanH said:
Good work, very useful! What does the formula say for white?
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The datasheets give the same graphs for the green and the white light distribution, and the white gives out about 85% of the lumens as the green. Since the green seems to range from 13.6 to 18 candles, the white should range from 11.5 to 15.2 candles.

Note, the datasheets give a range of light distribution pattern values for the green (and white). With the same light output, but in a more narrow band, the intensity could be as high as 18 lumens. Using the somewhat broader band, the peak intensity could be closer to 13.6 candles.
 
<<the white should range from 11.5 to 15.2 candles>>

Thanks Mike.

I've been reading datasheets, etc. Dumb student has more questions for anyone willing.

Am I correct in thinking that all Luxeon emitters (I, III, V, etc) have the same forward voltage drops, ie 2.95 for red and 3.42 for green and white? This is a standard, a function of their physics?

On another front, just how weather resistant are these things? I'm not talking about salt spray, just ordinary moisture and UV effects. Could you thermal epoxy a Star to an external aluminum surface and expect it to live, or does it really need lens coverage?
 
DanH said:
Am I correct in thinking that all Luxeon emitters (I, III, V, etc) have the same forward voltage drops, ie 2.95 for red and 3.42 for green and white? This is a standard, a function of their physics?
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I believe they differ at least slightly, but they are in that ballpark. It is on the data sheet for each model, search for "voltage drop" or "forward voltage".

As for durability, they seem tough after some rough handling by yours truly (dropping them on the floor, etc), and the stars do seem to have some built-in anti-static diodes, but I haven't seen any specific specs on what you can expect except for temperature ranges.
 
<<It is on the data sheet for each model, search for "voltage drop" or "forward voltage".>>

Got it, thanks Paul. Now I see it varies with drive current too.

Ok, I boldly propose to use three Luxeon III's per tip driven at 1000mA with a single 2008B PowerPuck. 1000mA is the max current for green (80 luminous flux). Reds can be driven at 1400mA for 140 luminous flux; the charts says about 105 underdriven at 1000mA. That should put them in the same ballpark in perceived brightness.

Three Lux III's per side seems to conserve real estate, but I've not waded through the heat sink equations yet (ugg!). Three of these may need the same heat sink as the six 1W that Sparky used, so perhaps I wouldn't really save any space. I would save a few bucks on the power supplies as I would only need two.

What say ye wise men? Always happy to have the education.
 
DanH said:
Ok, I boldly propose to use three Luxeon III's per tip driven at 1000mA with a single 2008B PowerPuck. 1000mA is the max current for green (80 luminous flux). Reds can be driven at 1400mA for 140 luminous flux; the charts says about 105 underdriven at 1000mA. That should put them in the same ballpark in perceived brightness.
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That should work - 3 x LuxIII should be PLENTY. That will allow you to get sufficient coverage. I'd drive them at 1000 or even 700mA - given that you are using 3 emitters, 700mA (60 lumens) should be fine. That will result in lower heatsink requirements. The PowerPucks are good, reliable drivers, BTW.
 
Thinking about the tail light. Mike, does your spreadsheet indicate that a single white Luxeon III might satisfy the tail requirement? I'm guessing a LuxIII is bright enough at peak, but maybe not bright enough at the 140 degree edge.

Second item. I've not worked with the thermal epoxy (Arctic Alumina?) used to mount stars on a heat sink. Here's the question (hello Sparky!); do you think you could cast this epoxy?
 
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