# Flying searchlight



## HugeOne (Feb 5, 2010)

Hello All,

I'm building a FPV plane* that I want to rig for night flying. So I built a head light out of 12 Cree XP-G and carclo lens (16deg.) see:







All leds are on 10mm PCB from cutter, I glued them with thermal epoxy to a 1mm aluminium plate and added ribs between the four leds strings. As you see it's is no major heatsink, but the that light is mounted on the front of the plane flying around 25mph. With that amount of forced cooling, what current do you think it will it be possible to drive the leds at?













*FPV plane is a radio controlled planes flew via a camera mounted on board.


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## A380 (Feb 6, 2010)

WOOWW!! 
Really nice work.
You could give up to 1.4amps to each led, driving them hard (better 1amp).
But you should mount a heatsink with fins and turn the lights few secons before take off. Too much heat.
I also fly RC, not FPV (First person view) and don´t know if its going to be usefull if you fly very high.
Have you try flying FPV with other lightning?

Offtopic: Is that an easystar? 2 cameras? Why?

Better to put on a diferent place the cameras, they are going to fry!


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## HugeOne (Feb 6, 2010)

> Offtopic: Is that an easystar? 2 cameras? Why?



This is a twinstar II. The two cameras, along with goggle provide 3D vision.



> Better to put on a diferent place the cameras, they are going to fry!



There's 1/4" space between the light and the cameras's pcb. I want the light to be there so it follow the pan/tilt action of the camera. 

Do you think installing a temp probe and have the data downlink with the rest of the plane's telemetry is worth it?


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## AlexGT (Feb 6, 2010)

I guess 800-900ma, would be about 2000 lumens! please post video of the finished product! Must be a very expensive hobby you got there.


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## luckybucket (Feb 6, 2010)

Just a guess here, but I would start off small at 350ma then go up from there. I would hate to have to redo all that work. If you have a powerful enough fan you can always try to simulate the conditions on the ground. A large squirrel fan from a furnace or the ones you buy for $200 should work well for testing.


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## A380 (Feb 6, 2010)

Its a good idea having a temp probe and somehow use a fail-safe so if temp goes to high, leds could turn to a low mode before frying the cams and get blind.
Don't know what sort of equipment you are going to use but would be great having a return-to-home sistem.
Also think about how many amps is going to consume and the runtime; that is going to be a huge li-po.


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## Magic Matt (Feb 6, 2010)

For night flying, wouldn't IR light be a better option?


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## LukeA (Feb 6, 2010)

I would not worry about overheating those LEDs, let alone the cameras.

If I was to do anything to that setup, I would try to force some airflow in a direction tangent to the aluminum the LEDs sit on. Also, I'd paint that face black for emissivity. (Really! it makes a measurable difference)


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## HugeOne (Feb 6, 2010)

> If you have a powerful enough fan you can always try to simulate the conditions on the ground.



You give me an idea there! I'm going to use the plane's motor and propeller, best fan out there 



> Don't know what sort of equipment you are going to use but would be great having a return-to-home system.



There's one, if radio-link is lost or it can be called manually. It also display an artificial horizon.



> Also think about how many amps is going to consume and the runtime; that is going to be a huge li-po.



3S lipo, 4200mAh. Plane use around 6A to maintain flight.
That's actualy a very small lipo, my helicopter use a 12S 5000mAh 



> For night flying, wouldn't IR light be a better option?



The best option would be a low-lux camera, but it been done before and only available in black and white.



> If I was to do anything to that setup, I would try to force some airflow in a direction tangent to the aluminum the LEDs sit on. Also, I'd paint that face black for emissivity. (Really! it makes a measurable difference)



I take good note of that, maybe something to catch airflow and direct it between the cam and light...


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## HugeOne (Jun 4, 2010)

http://www.vimeo.com/12284615

Here a vid of my first outdoor test.
Camera's sensibility is less than my eyes, the tall trees behind the house are clearly lit.


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## ^Gurthang (Jun 4, 2010)

Nice work! Now get it in the air so we can watch!


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## foxtrot824 (Jun 6, 2010)

Please keep us updated, that was an awesome demo!


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## wechnivag (Jun 8, 2010)

OMG this is so AWESOME!! 

Imagine if you could fly this stealthily somewhere in the dark and then turn on the lights suddenly. The local police would be flooded with UFO reports!!!


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## IlluminatedOne (Jun 8, 2010)

That's a great project you got there.


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## HugeOne (Jun 12, 2010)

> Imagine if you could fly this stealthily somewhere in the dark and then turn on the lights suddenly. The local police would be flooded with UFO reports!!!



Now, that would be funny! However flying this over populated area is out of the question.

New pics:
The driver is in the front for cooling, I had to move the video Tx in the back as it was wrecking current regulation.


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## HugeOne (Jun 18, 2010)

The beast is almost done, all systems are check


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## ma_sha1 (Jun 18, 2010)

AWsome, can't wait to see some flying shots


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## simplec6 (Jun 18, 2010)

Man, that is incredibly badass.


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## ICUDoc (Jun 19, 2010)

Looks wonderful- FPV flying must be awesome. What are the goggles like? What is the microphone for? Can the cameras see IR???


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## HugeOne (Jun 19, 2010)

I use EVG920 googles.

The mic if for earing on board noises, motor screaming, wind, unespected vibration....

The camera cannot see IR.

I'm already thinking of my next project 
Building a light similar to this one, but instead of XP-G I'd use SST-90.

However, packing 12 SST-90 in a 4x3cm package will require an incredible and heavy heatsink. So, I'm think of soldering the center pads along a 5mm square copper tube in which coolant will circulate.

Packing optics so close in another challenge, the SST's dome won't fit the carclo 10mm, maybe by removing the domes...

All this, off course, will be in a bigger plane.
Ready for 25k+ lumens?


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## ejot (Jun 19, 2010)

This has been a fun thread to watch, and a really cool project. I can't wait to know how well the air cooling works at speed. As a vintage VW enthusiast, air-cooling technology is dear to my heart. I bet an ultra lightweight, high surface area heatsink would really get you some extra lumens --unless you're already at the weight limit. 

Can't wait for a flight video! 

You should put a tiny aspheric lens over a couple of the emitters to punch out the throw a little bit. :devil:



HugeOne said:


> However, packing 12 SST-90 in a 4x3cm package will require an incredible and heavy heatsink. So, I'm think of soldering the center pads along a 5mm square copper tube in which coolant will circulate.



YES, DO IT!! :bow:
You do know what each SST90 costs, right?:duck:


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## Al Combs (Jun 19, 2010)

I love this project! It reminds me of when I used to fly (uh... crash) RC planes. I never had one fly more than a minute, so it got to be too expensive a hobby. Then I got into something cheap like flashlights.:laughing:

I was thinking your 1 mm aluminum heatsink is covered completely by the Carclo optics. The 25 mph breeze doesn't really do you much good. The only part that will actually catch the wind is the small tabs that protrude beyond the Carclo TIR's. The LED's are already thermal epoxied to the 1 mm plate so you can't change that. What if you thermal epoxied the 1 mm plate onto a CPU heatsink? There is then enough room to mount a 90° air intake cowling below the LED array to blow through the enclosed heatsink and have the exhaust come out the top. The slow 90° turn will reduce the air speed over the heatsink some from the friction of the turn. But as it stands now, there is almost no air circulating behind the LED's.

Looking forward to seeing a video of this night flight.


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## fyrstormer (Jun 19, 2010)

Al Combs said:


> I love this project! It reminds me of when I used to fly (uh... crash) RC planes. I never had one fly more than a minute, so it got to be too expensive a hobby. Then I got into something cheap like flashlights.:laughing:


For you, there is this: http://www.thinkgeek.com/geektoys/rc/b5c4/


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## Stereodude (Jun 19, 2010)

Where do you live so we can keep an eye out for UFO reports?


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## Al Combs (Jun 20, 2010)

fyrstormer said:


> For you, there is this: http://www.thinkgeek.com/geektoys/rc/b5c4/


Thanks. One of the last computer shows I went to had a guy flying a $15 version of a helicopter. He was doing touch and go's on top of CD stacks. Very tempting.


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## HugeOne (Jun 20, 2010)

> You do know what each SST90 costs, right?



Yeah, 12 ain't gonna be cheap.



> I was thinking your 1 mm aluminum heatsink is covered completely by the Carclo optics. The 25 mph breeze doesn't really do you much good. The only part that will actually catch the wind is the small tabs that protrude beyond the Carclo TIR's. The LED's are already thermal epoxied to the 1 mm plate so you can't change that. What if you thermal epoxied the 1 mm plate onto a CPU heatsink? There is then enough room to mount a 90° air intake cowling below the LED array to blow through the enclosed heatsink and have the exhaust come out the top. The slow 90° turn will reduce the air speed over the heatsink some from the friction of the turn. But as it stands now, there is almost no air circulating behind the LED's.



The light (when used) will be looking down and sideway most of the time.
Air can then circulate under the carclos and behind the plate.
Temp is monitored in flight, I set the alarm at 70C is that a good limit?
I'm pretty much near weight limit, also adding weight up in the front need counterweight in the back...


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## Al Combs (Jun 20, 2010)

HugeOne said:


> The light (when used) will be looking down and sideway most of the time.
> Air can then circulate under the carclos and behind the plate.
> Temp is monitored in flight, I set the alarm at 70C is that a good limit?
> I'm pretty much near weight limit, also adding weight up in the front need counterweight in the back...


Yes, 70°C sounds about right. I'm curious, how do you get telemetry on temperature from an RC plane? I would also like to know about the artificial horizon? Is it part of the video package? What's its name? Very cool stuff.


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## DM51 (Jun 21, 2010)

HugeOne, welcome to CPF.

In the matter of the size of your photos, you are rather living up to your name, lol. The maximum permitted size is 800 x 800 pixels. All the photos you have posted so far exceed this. Please resize them.


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## HugeOne (Jun 21, 2010)

Pics resized 



> Yes, 70°C sounds about right. I'm curious, how do you get telemetry on temperature from an RC plane? I would also like to know about the artificial horizon? Is it part of the video package? What's its name? Very cool stuff.


It with eagle tree system datalogger and OSD
The "datalogger" measure voltage, current, up to 3 temperatures, RPM and a servo channel. A GPS is linked to it as well. Then a little device "OSD" overlay the data on the video image like this:







The data is then part of the image which travel down the video RF link.
Also a nice women voice speak :"Temp A 7-1" when the light is too hot 

The artificial horizon is made with the CDP4 co-pilot. That thing has a thermal sensor that sense the temp difference between earth and atmosphere to draw the horizon. When I release the control stick the computer take the plane back to level. The eagle tree logger is tapped into the sensor and display the horizon on the screen.

Indeed that is pretty cool stuff


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## Al Combs (Jun 22, 2010)

Thanks for the look. RC planes have changed quite a bit since I was a kid.


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## HugeOne (Jul 14, 2010)

I finally flew the plane and crashed it!
I don't have video since I didn't had my capture device working.

Onboard data recording was enought to tell that the light will overheat with the current coolling it have. 

Damage was not too bad, broken pan servo, some cracked foam, lost a few lenses.

The rebuilt was an oppotunity to make things better, stronger pan servo which don't rely on gears to rotate 180 degrees. Better tilt servo and better cooling for the light.



> As a vintage VW enthusiast, air-cooling technology is dear to my heart



Sorry for your old VW, but air cooling just won't cut it without a big heatsink monted on the light.




















Yep, liquid cooling 

I found a 11g micro pump on the web, modified the light with a second aluminium plate spaced 1mm from the one that hold the leds. Coolant circulate between the two, finally a home-built radiator sink the heat into the breeze.

I felt confident on pushed the leds to 2A, with the airflow of a small fan the setup now top at approx 60C. after 2mins.

Before it would reach 70C in under one minute at 1A.


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## ma_sha1 (Jul 15, 2010)

Sorry to hear about the crash

the liquid cooling is cool


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## MikeAusC (Jul 15, 2010)

*Water cooling ?*

All this water cooling does is move the heat from one place to another, but where you've put the water cooler again has no airflow.

You'd be better off placing the LEDS on an aluminium bracket that also connects to a heatsink above the LEDs, with lots of fins in clear airflow.

They use air-cooling on aircraft engines for a good reason.


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## HugeOne (Aug 23, 2010)

Flew my barge this morning and tested the light temperature in flight.
It level off 31F above ambient @2A per string, so the liquid cooling work.

I have a digital video recorder on order, be patient a video is coming 

-Hugo


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## HugeOne (Sep 27, 2010)

http://vimeo.com/15312256

First vid with the light
I tried the WDR setting on the cam and it made the video noisy, which show even worst after processing, sorry for that. 

However, the proof of concept is there, at 0:26 I turn the light off to show how it look like without it. Then, I use the light to avoid powerlines and trees, finnaly to land the plane.

Temp of the light is shown on top of the screen.

Another video tomorow night, with better setting on the cam.

-Hugo


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## Walterk (Sep 27, 2010)

Great build! For the light I was very sceptic at first especially about how to fit it on board, but you know how to build small, very nice work. 
Still think direct air cooled fins is much more efficient.
Like the carbon protective slide part.


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## CKOD (Sep 28, 2010)

Very nice work! Do your cameras have a sync line so they can be synchronized to each other or to something external? You could pulse the LEDs for a greater brightness or lower power draw if they do.


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## HugeOne (Sep 28, 2010)

http://vimeo.com/15346593

No noise, but that big glare on top wasn't in my goggles...?
The north part of my field has no city light and thick clouds hide the moon, night flight is impossible without the light. I went 950m deep into that abyss, keeping alt. in the 20m and below. At 5:38 I turned the light off for a moment, scary! 

The cam don't have synch line, that's good idea however...


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## HugeOne (Sep 30, 2010)

I came to the conclusion that a cam mounted light produce to much glare/reflections that no cam can handle. 

I changed my approach:


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## CKOD (Sep 30, 2010)

Nice change there! Time to make some at home vaccu-forming equipment and make a clear nose cone for it? :naughty:


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## Illum (Sep 30, 2010)

Liquid cooled, servo controlled searchlight on an RC aircraft?!
I can see the need of a "gunner" copilot already, one to fly and the other to maintain the light at one spot, I'd imagine the drag to be pretty weird to fly with, stuffing them in the nosecone is a good idea, but that takes out the panning feature


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## HugeOne (Oct 2, 2010)

http://vimeo.com/15481143
(Sound is crappy)

Light in the nose make a much better experience, I can see ground from much higher and no glare problems. The ultimate setup will be to have the light on a separate pan/tilt.


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## bitslice (Oct 2, 2010)

I really like the water cooling idea,
but may I comment that the radiator doesn't look to be in an optimum position ?

have you considered reusing a PC's heatpipe heatsink mounted behind the leds (and hence inside the fuselage) and then ducting air inside and across the heatsink

much like a race car mounting the radiators inside the body and then using venturi ducts to direct air across them

of course with watercooling you then have a bit more flexibility as to where the radiator is mounted, perhaps further back inside the fuselage would affect laminar airflow the least?


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## HugeOne (Oct 3, 2010)

Even a small laptop heatpipe will be heavier than my whole cooling setup.
I want to avoid ducting air in the fuselage as I fly in winter too and it'll freeze my batteries. I'm building a better radiator right now. Aerodynamics on a twin-engines foamy is helpless, don't think I can make it worst.

What is impressive is not in the goggles, but the sight of the massive plume of light that cross the field 

Next step will be 12 cree XM-L if I can get them on 10mm pcb.


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## HugeOne (Oct 8, 2010)

New radiator:











New vid:
http://www.vimeo.com/15676719
Keep the light 20C cooler now.


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