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Ovation recog light replacment alternatives


rogerl

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15 hours ago, hypertech said:

Don’t buy a voltage converter. They aren’t fancy but that’s the kind of thing that is burning down cirrus jets. Get a part rated for 28V. It’s a better solution and also avoids needing to mount a converter. 

While I agree with you that it is best to get a 28V part, I would like to point out that Mooney didn't even do this in their original design. They put in a resistor that burns 25W of power, the same 25W that the original bulb was. Mooney is full of dropping resistors. The little clock uses them too. The cabin light switches that have a bright/dim setting are also done with resistors. 

 

I do like the LR11 solution. I bought  few, and I plan to test them on the bench to see if they are really 12V only or more flexible. If they happen to be 12V only then I could update the Mooney resistor value to an appropriate one or use an appropriate voltage regulator. I'll have to see what it looks like when I get in there.

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Hey @rogerl

how did you make these fit the existing rectangular mounting hole and clip? I have mine about ready to go back in and it doesn't look t me like the sidewalls  of the stems are thick enough for me to grind them down enought to fit.

did you enlarge the existing hole?  How?

thx

PJ

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Here is a Whelen LR11 update.

The LR11 module is indeed 12V only. There is a current regulator circuit that limits the current to about 0.65A. The unit achieves full brightness and current at 9.5V. Voltages above 9.5 have the same current, which means that increased voltage leads to increased heat. At around 25V, the overvoltage limiter kicks in and the unit starts blinking. 

Speaking of heat, this unit gets quite warm in operation. At 14V it is too hot to touch. At 9.5V it is hot but touchable. The unit has a robust aluminum mounting bracket that normally mounts to the light bar structure, a large heat sink. I am quite sure that in Whelen's intended application, police light bar, the unit has a large heat sink and doesn't get nearly as hot as it does sitting stand-alone on the bench.

Because of the heat, I believe the unit should be mounted directly to the aluminum wingtip structure to provide for a proper heat sink. A full metal-metal connection. It should not be mounted to the plastic. My plane just went into annual, so I'm not sure how that would work at the moment. 

Also because of the heat, I plan to run mine at 10V. That will give full brightness and minimum heat. I have a 28V aircraft. So this will involve either a regulator or resistor, I have not decided yet. 

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  • 3 weeks later...

No, I decided on a 10V linear regulator.  I wanted precisely 10V at the LED for max light and minimum heat.  I also wanted to mount everything in existing holes. There is a nice existing hole in the aluminum rib that I can mount the regulator to. It should have enough metal to dissipate the heat.

 

I'll leave the existing resistor in place for three reasons. First, I can't get it out...  I could cut the wires but removing the actual resistor is pretty impossible. It must have been assembled to the wingtip before the tip was riveted to the end of the wing. Second, It'll drop 3.5V and take some of the heat away from the linear regulator.  And third, I don't want to modify anything on the airplane. Speaking of the existing resistor, Mooney mounted it to a very tiny heat sink, about 2 sq-in of aluminum and that is mounted inside the fiberglass wingtip. 34 Watts of heat sunk directly into the fiberglass.  

 

The whole project is designed to be 100% removable. It'll plug into the existing plug. No Mooney parts will get modified, and if I need to the whole original setup can be re-installed in 5 minutes per side.

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31 minutes ago, WilliamR said:

@larryb would you mind providing a link to the regulator you used?  A pic of the hole you describe and how the regulator is mounted would be icing on the cake.

Thanks

William

The planned hole is the little hole directly above where the 2 wires are grounded. 4-40 hardware.   I think the rib will be enough of of a heat sink, but to be sure I plan to add this one as well. 

The regulator and heat sink arrive today. I'll probably work on it Friday or Saturday, and will post more pics when complete.

If you look closely, you can see the Mooney resistor mounted to the fiberglass wingtip rib with a tiny piece of aluminum as a heat sink. In my opinion, that solution is inadequate.

https://www.mouser.com/ProductDetail/511-L78S10CV

https://www.mouser.com/ProductDetail/984-ATS-PCBT1083

 

 

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Finally finished it. It was a lot more work than I expected going in. Here is a pic of the regulator mounted, detail on the 3-D printed part and how the module is mounted. 

 

The aluminum plate mounted behind the LED module is the heat sink. It is designed to touch the aluminum wing rib. A layer of thermal grease enhances heat transfer. The LED module generates quite a bit of heat and needs a good heat sink. 

 

The existing dropping resistor proved useless. Mooney wired it into the ground leg of the original circuit. Because the regulator is grounded to the aluminum the resistor is effectively bypassed. Fortunately the wing provides a sufficient heat sink for the regulator even without the resistor. 

 

I had to use ABS for the 3-D printed part to handle the heat. I still have the incandescent nav light, and that gets pretty hot too. The original Royalite shroud is also ABS, so my part should have heat resistance comparable to the original. I had to build an enclosure for my 3-D printer in order to get a good quality ABS print. Without the enclosure, it was warped and cracked easily. With the enclosure, it came out perfect. At least I can now print in ABS...

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  • 5 months later...
On 4/6/2020 at 5:36 PM, amillet said:

When you electronic wizards get this figured out, I’ll order a couple pre-made lights fro:Dm you 

Yeah me too.  I’ve read through this thread over and over trying to figure out how to do this and which setup is the brightest.  Perhaps I am overthinking it.  
 If someone could list parts they used, (24v) I would appreciate it.  Questions I have are:

maglight reflectors, how did you get them to mount in the rectangular hole? I see PJ just squared them off and painted them.  I thought they may be undersized for that, but I must be wrong..

what part number for the AMP connectors that make these “plug and play”

 

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