Recognition Lights

[Airways]

38 minutes ago, Fry said:

Thanks PJ - installation will happen in 2 weeks or so.

Certainly perfectly willing to share files and instructions.

Are we talking N-reg or EASA here ?

[carusoam]

Owner produced parts are a US FAA norm...

A whole procedure exists to support planes whose parts have gone out of production...

 

As for the lens melting heat of recog lights...

• The lens softens around the boiling point of water...
• The original bulb is hot enough to sear a steak...
• Air motion can keep the lens surface cool enough to not soften...
• Taxi speed is not enough air motion...
• If you don’t turn the recog lights off, after landing check list...
• They will deform by the time you turn them off in front of the hangar...
• Recog lights probably are on the Pre-T/O check list as the last thing to turn on... before pushing the throttle in.

Some of the substructures made to support lights in the original installation appears to become brittle with age and heat...  Finding viable replacements may be difficult...

PP thoughts only, not a mechanic...

Best regards,

-a-

[warren.huisman]

There is an entire thread regarding owner produced LED recognition lights.  My hangar fairy decided on the crazed pilot landing light / Mag reflector as it looks a lot like the original part.  It's bright and does not create much heat.  Not a terribly difficult job either.  

Search for Ovation recognition light and you can find the thread....

[moosebreath]

I was going to give up on this and go down to the shop and make some LED replacements for Covid fun.  But ... I ... HAD ... to reply one more time.

What started this tread was my leaving my recognition lights on while on the ground for 15 minutes.  I did only a slow taxi for a short distance but was mostly stationary during that time.  My lenses are perfectly fine.  Therefore mine will not melt the lenses between the end of the runway and my hanger (which is only 5 minutes away at home).  They were not damaged in 15 minutes.

My lenses are the 1997 factory originals.  If replacements are thinner perhaps they are more effected by the bulb heat.

In need of fun during isolation I went to the hanger this morning.  I turned on the recognition lights and put my hand over the face of the lens ... and waited.  It gets a little warm but it didn't melt in my hand or burn my hand either.  Interestingly the sheet metal lens shield on the edge of the lens gets pretty hot.  That is not where the burned lens pictures show damage though.

I have read all I can find on the forum concerning this issue.  One comment that made sense is that the voltage dividing resistor on 28v airplanes can become open.  If that happens the bulb receives not 14v but 28v.  Double the voltage is four times the energy output while the bulb lasts.  I can believe that would be enough to damage the lens.

I should have simply done the hand test in the first place I suppose ...

As they say, your experience may (does in this case) vary.  Why I have no idea but the above thoughts.

 

 

 

[moosebreath]

One more thought.  I do not, sadly, own an Ovation.  Perhaps the bulb to lens distance or the lens material/thickness is different than my J.  There are none on my home field for me to examine and it is a bit hard to compare from pictures.

[larryb]

3 hours ago, moosebreath said:

One comment that made sense is that the voltage dividing resistor on 28v airplanes can become open.  If that happens the bulb receives not 14v but 28v.  Double the voltage is four times the energy output while the bulb lasts.  I can believe that would be enough to damage the lens.

While a nice theory, I can debunk it. When I was working on my LED upgrade, I had the factory original on the bench to measure it's power. Temporarily forgetting that it was a 12v bulb I started cranking up the voltage on the power supply. The bulb blew as I got to around 20 V,.  It won't last a second at 28 V.

 

If the resistor failed open, then the bulb would not light. Resistors typically do not fail shorted. All that said, the resistor is another weak point in the factory design. It is mounted to a 2" square heat sink which is mounted to a fiberglass rib in the fiberglass wingtip assembly. It is dissipating 25 watts. I hate to think how hot it gets that fiberglass section.

[PJClark]

I think it's actually even better than that.

In any series circuit, the current is the same through the whole circuit. In the old circuit, for the resistor to have dropped half the voltage, the bulb's resistance and the resistor's had to be the same since the current has to be the same, and the resistor was selected to halve the voltage.

the LED is different from the old bulb.  It will pass a specified current at a given voltage...for example, 1 amp at 14V or 1/2 amp at 28V.  That means the current in the ENTIRE circuit, including through that old resistor, is reduced to the current through the LED.  Thus, the old resistor is now not getting as hot as it used to, because the LED is limiting the current:  it's acting like a massively larger "resistance", kicking the total circuit's apparent resistance way up, reducing the total current.

So your old resistor is cooler, probably about 10X cooler.

I think. But that EE degree is now 38 years old so I may need correcting. War Eagle!

[larryb]

Sure, with an LED replacement the resistor will have much less current and voltage, so it's power will be much less. But I was discussing the resistor in the factory original projector lamp application. Another oddity, they put the resistor in the ground circuit not the battery circuit.

[moosebreath]

I left a shiny penny on each wingtip and the hanger elves installed LED recognition lights.

They are certainly much brighter than the old halogen projection bulbs.  Each draws .16 amps at 28 volts exactly as expected.

They were a bit fiddly to construct however the total cost, say the elves, was $20 total.  They don't generate any heat either

[Fry]

Here's what I did (note I had to source in Europe):

These for the back-facing white NAV lights on the wingtips.

Sockets, LEDs, Parabolic mirrors,

Painted the outside of the mirrors black

Sawed the mirrors using  a little rig (STL for 3D printing attached, please scale down by factor 10) and a jigsaw.

Glued the mirrors, the sockets and the male part of the adapter (STL attached, print these adapter parts with 100% fill rate to get the necessary strength) together.

Used distance rings (STL attached, please scale down by factor 10) and put it in place in the wingtip.

Don't worry about the resistor, with the lower current it is not getting hot, and if you like you can even take it out.

Will post a picture of the wingtip later, attached is  just a preliminary picture, but it is close to the final product.

You have to judge the legality of this yourself. Frankly, I could not care less, as the part is nonessential for flight.

PS. Thanks to PJClark for his useful hints.

Sawing Rig.stl Distance Rings.stl

Recognition Light Adapter Male.stl Recognition Light Adapter Female.stl

[Leonard]

@Fry

Hows your LED project coming along? Any new developments we should know about or maybe problems you ran into during the installation or maybe even some more pictures? I’m about to do the same thing.. any additional info would be appreciated. Thanks

[Fry]

13 hours ago, Leonard said:

@Fry

Hows your LED project coming along? Any new developments we should know about or maybe problems you ran into during the installation or maybe even some more pictures? I’m about to do the same thing.. any additional info would be appreciated. Thanks

The new lights are working flawlessly. While doing the install, I accidentally broke one of the wingtip covers - but that's nothing to do with my approach, it was just pure stupidity.

You can try with the files and instructions I posted above. Let us know if it worked.

[Leonard]

Contouren have a 12 or 24 volts system?

 

[Airways]

Hey @Fry, @PJClark

how did you define the contour of the reflector ? Did you just cut until it fitted inside the lens or did you use an old Whelen 70303 as a template ?

 

Thanks !

[Fry]

6 hours ago, Airways said:

Hey @Fry, @PJClark

how did you define the contour of the reflector ? Did you just cut until it fitted inside the lens or did you use an old Whelen 70303 as a template ?

 

Thanks !

Cut until it fitted. 

[PJClark]

I started by putting the old whelen on a sheet of paper and marknig the corners and edges of the ends that met the paper.  Eyeballed cut line to approximately match.  I had to do just a little grinding of one corner to fit when I got them back to the airplane.

[Airways]

Thanks guys !

[PeytonM]

I’ve got Precise Flight’s PulseLights on my recognition lights, which stopped lens deformation.  I leave them on all the time, so every few years I’m replacing the bulbs, so I’d consider LEDs the next time.  Can I use the Pulse Light with the LEDs?

[ArtVandelay]

I’ve got Precise Flight’s PulseLights on my recognition lights, which stopped lens deformation.  I leave them on all the time, so every few years I’m replacing the bulbs, so I’d consider LEDs the next time.  Can I use the Pulse Light with the LEDs?

Yes

[flyer338]

On 7/15/2020 at 12:21 PM, shawnd said:

Holes are definitely a reality by turning on recog lights on ground while not in moving (cold) air. I bought mine that way Speaking of which - where can I pick up replacement ones?

Shawn, I needed a wingtip lens recently. They are available from Knots2U.

Fitting the lens required about three hours. The rear edge, top and bottom, was the only place where I had to remove material. I used a bench grinder with a fine stone to remove the material.
Knots2U also sells a set of special drill bits for drilling and countersinking the mounting holes. I bought the drill bits because after three hours of careful fitting, I did not want to chance cracking the lens when drilling the holes.

Here is the link for the wingtip lenses.

https://www.knots2u.net/categories/mooney-aircraft-models/wing-tips.html

[shawnd]

Thanks @flyer338.  BTW Great Lakes Aero also has these pieces. Don't need them just yet but you can find them here: https://www.glapinc.com/Mooney/m20K.htm

[tmo]

FWIW, my OPP cowl landing light lens cost around $15... Waiting on a new set of screws and washers for it to arrive, it so perty, I just had to get shiny new ones...

Fully granted that it is the easiest piece to OPP, but still makes me smile.

[flyer338]

6 hours ago, shawnd said:

Thanks @flyer338.  BTW Great Lakes Aero also has these pieces. Don't need them just yet but you can find them here: https://www.glapinc.com/Mooney/m20K.htm

When I needed it, the lens time was critical. Great Lakes did not have it in stock but promised to manufacture a lens in time for me to do the installation. Knots2U did and does have it in stock. The price was the same. I suspect Knots2U gets the lenses from Great Lakes Aero. The MSC in Florida told me Great Lakes Aero makes the wing tip lenses for Mooney.

[shawnd]

Thanks, good info to have!

[Missile=Awesome]

On 7/15/2020 at 8:34 PM, larryb said:

What is that beauty?