Overhead Light Air

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Rich
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Re: Overhead Light Air

Post by Rich »

dant wrote: Sat Jan 22, 2022 4:37 am
In fact the fixtures combined with the cover weigh in at 3 oz. each.
I just read the OSB, and mentally ballparked 333g as a little under a pound.
I.10 Mass (Weight) and CG
This installation results in a mass increase of approximately 333 g
If only adding the covers, which I measure out as 1 ounce each for t total of 3 oz. So unless they have changed the design radically in the last 2 years, comes to 3/16 pound, rather than 3/4 pound. Changing to the new design fixtures altogether might be closer to the 3/4.

The original fixtures, even when sealed against the structure still leak air around the switch operator itself. That’s what the covers prevent. These switches are apparently Renault parts - the guys who brought you “Le Car”.

The newer design is fully enclosed. It’s also easier to remove and install, thought it winds up being surface-mounted, as it has different dimensions. It is far more expensive.
2002 DA40-180: MT, PowerFlow, 530W/430W, KAP140, ext. baggage, 1090 ES out, 2646 MTOW, 40gal., Surefly, Flightstream 210, Orion 600 LED, XeVision, Aspen E5
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Re: Overhead Light Air

Post by dmloftus »

This is a great solution for air coming from the overhead lights. Simple to install baffle at the pilot-side wing root cuts off the air at the source.
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Wing root vent baffle.jpg
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Rich
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Re: Overhead Light Air

Post by Rich »

dmloftus wrote: Sat Jan 22, 2022 5:18 pm This is a great solution for air coming from the overhead lights. Simple to install baffle at the pilot-side wing root cuts off the air at the source.
The problem with blocking off the incoming air as the universal solution is it doesn't cover the significant part of the year where it's 80 deg on the ground and 35 at cruising altitude.

I have replaced the pilot side light with the new design and have the cover on the copilot light. No air leaks coming from those sources. The rear seat light you can leave alone, as it doesn't push cold air directly on anyone.
2002 DA40-180: MT, PowerFlow, 530W/430W, KAP140, ext. baggage, 1090 ES out, 2646 MTOW, 40gal., Surefly, Flightstream 210, Orion 600 LED, XeVision, Aspen E5
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Re: Overhead Light Air

Post by dmloftus »

Rich wrote: Sat Jan 22, 2022 5:28 pm
dmloftus wrote: Sat Jan 22, 2022 5:18 pm This is a great solution for air coming from the overhead lights. Simple to install baffle at the pilot-side wing root cuts off the air at the source.
The problem with blocking off the incoming air as the universal solution is it doesn't cover the significant part of the year where it's 80 deg on the ground and 35 at cruising altitude.
I wasn't suggesting this as a universal solution, it is a winter solution. Takes about 10 seconds to install or remove when weather dictates. I had Southtec remove and reseal everything during my annual last May when I switched overheads to LED's. I still had air leaks this winter. This is a poor design from Diamond - the winter baffle is a good compromise for colder months.
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Rich
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Re: Overhead Light Air

Post by Rich »

dmloftus wrote: Sat Jan 22, 2022 5:56 pm I wasn't suggesting this as a universal solution, it is a winter solution. Takes about 10 seconds to install or remove when weather dictates. I had Southtec remove and reseal everything during my annual last May when I switched overheads to LED's. I still had air leaks this winter. This is a poor design from Diamond - the winter baffle is a good compromise for colder months.
Here are my front overhead lights. Lots of flying at temperatures of -2 to +5 C lately. Neither of these leak air:
E743AABF-DF88-49C8-A8B4-F87DD07FD2FB.jpeg
The speaker no longer leaks air because it is sealed off with Gorilla Tape. This is another area where leaks can happen, especially if the air pressure has ruptured the paper speaker cone.

The throttle quadrant is the only place I have to deal with cold air coming in. I believe that is also from the vent It’s not a terribly big deal as I only intermittently fiddle with these controls and the effect is confined to this limited area.
2002 DA40-180: MT, PowerFlow, 530W/430W, KAP140, ext. baggage, 1090 ES out, 2646 MTOW, 40gal., Surefly, Flightstream 210, Orion 600 LED, XeVision, Aspen E5
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Re: Overhead Light Air

Post by Rich »

Here is my original pilot map light disassembled. Sometime, years ago, the device was broken. I never use the thing so I couldn't tell you when it happened. I had thought the bulb simply burned out. I figured I'd replace the bulb with a LED. When I started to remove the fixture I discovered the switch was simply flopping in place. I found the bulb was fine, but a really tiny plastic piece of the switch had broken off (in the circle). No way to repair it. That open space on the right of the frame shows a gap where air leaks past the switch. This is in addition to around the edges of the frame and possibly the edges of the lamp gimbal.
Original Map Light With Broken Part.jpg
FWIW, the picture below shows the newer design light in action. It consists of an array of LED elements rather than the original single incandescent or replacement LED. It's pretty expensive but provides much brighter and broader illumination. It's also a sealed unit so there are no air leaks and it is more easily removed and installed. The bad news is it's not a physical fit into the pocket in the plenum of the older airframes and winds up as a surface mount. It's also possible that it will draw as much current as the incandescent bulb of the original fixture, though I have not measured it.
New Cabin Light In Action.jpg
2002 DA40-180: MT, PowerFlow, 530W/430W, KAP140, ext. baggage, 1090 ES out, 2646 MTOW, 40gal., Surefly, Flightstream 210, Orion 600 LED, XeVision, Aspen E5
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Re: Overhead Light Air

Post by Steve »

Rich:

My original light assemblies started working intermittently (in addition to leaking air) several years after I bought the airplane. When I removed the assemblies, I found that Diamond had installed (for want of a better term) condoms around the switch component of the assembly. These had deteriorated into a sticky residue in places, and actually contaminated the switch contacts. After much cleaning with solvents and scraping with a razor blade, the contacts now work (fairly) reliably. I never reinstalled the Trojans, and at least in Texas, the air leakage is not troublesome.

I did convert to the LED bulbs, but they are still quite dim...
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Re: Overhead Light Air

Post by Rich »

Steve wrote: Mon Jan 24, 2022 4:43 pm Diamond had installed (for want of a better term) condoms around the switch component of the assembly. These had deteriorated into a sticky residue in places, and actually contaminated the switch contacts.
There was much of that goo remaining, most of which I stripped off before taking this picture. The larger cover is more effective, should last a long time and uses no gooey-sticky stuff.
2002 DA40-180: MT, PowerFlow, 530W/430W, KAP140, ext. baggage, 1090 ES out, 2646 MTOW, 40gal., Surefly, Flightstream 210, Orion 600 LED, XeVision, Aspen E5
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Re: Overhead Light Air

Post by Chip&Al »

Rich wrote: Mon Jan 24, 2022 4:18 pm Here is my original pilot map light disassembled. Sometime, years ago, the device was broken. I never use the thing so I couldn't tell you when it happened. I had thought the bulb simply burned out. I figured I'd replace the bulb with a LED. When I started to remove the fixture I discovered the switch was simply flopping in place. I found the bulb was fine, but a really tiny plastic piece of the switch had broken off (in the circle). No way to repair it. That open space on the right of the frame shows a gap where air leaks past the switch. This is in addition to around the edges of the frame and possibly the edges of the lamp gimbal.

Original Map Light With Broken Part.jpg

FWIW, the picture below shows the newer design light in action. It consists of an array of LED elements rather than the original single incandescent or replacement LED. It's pretty expensive but provides much brighter and broader illumination. It's also a sealed unit so there are no air leaks and it is more easily removed and installed. The bad news is it's not a physical fit into the pocket in the plenum of the older airframes and winds up as a surface mount. It's also possible that it will draw as much current as the incandescent bulb of the original fixture, though I have not measured it.

New Cabin Light In Action.jpg
Rich,

What’re your thoughts on 3d printing the broken bit and putting it back together? Or do you think once its taken apart the only feasible fix is to buy the surface mount unit?
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Re: Overhead Light Air

Post by mhoran »

I ordered two of the Renault parts from eBay to replace my broken fixtures: https://www.ebay.com/sch/i.html?_nkw=770082054. They came broken in a different way but I was able to bend the copper back into place and now they work great. I also installed LED bulbs: https://www.grainger.com/product/LUMAPR ... amp-26CU04.
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