Broken Landing Light Lens on Install

[MechaSteve]

I managed to break the landing light lens during install, but probably not the way you would expect.

I installed the landing light components, and lens, almost all according to the instructions. One exception was that I had not tightened the side screws locking the aim of the landing light in place, prior to installing the lens. I elected to work in this order as I was installing the light during the original wing build, rather than a retrofit.

I finally tightened these two bolts and all looked well, but when I came back to it in 15-20 minutes cracks had formed and continued to develop as I examined the cause.

My assumption is that the lens was over constrained by the Lens mounting screws, and when the light mounting bolts were tightened, the structure flexed slightly.

Any tips on how to better ensure the fit of the lens to prevent a repeat when installing a replacement?

Any tips on how best to cut a new lens, given the mounting holes are now dimpled to accommodate the #6 flat head screws?

How much risk is there if I un-dimple the mounting holes with a flat squeezer, before re-dimpling? Has anyone had cracks form from this?

 

[Avanza]

I managed to break the landing light lens during install, but probably not the way you would expect.

I installed the landing light components, and lens, almost all according to the instructions. One exception was that I had not tightened the side screws locking the aim of the landing light in place, prior to installing the lens. I elected to work in this order as I was installing the light during the original wing build, rather than a retrofit.

I finally tightened these two bolts and all looked well, but when I came back to it in 15-20 minutes cracks had formed and continued to develop as I examined the cause.

My assumption is that the lens was over constrained by the Lens mounting screws, and when the light mounting bolts were tightened, the structure flexed slightly.

Any tips on how to better ensure the fit of the lens to prevent a repeat when installing a replacement?

Any tips on how best to cut a new lens, given the mounting holes are now dimpled to accommodate the #6 flat head screws?

How much risk is there if I un-dimple the mounting holes with a flat squeezer, before re-dimpling? Has anyone had cracks form from this?

I'm not a builder of a RV12 so I can't comment on your specific installation.
But I would consider using Sikaflex, a marine adhesive and sealant for fixing the landing light in it's final position.

Sikaflex

Our incredible line of Sikaflex® bonding adhesives and sealants meets many industry applications requiring high flexibility, durability and superior bond strength.

usa.sika.com

Good luck

 

[N8DAV8R]

I would expect that you could insert the new lens and mark and/or match drill the holes even with the dimples in place. You can slightly oversize the holes in the lens and same with the countersink, since it's the nut plates on the back side that are actually doing the work. Any wiggle room caused by the error in drilling through the dimpled holes will allow for thermal expansion and unlikely to cause any problems. This would be my approach over flattening the dimples.

 

[Ralph Inkster]

Sikaflex would be a great sealant & adhesive but this would make it very messy & difficult to remove the lens for maintenance in the future.

 

[Baron71]

I managed to break the landing light lens during install, but probably not the way you would expect.

I installed the landing light components, and lens, almost all according to the instructions. One exception was that I had not tightened the side screws locking the aim of the landing light in place, prior to installing the lens. I elected to work in this order as I was installing the light during the original wing build, rather than a retrofit.

I finally tightened these two bolts and all looked well, but when I came back to it in 15-20 minutes cracks had formed and continued to develop as I examined the cause.

My assumption is that the lens was over constrained by the Lens mounting screws, and when the light mounting bolts were tightened, the structure flexed slightly.

Any tips on how to better ensure the fit of the lens to prevent a repeat when installing a replacement?

Any tips on how best to cut a new lens, given the mounting holes are now dimpled to accommodate the #6 flat head screws?

How much risk is there if I un-dimple the mounting holes with a flat squeezer, before re-dimpling? Has anyone had cracks form from this?

I did my W-00036 last year and haven’t encountered any cracks. But I ordered a replacement, because I am not happy how I countersunk the plexiglass (see picture). Haven’t installed the replacement so far, but my plan was a follows:
- wrap the W-00036 with tape to prevent any scratches
- Cut the length with a bandsaw
- remove the tape at one side only
- place the W-00036 on top of the dimpled holes with the transparent side and mark the positions
- drill and machine countersink this side
- remove the tape on the other side (again just the side to make sure I don’t get any scratches in the lens area)
- add the tape harness as per KAI to pull the lens forward once inserted
- insert the W-00036 in place (the drilled side should already fit nicely) and mark the other side
The rest should be self explanatory, I think. (BTW: I know was working too late and forgot to remove the blue plastic on the mounting plates. Fixed it prior to installation by melting it with a heat gun).

 

[MechaSteve]

I think my longer term plan will be to replace the acrylic lens with 0.030” polycarbonate.

Even if the polycarbonate is more likely to get scratched, I think it can be far cheaper and easier to replace.