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Filling stall warning holes

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xblueh2o

Well Known Member
I tried searching old threads using various search strings but never found anything.
I have a QB8 wing that has the holes for the stall vane already pre-punched. I will be doing an AOA system (don't know which one yet) so I need to close these holes up. I have some ideas of my own plus some suggestions from local builders but wondered what others have done to close up these holes. Just looking to see how others have done it.
 
I am building a 6, so don't have this issue. If you can get access behind, I would rivet on a .025 backing plate and fill with filler. You can use HSRF if you don't think standard polyester filler will be strong enough. The HSRF is very strong with a tenacious bond.

Larry
 
Robert, the hole is about 1"x2" big enough for the stall warning divide to mount and catch air. It will be a job to hide it, but can be done.

Correction - I went and looked at my wings today and the opening is about 3/4 x 3/4.
 
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Perhaps a cut-to-fit flush patch the same thickness as the skin, and a doubler behind it flush riveted to both the patch and the skin?
 
lr172 said:
I would rivet on a .025 backing plate and fill with filler.
Click to expand...

Exactly what I did about 2 weeks ago. I made the backing plate to fit the existing rivet holes and filled the slot with West Systems epoxy and micro. It's now painted and you can't tell it was ever there.
 
rockwoodrv9 said:
Robert, the hole is about 1"x2" big enough for the stall warning divide to mount and catch air. It will be a job to hide it, but can be done.
Click to expand...

I might be remembering this wrong, but when I received my -8 wing kit the vane opening wasn't pre-punched. The leading edge skin included two small (1/8"?) locator holes for this opening. The vane opening was created by removing the material between these holes. My comment assumed the OP was only filling the locator holes.


Robert
 
I am confused.......the opening in the leading edge for the switch is something like 3/8" x 3/4, not 1" x 2. Are we all talking about the same thing here? Or do different models have different switches and openings?
 
DaAV8R said:
I might be remembering this wrong, but when I received my -8 wing kit the vane opening wasn't pre-punched. The leading edge skin included two small (1/8"?) locator holes for this opening. The vane opening was created by removing the material between these holes. My comment assumed the OP was only filling the locator holes.


Robert
Click to expand...

This is what I have. Two small (undersized #40) holes in the leading edge that you would open up and connect to make the slot if you were going to install the vane and then some other pre-punched holes trailing back from the leading edge to secure the internal bits of the vane assembly.

Dimpling and filling with rivets is certainly one of the possibilities but wondered if others had come to a more elegant solution.
 
xblueh2o said:
Dimpling and filling with rivets is certainly one of the possibilities but wondered if others had come to a more elegant solution.
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Fill the hole from behind with HSRF or filler. leave a blob on the back that will keep it secure. Be sure to scuff around the hole first. On the outside. fill the hole with filler and sand smooth.

Larry
 
xblueh2o said:
This is what I have. Two small (undersized #40) holes in the leading edge that you would open up and connect to make the slot if you were going to install the vane and then some other pre-punched holes trailing back from the leading edge to secure the internal bits of the vane assembly.

Dimpling and filling with rivets is certainly one of the possibilities but wondered if others had come to a more elegant solution.
Click to expand...

You don't even need to dimple....
Get a couple of NAS1097-3 rivets (commonly refered to as oops rivets when using the -4 size...)
You need the -3 size that is often used for installing nutplates.... they will match the hole size you have now.
They have a small sized head that will only require you to very slightly machine countersink the skin.
Lightly set the rivets.
Use a file and then sanding block to make the heads totally flush to skin.
After paint the will be invisible.
 
That was one of my possibilities too so it's good to hear that the oops rivet idea is a valid one. Thanks for the info.
 
DaleB said:
Can I ask -- what's HSRF?
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This stuff is great. Very strong grip and very hard. I have used it in a few areas where poly filler is not strong enough. You just have to get it filed down before it fully sets, as it doesn't sand well due to the hardness. It is vynal ester based, not polyester.
 
az_gila said:
Perhaps a cut-to-fit flush patch the same thickness as the skin, and a doubler behind it flush riveted to both the patch and the skin?
Click to expand...

reviving an older thread.

What's the thinking on creating a flush patch and welding it in place, either TIG or gas.
It can be an invisible patch after grinding the joint smooth.
Care must be taken to avoid overheating and causing cracks. But aside from that is there any reason not to do this? I'm just curious that so many posts talk about complicated methods using backing plates etc. For those with access to welders, isn't this easier?
I'm thinking about plugging the hole left by the stock pitot after I replace it with a heated one (probably Dynon).

Thanks
 
chubsterini said:
reviving an older thread.

What's the thinking on creating a flush patch and welding it in place, either TIG or gas.
It can be an invisible patch after grinding the joint smooth.
Care must be taken to avoid overheating and causing cracks. But aside from that is there any reason not to do this? I'm just curious that so many posts talk about complicated methods using backing plates etc. For those with access to welders, isn't this easier?
I'm thinking about plugging the hole left by the stock pitot after I replace it with a heated one (probably Dynon).

Thanks
Click to expand...

Do not weld 2024. It isn’t considered a weldable alloy. I didn’t want the stall warning either, but decided to just go ahead and install it anyway. It can’t hurt to have it, and may keep the next guy safe. What’s the real benefit in covering it up? .0001 knot? If it wasn’t pre punched, I would have not installed it.
 
Taltruda said:
Do not weld 2024. It isn’t considered a weldable alloy. I didn’t want the stall warning either, but decided to just go ahead and install it anyway. It can’t hurt to have it, and may keep the next guy safe. What’s the real benefit in covering it up? .0001 knot? If it wasn’t pre punched, I would have not installed it.
Click to expand...

Thanks for the info. I didn't know it was 2024.
-c
 
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