Phil
Well Known Member
I posted this mistake on Matronics earlier in the week and thought I'd share the fix with everyone else here.
Thanks,
Phil
===================================
Hi Everyone,
I've had a couple of people ask how I repaired the mistake on the aft deck.
Last night I finally got around to repairing it and thought I'd share with the group. Maybe you'll have an opportunity to do something similar during your build.
It sounds like a lot of work and definitely is not the simplest fix, but I have absolutely no concerns about the long term integrity of the repair.
I can't claim credit for solution. David McNeill put me in touch with an A&P IA who sketched out the design and sent it to me Thanks David!
Phil
This is the original damage... You can see the longeron below and it's fine, but the aft deck skin was pretty messed up. The damage extended beyond an AD5 rivet and it's possible that an AN3 bolt probably wouldn't have fully removed it.
======================================
I was only 7 rivets into installing the aft deck when my screw up happened, so I went ahead and removed the entire deck. It made working on the pieces much easier.
Once it was off the airplane, I removed the damaged area with a uni-bit and deburred the hole. It required a 5/16" hole to remove the damaged area.
Next up was to create a 5/16" plug for the hole. The plug was made from .040 scrap and matches the same .040 thickness of the deck. My buddy is an A&P and he stopped by take part in the process. He did a great job of building a round plug that fits the hole perfectly!
The first photo shows the plug sitting beside the hole. The second photo shows the plug sitting inside the hole.
======================================
Next up was to re-create the rivet hole. We did this with a 90 degree drill and came up through the bottom of the longeron. To keep the plug from spinning, we taped it down with duct tape and applied pressure with a wooden block from the top. It worked pretty well. We were able to get 80% of the way through the plug before the tape gave and the plug started to spin. However the hole was deep enough that we could finish drilling it out on the workbench. Looks pretty good!
======================================
Finally, we created a doubler out of .040 scrap (same thickness/strength as the deck skin). The doubler has 5 rivets. Obviously it's centered on the plug and we picked up the adjacent longeron rivets. Then we attached the doubler to the deck skin inboard of the longerons.
We thought about adding two additional rivets by splitting the distance between the plug and the adjacent longeron rivets, but after looking at it closer we opted out of that decision. There isn't much clearance for rivet pitch (spacing) by splitting those holes. Sure we could have done it and it would have been fine by the book, but we would have been sitting a minimums. When we weighed that reality with the reality weakening the longeron by drilling additional holes - we decided it was better to leave well enough alone.
On the inboard deck rivets, we chose to split them between the plug and the adjacent longeron rivets. This was by design to share the shear load between the plug rivet and it's adjacent longeron rivets.
Here is the finished product.
Thanks,
Phil
===================================
Hi Everyone,
I've had a couple of people ask how I repaired the mistake on the aft deck.
Last night I finally got around to repairing it and thought I'd share with the group. Maybe you'll have an opportunity to do something similar during your build.
It sounds like a lot of work and definitely is not the simplest fix, but I have absolutely no concerns about the long term integrity of the repair.
I can't claim credit for solution. David McNeill put me in touch with an A&P IA who sketched out the design and sent it to me Thanks David!
Phil
This is the original damage... You can see the longeron below and it's fine, but the aft deck skin was pretty messed up. The damage extended beyond an AD5 rivet and it's possible that an AN3 bolt probably wouldn't have fully removed it.
======================================
I was only 7 rivets into installing the aft deck when my screw up happened, so I went ahead and removed the entire deck. It made working on the pieces much easier.
Once it was off the airplane, I removed the damaged area with a uni-bit and deburred the hole. It required a 5/16" hole to remove the damaged area.
Next up was to create a 5/16" plug for the hole. The plug was made from .040 scrap and matches the same .040 thickness of the deck. My buddy is an A&P and he stopped by take part in the process. He did a great job of building a round plug that fits the hole perfectly!
The first photo shows the plug sitting beside the hole. The second photo shows the plug sitting inside the hole.
======================================
Next up was to re-create the rivet hole. We did this with a 90 degree drill and came up through the bottom of the longeron. To keep the plug from spinning, we taped it down with duct tape and applied pressure with a wooden block from the top. It worked pretty well. We were able to get 80% of the way through the plug before the tape gave and the plug started to spin. However the hole was deep enough that we could finish drilling it out on the workbench. Looks pretty good!
======================================
Finally, we created a doubler out of .040 scrap (same thickness/strength as the deck skin). The doubler has 5 rivets. Obviously it's centered on the plug and we picked up the adjacent longeron rivets. Then we attached the doubler to the deck skin inboard of the longerons.
We thought about adding two additional rivets by splitting the distance between the plug and the adjacent longeron rivets, but after looking at it closer we opted out of that decision. There isn't much clearance for rivet pitch (spacing) by splitting those holes. Sure we could have done it and it would have been fine by the book, but we would have been sitting a minimums. When we weighed that reality with the reality weakening the longeron by drilling additional holes - we decided it was better to leave well enough alone.
On the inboard deck rivets, we chose to split them between the plug and the adjacent longeron rivets. This was by design to share the shear load between the plug rivet and it's adjacent longeron rivets.
Here is the finished product.
Last edited:
