F-1011D misdrilled angle

[echozulu]

Here's a picture: https://imgur.com/a/2K9Kud2

Way back when I did my part fabrication I misdrilled the line of rivet holes at an incorrect distance. I subsequently drilled the correct holes at the correct distance, verified they were adequately spaced apart and didn't think too much more about it.

After riveting yesterday I kind of realized this may compromise the strength of the structure.

Vans Support says they don't have any specific information on the load for that part, just that their testing assumes it's installed but they recommended to replace.

I've ordered a new angle, but would like to get some opinions from the community on whether to replace or not. .

[lr172]

I would replace. I don't like the edge distance on the vertical bolts. Angle was shaved back too far. Those two bolts are pretty critical. They are taking a good amount of HS load. Looks too close for my comfort. It's a pretty simple replacement.

Larry

[echozulu]

You're right! I didn't even think about that and I was struggling with that bolt all of yesterday (solo builder makes everything harder).

That does make the decision easier, I'll replace when the new angle comes in. Not the worst thing in the world to do, it'll just make my scrap pile a little bit higher...

[jacoby]

How do you match drill the new angle? Pull the F-1011B and use that? Use hole finders? Replace the F-1011B along with this but then you still have the #12 holes that go into the longerons for the bolts to locate?

And yeah, the F-1011D is supposed to match the front of the F-1011B. It looks like you cut it back more than the 1/8" the plans call for. It works out to about a 9? angle.

PS, did you pull the vinyl from the F-1101C attachment bars? It might be camera trickery but it looks like it's peeling back. It's clear on those parts and really hard to see if you aren't looking for it!

[echozulu]

My plan is to fabricate a new angle, clamp it to the attachment bars and the aft deck, and drill into it from inside the tailcone.

Yeah, I don't know why the cutback is what it is. I'm chalking it up to an error (on my part of course) but I don't remember ever thinking it didn't look right. But now that you mention it yeah it does not fit what the plans are calling out.

I did peel the vinyl. What you're seeing is the primer that I used flaking off I think. I used the SEM EZ Coat system for parts of my build and it didn't adhere well. While the surface is clean the ambient temperature was below 40 for much of the time I was shooting primer. Never been an issue with SEM self etching primer but the EZ Coat system didn't like it. I sanded and redid the mating surfaces for the stiffeners with SEP but not for the rest, I'm planning on using Boeshield T-9 after it's flying instead of worrying too much about primers.

[jacoby]

Originally Posted by echozulu

My plan is to fabricate a new angle, clamp it to the attachment bars and the aft deck, and drill into it from inside the tailcone.

Yeah, I don't know why the cutback is what it is. I'm chalking it up to an error (on my part of course) but I don't remember ever thinking it didn't look right. But now that you mention it yeah it does not fit what the plans are calling out.

Gotcha. Those longeron bolt holes are going to be a real bear to match in place. I almost wonder if you can match the rivet holes then pull the doubler and angle off and use that to drill the holes? Or find a #12 transfer punch and use that..

It almost looks like you cut the angle 1/2" back instead of 1/8"? That part is slightly annoying to make since you cut it vertically then cut the 45? clearance notch on top. Page 10-14 has a good picture of it in place.

I only asked about the vinyl since I almost missed it!

[echozulu]

Doubler is riveted in the back already, so I probably don't want to pull that off. I'm not sure how I'm going to do it yet. It might just involve me with a flashlight and a drill and hoping for the best. I think it should be ok coming from inside once I get the rivet holes drilled and cleco'd, it'll just be tight space.

[lr172]

Originally Posted by jacoby

Gotcha. Those longeron bolt holes are going to be a real bear to match in place. I almost wonder if you can match the rivet holes then pull the doubler and angle off and use that to drill the holes? Or find a #12 transfer punch and use that..

It almost looks like you cut the angle 1/2" back instead of 1/8"? That part is slightly annoying to make since you cut it vertically then cut the 45° clearance notch on top. Page 10-14 has a good picture of it in place.

I only asked about the vinyl since I almost missed it!

Use the old part to drill the new part. Cut off the vertical part of the old angle without disturbing the flat back edge (make sure new piece can lay flat on the old piece), place under new angle and butt both back edges against a straight stock that is at a 90 angle to the table and clamp. Then drill. Leave it long on both sides and then mark them for cutoff when cleco'ed in place. Holes in vertical edge should be easy to match drill.

Larry

[jacoby]

Originally Posted by lr172

Use the old part to drill the new part. Cut off the vertical part of the old angle without disturbing the flat back edge, place under new angle and butt both edges against a straight stock that is at a 90 angle to the table and clamp. Leave it long on both sides and then mark them for cutoff when cleco'ed in place.

Larry

Ha! That's so obvious now that you say it! I was trying to find a way to save the old part for whatever reason.

[lr172]

Originally Posted by jacoby

Ha! That's so obvious now that you say it! I was trying to find a way to save the old part for whatever reason.

Clearly this is not the FIRST mistake I have had to reverse engineer :-)