F-711B Bulkhead Extra Rivet Holes in Flange

[snoopyflys]

Just when I thought all was going well I discovered that I drilled some extra rivet holes in the F-711B bulkhead flange of my -7A. .

So, I am asking for the opinion of the collective knowledge of my fellow builders here, is this recoverable without ordering new parts? Would a backer plate the width of the F-711B flange be an acceptable repair since the edge distance does not appear to be an issue and the F-711A appears to be ok?

Would NAS 1097-4 OOPS rivets be an option here?

Or is replacement F-711 bulkhead the best route?

Any and all feedback is appreciated.

Thanks,

 

[lorne green]

dan

Look on bright side of this.....it won't be the last part you get to re-do!
Ooops rivets? Nope, this part is hooped. There are few options here. IMHO

 

[Flyguytki]

Im pretty sure that is a picture of my pieces from a few months back. I did the exact same thing. The only option for me was to replace the part and start over again. Ironically with the new part everything went together much smoother the second time around.

 

[swisseagle]

Known situation, difference between design and real live!

Hello Snoopy

There are a few places where you can see this:

- at the counterbalance ribs on the elevator
- at the F711 bulkhead
- and other places.

The reason is that the two ribs are not close enough thogeter. You nearly can not insert the clecos also.

The root cause is that there is a difference between the designe and the "real live parts". The flange radius is in the CAD extrem precise, but not so in the manufactured parts.

This does not have a big effect on a single bulkhead part. But will have the doubled effect in a "back to back" situation on the mentioned parts.


It would be really nice iff Vans would correct these places by overriding the CAD system by a small amount, so that the "real live production parts" would fit nicely, or only pre punch one of the bulkhead and the 2nd flange is drilled with the skin as a guide by the builder.


For you, there is only one way to go:
- Order a new set of F-711 bulkheads.
- Do not drill the holes to size, use a file and open up the holes in the direction that help to improve the situation, instead of drilling. If you do that in the skin and the ribs, you can fix quite alot of offset. Be carefully, on the skin compared to the ribs, you have to file in the opposite direction. Mark the direction to file, on the parts.
- Use a cleco in every other hole ON EACH FLANGE (shifted by one for the 2nd. flange).
- DO NOT DRILL as long as you do not see the holes are aligned.
- Clamp the bulkheads really good thogether.
- Put the two bulkheads/ribs thogether and press the flange a bit in a vise, so that the flange radius gets a bit smaller and you reach a better fit.

I hope this helps,

regards, Dominik

 

[snoopyflys]

Oh well, redo it is!

Thanks Lorne, FlyGuyTki and Dominik for the reply and feedback. I was thinking that since the A side of the 711 was ok, that I could fab a doubler and sandwich the 711B flange between the skin and the doubler. But after thinking about it and checking the AC, even though it appears to be an acceptable repair, it will add weight and reduce the flexibility of that section.

So it's off to the Store I go. Once again thanks for the feedback.

Kind regards,

 

[instructor_bill]

why not just go to 426 ad 4-x rivets? or...

never you mind. I looked at the picture better. The others are certainly right.