Flap Assembly Bearing Block Nutplates

[dwollen89]

Building a 7A. I drilled the F680 bearing block to the center bulkhead and baggage rib. The instructions say to install nut plates for the bearing block bolts. The aft one on the baggage rib is no problem. However, the forward is a problem. No matter which way I turn it, it can’t be installed without drilling a hole through either the edge of the baggage rib flange or bulkhead flange. Is there any reason I can’t just use standard nuts here?

 

[recapen]

Note that the forward one is a one-legged nutplate...
They are underneath multiple overlapping floor layers. You can't get a wrench in there until that part is removed.
I did mine in my 6A like this...

 

[wirejock]

Floors are riveted. You won't have access. That said, mine are removeable and I trimmed out that rectangle so the floor can be removed without removing the bearing block.

 

[dwollen89]

Unless I’m missing something, there is access to those nuts. The instructions say to trim the tunnel cover around the bearing block. Then it can be removed without removing the bearing block. Do they make a one legged nut plate that has a longer lug?

 

[recapen]

Unless I’m missing something, there is access to those nuts. The instructions say to trim the tunnel cover around the bearing block. Then it can be removed without removing the bearing block. Do they make a one legged nut plate that has a longer lug?

You can easily make a longer legged nutplate by riveting it to a longer legged piece of sheet aluminum. The clamping action of the bolt/nutplate combo does the necessary work.

 

[dwollen89]

It looks like it’ll just clear the edge of the bulkhead, so I might be ok. If I use an oops rivet, I should be able to counter sink it into the baggage floor.

 

[wirejock]

The stock callout works. Double check the plans.

 

[Richard Connell]

I mounted that one legged nutplate laterally in the 705 with a shim under the leg to make up the thickness of the flange of the 727. I suspect that I had the same issue as you and the first rivet hole was too close to the 705 flange edge. But it’s a very long time ago so I can’t be sure.
Don’t think it matters either way. I have made heaps of funky plate/nutplate/shims over the years where tolerance stackups or non pre punched parts created issue.