Quick question …
I’m about to start on my floor panel and need to get my spar tunnel fitted. I’d like some advice on the best way to go about the countersink/dimple process where the vertical angles of on the sidewalls attach to the forward zee (same for the rear, I guess).
The instructions say to install the rivets into the shear plates, but to only drill the holes for the uprights up to accommodate CCC-47 rivets.
Here’s detail R as mentioned in the photo above:
This is all fine and dandy for the shear plates, but if I rivet the shear plates as instructed, the uprights will be a tight fit between the skin/webbing and the shear plates and if I dimple the webbing where it attaches to the uprights, I likely won’t be able to insert the uprights anymore.
I’ve been hmming and hawing about this for a weeks and my plan is this:
- Go ahead and up-drill all holes thru the webbing, uprights, and shear plates to full rivet size.
- Counter drill all holes that meet up with the skin (shear plates and uprights alike).
- Dimple ONLY the skin areas that attach to the shear plates (using my Sonex dimple die), but leave the holes in the skin that attach to the uprights un-dimpled for now.
I think I’m OK up to that point.
When I have everything assembled, what’s the best way to dimple the skin where I’ve left it for uprights?
Should I:
Option 1: use the convex side (only) of the dimple die to dimple those holes into the countersunk holes in the upright (e.g. use the upright as the concave half of the dimple die)?
Option 2: forego the dimple die altogether and let the rivets dimple the skin into the the countersunk holes? Not sure if this is the best way to remove all gaps in the dimple/countersunk holes.
Option 3: dimple everything, assemble with Clecoes in position in the fuselage and pull the rivets there? This won’t be an option for the rear spar tunnel assembly as I’ve already pulled the rivets into the shear plates as instructed in an earlier assembly drawing, so I’ll have to use option 1 or 2 for the rear.
I think any of these options are probably OK, just want to get a second or third opinion before I jump in. This is arguably one of the most important connection points in the airplane.
Thanks!