What's new
Van's Air Force

Don't miss anything! Register now for full access to the definitive RV support community.

Rudder Final Drill, 07-07, Step 3

md9680

Well Known Member
Friend
In Step 3: ..."Final-Drill #40 all the holes common to the skins and trailing edge..."

Also, ..."Final-Drill #40 all holes common to the skins and flanges of the R-903 Tip Rib and R-912 Counterbalance Rib."

It appears that all these "holes common", along with the substructure holes, have already been punched to size at the factory since the #40 bit easily slips through them. My builder number is 140805, so it's a pretty recent kit.

Could it be (with the evidence before me) that I don't need to final-drill these holes? That they could be ready for deburring (if needed) and dimpling?

Any commentary is appreciated.

Thank you.
 
Hi Mike,
Our kit is a little older than yours (140726) and once in a while there is a part that I think is common to several models, that still has the smaller holes. If memory serves the top rib on the vertical stab was one of them. So possibly they have the wording in the instructions to cover for those parts. Just my guess. Happy building.
 
In Step 3: ..."Final-Drill #40 all the holes common to the skins and trailing edge..."

Also, ..."Final-Drill #40 all holes common to the skins and flanges of the R-903 Tip Rib and R-912 Counterbalance Rib."

Mike, the way that I read this to final drill all holes common to only R-903 Tip Rib, R-912 Couterbalance Rib, and trailing edge.

On my kit (144349) I checked the holes of R-00915 and the matching skin for size. They were already to the final size.

Hope this helps
Marc
 
What others have said - I just recently had this discussion over email with another -14 builder; this is what I sent him:

"I think the rivet holes are different sizes. The holes for the R-903 Top Rib and R-912 Counterbalance Rib DO need to be drilled, like the plans say. But I noticed that my #40 reamer was "falling" into the holes along the spar when I started drilling the skin to spar holes. Which is why I asked the question. I tested about 2 dozen holes in other locations with a #40 dimple, and the dimple easily went in the holes just fine, whereas it will not go into an undersized #40 factory hole in other locations.

In general, I *think* these #40 holes need to be match / final drilled:
- R-903 Top Rib & skin, where the plans say
- R-912 Counterbalance Rib & skin, where the plans say
- Trailing edge wedge & skin

Whereas, "trust but verify" that these #40 holes don't:
- R-00902-1 spar & skin
- R-00915 stiffeners & skin
- R-00904B-1, R-00904A-1 & skin"
 
Last edited:
Thanks for the replies, everyone. Most helpful as usual.

I like and will adopt tyconnell's approach of "trust but verify". I would guess this will be less and less an issue as I get into the tail-cone, etc.

Building on!
 
Back
Top