F01411 Bulkhead / HS rear spar attach

Hi,

I’m completing the riveting of the doubler to the HS rear spar, and the plans call to leave a group of 6 holes on each side un-riveted.

Here are the holes - the 6 blue holes are where you rivet the inspar ribs later on, and the 6 red holes are where the F01411C bulkhead bars attach later (on the forward side of the HS rear spar / bulkhead: https://photos.app.goo.gl/HB6WXBUtGodBq3h89

The attach method is to updrill 4 of the 6 red holes to 1/4 and a AN4 bolt is used. Here is the image from the instructions https://photos.app.goo.gl/8Cp88QBfkqTFJNe59

There is also 3 matching holes in the F01411C attach bars (photo here https://photos.app.goo.gl/Ap4GfH8sSxF1PXgJ9)

Question - what happens to the middle hole??

I can’t find where anything further is done to this hole? (Or am I missing something?)

Should a countersink the doubler and install an AN426 flush rivet? Or leave it as it is? Maybe updrill all 6 holes and use 6 bolts instead of 4?

I am assuming this hole was used in the RV10 and I think it might be the same HS rear spar.

Thanks in advance

Greetings.

See page 11-05, Step 1, Figure 2. Those holes are for clecos to secure the HS for the final drill tasks you cite on page 11-06 (it's similar to the hole on the VS for the same purpose on page 10-28). They are not used for later securement.

You can see clecos in those holes where when I did my initial empennage attach. Front side, harder to see:



Back side during drilling of elevator horns. You can see the pins of the clecos in place:



Finally, here are those holes (unfilled, per plans) in my plane after it had been flying for 29 hours (decided to put Spirap on the elevator trim wire):

Ok, thanks very much.

Glad I?m not going crazy.

I suppose that is easier than using bolts in 2 while you updrill the other 2 (although that seems a sensible procedure to me).