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