Scott & Tanya Card RV9A build log (N4822C)

I got the tank attach brackets drilled to the fuselage before I start removing the wings for nutplate installation. I had a new first at the hangar: A serious thunderstorm (summer in central Texas) blew through around 8:15pm while I was out there. I found some frustrating quirks with my hangar door not wanting to close in certain “conditions”. That will require a little prepared engineering for next time. I also found just how loud it is inside the hangar with the door closed and the rain coming down in sheets on the metal roof. It was a weird experience. I felt like a scared dog in a thunderstorm. It took me about 20min. to decide that I wasn’t going anywhere and to overcome my urge to flee (the noise) and just hunker down and get back to work. Weather radar on the cell phone really helped to know exactly what was out there that sounded so horrible. Especially knowing a tornado wasn’t getting ready to hit me was a big help. These are real concerns in these parts.

So, not a whole lot accomplished with all the other excitement, but I’ll add new experiences to the progress list. That is what this is all about anyway.

Tonight I got the lower wing intersection fairings drilled. It is still very weird going all the way out to the hangar to work on the project. Why didn’t I get more done? Hangar talk… (Thanks Jim :).

 

  

  

 

This evening I did a bunch of rechecking of the wing alignment (square, sweep, incidence), then marked and drilled the rear spar attach bolt holes. For edge distance, I ended up with a target square about 1/8″x1/8″. Not a lot of room for error here, but I didn’t have to do any additional trimming either. I started with a #30 bit and worked my way up to just under 5/16″. I used some drill guide inserts for general squareness checks at #30, 3/16″, 1/4″, and 5/16″. I didn’t drill all the way up to 5/16″. The bolts measured .310″ and I have a .3110″ reamer that I used for the final hole. The holes are a perfect fit with that reamer. 5/16″ would be just a bit to big.
For those not “in the know”, these are very critical holes to be drilled, with very specific tolerances, that are dependent on a lot of previous construction coming together correctly. Definitely a flight safety concern if they aren’t right.
The holes are drilled and alignments rechecked again. Everything is spot on. The wings are square, don’t have any sweep, and both are straight without any twist. I’m very happy.

 

  

  

  

  

 

I did my first weekday commute to the hangar to build this evening. The drive was about 38min. at 6:30pm. I got to work stretching a line and hanging plumb bobs from the leading edge of the wings. I’m liking the taught line instead of a chalk line. Line adjustments can be made to the line and not the airplane. Anyway, I was able to level the airplane fore-aft, and left-right just by adjusting the air pressure in the tires. My hangar floor must be sloped just right. I did all measurements and alignment except for the angle of incidence. I got things setup to do the incidence alignment next time. Everything is looking good so far (plenty of meat on the rear spar for hole edge distance, whew).

 

  

  

  

  

 

We got both wings on with temporary hardware for their first fitting. Very cool stuff.