We started today by making sure our measurements were still correct from yesterday (measure lots of times and drill once.....I’m learning)! This picture shows (tough to see) the Wing Box J-Channel (as they are called) clamped on the inside of the Lower Left Main Spar Flange. The three areas that have orange tape are holes that DO NOT get match-drill at this time.
The plans call for a 1/16” rise between the edge of the Main Spar Flange and the edge of the J-Channel. To do this, we used a square set to 1/16” to verify the distance. You can see the “rise” of 1/16” in the picture below.
Here are the first 18 holes in the Lower Spar Flange. The plans instruct you to monitor the position of the J-Channel relative to the Spar Flange as you progress with match-drilling to ensure the correct distance. We used the square on every two holes to verify the correct distance. I don’t know if you have to be this anal about it, but it’s 1/16” all the way across.
Below is the entire lower flange after all the match-drilling. Like I mentioned earlier, the holes with the orange tape do not get match-drilled now. In a few steps, the plans will have us roll the Lower Spar J-Channels 180 degrees to the Upper Spar and finish the match-drilling process. I’ll show a few pictures when we get there.
This is the same picture with the clamps removed.
Here we “fitted” the Wing Box J-Channels to the Upper Left Main Spar using spring clamps to hold them in place.
This picture shows the overlap between the J-Channel Short and Long. With a little massaging, these pieces fit together pretty well.
We match-drilled all 131 holes between the Left Upper Main Spar Flange and J-Channel (forgot to take a picture before removing all the clecos). Now, the instructions says to uncleco the J-Channels from the Lower Flange, roll them 180 degrees, and recleco them to the Upper Flange. The pictures below show the only way I could get the holes to match up correctly (which is rolled 180 degrees) between the J-Channels and the Upper Flange. Now, we have to match-drill the 32 holes from the three sections that we purposely skipped earlier.
This is one of the three sections that needs to be match-drilled (holes between the first two clecos).
After all the drilling, the plans say to set the J-Channels aside for later use in Section 20-Bottom Wing Skins. So, that completes the work on the J-Channels for the Left Main Spar. Now, there are many holes in the Main Spar that need to be final-drilled to #40 and the many nutplate locations that need to be countersunk. We will start there at the next session.