I spent about 6-7 hours in the factory today and made some good progress. I started by match drilling the holes for the aileron gap seal and the flap support. I had to leave 3 holes of the flap support because I need to trim excess material from the inboard edge which currently interferes with the spar doubler so it does not sit flush against the holes in that area. Once the holes were match drilled I removed the gap seal and the flap support. The trick here is that some of the holes are also rivet holes that attach the rear spar to the ribs. So you need to make sure that that you do something to remind yourself NOT to put any rivets in these holes because the gap seal and the flap support get riveted into place later on, but not right now.
I simply placed clecoes in the holes, but you can use tape or some other method that works for you. I started from the inboard section, which calls for AN470AD4-8 rivets to get through the two 1/8 inch thick spar doublers, the spar, and the rib. I was looking forward to using the pneumatic squeezer for this as a nice break from bucking rivets for all the ribs. I inserted the rivet into the first hole, and checked it with my gauge. I was disheartened when I saw that the rivet appeared to be too short for the material that it was sandwiching together. But, like an idiot that I sometimes am, I did not believe what I was seeing, and instead made the all too fatal mistake of believing that Vans had the correct rivet call out, so I decided to set the rivet with the squeezer. And of course that confirmed that it was too short. So almost immediately I had another repair to make to remove a rivet in a very hard place to do so. I decided to let it sit for a bit while I set the rest of rivets.
Here is a shot of the wing frame moved slightly back on the table to allow a small gap between the table and the rear spar so I could get my squeezer inside to set the bottom two rivets for each rib to the spar. This worked out quite well for me.
I had to put the squeezer underneath the spar to set the bottom two rivets, and on the top side of the spar to set the top two rivets. I used the flange yoke and the 1/8 inch cup rivet set on the top of the yoke with a 1/2 inch x 1/8 inch thick flat set on the bottom. Per the plans I inserted the rivet so that the manufactured head was against the rib flange so I could pull the rivet head and the rib flange into the rear spar to keep them tightly held together while riveting. This worked well, and it means that the shop heads are all on the rear spar as shown below. Note my place holder clecoes as a reminder not to put rivets in these holes just yet:
I continued this process until I got to the last rib on the tip. Here the rivets change to an AN426AD4-5, which is a flush rivet which the rear spar is already countersunk to accept. Basically what happens here is that the flush rivet needs to be used to retain a flat surface on this section of the rear spar because the outer aileron hinge bracket fits over this part of the rear spar and must be flush to the rear spar, which is why you cannot use round head rivets in this location. In short, this became almost as difficult as setting those pesky nut plates on the main spar. I could not use my pneumatic squeezer here because the flange of the rib is inward, not outward as it is at the root. The air squeezer is too bulky to set the flush rivets. SO I switched to my hand squeezer with the standard 3" yoke and two 1/2 inch x 1/8 inch thick flat rivet sets. Problem was that the hand squeezer did not provide much more clearance than the air squeezer did, and I was forced to try to set 1/8 inch rivets with it. This is not fun with a hand squeezer as it takes considerable force, but I managed to set them to my satisfaction.
This led to a problem with setting the rivets shown in the next pick. Because these rivets must be set with the manufactured head against the rear spar and shop heads formed on the inside against the rib flange (opposite of all the others), of course the rib flange separated from the rear spar web at the very top. I was really pissed about this, but decided I was going to leave it that way for two reasons:
1. Trying to drill out these rivets and reset them would most likely just cause more damage
2. That corner is further secured by the angle brackets of the beefy aileron hinge, which is riveted in place along the rib web and the rear spar,so I am not worried about any structural issues due to the separation of the rib flange in this area.
This is a risk I am willing to accept. Here is what the shop heads look like:
I failed to get a shot of the flush heads on the rear spar so I will post that tomorrow. But here is the aileron hinge bracket assembly which fits over the flush rivets similar to the way this was done to attach the elevator control horns to each elevator a long time ago.
After all that was completed I turned my attention to drilling out the first rivet I set at the root. I was able to successfully drill out the rivet from the shop head side (rear spar web) and was able to successfully knock out the rivet with a 1/8 inch punch without damaging the rib flange.I replaced it with an AN470AD4-9 rivet, which worked much better. Here is the shot after the holes for the first two ribs were set using these correctly sized rivets. Again note the clecoes as reminders NOT to set rivets in these holes until the flap support bracket is installed:
And as if that was not enough, after all these rivets were set for the left wing, I returned to the right wing spar on the work bench and managed to set rivets for over half the main ribs to the main spar. Tomorrow I will finish setting these ribs,then I will move the left wing frame onto the wing stand, and move the right wing spar/ribs onto the table for the same rear spar treatment. If this keeps up I may find myself neck deep in proseal and fuel tank assembly in the not-too-distant future.'Nuff for now....
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