Sun Jul 5 2009

Drilling top fuselage skins

Today we got up early to get some work done on the plane before we had to jump in to the car and deliver my dad to my aunts and grandmother in Cleveland. First was to cleco in the stiffener rib between the F-706 and F-707 bulkheads. You can see the aft end is just flapping in the breeze at this point.

We put a few clecos in the forward top skin to hold the rib and bulkheads in place relative to each other.

Now the end of the rib is held in the correct position.

After clamping on the angle clip and transfer drilling through the F-707 bulkhead, we transfer drilled the last two holes in the side of the clip through the stiffener rib.

Update: The little angle bracket is on the wrong side of the stiffener rib. The forward facing flange of the angle bracket is supposed to go on the right side of the rib, not the left.

Yesterday we had cut and trimmed the J-channel stiffeners per the plans, but upon fitting them I realized it would have been better to cut a much smaller relief at the aft end of the stiffeners. Say, 1/4 inch rather than the ~5/8 specified by the plans. That would have allowed a much smaller gap between the end of the stiffener and the bulkhead web. If you choose to do this, one flange of the bulkhead will have to be trimmed slightly to clear the radius of the J-channel, but I think it's a worthwhile modification.

Although I had drawn a centerline along the flanges of the two J-channel stiffeners, I found the same issue applied to these stiffeners as the previous ones (along the sides and bottom of the fuselage). The locations of the stiffeners are best determined by centering them in the bulkhead pass throughs (F-707) and observing the hole locations at the ends of the stiffeners. The holes we drilled were as much as 3/32 off from the centerline I had previously drawn. I'm convinced this is the better method.

After peeling some of the blue plastic off to ensure the thickness wasn't causing hole mismatch, we clecoed thse skins back on and match drilled everything. Then it was time to leave for Cleveland.

After 6 hours on the road, I got home and had time to debur all the holes and edges of the two top skins. I was going to start dimpling, but it was past 11PM at that point and Kerin was sleeping, so I thought that might not be such a good idea.

Because of the coil set (curvature), the aft top skin didn't want to stand up on its own, so I layed a scrap piece of plywood against it to hold it in place.

On my way back from Cleveland, I called my friend Scott to see if he would be willing to come help rivet these on this week. He was available, but after reading a bit further ahead in the plans and instructions, I think I'm going to delay riveting these on until later. It appears it would make some of the upcoming tasks easier to work on if I can remove them (like the canopy frame).