Finished the F-6111 aft skin reinforcing ribs - 5 hours

 I played with the fit of the pilot side F-6111 rib. I managed to get the rim to sit/fit much better after trimming the ends. The bulkhead interferes just a tad at the top of the rib, so I need to do a little careful trimming here. In the end, this is what I finished with. 

This is what the top of the rib is trimmed like.

I began working on installing the right (co-pilot side). Repeating the exact same process as before, start at the bottom and work my way up. The fitting on this side is a tad more tricky than the other side, but its going. The ribs have a real twist in them....like a real good twist. Here is what they end up looking like after final fitting.

In the end, I'm extremely happy with the fit. Not a quick process....but it turned out very nice.

Still feeling like moving forward. I drilled and trimmed the seat belt cable guides.

F-6111 aft skin reinforcing rib - 5 hours

 Fitting these F-6111 aft skin ribs is a bit of a head scratcher. The instructions are not helpful. Doing some research on them the general consensus is to start at the bottom and work your way up. Trimming only to match the angle in the longeron and where the rib meets the bulkhead.

Firstly I carefully drew a centerline down the ribs. The interesting thing is that the rib flange varies in width along the length so I was careful to account for this. Starting at the bottom where the rib meets the longeron, I found that the angle is 42deg. (A piece of paper was used behind the skin and a pen dot through the holes....connect the dots and the angle is found).  I transferred this to the ribs and cut accordingly. 

Next I trimmed the angle at the bottom of the rib, fit it to the skin/longeron, aligned the centerline with the first few holes and drilled the bottom hole.

One by one I started working my way up. Aligning, then drilling one hole and cleco at a time.

At this point the bottom of the rib begins to rub against the longeron. So I will need to think about trimming this down.

As I work my way up, I now need to start trimming the top of the rib to match the angle with the bulkhead. Very much a guess and test situation here. I trimmed a little bit.

Kept drilling and clecoing, one by one.

As I got closer to the top, I trimmed a bit more as needed, and then I began to see where I need to account for the flutting in the bulkhead in two spots.This ends up being a compromise of sorta flattening the 2 flutes, and creating 2 shallow flutes in the F-6111 rib (Too much fluting in the ribs cause the centerline to deflect too much) 

By the end, I am really happy with the fit and I did a little trimming at the bottom of the rib for the longeron. I'm still not satisfied with it and I'll get this trimmed better later. 

Re-made the F-707B angle - 1 hour

 Small day building, I re-made the F-707B angle and made it slightly longer than the original. I took my time and trimmed it to fit the angle/radius of the F-787 stiffener web.

 

Final fitting of the F-7112 Aft top skin - 5 hours

Started the build session by messing with the fluting on the F-706 bulkhead and now I have a great fit. With all holes nicely cleco'd I match drilled everything (with the exception of the holes along the longeron. I'll do those later).

I am not ready to fit the F-656 gusset plates. Using the same method as before, I clamped everything in place.

Once the #30 holes for the gusset plates are set, I was ready to partially un-cleco the top skin to access the F-707B angle. I drilled the angle, and then noticed that the fit isn't as nice as I would like it to be. I'll have to re-do this part.

To finish off the evening, I riveted the gussets to the longeron and bulkhead.

 

 

 

 

More fitting the F-7112 Aft top skin - 4 hours

 The fit of the F-7112 top skin is really tight. To help with this I de-vinyled top skin.

Next, I need to adjust the J-stiffeners cause they are just a tad long and they do interfere with the bulkhead. They need to be trimmed about 1/8" give or take.

 

I had the F-707B angle fabricated some time ago so I cleco'd that on and installed the F-787 stiffener web. 

I still need to play with the fluting on the F-706 bulkhead to get the fit right. I'm surprised by the amount of flutes needed on these, its more than I thought I would need. But the fit is looking really good.

Fitting the F-7112 Aft top skin - 3 hours

 I spent some time tonight tweaking the fluting on the F-707/F-708 and F-709 bulkheads to ensure the best fit possible. I now have every hole clecoed and checking the flange on the inside, the fit is very good.

 

I am ready to fit the F-7112 top skin. Like the rear top skin I really need to adjust the fluting on the F-706 bulkhead to get all the holes to align. Since the fit at the top is really good. I match drilled the J-stiffener. However I need to trim the forward end a bit as it appears that there is interference with the bulkhead.

 

Fitting the F-775 Rear top skin - 5.5 hours

 The F-775 rear top skin was ready to go on. I managed to get the top/middle of the skin cleco'd on just fine. however getting the holes to line up on the bulkheads as they get closer to the longerons was not easy. Looks like I will need to flute more on the bulkheads. Since things were lining up well at the top, I match drilled the J-Stiffeners.

I then used masking tape to make note of which areas needed more fluting. It took me a few tries to get it all lined up and cleco'd 

 

Next I placed a straight edge across the bulkhead which would allow me to set the final placement of the F-656 gusset plates. Once I had the gussets clamped, I removed the top skin and then drilled the #30 holes.

I noticed that the fit of the F-786A J-stiffener with the F-708 bulkhead wasn't great. I needs a little trimming to clear the flange. I checked the fit and took measurements, verifying that the area of interference was much less than the dimensions shown on Drawing #18. I trimmed the Stiffener just enough to clear the flange.

The top skin was ready to go back on, but still seems like minor adjustments are still required.