January 25-28, 2010

Roll Bar Assembly - continued - 8.5 hrs.

Well, over the last few days the work is continuing on the cabin frame. It seems like I'm putting a lot of hours into this. I wasn't prepared for how much work this part is. But I'm slow. I admit it. Anyway, I finished drilling the top strap to #40 and then to #30, as seen below. Now it's time to fit the other pair of channels to this assembly and drill them to the straps as well. But first, there's the task of getting them to fit. I wanted the butt joint in the middle to be tight and straight. To do this, the logical thing to do is set them in place over the top of the straps. However, the clecos from the middle joint plate stick up too far to allow the top channels to sit down in place. I don't have any of those shorty clecos on hand and I'm not going to buy any this late in the game. But I wanted to keep the joint plate in place if possible while working on the top half. So I cut a hole in my jig underneath the bow (can't see it here) for the clecos to stick down through. So the joint plate is still firmly in place but the clecos won't interfere with fitting and drilling the top two channels. I hope that makes sense. So in the picture below, you can see the ends of the clecos sticking up through the joint plate from the other side. I can now work on fitting the top channels (the forward ones) in place.

But first, the plans call for the proper dimension to be 1-1/2" thick for the finished cabin frame. Since the two aluminum channels are made from 1/16" material, then the space in between them inside the channel needs to be 1-3/8". So I cut some scrap 2 x 4 into some spacers 1-3/8" long and placed them around the channel as seen above.

Then I began fitting and carefully filing the ends until I had a good fit. When all that was done, I pushed the channels down over the straps and clamped them in place with the spacers underneath the clamps. I measured to verify the 1-1/2" dimension. Then it was time to mark the channels for drilling.

See how nice and tight this butt joint is? This was the goal I was shooting for. If you look close, you can see that I marked the centerline on the flanges 1/4" from the edge of the flange. Next, I pulled one cleco at a time, and using a straightedge, I transferred the marks from the blue tape below to the channels on top, to mark them for drilling. Then move the cleco back and move on to the next one. Then do the other side. Now it's ready for drilling.

Above, you can see the transferred marks if you look close to the left at the undrilled holes. Here I'm drilling the holes to #40, clecoing as I go.

Above: Here's the whole thing, drilled to #40. Below, finished to #30.

Next, I clamped and drilled the joint plate to the two channels. Even though this plate goes on the inside, it can be drilled from this side now.

Finally, I unclamped the whole assembly from the jig and pulled it off. Wow! This was a lot of work to get to this point. The empty cleco jug tells a story, too. I used up every last #30 cleco to get to this point (there are a number of them inside the fuselage, however). Anyway, next, you stand it up and measure the height. I have some more filing to do on the ends to get them nice and square and to get it down to the right height. There's still a lot of work to get this done, but it's a good time to pause and admire the progress.

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Contact me: swayze "at" europa.com (replace "at" with the @ sign... no spaces... you know the deal)