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Fuselage Sides

 Once the tail surfaces were done and I decided to pursue widening the fuselage to 38" I could clear the jig blocks from the table and paint over the lines for the tail. I then laid out all the dimensions for the fuselage side onto the fresh white paint.

It's worth noting here that the plans give views of the top, bottom, and side of the fuselage, as if you are looking straight at the side. However, the sides angle back in space, so if you were to flatten that side out to lay on the table, it will actually be longer than the dimensions given on the drawing. In drafting, flattening out a panel like that is referred to as "developing". Widening the fuselage by almost 5" also changes the length of the side, so the developed side is actually 1.5" longer than shown in the side view. I drew up the developed side in CAD and used the dimensions from CAD to lay out on the table.

The dimensions given on the drawing are to tubing centerlines and need to be offset to show where the jig blocks will go, like with the tail surfaces . I made some little metal spacers the width of my tubing to make marking these offsets easier.

The long pieces of tubing that will make up the top and bottom of each side are called "longerons." The upper longeron is easy, it's just a straight piece, but the lower one needs to be bent in two places. This one done by placing the tubing on the table with a block at the first bend, then the tubing was heated with a torch and gently coaxed until it matched the angle I needed. That section could then get held in place with more jig blocks and the next bend was made in the same way. Both longerons were left long so I had some room to adjust things if I had to. While I had the torch out and jig blocks in the right places, it made sense to bend up the second longeron for the other side.

The longerons were dropped into the jig and then I could start cutting tubing to fit between them. Once again CAD helped out. I could measure the angle between the tubes in CAD and then print out a template at that angle to mark the notch in the tubing. I used https://www.blocklayer.com/pipe-notcheng.aspx to develop the templates. I could walk through the whole tubing notching process, but I'm sure other people have done it better.

Once everything was fitted for one side, I numbered each tube, pulled it out, and made a second one for the other side.

Once I had tubes made for both sides I tack-welded one side, hung it on the side of the table, laid out side two, and tack-welded it. The fuselage can go 3D now!




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