Framing the Fuselage

5-23-18, 1.5 hours Jay and Don.  5-24-18 2 hours Jay, 3.5 hours Don

So after the frames comes the framing.  We have already set out the fuselage jig, and laid out the frames in their rough locations.

Seems like you can never just go to town.  There are always so many more things to do.  Today (5/23), it was zinc chromate the seat ribs.

Not much to say about this.  The ribs are attached to frame 604 and 605 on either end, and form the floor of the seat area.  After transferring the measurements over, it was time to set them in position.

Here is the rearward end of a central rib jutting forward from 605.  It proved to be rather difficult to place them exactly in position vertically.

In the end, I clamped a sheet metal “ledge” to the upper edge of 605.  This allowed easy placement.

Here is the rib, set on the ledge and clamped in place.  One hole was already predrilled when building frame 605, so location of the first cleco was easy.

Moving outward from the center, clamping, drilling, and clecoing.

And here are all of our seat ribs in place on 605, and set against 604.

Clamping the ribs into position on 604.  Here, they fit into the lips on the rear of the bulkhead, so location is much simpler.

Drilling all the rivet holes in the bulkhead.  These will be riveted in place with AN426-3 rivets, so there are a lot of them.

Notice the two center ribs do not have the same drill pattern.  On of them (the left one) gets three screw instead of some 8 rivets.  This is so that the rib can be disassembled to allow the control yoke to be installed or removed later on.  More on this in a few pictures.

Jason drawing straight lines in to drill the remaining rivets on frame 605.

Drawing in.

And here are pilot holes all drilled.  We will enlarge the 3/32 inch holes as we rivet.  This side gets 470-4 rivets, and does not fit against anything flat.  This makes it easier.

Remember the disassembleable rib?  Here is the drawing showing where it is cut and bolted back together.  I have drawn in my line mostly as per plans.

The plans didn’t specify what to make the scarf piece with.  I went with .032 2024-t3 because I had a scrap the right size.  Here you see it being laid out.

Here the scarf is cut as per plans, drilled and clecoed for rivets, and drilled for the AN3 bolts on the other side.  The rib isn’t cut yet.

Drilling holes co form radiused corners

Cutting out the edges up front.  Here you can see the one change I made to this part – I left the tab on the bottom that will hold when the skin is riveted on later.  This will make this rib consistent with all the rest.  You can also see all the drilled holes.  Only now are we ready to cut.

And there is the cut.  Since we fit the rivets and bolt holes perfectly before the cut, it will still be the exact same shape when bolted back together.

While I was at it, I had to make a couple of small clearance notches in the next pair of ribs.  This is to allow the wing spar bolts to be installed without interference.

Once again, I start the cut by drilling hte corners.

Here you can see one of those ribs in place.  You should be able to see where the wing bolts will fit, and why the clearance was necessary here.

Here is the back side of the completed sectioned rib.

I set the section up on the fuselage jig.  It reminded me of a tugboat or an airtractor, so I decided to make airplane noises.

Actually, this was just an excuse to use the self timer and take my own picture!

I decided to set the firewall loosely into place on the wing jig.  Bad idea.  I slipped and drew my first significant blood on the project.  No stitches, but that end’s today’s (5-24) work.

One more view of the progress on the frame before calling it a day.

 

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