This rib mounts horizontally on the F-706 bulkhead.  It helps strengthen the bulkhead and it also one of the attach points for the elevator bellcrank.  Not much to it other than the rib itself and the reinforcement angle.

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Riveting rear bulkheads   October 10th, 2010

Riveting the rest of the bulkheads in the tailcone is also pretty straightforward.  This is the F-706 with just a few rivets to hold the three pieces together.

And the F-707 with all of the rivets on the bottom and only two on the top (the other two are used for a piece of angle that holds a rib between F-707 and F-706.

F-711 gets the doubler bars that eventually are used to attach the empennage.

Note that the horizontal angle is not riveted on yet — just clecoed in place for now.

Finally, F-712.  Note that the tail tiedown extrusion is also not riveted just yet.

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Riveting F-705 Bulkhead   October 7th, 2010

The F-705 bulkhead is the dividing bulkhead between the seating area and the baggage compartment.  This bulkhead also includes the ‘fork’ where the rear spar of the wings attach to the fuselage.  Only a few rivets need to be set at this time.  These are mostly to hold together the lower horizontal section of the bulkhead to the two vertical sections, and the rivets that attach the doubler bar to the bulkhead.  Even then, there are quite a few rivets in the doubler bar that are set later.  Every place with a cleco in the picture below gets riveted later.

The F-705 bulkhead also holds the flap mechanism, and there are two ‘bearing blocks’ that need to be bolted to the bulkhead.  These plastic pieces need to be drilled for bolts first.

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F-711 Bulkhead   September 30th, 2010

The F-711 Bulkhead is a double bulkhead, since it is one of the attach points of the horizontal stabilizer.

The first step is to cut out a notch as shown below.  I used a dremel tool for the rough cut, and then  a file and abrasive wheel to smooth it out to final size.

There are two aluminum bars that get riveted to the bulkhead, so you have to clamp them and match-drill them to the web of the F-711

The bottom of the bars are slimmed down (weight savings?).  While at it, I also marked the extrusion used for the tail tie-down.

Finally, here is the completed F-711.  Note the additional angle between the two bars.  Also, note that this bulkhead is near the aft end of the fuselage, and the angles of the flanges start to get sharp enough that you must bend them with the seaming pliers before you even attempt to fit it into between the side skins of the tailcone.

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F-710 Bulkhead   September 26th, 2010

The F-710 Bulkhead has a reinforcing angle across the top.  In order to clear the longerons, the angle is notched at the ends.

The idea is that the angle fits within the flanges of the F-710

And here is the entire bulkhead with angle clamped in place, ready for drilling.

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F-707 and F-708 bulkheads   September 25th, 2010

The F-707 and F-708 bulkheads are pretty simple — just join the two halves and drill the two 5/8″ for the electrical wiring.

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Drilling F-706 Bulkhead   September 19th, 2010

This is the next bulkhead on our way to the tail of the plane.  The elevator bellcrank sits between the two ribs shown here.


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Bending the F-729C Angle   September 19th, 2010

This little angle serves as support in the F-706 bulkhead assembly.  The drawings show how it has to be bent to 88.5 degrees (rather than 90 degrees).  So, how do you bend this thing by 1.5 degrees?  Well, I just clamped it to my vise and cranked a little at a time until it was about right!

I checked it against a square and measured the distance between the angle and the edge of the square.   I was looking for 19.5 mils, if you’re curious 🙂

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Drilling the F-705 Canopy Angles   August 30th, 2010

These two brackets start out as 3/16″ aluminum angle.  Once they are cut the right length, they are match drilled to the top of the F-705 bulkhead.

After screwing one of these up, here is the correct procedure to match drill these angles.

  • Clamp the angle to the F-705F channel as shown below, but only drill the holes on the forward side of F-705F! (i.e., the holes facing up on the picture below)

  • Now insert the F-705D side channel and the F-705E doubler between the F-705F channel and the F-705G angle.  Cleco and clamp everything in place, and match drill the holes on the top side of the F-705F channel (the holes on the right face of the channel in the picture below)

The result is a bunch of nice holes.   If you forget to insert the side channel/doubler, you end up with misaligned holes on the top face of the angle (on the right if you look at the picture below).  At the same time, it is very cumbersome to try to align the top channel, side channel, doubler and angle all at once with no holes on the angle.

Finally, once all the holes are match drilled, you can cleco the angle and draw where the oval slot should be.  I started the slot by drilling two holes, and then used a dremel tool to give it the final shape.

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The seat backs have a clever two-position adjustment mechanism.  The top of the F-705 bulkhead has two slots.  A tab that holds the seat back can be adjusted to one of the two positions depending on how much you want to lean back.

The first part of making this part of the bulkhead was to put a very slight bend on the two F-705K aluminum strips that act as guides.  This was a good excuse to buy a little bending brake from Harbor freight.  It is as simple as it gets, so I figured this one thing from Harbor Freight would be OK :-).

I clamped the F-705K aluminum strip in place, and started cranking on the brake.  Just a little at a time to get the right bend angle.

Here is a closeup of the F-705K after the bend was complete.

The next step was to take the F-705L shim and match drill it to the top of the bulkhead.

Then came the tricky part.  The F-705J angle has to be drilled to the side of the bulkhead, but has to sit 1/8″ from the top surface (refer to the drawing at the top of the post).   I used some 1/8″ angle as shown below just to the set the right distance.  After the F-705J was drilled and clecoed in place, I simply pulled out the 1/8″ angle.

Finally, here are two shots of the entire assembly clecloed together.

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