The seat belt anchors do not have pre-punched holes, so they have to be lined up with the holes in the F-705 bulkhead.  Each anchor is made up of two F-634 brackets.  To attach the anchors, I first drilled a hole in the left brackets as shown in the plans.  I then made a spacer out of wood in the shape of the bracket to position the right brackets.

With one side bolted to the bulkhead, and the spacer in place, I put a bolt through the opening where the seat belt would normally attach to keep the two brackets aligned.

I used clamped the right bracket to the F-705 bar with a block of wood to give it some support, turned the whole thing over, and match-drilled the hole.

Then I simply repeated the process for the four anchors, and put all the little brackets away for a while!

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Trimming F-705C Rear Spar Fork   July 25th, 2010

The two F-705C form a ‘fork’ that the rear spar bolts into.  The inboard end of the F-705C gets trimmed to save some weight.  I drew out the patter to trim out, making sure there were at least 0.25″ from the center of the hole to the edge.

I used the bandsaw to remove most of the material, and then used a hand file to round out the end.  Unfortunately, I can’t find any pictures of the finished part!!

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Fabricating F-705B Doubler   July 24th, 2010

This doubler bar is where the wing rear spar is bolted to the fuselage, as well as the seat belt anchors.  The picture below shows how a single bolt through this bar attaches the wing rear spar to the fuselage.  The distance from the bolt to the edges is critical.   The drawings call for the bar  to be 45-3/32″ long.

I started out by measuring 45-8/32″ to get 5/32″ of ‘headroom’ before cutting.

This is my el-cheapo abrasive cutter — makes these kinds of cuts very easy.

After the bar was cut to the right length, I used the drill press and the lower piece of the bulkhead to drill all of the holes.

Here is the F-605C, which goes on top of the F-705B bar.  This one is a little long as well, so it had to be cut down to length.

Finally, here are all of the bottom F-705 pieces , including the little spacer bar.

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F-705 Real Bulkhead Spacer   July 14th, 2010

This little bar goes between the ‘fork’ that accepts each wing’s rear spar.  We start out with a piece of aluminum bar, and cut out two pieces:

I am still surprised how well my Sears bandsaw cuts through aluminum.  I just use a little cutting oil and it goes through like butter (well, not quite, but still very effortlessly).

One of the corners needs to be filed about 1/32″, so I just clamped in a vice and filed a little at a time until it matched the dimensions on the drawings.

Here is the end result.  Nice and shiny…

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The control stick assemblies mount on the center section, and tie the stick to the elevators and ailerons.  The first step is to trim the little brass tubes to size.  These go inside the main stick assembly, and get a bolt through them.  The brass tube stays in place, and the stick assembly moves around it.

This arrangement is very similar to the aileron bellcranks, so I used the same technique — drill a hole the size of the tube on a piece of wood, then notch out some of the wood to make sure I could get the tube out.  Then insert the tube in the hole, clamp the hole thing to the drill press, and ream the inside of the tube to 3/16″

Next, I installed all the hardware on the control column mounts, and reamed out the holes to 3/16″.  These holes are already drilled to size, but the powdercoating makes them slightly undersized.

This shows the hardware required for the rod that connects the two sticks together.  Looks like I need another washer on the right of the bearing.

This is the entire assembly.  The bottom of the sticks will connect to the aileron control rods, and the center fork will connect to the elevator control rod.

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Riveting Center Section   July 3rd, 2010

The center section has a bunch of ‘accessories’ — nutplates, angles to hold the floor planers, and the channels that will eventually rivet to the side skins.

Most of these rivets cannot be squeezed, so I had to figure out a way to hold the center section halves  in place while using the rivet gun.    Simple enough — I used some 2×6 and 2×4 pieces I had laying around.  I just put some tape on the ends to protect the work, and notched out a small area to clear the bit rivets set at the factory.

The side channels include holes for the bolts that hold the wings to the fuselage.  These are close tolerance bolts, so it is very important that they absolutely lined up.  To make sure everything was perfectly aligned, I first inserted four of the bolts through the hole (not all the way, as you can see — just enough to line up the holes), and then used a cleco in every hole.  After all the clecos were in place, I removed the bolts and started riveting.

Another picture of me doing actual work…

After riveting the wing skins, it’s so nice to have full access to both sides of the rivets!

Notice the tape along the bottom of the center section to protect it from the rivet gun.

Finally, more pretty rivets.

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Starting on the Center Section   July 1st, 2010

The center section is the main bulkhead in the fuselage.  The wing main spars attach to to the fuselage here, as well as the seats, control columns, etc.

There are a bunch of little brackets, angles, etc, that need to be drilled and riveted to this bulkhead.  

Then there are the two doubler bars for some of the wing spar screws.  These have two rivets that just keep them in place.  There are no holes for the rivets in the bars, so you have to use the pre-punched holes in the center section as guides.  To drill the holes, I put two bolts through the bolt holes, and then clamped the bars to the center section.  I then started the hole with a hand-held drill — just enough to know where the hole center should be.

I then took the spacer bar to the drill press to finish drilling the hole.  This guarantees the hole will be straight.

And here are the two bars with the rivet holes

Finally, there are two reinforcement angles that need to be drilled to the center section.  To drill these, I just drew a line down the centerline of the angle, and lined up the markings with the pre-punched holes on the center section.  Note the bolt on the lower right — there is one on each end to hold the bulkhead upright on the table.  This will of course come out when I’m done riveting all the ‘accessories’ to it.

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The control column mounts is the pivot point for the control stick, and where the entire control system for the ailerons and elevators comes together.  They come with a bearing pre-installed, so all there is to do is drill holes for the bolts that will fasten them to the center section.

I drilled the first hole on a drill press to the dimensions given on the drawings.  For the second hole, I positioned the piece on the center section and made sure the mount was at 90 degrees to the flange of the center section.

I used a vise-clamp to hold it in place, and then turned the bulkhead over.

Before placing the mount on the center section, I drew a centerline as well as a line showing the minimum edge distance.

I then started the hole with a hand-held drill as shown below.  The aluminum angle is very thick, and I did not think I could drill a straight hole by hand.  I took the mount off the center section and finished drilling the hole in the drill press.

Here is the part after drilling both holes and marking the material to be removed for weight savings.

I then used a bandsaw to cut away most of the material.  Here is the obligatory picture of me actually doing the work.

And this is the rough-cut part:

Finally, much nicer looking after polishing in the Scotch-Brite wheel.

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