December 9th, 2012

A lot of non-airplane building stuff has been going on the last few weeks so progress on the tail cone has slowed somewhat.

 Last Friday I took a day off that also happened to have some good weather, so I finished priming some of the parts I'd had to put off.

 I primed the J stringers, the two longerons, reinforcing angles for the bulkheads, the last part of the F706 bulkhead that had not been primed as well as the baggage ribs so all the center section would be ready.  One of these days I'll remember to take a picture.  There is a lot going on with getting all the parts cleaned for painting, mixing up the paint (it's a 2 part epoxy primer) then letting it "cook" for 30 minutes.

Next step was to remove the vinyl along the rivet lines, then debur and dimple all the skins, bulkheads and J stringers. Once that was done it was time to reassemble the tail cone and start riveting.

 The F779 bottom skin is a pretty heavy piece - .040" thick. When I was match drilling it was very difficult to get it all pushed up so I could match drill the holes and J stringers. This time I put a little more pre-bend on the skin, then put it in by itself before adding the F711 and F712 bulkheads. The fit was *much* better not to mention it was way easier to get everything lined up and clecoed in place.

Van has you start off riveting the two aftmost bulkheads (F711 and F712), then the F779 bottom skin at the tail, then finally the main bottom skin.

Here is a shot of the tail cone as I'm starting to rivet it. I was able to use the squeezer on most of the F712 (furthest aft) bulkhead and a lot of the F711 bulkhead. You can see an elliptical hole on the lower forward part of this shot. There are two of these (one on each side) that will be where the rudder cables will exit the fuselage and attach to the rudder, which will be attached to the aftmost bulkhead.

From Fuselage

Next they have you start working forward along the lower J stiffener line, riveting the J stringer, side skin and F779 bottom tail skin together.

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Becca helped me with back riveting the tail cone bottom skins.  It would have taken me a few hours to get as much done as she and I did in 30 minutes.

Here is the cone with all the bottom skins riveted on (it is laying on its left side).  This is looking from the tail forward.  Basically this section will be from the back side of the canopy aft.  The baggage compartment, seats/cockpit and engine will all attach to the forward section of this piece.  The tail will attach to the near end.

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On Saturday I finally finished riveting the tail cone.  I did a quick guesstimate count - close to 1000 rivets in this dude.  Took a while.  Back riveted almost all of it.  The entire assembly probably weighs less than 30 pounds.  Amazing how light all this stuff is.

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Here's a view looking aft inside the tail cone.  The lengthwise J-stringers add considerable strength.  The F706 rib in the foreground will be riveted when the center section and tail cone are riveted together.

The vertical member is for the elevator bellcrank assembly.  There is a pushrod from the control sticks that passes through the small hole at the bottom, attaching to the bellcrank which will later be mounted just aft of the bulkhead.  The elevator pushrod will continue aft through the large round hole in the far bulkhead and attach to the elevator.

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Next step is to start working on the center section.  The plan view is below.  The aft bulkhead supports the seat back.  Aft ribs are baggage floor ribs.  Forward ribs support the seats.  The forward bulkhead is the main spar carry through structure.

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Started fabricating the seat shims from 1 1/2" bar stock.  4 required.

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4 of the seat ribs have to have the forward holes enlarged to provide clearance for the control columns.  Two will be cut for an access plate cover.  I used a standard hole saw in the drill press to cut the ribs.  Worked great.

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Here are the 2 916 L + R inboard ribs after the holes have been cleaned up.

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Plan of the two ribs that have to be modified with access plates.  Should finish those up tomorrow.

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Finished up prepping the two access ribs, then riveted up all the seat rib nutplates.  Next step is to cleco the aft portion of the F904 bulkhead to the seat ribs, the F705 bulkhead and the baggage ribs.

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Then you cleco on the skin. I decided to flip it upside down to do that.

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Here's another view from underneath.

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Had some fit issues with the two center baggage ribs (F727 L+R) and the F705 bulkhead. Turned out to be interference between the rib spacers on the two access ribs and the seatbelt anchors. Once that was cleared up everything went together correctly.

November 25th, 2012

Finally got to put some larger parts together this week.  Nice to have something that is looking like the tail of an aircraft.

This week I finished up the longeron bends, then started assembling the tail cone.

Since I'd finished up the aft ends of the longerons in my last session, it was time to bend them as prescribed in the plans.  There are a couple of things that fall into the "dreaded tasks" category among RV builders, and this is one of those tasks.  You're going to take a nearly 15 foot long piece of aluminum angle, put a pretty significant curve in it (all while keeping it flat), then put a vertical bend in it (also keeping that straight), then twist it almost 20 degrees.  Fun note in the plans - "if you are within 1/16" of the template that should be adequate".  Love the understatement. :)

Plans page for the longerons:

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I don't have much in the way of pictures.  Basically you clamp it tightly in a vise (after a gazillion double-checks to make sure you really are bending it in the right direction), put a pre bend on it, then whack it with a rubber mallet (I used a deadblow hammer).  Move it an inch, do it again, etc.  Once you think you're close to what they want, lay it against the paper template to see how you did.

Repeat.  Take the unwanted bend out (oops, you mean you straightened it out more than you wanted when you made it level again???  try again).

Here's what it looks like when I'm getting close.

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The first bend on the right longeron took me nearly 2 hours before I was satisfied.

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Nov 18th, 2012

This week I finished up the F705 bulkhead assembly, then did the F706, F707, F708, F711 and F712 bulkheads.  Kind of nice working on the tail cone guys.  Not much to them.

Last week I fouled up a couple of the seat belt attach brackets.  Failed to notice some of the fine print on the edge of the plans and made a mistake match drilling them.  I ordered a couple more.  They arrived this week and I match drilled them to the F705B bar.


The F711 bulkhead is another two part unit. There are two basically identical bulkheads that get riveted back to back. The top center section is trimmed out per the plans to provide clearance for the elevator pushrod tube to connect to the elevators. Two large 1/4" flat aluminum bars provide reinforcement on each side and stick up vertically above the bulkhead. These will be used later to attach the empennage to the fuselage.

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Riveting the two bars to the F711 bulkhead.

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Completed F711 assembly.

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The last thing I did this week was dig out the longerons. It's finally time to use them. They came with the wing kit almost a year ago and have been hanging on the wall waiting for the day I could use them. The longerons are each about 15' long and have to be trimmed down to 173 7/16" inches. I must have checked the measurement a dozen times before I finally did the cut. Do *not* want to have to get another one of these because I messed up. The first thing they have you do is mark them up for left/right up/down fore/aft so there is absolutely no doubt about which is which. Then a couple of slots and a tang are cut out of the aft end to provide clearance for the F711 bars. Here's a shot of the cuts after they were more or less done.

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Next week I'll do the bends. Then it will finally be time to rivet some of the pieces together.

October 28th, 2012

Spent most of the week either working, doing chores, or in Atlanta at Becca's last big band competition. They did well, but missed finals by 1/10th of a point, which was a bit disappointing. They did very well though, and had a lot of fun. It was great to get to go so see them compete against so many excellent bands from all over the south.

 This week I finished up the 904 bulkhead assembly. Started off installing nutplates all along the top of the main fore and aft bulkheads. I assume these will later be used to screw down the seat pans (haven't read that far ahead in the plans yet).

 I then finished up the attach angles, installed nutplates in the ribs and angles, then riveted the ribs and attach angles to the forward spar (no pictures at all - totally forgot to take any).

 After that, they have you fabricate a couple of close tolerance spacers that are used to make sure that the two bulkheads are exactly the right distance apart when they are finally riveted and bolted together.

 Here is one of the two spacers - they have to be exactly 1 7/16 inches long. I cut them a bit long on the band saw then chucked them into my drill press and snuck up on the correct dimension by running the tubing up against a fine metal file on the drill press table. This also ensures that they are exactly square on each end.

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The last thing to do is to make a couple of precision wood spacers (also 1 7/16" thick) to test how the wing spars will fit. These are drilled oversize where the spar attach bolts go, then the entire thing is bolted together to validate that everything is assembled and fits correctly.

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You can also see the bushings for the fuel lines have been installed in the forward ribs. They are the black nylon parts.

October 21st, 2012

Worked on the F-904 bulkhead this week.  This assembly is really beefy - the wing spars bolt into each side.  The two major fore and aft bulkheads actually came with the wing because they are precision match drilled to the wing spar and are shipped as a unit.

Here's the assembly clecoed together just to get a feel for how everything goes together. The 4 small ribs are where some cover plates will be bolted - fuel lines run through holes in the ribs. The fuel selector and fuel pump will mount in a center section between the two large ribs. We're looking at the forward side of the bulkhead.

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Once it was all clecoed together, Van has you install the main spar bolts (*very* tight fit - they are precision bolts and the holes have been reamed to the exact size) to hold everything in alignment, then match drill the F904C/D left and right components to the F904A & B bulkheads.

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There are also a number of holes which are either enlarged or laid out and drilled for 5/8" nylon bushings. These are used for rudder cable and wiring bundle runs. These are drilled with a step drill for a nice clean hole.

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Here is the aft bulkhead's corresponding holes after drilling with the step drill. The holes will receive a nylon bushing and will be used to for wire runs.

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The control column assembly mounts to the aft side of the aft bulkhead. The two F633-L/R brackets need to be match drilled and machined down to size for lightening. Here I'm match drilling the F633-L to the aft 904 bulkhead (match drilling means you back drill through an existing hole in the bulkhead into the bracket). This ensures proper alignment of the holes. I put a centerline down the back side I can see through the hole to make sure all is lined up correctly.

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Once they were match drilled, I used to band saw to trim off the extra metal (Van's has a cutting diagram) then spent a couple of hours filing and polishing to get to this:

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Not sure I'd do it again - took a lot of work to drop a few ounces, but I'm pleased with the result, so no regrets. 

Since I had the control column mounts done, I went ahead and put the control assembly together. Van recommends doing it while there is plenty of room to work. Once it's all together it's set aside until it's needed much later in the project.

 Here I'm working on finding all the bolts and working out how it all fits together. Although most of the parts are prefabbed and powder coated (they are steel), a number of holes have to be drilled to size and the bushings need to be final ground to fit.

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There are specific numbers and thicknesses of washers used to ensure no slop in any of the parts. Really fun trying to work all these washers in such a tight spot.  I can see why they have you do this while it's easy to get to (although you'll still have to do it in a tight spot later, since there is no way to leave this bolt in place).

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Here's the entire assembly after putting everything together and getting it all lined up.

 The column mounts on the back side of the bulkhead. The columns come up through the seat floor (so the stick ends up being just aft of your knees) and your legs go over the bulkhead. I had to put it on the floor to see how it all worked. The controls feel just like the demo plane I flew in - absolutely smooth as butter and no slop whatsover. Wonderful feel.

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Once all the fitting is done the sides are riveted on.

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Finished up the week fabricating and drilling the attach angles that will serve as doublers behind the ribs mounted to the forward bulkhead.

October 14th, 2012

October 7th, 2012

September 30th, 2012

September 23rd, 2012

I only have a couple of pictures this week.  Not much that I did was worth a picture.  Just a lot of deburring and flanging parts getting ready to prime them.

Used my home made flanging tool (originally got the idea from the Van's 26 years of the RVator book) to flange all the seat ribs and bulkheads.

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The way this tool works is it has a wooden "anvil" mounted to a sheet of plywood that is angled backwards at 11 degrees.  By placing the rib/whatever on the surface,  putting the moveable lever inside (it is also cut at an 11 degree angle) and pushing the rib back against the anvil, the flange will be bent and then spring back to exactly square.  You can go through ribs like mad with this thing.  What a great idea.  I just made it out of some random stuff I had laying around.  Definitely a great time saver.

Here are all the seat ribs after flanging.

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Here are some of the fuselage bulkheads after deburring and flanging.

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These are the aft most fuselage bulkheads after flanging and cleaning up in preparation for priming.

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I wanted to get as many of these done ahead of time as possible so that I would be able to keep working without having to stop and prime every day or two.

September 16th, 2012

Had a lot going on this week, so pretty much all that happened was inventorying the fuselage kit.

 I did get to mock up the firewall just to get a feel for it, but didn't do any work on it.

 The fuse kits seems to have more parts (and more rivets) than anything I've received so far. I spent about 14 hours total unpacking, inventorying, labeling and organizing all the parts.

 One thing I did this time that has helped a lot - if there was a part that wasn't well identified (angle, bar and tube stock often fits in this category) I marked it as soon as I identified it. That's helped a lot as work progresses.

 Here's the crate. It's amazing how much stuff Van's can cram in one of these things. Very little extra space.

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As always, a very thorough and complete inventory is included.

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Start unpacking the box and separating all the sub kits.

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Control yoke and rudder pedal assemblies.

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Seat backs, console and some misc sheet parts.

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Box full of various parts - the large powder coated parts are the main gear attach brackets.

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Main gear brackets out of the box.

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Left and right rear skins and both bottom skins. One of the skins is shipped rolled.

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Getting down toward the bottom of the crate.

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Welded steps. I got one for each side.

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Main gear legs were attached to the bottom of the crate.

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This bag is nothing but hardware - rivets, bolts, washers, etc. Had to buy two more parts boxes to organize it all.

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Misc angle stock. I labeled all of these to make finding it later a bit easier.

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