Fuselage: Forward mid fuse bulkheads. Forward center completed.

Remarkably, I finally completed the forward center bulkhead.  What was holding me up was my third and finally successful attempt at the right bearing bracket assembly.  See here for details on try #1 and here for try #2.

It is my suggestion to rivet the F-01441-L/R bearing bracket braces to their respective inboard F-01438-L/R cover ribs prior to riveting those ribs to the F-01403 forward center section bulkhead.  The plans have you rivet the braces after the cover ribs get riveted to the bulkhead.  That makes accessing the rivets holding the braces to the ribs difficult (see below).  I see no impediment to accessing the rivets holding the cover ribs to the bulkhead with the brace riveted on beforehand.

I have no isolated picture of the completed bulkhead, as I attached it to the lower forward fuselage prior to thinking of capturing an image.

Fuselage: Forward mid fuselage bulkheads. Bearing bracket assembly miscut.

As I was assembling the right bearing bracket assembly, I saw that the F-01450-L bracket (top bracket in images below) didn't have its aft edge properly cut.  You can see below that it doesn't match the -R part when cleco'd together.  This is an important assembly as it defines the control column travel limits, as seen below from page 36-13.

Van's said "It is fine.  It would make no difference, if you get a new/another one."  So they opted not to replace the part for me.  Whilst they may be right that it wouldn't matter, I am not comfortable with the defective -L part at such a critical location in the aircraft, so I shelled out the $8.79, shipped, for the replacement.

This is what well-cut parts should look like.  This is the right side bearing bracket assembly after replacement.

Note:  DO NOT use a #12 bit when a #19 is called for when match drilling the bearing bracket assembly to the cover rib.  I got to redo the right assembly for a third time!  Based on advice from a fellow builder, I now have a set of drill guides to verify I have the right bit in the future.

Fuselage: Forward mid fuselage bulkheads. Replaced.

Click the following for the post explaining why I had to replace the bulkheads.

My new bulkheads and associated parts came in a quaint little crate.

This time the bulkheads were packed with some material between them to isolate the parts.  When shipped in the fuselage kit, they do not come that way and end up with some surface marring.  Guess there's one good thing about having to replace these, right?

So, not wanting to repeat the mistake made on reaming the original bulkheads, I opted to do it myself in my shop.  You'll notice that the cover ribs are not yet on the forward bulkhead, but the angles are.  I decided to ream the bulkheads before the cover ribs are riveted on, contrary to plans.  This makes the assembly easier to negotiate on the drill press.  You'll also notice judicious clamping and cleco usage (latter isn't visible) to ensure the bulkhead web sits flush against the flange at all times.

Van's reams the bulkhead parts at the factory (this is verified by communication with Van's).  Thus, if everything is lined up properly, the reamer should slip in and out of the bulkhead hole with no friction.  That is how I ensured alignment.  Once I could lower the reamer down into the hole with no impediments, when on the chuck, I lubricated the reamer, fired up the drill press and very slowly dropped the chuck to ream the angle and webs.  Below shows just how little material needs to be removed. This was after reaming a 0.375" hole in the angle.  The material that was removed appears to be mostly primer (due to the camera's flash), but it is aluminum.

Using gauge pins (both 0.375" and 0.311"), it's easily verifiable that my reamed holes are perfectly cylindrical and quite snug.

With that out of the way, it was time to rivet the associated ribs on to both bulkheads.  I mostly used the same approach as on the original bulkheads.  Except...

Turns out that the longeron yoke can reach a lot of floor rib rivets.  I wish I had realized this before I had bucked almost all of the other rib-to-bulkhead rivets.  In fact, I believe it could be used to rivet the topmost rivet in the cover ribs, which I had to put on backwards because I couldn't find a way to get the rivet set in there.

And here the aft bulkhead assembly sits awaiting mating to the skin.

Fuselage: Forward mid and lower structures. Priming.

As usual, priming is an unremarkable affair.  Used my HVLP gun and two part epoxy primer.

First the forward lower skins.

Then everything else.

The astute might notice the F-01421A and B aft fuselage bulkhead pieces.  I'm going to try to replace the ones I currently have due to what happened here.

Fuselage: Forward mid fuselage bulkheads. How to ruin them.

The bulkheads have some bolt holes that are used to hold the bulkheads together after they've clasped a "lower drag fitting" (see page 29-03).  These holes should have a tight tolerance.  The holes in the bulkheads were reamed to size at the factory (as verified by consulting with Van's).  However, the holes in the mating angles and bulkhead webs have not been.  The builder is tasked with reaming them him/herself once the parts are mated.

To properly ream, one ought to use a drill press to prevent the introduction of an incorrect bit trajectory.  Negotiating these bulkheads on a consumer drill press is difficult.  So I enlisted the help of a friend with a legitimate shop that has a milling machine and more spacious digs for the task.  Well, turns out things didn't go well at all.  Below are some pictures showing some of the holes with and without the proper bolts.  The issue is obvious.

I believe the problem was caused by the reamer not being properly lined up with the holes to be reamed.  I think the reamer came in at an angle.  Lots of material came off the reamer and the lubrication got hot enough to smoke.

Unfortunately, this is an example of always being sure that you understand every element of the work being done, especially when someone else is doing it for you.  I let my guard down and should have being more proactive in involving myself in this process.

Anyway, the parts needed to be replaced.  For the curious, new bulkheads cost $575 for the forward and $540 for the aft.  Angles cost $11.10 each for the forward and $19.30 for the aft.  Cover ribs are $12.00 each.  So that's a good time.

Click here to see the post involving the redo of these parts.

Fuselage: Forward mid fuselage bulkheads riveting.

Got nearly all of the forward mid fuselage bulkheads riveted.  Only needed to fashion a way to support the work so I can drive all the rivets solo with my even fancier new tungsten bucking bar (even better than my first one), a.k.a. "Mr. T.".

Left shows good shop heads all around.  Right is the manner in which the bucking bar was used.

Aft center section bulkhead.

Bulkhead bottom channel.

Cover ribs ready to go.

For the forward center section bulkheads there are eight cover ribs.  I wanted to place the manufactured heads on the ribs so I didn't end up with gaps as I did with the wing ribs (before I knew better) and I didn't want to use the evil offset rivet set.  I found that as long as each hole is cleco'd (can use 5/32", #21 clecos for the bolt holes), the flange will sit flat when you deflect the rib to fit the rivet gun with a short straight set.  Left is an example of the holes cleco'd (the uppermost #30 hole is cleco'd from the aft side since it cannot be placed on the forward side, so there's no need to cleco the bolt hole above until later when that uppermost #30 hole is bucked up).  Right shows how much deflection the rib undergoes when placing the gun.

Because of the upper flange impeding access, I decided the only way to rivet the topmost hole was with the manufactured head on the aft side.  I used one of my tungsten bucking bars, Mr. T, in the manner shown below to buck a nice straight shop head.

Here's what each what the rivets look like for the ribs on both sides.

The missing ribs, #3 and #5, are due to bag 3076 being on back order. That bag has the bearings for the bearing bracket assemblies which sits on the missing ribs. Once I get the bearings, I can complete and attach the bearing bracket assemblies to those two missing ribs and rivet them to the spar.

Fuselage: Forward Mid Fuselage Bulkheads. Priming.

Nothing more exciting than priming parts.  But, I hadn't primed anything since 30-Jun-14.  So, my two part epoxy primer had been sitting, untouched and sealed in their cans for nearly 5 months.  Wow, the contents of the Part A can turned to pure sludge.  All the solids settled.  I had to don gloves and get my hands in there to break it up before I could even attempt to mix it (I'm not that only one to experience this).  Took a good 30 minutes before having something that was reasonably mixed.  After finishing this priming session, there were about 13 fluid ounces of final product remaining, so I chose to toss it in favor of using the additional amount I ordered last week to finish the fuselage. 

Beginning.

End.

I sneaked in the seat ribs and some a few other small parts from the next section.

Fuselage: Forward Mid Fuselage Bulkheads.

There are a few steps in this section that benefit from a deliberate approach before executing:  Check, double check, check again.

The bearing bracket assemblies.  There are four of these, two pairs of each.  Only one side on each pair is countersunk.  And it's the side that doesn't hold the bearing.  Additionally, only the outboard sides get #19 countersunk for #8 screws (so one -L and one -R part).  These assemblies are an attach point for the control columns (see page 29-05).

Update 27-Nov-14:  As I was riveting the mid fuse bulkhead parts together today, I came to realize that I should not have countersunk the outboard AD4 holes on these assemblies (left image).  Indeed, the plans are clear on this.  Slashes (right image) shows the AD4 holes that should not be countersunk.  Easy ~$15 of replacement parts to fix.

Similar deal for the bulkhead bars.  These will capture and bolt on to the rear spar of the wing (remember that "critical hole" you reamed back on page 15-04?).  These can use some minor straightening.  I suggest this approach, used to straighten the horizontal attach bars.

It helps to have a countersink extension (needed in Section 28 anyway) to countersink the top hole in each of the F-01441-L/R bearing bracket braces (see page 25-05), as the flange impedes cage access.  I used a pilotless, zero-flute countersink, which is potentially disastrous if not done carefully.  By the way, if you're having trouble locating F-14143 (bearing bracket angle), it's in bag 3062.

Be sure you countersink the correct holes on the F-01404D-L/R side angles.  I originally marked off the wrong set of holes and caught the oversight on the "measure twice, cut once" step.

Here are the flush rivets holes in the bulkhead top and bottom flanges after countersinking and spot priming.  You'll want to grab a 0.311" reamer (Avery's or McMaster-Carr) for a few holes on these and on the F-01405 bulkhead assembly.

All parts are prepped for Section 25.  Next step is priming and assembly.  However, I will prep some parts in the next section too so I can more efficiently use the time spent in overhead setting up the priming accoutrements.