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THE REAR FUSELAGE
I started the rear fuselage assembly in November of 2003. The first sub-assembly is the aft bulkheads and the aft lower skin. The photo at upper left shows the three aft bulkhead assemblies ready for installation. The F-710 bulkhead does not get installed until the tail bottom skin F-779 is riveted to the aft bottom skin F-778. The photo at upper right shows the F-711 and F-712 assemblies installed in the aft lower skin for a trial fit.
The tail bottom skin F-779 needs to have an oblong segment cut from it to clear the tail wheel spring mount bracket WD-409. This process looks simple enough but looks can be deceiving. A considerable amount of trial and error is involved in getting this “Mouse-hole” as it is affectionately called, shaped just right. The photos directly above show the finished product from the outside (left) and the inside (right) after the F-779 was primed. I actually primed this part at the same time as I primed the bulkheads and trimmed the hole later.
The photos immediately below show the tail-wheel spring mount WD-409 and bulkheads F-711 and F-712 cleco’d to the lower aft skin F-779. It appears that I have left too large a gap between the “mouse-hole” and the WD-409 and perhaps I have but my rationalization is that this is a good place for any water that may accumulate in the fuselage to drain out. The drawing, #27, shows the F-779 skin with a note that says, “See detail A.” Detail “A” is a drawing of the cutout with no dimensions whatsoever with another note that says “Remove shaded area.” The Vans drawings are very good for the most part but the parts that are not good are so bad that they are almost humorous.
Alright already! Enough harping about the “mouse-hole.” On with the rear fuselage assembly. The photo below left shows the F-707 and F-708 bulkheads cleco’d to the F-773-R aft side skin and the F-778 aft bottom skin. In the photo at right, the F-773-L aft side skin has been added. As with the rest of the skins on this airplane, all of the holes lined up and this fit check was merely a formality. Every time a put pre-drilled sheet metal pieces together with this holes in them and they all match, I am simply amazed.
One more little detail about the WD-409 tail wheel spring mount and I will put it away for awhile. The photo below left shows a bolt in the tube section of this assembly. This bolt holds the tail wheel spring to the mount and the hole has to be carefully drilled, otherwise the wheel may not be vertical. The photo at the right below shows the F-706 bulkhead in place in the rear fuselage assembly. The F-728A bellcrank channel and the F-729 bellcrank rib have been added to check for fit also. If you look carefully you can see the F-711 bulkhead in place as well. On the right side of the assembly the F-786B-R has been installed. There are 6 F-786 skin stiffeners total in the rear fuselage. They come un-drilled and un-trimmed but the holes are present in the rear fuselage skins.
The photo below left shows the rear fuselage assembly with the F-786B-L and F-786C-L skin stiffeners drilled and cleco’d in place. The photo at lower right shows several parts of the rear fuselage after I primed them. Note that the F-779 is back for more primer. I scratched a lot of primer off fitting the F-711 and F-712 bulkheads to this part. The parts in this section of the kit do not fit as well as the rest of the airplane parts do.
After I had the entire rear fuselage assembly assembled temporarily with clecos, I needed to come up with a plan for assembling it with out it twisting on me. The first thing I decided to do was make sure that I could level the assembly on the sawhorses. Below left is a level placed at the F-706 bulkhead. Notice that I actually have the level clamped to the bulkhead but it is still resting on the side skins. The photo below right shows another level F-710 bulkhead. This level is taped in place. At this point I have decided to assemble the rear fuselage upright and I know I can keep it level.
Now it is time to add the last 2 bulkheads, F-711 and F-712 to the assembly. The F-779 tail bottom skin was installed first. At this point I realized that I was premature when I riveted the two sections of the F-711 bulkhead together along with the F-711C stabilizer attach bars. The photos below show that the F-711 bulkhead is disassembled and held together with clamps. I had to do this for several reasons. One was that for some reason, I could not seem to cleco the assembly to the side skins. I could, however, cleco one half of the bulkhead to the skins and then, with much effort, cleco the other half in. The two aft bulkhead assemblies are the poorest fitting parts in this kit.
The lower left photo shows the F-711 bulkhead installation from the rear. The photo at right below shows the F-712 bulkhead in stalled. Also the WD-409 tail wheel spring mount is installed along with the tail wheel assembly. I really did not need to install the tail wheel and spring assembly at this point. I just wanted to see what they looked like put together on the ship. It was one of those "keep the personal morale up" things, if you know what I mean.
Well now! Isn’t this interesting? The forward and aft flanges of the WD-409 tail wheel spring mount are not parallel with each other. They are also not perpendicular to the actual center tube which mounts the tail wheel spring. That means that there is a gap at both the F-711 bulkhead (below left) and the F-712 bulkhead (below right). There must have been some sort of a problem with the fixture that this assembly was welded in. It is too late to worry about it now, since I have had the kit for a year and a half, but next time I certainly will make it a point to check this part as soon as I open the box.
In the picture below left, you can see that I rotated the assembly on to its side. The reason I did this was because I removed the protective coating from around the rivet lines and I decided that these long skins would be easier to handle if I performed this procedure with the assembly cleco’d together. The same was true with the coating on the rivet lines on the sides (below right). Also in the picture below right you can see that the upper longerons are in place. I have detailed the installation of these parts in the longeron section of this assembly log. Notice that bulkhead F-709 is riveted to the F-714 aft deck (per drawing 26) and the assembly is cleco’d in place. I drilled all of the attach holes for this assembly at this time.
In the photo at right above and also at left below, there are levels attached to the fuselage again. I kept levels in place throughout the rest of the assembly of the fuselage from this point forward. I wanted to insure that I did not twist the fuselage if at all possible. The plans call to use plumb bobs but I felt that levels were a little more manageable on the fuselage. The photo at right below shows the entire aft fuselage cleco’d together including the top skins. I did this to make sure that I would have no surprises later. It all fit together like a tight glove. The upper skins were particularly tight but they fit. In sheet metal, tight is good.
The photos below show another reason why I was premature in attaching the F-711C stabilizer supports to the F-711 bulkhead assembly. The upper longerons get notched to allow the supports to penetrate them and it was easier to install these notches with the longeron in place. I could then attach the supports with clecos to check for fit and clearance. The photo below left shows the left longeron is still too tight at the F-711C.
The longerons also had to be notched at the F-712 bulkhead (photo below left). There is a spacer P/N F-710C that goes between bulkhead F-710 and F-714 aft deck. I taped the spacer in place and drilled the four horizontal stabilizer forward attach holes from the F-714 (photo below right). I would have preferred to drill these holes all at once when the stabilizer is mounted but the holes are in the F-714 from the factory so you don’t have much choice. I will be drilling the bolt holes in the stabilizer with an angle drill from the bottom when the time comes I would guess.
The next thing on the agenda was to disassemble the rear fuselage and prepare for primer. Unfortunately, I had the garage door open and a breeze caught the left skin as I was taking clecos out. It wrinkled the bottom skin at the very aft edge (left photo below). There were also some small cracks (not shown at two of the rivet holes. I decided that I better make a repair doubler to re-enforce the aft bottom skin. The doubler I made is shown below right.
Well, it was now time to assemble what I believe to be the trickiest part of this airplane. It looked so simple. Rivet 2 halves of 2 different bulkheads together and rivet them to a relatively small (but pretty stiff) skin. At the same time install a steel bracket with a total of 5 bolts that is captured by these 2 bulkheads. What could be simpler? The first obstacle was to keep the 2 bulkheads straight while they were being attached to the F-779 lower skin so that when I installed the assembly to the rear fuselage, all of the rivet holes would still line up. I cut 2 pieces of .040 aluminum to the height of the side skins at the rear. I then transferred all of the holes from the side skins to these pieces and cleco’d them to the F-779 (photo below left). I will call these 2 pieces of aluminum my aft fuselage assembly tool.
Next the forward half of the F-711 bulkhead needed some final tweaking. It was a time consuming process to get the flanges of this bulkhead formed to fit correctly. Have I said this yet? These parts were not well made. The web of the bulkhead halves were warped and the holes in the flanges did not line up as well as all of the other parts of this kit. Below left is a photo taken while the F-711A was undergoing its final fitting. Photo at right shows the warped bulkhead parts.
Next, I started working the flanges of the F-711B (below left). Because they were warped, there was a gap between the 2 halves of the F-711 bulkhead. I decided to install a row of rivets down the center of the bulkhead to close up the gap. Either the F-711 and F-712 parts are the most poorly formed parts in the kit or I got a set of poorly formed parts as the exception and not the rule. Picture at lower right shows the use of a rivet fan to lay out an evenly spaced line of rivets.
This narrative continues on "The Rear Fuselage Page 2 (link below).
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