Now that the center section ribs are attached to the spar carry-through the rest of the center section can be fit. The principal components involved are the F705 bulkhead, the baggage compartment floor ribs, and the center section skin holding it all together. So exactly where on the aircraft is the center section? Well, the center section lies roughly in the middle of the fuselage, ha ha. To be a bit more precise, the pilot and passengers sit on the ribs between the spar carry through (gold) and the F705 bulkhead. Their knees go over the spar while and the seat backs rest against the bulkhead.
The first thing is to collect all the pieces, mainly the ribs and the already completed F705 bulkhead. The dark grey thing pictured below is one of the access steps.
The first thing is to collect all the pieces, mainly the ribs and the already completed F705 bulkhead. The dark grey thing pictured below is one of the access steps.
The F705 bulkhead is clecoed to the seat ribs prior to riveting.
The two combined are flopped over a sawhorse and the center section skin is clecoed on for match drilling.
After all the holes are drill they must be deburred. I find the angle drill makes fast work of this process, but it takes a light touch.
One of the more difficult aspects of building your own airplane or any project of this level of complexity is the requirement of making decisions early in the build process that have ramifications later on. Some are bigger than others of course. Like choosing a tail dragger vs. tricycle gear, or a tip up canopy vs. a sliding canopy. Very often these decisions are irreversible or nearly so, and this aspect just adds to the anxiety of the decision making process. In any case, all of the things not decided for you by the kit manufacturer are your responsibility as the builder, and quite naturally require a good deal of research. I find that when I feel like I'm not making good progress it is invariably because I can't decide on some small issue and I'm just dragging my feet.
And so it goes that there steps that protrude from the fuselage side to aid in climbing up on the wing. And it seems that these steps are prone to cracking after some time. Many builders have reported online of the rather involved process of repairing or replacing them. One of the major impediments of repairing a cracked step is that they are attached to the plane's baggage floor ribs underneath the baggage floor, which is riveted down. Thus, the repair first involves drilling out all of the floor skin's rivets.
An alternative to permanently fastening the baggage floor with rivets is to use screws and nutplates in their stead. So my big decision this week is whether or not to take the time out to add the 40 or so nutplates required to make the baggage floor removable. Meet the nut plate:
This particular model is a dimpled nutplate for an 8R8 screw. Using a dimpled model allows the use of a counter sunk screw which, in turn, allows a flat baggage compartment floor.
Meanwhile, Carol cranks out many of the small flanges and other assorted do-dads that hold the plane together while Trina looks on innocently. Notice the plans draped over the dimple machine and the back of a chair while drying. The result of a mishap involving the exuberant puppy and bottled water.
When all of the center section holes are deburred they are then dimpled. My DRDT-2 dimple machine gets a good workout on this sheet.
Now its time to assemble the baggage compartment ribs
With all of the center section ribs in place the center section skin can be riveted on.
And that's about it for the center section.
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