04 July 2014

Empennage: Aft fuselage. Bottom and side skins on.

I'm out of space in my small living quarters.  So we (my -9A friend and I) riveted the bottom and side skins together in the entryway.  I chose not to back rivet after trying a few and not being satisfied with the results.  Others prefer back riveting and will surely have a nicer finish as a result.

It really pays to read this entire section in the plans prior to starting.  Several steps are completed out-of-order (e.g., wiring harnesses) and some are missing entirely (e.g., when do the bellcrank ribs get riveted to the bulkhead?).  And many rivet lengths are inaccurate:  Most AD3 rivets not relating to the overlap of two layers were short by 0.5.  A rivet sizer is valuable.

Here is everything cleco'd up, every other hole, on some saw horses.   Eventually all holes were filled with clecos.  Be sure to tape off the holes that don't yet get riveted.



Flip it over when ready to rivet.  My buddy stayed under the structure on a wheeled desk chair with the bucking bar and I stayed outside with the gun.  Yes, my front door was open in order to take this picture.


The phone cable (WH-00059) could not fit through the SB437-4 bushings in the bellcrank ribs because the RJ-11 connector is too big. Another -14 builder I know simply drilled the bushing holes to the next size.  I found it easier to simply snip the RJ-11 connector off, route the cable and then crimp a new connector on as I already have the requisite tool.


Yes, the thick F-01479 bottom skin really does go between the F-01410 bulkhead and F-01478 bottom skin.  No, it is not easy to make that happen.


The F-01412 aft bulkhead's tabs overlapped the F-01473-L/R side skins. Unfortunately, this wasn't noticed until after it was impractical to remove the piece.  Rather than risk Dremel'ing, we used the bucking bar strategically to bend the tab across the gap in the overlap before setting the rivet.  I suppose we could have filed it down and that probably was the better option.  Don't worry, that dimple on the right image isn't cracked.  It's a superficial primer scratch.  I got worried after I saw it in the picture too!


Work-in-progress.


Side skins completed in approximately 15 hours.  View from the front door when open.


Flipped over.


My new roommate will be couch surfing for a while until he gets a place of his own.  At least he has some good company next to him.



After plumbing the static lines and doing some more harness work, the rest of the structure will eventually be completed.

Where the side skins meet the longerons, I had to press out the dimples I made in the side skin for the access panel.  I was aimlessly following the plans and dimpled the skins there for flush screws.  Turns out, the plans are very specific on page 10-14, step 11 to not dimple the two screw holes in the skin where they meet the longerons.  Oops.  Here's what the pressed out dimples, that were then countersunk through to the longerons, look like (will need to spot prime).  If the skin later cracks, it's in a location that can easily be stopped drilled if it doesn't propagate to a nearby edge.  Another option is to go deeper with the countersink or upsize to a larger hole and screw (my tech counselor provided those ideas).


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