First on today’s agenda was to do a little practice for the double flush rivets I would need to set for the forward fuse skin to F-821afb. I did this by drilling and dimpling a few holes in some scrap aluminum that had a similar thickness to the parts in question. Then I used a few different countersink depths and different rivet lengths in order to get an idea of exactly what I was looking for. My basic research online indicated that the best method is to make the countersink slightly less than that required for the machine head, as the shop head will not fill that size countersink fully. Using the rivet gauge, I found that because of the countersink, you’d want a half size to a full size shorter rivet than would be required without the countersink. This makes sense considering the gauge measures from the top of the countersink and as a result there is more area for the shop head to compress into. A couple practice squeezes later, and I had the results I was looking for.
The final step was to use a scotchbrite wheel to make the surface perfectly even. It would probably be best to use a rivet shaver first and then clean the area with the scotchbrite. Regardless, I’m confident that this rivet technique is a non-issue and I’m ready to tackle the real thing.
I also disassembled the forward fuselage, in order to begin the process of deburring and dimpling the associated parts. Before I could begin this though I needed to take off a little more area near where the forward skin meets the upper longerons to have a perfectly even and continuous fit.
You can see the area that needs to be removed marked in black. The dremel and the scotchbrite wheels made fairly quick work of this.
Next I turned my attention back to a few remaining tasks on the cockpit rails. In the Van’s diagrams there are two rivet holes that are marked to not be countersunk, nor riveted. No such annotation exists on the Show Planes instructions and I couldn’t seem to find what exactly the purpose was in the diagrams. (I’m pretty sure I’m missing a set of diagrams, which is normal for the big drawings, but not for the preview plans.) After taking a quick look at Jack Savage’s RV-8, it was apparent that these two rivet locations will become nut plates to attach the sliding canopy rails. Since these will not be needed in my kit, I drilled, deburred and dimpled these remaining holes.
When assembling the aft fuselage, I had overlooked two parts. These are supports to the forward most upper bulkhead and provide a location for securing baggage in the rear compartment. The fit was a little off, so I focused primarily on edge distance for the longeron as that is the most structurally important part in this equation.
When I drilled the rear passenger shoulder harness attach points, I had not notched the parts for overlapping the bulkhead flange. This would have resulted in a skin distortion when the part was riveted in place, so I took care of this today. I began the process of removing the blue plastic, deburring and dimpling skins. I no longer mess with removing portions of the blue plastic in portions. Just take it all off. The skin will need plenty of prep prior to priming and painting anyways, plus these skins will have very little opportunity for scratches.