Monthly Archives: August 2015


Fastback 7 (4.0 hrs)

When I attached the forward skin yesterday there were a few items I ignored in favor of focusing on the skin modifications. First among these were the baggage door support strips, that I had not included. I reattached the skin with these in place so they could be match drilled. 

Next I included the baggage door support rib and spacer. These require a dimple to the firewall.
  

The next bit is a little bit tricky. You need to clamp the F-821afb in place even with the new cut in the forward fuselage skin. Getting this perfectly even and centered can be done through multiple trial and error, as you can’t be assured that its even until you have a lot of clamps on place. The trick I used was to get it as reasonably close as my eyeball could get it. Then I marked the center of both parts (shown in red ink.) Next I measured the amount of offset, which was approximately 1/32 of an inch. I unclamped the part, adjusted the red marks 1/32″ and reclaimed. Easy day!
  After it was clamped in place, I began drilling and clecoing from the center out.


Fuselage 18 – Rudder pedals

While ago I began installation of the rudder pedals, but ran into a problem. That post can be found here: http://papalimabravo.com/construction/fuselage/fuselage-16

The problem was the rivets on the angles underneath the rudder pedal angles were not located in the same relative position as that show in the diagrams. If I followed the diagrams I would either be in gross violation of edge distance, or I’d be leaving out a rivet entirely. I decided to get new rudder pedal angles, and drill just one rivet for each end show here. These will get the BSPQ5-4 rivets in each.

This resulted in the angles being just slightly closer than the 15 1/4 inch, however, I was careful to move the rudder pedals along as I drilled ensuring the match drill process accounted for their movement and could accommodate them at any position comfortably. Problem solved!


Fastback 6

I’ve cleaned up the remaining work on the rail installation. Everything is deburred, and ready for the final installation of the new rails, save the nut plates between the F-804c bulkheads. Show Planes states that this should be a single leg nut plate that uses the existing rivet hole as the center hole and that the #6 screw hole should be approximately 1/4 inches from the longeron edge. The result would look something like the picture below (with the nut plate on the other side). However, this looks rather different from the picture, which is hard to make out. I plan to email Show Planes to make sure.  

I might be jumping ahead in the build a little bit, but I’m trying to get as many structural parts complete and ready for priming as I can for maximum efficiency. With that in mind I tackled the forward skin yesterday. This is a nerve racking cut, and it took me awhile of playing before I was happy with my lines. Here is the skin installed. You can see I’ve already made the cutout for the baggage compartment. You can see where the normal cutout for the stock kit would be made.

The lower cut is made parallel to the longeron. The longeron slopes down at this point, so you can make the cut with the skin still installed. Be vary careful at the beginning where the line is closest to the longeron. You do not want to cut that! The rest of the measurements are for the positioning of the 3/4″ radius at the corner. 25 3/4″ from the front, 1.5″ from the side, and 3/4″ from the nearest rivet.   

Here are my resulting lines.

At the top center, you’re looking for 4 inches from the bulkhead. You use the 821afb reinforcement to draw the line. This is the very tricky part. First I began by hand bending the reinforcement to match the skin as closely as possible. Then I used duct tape, and my measurements to correctly align everything. This took several iterations and a fair amount of tinkering until I was happy. Then I traced the line and removed everything for a final set of measurements. Then it was time for the radius.

I cheated just slightly on the 3/4″ radius. I used a 1 3/8″ unibit which is slightly smaller than required. I’ll clean up the remainder with a file and scotch brite wheel.   

Using a pneumatic cutting disc, I slowly made the cut. The rotating fuselage stand was invaluable during this entire process. Here are a few pictures of the result.
  

I used scotchbrite and a file to get everything cleaned up. There is still a little more cleanup to do. Particularly on the sides near the longerons which will need to be cleaned up after the removal of the skin. Finally, I added the 821abf reinforcement and clamped it in place. This will be double-flush riveted, which is something I’ve never done before, so more to follow on that.
  

My neighbor across the hangar keeps inadvertently leaving her tools in my hangar, so I made her a little box so she knows where everything is. She tends to whine a lot.