Finished the F-706 Bulkhead....Or so I thought - 4 hours

Yesterday I had cleaned and primed the pieces and tonight I will assemble them.

I started riveting the F-730 plate to the F-706B bulkhead using the back rivet method for the flush rivets, then used a squeezer for the innermost rivets. Then I fitted the F-729 rib.


Then I riveted the F-729C angle thinking it would be easier to set the innermost rivet now.

Then I was ready to squeeze all the rest of the rivets. I was thinking more about aesthetics than I was about placing the shop heads on the thicker material. Slight curling of the webs...not horrible, but not great.


I then squared up the F-729C and final drilled it to the F-729B angle. Then I squeezed the rivet.

I finished the evening by riveting the F-706B bulkheads to the F-706A bulkheads halves. Once everything was together I double checked square on everything and noticed that the holes for the Elevator Bellcrank bolt, were not perpendicular to the webs. Something looked off. So I started in on figuring out why the holes were not aligned. I cleco'd the assembly to the bottom fuselage skin and things started to look better. However I was still out. I disassembled it and measured the holes for the mounting bolt and sure enough they measured 1/8" different from the aft side of the web flange to the hole. I was floored. I was so careful to open up the factory punched holes to 1/4" and it really seems like they were not aligned from the factory. 

I'll send an email to Van's to see what's up and go from there.

Update - I received an email back from Van's and in a nut shell they gave instructions on how to install doublers and re-drill the holes so they are perpendicular. I wasn't too keen on doing that at this stage (pre-fuse assembly). I checked the prices for a new F-706 bulkhead assembly and its only $110 so i'll just bit the bullet and do the piece over again. This time making absolutely sure that the holes from the factory are aligned and not the 1/8" out. I sat and stared and measured, and scratched my head for an hour trying to figure out where things went wrong, and All I can come up with is one of the F-728/729 ribs must have had a hole in the wrong spot? Well, If I rebuild it I can double check everything.

And some more work on the F-706 Bulkhead - 4 hours

Managed a decent day in the garage today. One of the tasks needed to be done was to open up the 7/16" diameter holes in the F-730 plate, the F-728 and F-729 webs. A little bit tricky to do, but best way I though was to mark it and then slowly chip away at them. Fist step I cleco'd the F-730 plate and marked it.

Next I cleco'd the F-728 and F-729 ribs and marked those.
 
 I pulled out the dremmel tool and with a very small diameter sanding drum I started in on removing material.

I then used very small round chainsaw files and sneaked up to the line. It took a few tries but I managed to get things close.

Once I was happy with the pieces, I cleco'd the assembly back together and used the dremmel one last time to even the holes out. After that, everything was debur'd and edges were files down.

More work on the F-706 bulkhead - 3 hours

I haven't been feeling well lately so I've not been very motivated to get in the garage a work away. I managed to put in some hours today and advance the F-706 bulkhead. I completed drilling the F-728B angle to the 728A rib. All that was left was to drill the 1/4" holes for the bellcrank assembly. This was a head scratcher for me as how best to do this. 1/4" hole is fairly large to get centered with only the hole in the rib skin as a guide.
 
I decided to make a jig with a piece of oak. this will allow me to start a centered hole with a hand drill and then I can finish it on the drill press.

I used the 1/4" drill bit to ensure center of the holes. 


I then clamped the oak to the web and double checked hole alignment.



I clecoed on the angles to the web and then used the hand drill to start the 1/4" hole.

I double checked centering of the pilot and it was looking great. So I finished the 1/4" hole in the drill press.

Both holes turned out perfect.

I then completed the match drilling of F-705B/F-730/F-728/F-729. All I need to do now is debur, break edges, 3M, clean and prime. I'll save that for another day when I'm feeling better.  

Working away on the F-706 Bulkhead - 3.5 hours

I received new 0.63" 3/4" x 3/4" angle a few days ago so I can recut the F-729B angle and make the F-728B angle. I was really stumped by the 1/8" diameter hole callout on the F-728B piece and then it occurred to me that this was the initial hole for the first cleco to attach the angles to the webs. When working on the F-729B and F-729C pieces I thought that he 1/8" holes were to match up. And technically that's half true. Turns out that the 1/8" hole is a pilot hole for F-729C to attach to F-728B. However the 1/8" hole in F-728B is for the first cleco to the 728A rib. This is why I was having edge distance issues when using the Van's Dimension given for the overall length (24-5/32"). Silly me. Of course I figured this out after I drilled the 1/8" hole for my new F-729B angle, so I just have to roll with it. In the end, I recut the F-729B angle and managed to get all those pieces fit together and holes perfectly aligned with excellent edge distance. It just took me way longer than necessary.

I began assembling the pieces as per Drawing 26. however, I noticed that the webs and pieces weren't sitting parallel. I was unsure about the final fitment at this point.

I disassembled the pieces and drilled the F-729A and B pieces together. Next, to ensure the most correct alignment, I clecoed the assembly/ribs to the bottom fuselage skin to ensure all piece where in the correct position. Once I was happy with fitment I then drilled the F-730/F-729C.


I have the 1/8" holes aligned. I will final drill these to #30 when I am ready to rivet.

I have excellent edge distances on the F-729A angle.

Finishing up the F-705 Bulkhead - 2 hours

Tonight, I bolted the seatbelt anchors onto the bulkhead and torqued them. I also installed the nutplates on the side of the bulkhead (with NAS1097 rivets).

 Next I began to setup to drill the plastic flap bearing blocks. I installed both blocks on the bulkhead and measured each side to ensure that they were parallel.


Once I was sure that both were in the correct location, I clamped them and checked twice.


Once I was happy with the setup, I used the palm drill to start a pilot hole with the #12 bit. I then set up the drill press to complete the holes.

When finished drilling, on inspection. The holes didn't line up, the new hole seemed to be crooked. Really weird. It bugged me for quite a while, and then as soon as I put the blocks together....I figured out what happened.

The blocks from Vans are not cut straight at the factory...one block is at a slight angle when placed on a flat surface. So depending on how it sat when I drilled it....the holes were not going to be "Straight". Ugh...what a silly Gotcha. I will order a couple new flap blocks and drill it again. I will have to be careful to ensure that they are both straight to begin with before drilling.

Finished riveting the F-705 bulkhead - 2 hours

Again, another small night on the build. Ugh....work gets in the way too much. I clamped the F-705 bulkhead to the table and finished squeezing the remaining AD4 rivets. Note that I did not attach the F-705F channel crosspiece as I am fitting the Anti-Splat Almost an RV14 mod during my build.

Started Riveting F-705 Bulkhead - 2 hours

I managed to squeeze in a small amount of work tonight. I began riveting the lower portion of the F-705 bulkhead. I decided to buck these rivets since with a proper setup, I have really good success setting straight and virtually perfect rivets. The pictures don't show it well, but I stand the bulkhead vertical and clamp it to the wood uprights on the edge of my table. I then have excellent access to buck all the rivets along the bottom.

All finished for the night, just will need to squeeze the rest as the material is too thin to buck the other rivets.