Wednesday, January 30, 2019

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.