After a long period of inactivity, I restarted work on the airplane today.
Hugo came by for moral support in what seemed to be a difficult task.
In this project, we positioned and drilled the WD-409 tail spring mount to the F-711 adn F-712 bulkhead.
First we had to position and adjust the spring mount to the tail cone skin with the bulkheads in place.
All this, just to see that the alignment of all parts fitted fine.
It looked like the picture below. It looks like there will be no need for a shim in my case on the F-711 and WD-409 as the manual suggests.
Looking from the back, the tail spring mount fits smoo
thly through the previously cut mouse hole.
I used the occasion to mark through the pre-drilled holes of the skin to check the alignment and edge distance on the holes that will be drilled in the side tabs of the bulkheads.
After removing the bulkheads, this is what I saw.
very nice positioning. (can not really go wrong as it's pre-drilled, but as you know by know, I'm sometimes being anal on these things)
while the spring mount was in place, I drew one horizontal line where I thought the best match would be according to matched centerlines on tail spring mount and bulkhead center.
When the bulkhead was removed, we made some more precise measurements to verify that everything was nice and perpendicular and then drew the contour of the tail spring mount on the bulkhead.
While the tail spring was mounted, I also used a pencil to mark where the predrilled holes in F-711 would line up on the tail spring mount.
Looks like they end up right where they belong.
Finally, I installed the tail fork that will hold the tailwheel in the tail wheel mount.
It's really hard to tell if everything is dead on, but you get the impression that it looks fine.
Then, we clecoed all together again and clamped the tail spring mount in place. and started drilling with #30 drill through the existing holes in F-711 through the steel tab.
We then continued with a #19, #12 and finally 1/4" drill to up-drill to the final size for the AN4 bolts
Finally, on the other side, you need to drill 2 #40 holes for 2 "keeper rivets". These are two rivets that will be removed later and replaced by the final bolts once the vertical stabilisor is matchdrilled. The plans are pretty vague on the exact location of these so the only thing I could read from them is that the height should be on the centerline of the backward tab and that both holes are 1/2" from the centerline. So that's how I measured and marked that.
Last but not least, drilled the 2 #40 holes and ran clecoes through.
That's it for the day and here is how it looks like on the inside.
