Fuselage Questions (7A)

[macrafic]

A couple of questions regarding the fuselage (7A).

Does the front edge of the 779 tailcone go between the 778 aft bottom skin and the 708 bulkhead?

Also, on my 711 bulkhead (forward most bulkhead of the two in the tailcone), if I clecoe the 773 side skin to the forward vertical line of rivet holes, the rear line of rivet holes do not line up with the skin. At the top of the vertical line of rivet holes, the hole is about 1/4 hole off. By the time it gets to the bottom, it is nearly one full hole off. Yet, everything else lines up. What have I done wrong here?

Thanks, Perplexed!!!

 

[DGlaeser]

Some 'adjustment' required . . .

Yes the tailcone goes inside the 778 skin.

IIRC, I had to work on the flanges of the back-to-back bulkheads to get things to align. I also had to bend (curl in) the upper edges of the F779 to get it to fit better. All the parts in that area are stiff and thick, so nothing pulls together easily - not much flexing going on.

Which way are the holes off?

 

[macrafic]

As has been recognized in previous posts on this topic by others, I find that the distance between the rows of holes on the 711 are slightly more than the distances between the rows of holes on the skin. Therefore, when I clecoe the forward row of holes, the aft row of holes in the 711 is aft of the row of holes in the skin.

In previous posts, people mentioned "coaxing" with a soft hammer and a block of wood. Can someone expand on that? I can't picture it in my mind.

I can try bending the flanges to a sharper 90 degree bend and seeing if that would allow me to squeeze them together more, but that would also sharpen the bend, producing a potential cracking point.

I also could straighten the flanges then rebend, only further out from the 711 bulkhead web, which would shorten the distance between the holes but, again, straightening and rebending the flange would produce a potential cracking point.

I could drill out the aft row of holes to -4 and use a larger rivet, but some of the holes are so far off that I don't think drilling out to -4 would completely encompass the existing drilled holes.

BTW, my two halves of the 711 are very tight to one another. That isn't the issue here.

Appreciate your help on this one.

 

[boom3]

You are probably past this now, but I will add my comments as I have just finished this part.

I used the duct tape to 2" conduit trick and rolled the edges on the F-779 until they fit better. Pretty thick stuff so it took 2 people to do. One to hold the conduit straight with both hands, and the other to roll the conduit with large channel locks or pipe wrench. That made the fit so much better.

I had the same problem as you with the pre-punched holes in the F711. I think the problem is when you bend the flanges to fit the skin the bulkheads spread out a little and it's hard to help it. If I did it again I would make sure the angle is perfect on both F711 halves before I ever riveted them together. Anyway when clekoed together the clekos were slightly angled but when I match drilled they turned out great and the holes are still round. (Seems like I had a similar problem on the elevators near the counterweights)

It all works out, but not without a lot of effort.