[Nihon_Ni]

I may have been in the sun too much this weekend, but I'm having trouble understanding when to join the center bottom skins (under the seat rib assembly) and I hope someone can point me in the right direction.

In the "Seat Substructure Assembly" section of the plans, p. 8-13 says to dimple all #40 holes in the F-826/27 which are common in the Seat Rib Assembly. There's a note against dimpling the forward and aft two rows of holes that are not common with holes in any of the seat ribs, but no mention of the holes that join the two skins in the center of the aircraft. A few steps later the plans say to rivet the F-826 & 827 to the rear spar attach bulkhead assembly and the inboard seat ribs, so it seems like these holes should be dimpled prior to this step, but I haven't been able to find mention of them. Dwg 74 calls out AN426AD3-3.5 rivets for these holes, so they certainly need dimpled, but when do I do it?

Thanks,
Rob

 

[sapeloson]

You will final rivet the "center portion" of bottom skins long before the rest...

During fuse assembly the whole unit sits on the bottom mid section on carpet on a table. You can't have cleco's here. I'm away from my plans but you ask when to dimple, then you ask when to join.... not sure where you are in the process but naturally as long as the holes are dimpled prior to you riveting the skins to any ribs, you'll be fine.... maybe this picture will help...center run connecting the two skins was done during this step...



You'll do this before you assemble the fuse itself first time and you will not rivet some of this stuff until late in the "riveting the fuse" part... outboard ribs, center section under spar and rear where tail cone attaches... I have just finished "riveting the fuse" section. A lot of these outer holes just got done...

Hope this helps!
Tim

 

[Nihon_Ni]

Thanks Tim,

That helps a lot. I couldn't find any mention of these rivet in my plans (v 6/23/11) but I know they have to be dimpled at some point. Did you join the two skins together prior to riveting them to the internal seat ribs (F-814A & F-814B) or at some point afterwards? I see the note about not riveting the skins to the aft outboard seat ribs on page 8-14, but again, no mention of joining (or not joining) the skins to each other. Because of the dihedral, I could see that this might be the last step in the process, but I can't find instructions on that row of rivets.

Rob

 

[sapeloson]

I think......

Rob,
I think I started in the center and then worked my way out 6 or so rivets at a time in every direction, center joint included....... finishing up at the ends of each rib and the ends of the center joint.......Don't forget to fold the edge of the overlapping skin prior to dimpling....
Tim