Overlapping Elevator Skins - Reason?

[CharlieWaffles]

I am wondering about the skins on the elevator as shown in the picture. In it, the outboard counterbalance rib and skin are placed BENEATH the main elevator skin and there are about 3 holes worth of overlapping material. Is there a reason the skin overlaps as opposed to simply butting? Is it a shrinkage/expansion type issue? I'm wondering if there's a reason not to cut the counterbalance skin to but against the main skin instead?

 

[mcencula]

If it's like the counterbalance skins on the -7A, the overlap makes the structure much more rigid for the counterbalance mounting. Most of the strength comes from the skin itself rather than the ribs.

 

[TSwezey]

I am wondering about the skins on the elevator as shown in the picture. In it, the outboard counterbalance rib and skin are placed BENEATH the main elevator skin and there are about 3 holes worth of overlapping material. Is there a reason the skin overlaps as opposed to simply butting? Is it a shrinkage/expansion type issue? I'm wondering if there's a reason not to cut the counterbalance skin to but against the main skin instead?

I believe that is a high stress area and is done for extra strength.

 

[aturner]

The skins carry most of the loads, and the stiffness of the structure will affect its harmonics and its susceptibility to flutter.