Originally Posted by ChristiaanJ
Clive, I think we need your help here. I was also told, both while I was at Fairford and during one of my two ground school courses at Filton in the early 80s, that the lateral stiffeners (underneath the wing just inboard of the Rib 12 area) were added to reduce outer wing flexure and in themselves gave us a performance penalty. Can you shed any light Clive?
Somebody is for sure going to come back and say I haven't a clue what I am talking about on this one! But here goes:
I had never heard of any such stiffeners before I started reading this thread.
The wing inboard of Rib 12 was pretty stiff as was Rib 12 itself, so it didn't need stiffening there.
I don't see how tiny stiffeners like that, mounted INBOARD of Rib 12 could ever have have any significant stiffening effect on the wing OUTBOARD of Rib 12. if anyone wanted to stiffen the outer wing it would be much more efficient to do it with internal structure, so any external addition would have been some sort of panic measure and I think I would have heard of it.
The external shape of the excrescence looks to me much more like a streamlined fairing to get some sort of cable or pipe from A to B when for some reason it couldn't be passed through inside the wing. In this connection I see that the objects in question run fairly close if not along, area where one might have something going from tank 5a to 6 or 7 to 7a.
Yes there would be a small performance penalty for these fairings.
In summary I don't really know, but would need a lot of convincing that these things really were external stiffeners!
CliveL