Originally Posted by
Propduffer
This is an outstanding thread, a credit to PPrune but there are two kinds of posts I've mostly skipped over. The first kind are the "picture analysis" posts which seem to be a separate subject to me. The second type of posts I discount are the ones that propose that if the front joint of the HS were to disengage the HS would flop to 90° to the flight path. I don't have a picture of a ready to install 321 HS but if someone can find such a picture I'm sure it will show that about 2/3rds of the surface area is behind the pivot point. Thus MD80 fanatic is correct in his statement that the HS would align itself with the wind direction in case of loss of the front connection.
It is possible that when the tail section separated from the rest of the plane the VS caught the 280kt (IAS) wind blast and overpowered the HS effects and caused the HS to snap from leading edge down to leading edge up (or even back and forth) and imposed destructive loads. But that can only be a theory for now.
A second point that has been bothering me a bit is all the finger pointing at ISIS. The Russians have been very busy for the last few weeks bombing Al Nustra front positions (read: Al Quida), so they are more likely to be the group with a grudge against Russia.
Again: great thread!
Good points Propduffer.......
(a)My poor memory of early construction picture showed two rear pivots well aft.
(b)even so, loss of control stiffness would likely lead to flutter to destruction
very rapidly indeed, coupled with shredding and shedding of trailing edge components., rapid up downbending loads
Sorry to repeat. I've been there seen that.