PPRuNe Forums - View Single Post - BREAKING NEWS: airliner missing within Egyptian FIR
Old 10th Nov 2015, 22:59
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Control Eng
Join Date: Apr 2013
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Originally Posted by Bertie Bonkers
I take your point re this. As I'm seeing it up to now, the HS goes down, the lower edge of the HS pivot attaching lug striking the connecting pin/bolt/casting which connects the two halves of the 'sandwich'. This causes the pivot mounting to twist around the HS pivot, with aerodrag on the HS causing the lower pinion to push backward onto the APU cone, twisting the lower supporting frame with it. What you then have is the length of the pivot mount sandwich prising away the APU cone at the lower end below the slot, the two halves of the sandwich exerting equal force on the inner and out edges of the APU cone surround frame on both sides.

The key to why the surround doesn't distort could be in the alignment of the cone attachment lugs at the top - they are vertical - so as the pivot mounts force out the lugs at the bottom, the top end opens up like a hinge.

Having said all that though...
Simple mechanics of levers - if you apply a force half way along a lever to exert a force at the end of a lever, then the original force has to be twice the magnitude.

The resultant force ripped the mountings out of the framework and twice the force did not distort the framework - no!

The whole 'loss of HS control' theory is a non starter without tail cone damage in this area.
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