PPRuNe Forums - View Single Post - Qantas A380 uncontained #2 engine failure
Old 2nd Dec 2010, 21:26
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Fzz
 
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How does the "other 25,000lbs" of thrust from the fan get transmitted to the pylon to push the aircraft along?
If I understood the link correctly (I've no expertise in this area), the fan is producing 40,000 lbs thrust, but 25,000 of that is countered by the relatively high pressure in the cavity at the front of the LPT, which is why only 15,000 pounds acts on the thrust bearing. If that pressure produces 25,000 pounds pressure on the back of that cavity (the front of the LPT disc), then it must also produce 25,000 pounds pressure on the front of that cavity, which consists of static housing, bearing cases, and the IPT, producing 25,000 forward thrust on those.

A similar process presumably happens for the other turbines and cavities. So directly or indirectly, that 25,000 pounds force acts on the IPT and HPT thrust bearings and on the front ends of the various cavities. As there is a small net force on the IPT and HPT thrust bearings, the vast majority of that force must presumably act on the front static parts of the cavities.
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