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Martin's user avatar
Martin
  • Member for 7 years, 11 months
  • Last seen more than a week ago
  • Uppsala, Sweden
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Why are many parts of an airliner required to be triplicated, but not the "parts" most likely to malfunction (i.e., the pilots)?
NIce point with AF447. :) But it rather shows that averaging is the worst failure mitigation scenario, more-or-less guaranty the result will be wrong. Idea with median is when one signal diverges, median will never pick it, so yes, median would work here too. OTOH one important assumption for redundancy is that failures are independent events. So it does not work when speed reading is lost bcs of icing (external event affecting all inputs simultaneously -- at least as long as you do not have sensors with different physical mechanism) and likely pilot errors are not independent events either.
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Function of the compressor in a gas turbine engine
Would en.wikipedia.org/wiki/Ramjet be an answer to your question, or are you looking for an possible engine where no compression occurs at all (regardless if powered by a shaft or air inertia)?
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If in a coordinated turn, the horizontal lift vector is equal to the Centrifugal force. Then how is the aircraft still turning?
Philosophical in sense what words "real", "to feel" etc. mean. There is definitively more ways to look at situations and whatever fits your "worldview" and gives correct prediction of objective outcomes is as good way as another. :)
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If in a coordinated turn, the horizontal lift vector is equal to the Centrifugal force. Then how is the aircraft still turning?
@CharlesBretana: this is starting to be more philosophical (my note was actually only about choice of words anyway), but real=feel-able is not good universal measure neither, because feeling depends on particular organs/biology. We are actually not sensing absolute force, but difference over our body parts. You would definitively feel gravity in (strongly) non-homogeneous field despite being (your c.g.) in free fall. And same goes for other "fictitious" forces. (Beletry link: Neutron Star by Larry Niven :-) )
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If in a coordinated turn, the horizontal lift vector is equal to the Centrifugal force. Then how is the aircraft still turning?
@quietflyer: True, I have realized this later, but had not found time to add it to my answer.
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If in a coordinated turn, the horizontal lift vector is equal to the Centrifugal force. Then how is the aircraft still turning?
I do think "force is balancing out acceleration" formulation is misleading. Force is causing acceleration. In any reference frame. The problem with centrifugal force is that it is result of choosing accelerating frame of reference. So you could say, in some sense (this particular) force is "balancing out" acceleration of frame of reference (even if it is bit unusual wording), but frame of reference is no real object. For any physical object, force is causing acceleration, not "balancing" it.
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If in a coordinated turn, the horizontal lift vector is equal to the Centrifugal force. Then how is the aircraft still turning?
Note: centrifugal force is for most purposes as real as for example gravity. The fact that it appears because of choice of frame of reference does not make its effects less real. (You are actually telling just this in the last paragraph mentioning indistinguishably of gravity force and accelerating-frame forces.)
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If in a coordinated turn, the horizontal lift vector is equal to the Centrifugal force. Then how is the aircraft still turning?
No, that's not true. With forces in balance (as seen from the given reference frame), the movement will continue along straight line with constant speed.
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Can any aircraft do donuts under their own power without significant damage?
It is called ground loop (en.wikipedia.org/wiki/Ground_loop_(aviation) ) isn't it? :-) Maybe not exactly, but it shows you main weak point, fuselage, landing gear attachment etc is generally rather weak against such forces.
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