Originally posted by Gabriel
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Runway Incursion at Shanghai Hongqiao Airport
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Originally posted by Black Ram View PostMaybe I'm arguing over semantics, but I'm not sure it's correct to say "Hal won't follow your command", because it will give you the maximum available nose-up without stalling
Below that threshold, it will give you a pitch rate proportional to the stick displacement. At 100% stick back it will be... I don't remember... was it 5 deg per sec?
In both cases, the AoA will be capped first by Alpha max, so if Alpha max is achieved before 2.5G or 5 deg per sec, it will not pitch up past Alpha max.
Alpha max is less than Alpha stall.
I am simplifying. There are changes in the behavior as you pass through Alpha floor and Alpha proc before reaching Alpha max.
And during the take-off run, rotation and the very first seconds of climb, the behavior is also different, as explained by Evan.
--- Judge what is said by the merits of what is said, not by the credentials of who said it. ---
--- Defend what you say with arguments, not by imposing your credentials ---
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Originally posted by Evan View PostFBW itself is just a means of translating pilot commands into flight surface movements... It's almost funny how ignorant everyone on aviation forums are about FBW. They spout this kind of nonsense as if legions of aerospace engineers are just complete idiots. If you knew how much redundancy Airbus had to build into the A320 to get it certified, how paranoid the regulators were and how over three decades that redundancy has never been needed to it's full extent you might begin to understand how counter-productive all this scarebus chatter is.
--- Judge what is said by the merits of what is said, not by the credentials of who said it. ---
--- Defend what you say with arguments, not by imposing your credentials ---
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Originally posted by Gabriel View PostFor the record, I have nothing against FBW. I do have some objections to Airbus' approach to FBW, i.e the "transfer function" that "translates pilot commands into flight surface movements". Do I think it's unsafe? No. But I do like Boeing's approach better.
I probably prefer the yoke/column as a FBW traducer. The sidestick was a noble idea inspired by the space program but it really overestimated pilots not trained in a space program.
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Originally posted by Gabriel View PostBelow certain speed threshold it will give you a load factor proportional to the stick displacement. 100% stick back will be 2.5G.
Below that threshold, it will give you a pitch rate proportional to the stick displacement. At 100% stick back it will be... I don't remember... was it 5 deg per sec?
In both cases, the AoA will be capped first by Alpha max, so if Alpha max is achieved before 2.5G or 5 deg per sec, it will not pitch up past Alpha max.
Alpha max is less than Alpha stall.
I am simplifying. There are changes in the behavior as you pass through Alpha floor and Alpha proc before reaching Alpha max.
And during the take-off run, rotation and the very first seconds of climb, the behavior is also different, as explained by Evan.
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Originally posted by Evan View PostBoeing is also using c-star control law. What do you mean by "transfer function"?
I probably prefer the yoke/column as a FBW traducer. The sidestick was a noble idea inspired by the space program but it really overestimated pilots not trained in a space program.
In any event, in Boeing the yoke deflection is related with a speed offset from the trim speed (which, for practical terms, means an AoA offset from the trim AoA as long as you are not changing the flaps or spoilers settings). If you reduce thrust and don't touch the yoke the nose will go down to keep the speed/AoA. In an Airbus, the nose will go up to keep 1G or will stay put to keep zero pitch rate.
--- Judge what is said by the merits of what is said, not by the credentials of who said it. ---
--- Defend what you say with arguments, not by imposing your credentials ---
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Originally posted by Gabriel View PostI don't know what is C*, but I thought Boeing was using U*.
In any event, in Boeing the yoke deflection is related with a speed offset from the trim speed (which, for practical terms, means an AoA offset from the trim AoA as long as you are not changing the flaps or spoilers settings). If you reduce thrust and don't touch the yoke the nose will go down to keep the speed/AoA. In an Airbus, the nose will go up to keep 1G or will stay put to keep zero pitch rate.
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