PPRuNe Forums - View Single Post - Has everyone suddenly forgotten how to build airplanes?
Old 13th Sep 2019, 01:50
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gums
 
Join Date: Jun 2009
Location: florida
Age: 81
Posts: 1,610
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Salute!
Prolly a flight control law that needs some work.

As the bus model(s) in question go, they do not have to meet the same control column pressure WRT AoA requirement that the 737Max does (no direct or indirect control surface posiiton/force feedback required for the FBW bus) They also do not have a stick vibrator like the Boeing stick shaker for stall warning, just "bells and whistles".

Besides using direct AoA values for the control laws, we also have gains due to CAS ( Q, or dynamic pressure) and some rate variables. So unless there are serious aero pitch moment problems that the existing control surfaces cannot overcome, this should be a quick fix,and an effective one.

EDIT: The AoA limiter ( they call it "protection") should have some degree of "rate" or pitch onset to prevent overshoots, but we would have to see the curves/plots and time constants for all the variables to gain a good understanding..

This problem appears to be an overshoot one, does it not? So maybe the rate variable could use some attention, as well as the gains in effect got TOGA scenarios.. END EDIT

Gums opines...

Last edited by gums; 13th Sep 2019 at 04:26. Reason: added rate stuff
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