Originally Posted by
infrequentflyer789
I suspect Boeing could have met the requirement by just making the control force larger, but that might have made them too hard to move in other parts of the envelope, where STS is inactive. But I'm not sure, I might have that wrong - my aerodynamics is probably past it's use-by date.
I asked myself the same thing earlier, why can't they fix the stick force per knot problem by tweaking the artificial feel unit? That's literally why it exists. Then as I wrote that post I figured out a possible answer... (but, again, this is just supposition.)
There are two aspects to the problem: First, the stick force per knot gradient, i.e., how much pull does it take to hold away from the trim speed. This aspect by itself is easily fixable with artificial feel setting.
But the second one is changing of the trim speed itself. When you increase the thrust like the 737 if famous for, the low thrustline offset tends to pitch the plane up, which is effectively the same as applying aft elevator and/or trimming aft. Say you're approaching at 140 knots, after you apply TOGA the trim speed becomes 100 knots (these are only example numbers). This is only fixable by retrimming.