Originally Posted by
hans brinker
Lower ANU moment with higher assumed temperature due to lower thrust? And calculations weren't as accurate back in the NG days, or NG has less thrust couple? Just taking a stab at it....
I think the geometric thrust line of the MAX is nearly a foot, vertically, closer to the fuselage center line and that drag=thrust means the couple should be less.
If there's an effect of engine I'd consider looking into if it's from the larger bypass ratio as more air will be passing through the fan and not having heat added to it making the thrust more sensitive to the density of the air. Also, in increased density conditions the CL required is lower so the trim should also change; if the density goes down then a higher CL is needed - also a trim change.
Perhaps the better question is why the delay on the NG? Maybe with the smaller bypass ratio the effects tended to cancel?
I know - more questions than answers.