Procedure for calculating weight and balance

Thomas Borchert writes:

Ok, you got me curious. No default position in all Cessnas I have flown.

Both neutral and default positions were mentioned. While there is no
default position, there is most definitely a neutral position, wherein
the trim tab is aligned with the control surface, so that it creates
no deflecting force.

--
Transpose mxsmanic and gmail to reach me by e-mail.

Anno v. Heimburg wrote:

Okay, now that I've made the mistake of reading this discussion, you've got
me curious: How does your plane's trim work? It's obviously not a trim tab.
And how can there be no neutral/default position of the elevator or the
trim device?

It's the common anti-servo tab across entire trailing edge
of the elevator. The trim tab position indicator is marked
only as to a "takeoff" setting, which is roughly in the
center. There is a sweet spot for aerodynamicists where all
three horiz flying surfaces are in trail, not marked on the
indicator, and it is forward of "takeoff," well toward nose
down. A logical way to set tail incidence is so everything
is in trail at 75% cruise velocity in std atmosphere at the
alt where you can have the best cruise book number
(marketing, really). As long as you still comply with Part
23 re trim effects.

In MSFS, the indicator has a center mark, an apparent
"default". In a typical real airplane, this ain't cruise.
Where MX is getting all screwed up besides not understanding
the the lift/drag effects of trim (it's almost a whole
chapter in Dr. S. Hoerner's classic text, Fluid Dynamic
Lift), is assuming MSFS knows when all surfaces are in
trail. Such a tiny flight model tweak would be bizarre for a
game sim which doesn't even fully understand air density.

All trim essentially does in MSFS is tweak the same variable
as elevator to allow for centering springs in joysticks.
I've removed the springs from some of my joysticks, because
then one fiddles less if at all with trim, and it can make
hand flying even the jets easier. Much less unrealistic
phugoid chasing.

F--