Bob Chilcoat wrote:
Ron,

I posted this over on RAP but apparently managed to stump everyone. I
thought that perhaps some of your contacts at Boeing might know if this
word, "unporting" was misused by Gann, or is an old term that is no longer
used. It just doesn't sound right to me.

Before Ron provides you the right answer, let me offer what is probably
a wrong one. This is what the internet is all about...wild ass guessing
at it's finest.

"Unporting is the balance destruction of the elevators by aerodynamic
force. I won't confuse you with theory, but if enough separation between
the fixed and the balance portion of your elevators occurs, your airplane
will go into a vertical dive or even beyond the vertical, and no two men in
the world are strong enough to bring it out. This can be caused by a
missing hinge bolt."

I'm guessing that it has something to do with the flow of air between
the top (high pressure) side of the elevator and the bottom through the
gap between the fixed and movable pieces, which for certain geometries
and separation can enter an unstable mode (flutter).

How close am I?