On May 30, 2:47*pm, Dudley Henriques wrote:
Just what is it that you are expecting to happen to cause the necessary
bank/lift imbalance to enter a nose low spiral?

Well, I am expecting normal behavior for a light airplane. Most light
airplanes have approximately neutral static and weakly negative
dynamic lateral (roll) stability. Thus, if left with no pilot input,
they will eventually roll into a turn. Maintaining AOA (which the
trim will do) will result in the increased airspeed.

Now the real question is why this is the case. Airplanes could be
built with positive dynamic lateral stability, and in fact ram-air
(square) parachutes (powered and unpowered) are built that way, which
is what makes it possible for them to be flown through clouds (absent
the legalities) with no gyros at all. However, airplanes are
generally not built that way. It's been tried before, and the results
were generally unsatisfactory.

Making the airplane too stable also made it too sluggish, and because
of the yaw-roll coupling involved gave it a really nasty ride in
turbulence.

A pretty good primer on stability issues can be found he

http://selair.selkirk.bc.ca/aerodyna...ity/Page5.html

Michael