It always amuses me when someone says an airplane is stall proof.

If you dive and pull up into a vertical climb what happens when the

airplane

stops climbing and just plain stops. Does the nose only drop 3 or 5

degrees

and start flying again or does it fall completely through to a vertical
dive or does it fall over backwards? What about the torque reaction from
the prop when the airplane is vertical and is not moving?

Paul Lamar

This situation is not a stall since the wing is not supporting the weight of
the aircraft at any speed in the vertical. A stall occurs when flow
separation at a particular angle of attack destroys sufficient lift to cause
the weight of the aircraft to exceed the lift being generated. The stall is
the same and meets the same rule for a Mig-29 and a Piper Cub. The wings
follow the same rules as conventional aircraft. Pitch authority is a

function

of the distance between the center of pressure of the elevators (elevons)and
the average center of pressure on the wing. Pitch sensitivity is a function
of the distance between the average center of pressure of the wing and the
center of gravity. The greater the distance, the less sensitive. There are
some very pitch sensitive aircraft (BD-5) and there are some pitch
insensitive wings (Dyke Delta) As old as the Dyke Delta is it remains a very
efficient design. Lynn E. Hanover

That is an interesting definition for a stall Lynn.

My copy of the New World Dictionary says "Aeron. any condition in which there
is such
a loss of lift  and increase of drag that the aircraft tends to drop or go
out of control."

Your dictionary definition is accurate but brief in the extreme.  I hope mine
was more visual. Both are the same, except for the out of control part. I can
full stall a Stinson and fly it down final (like a steerable stone)unstall it
and land without a problem. (full stall no loss of control).
   I am at a loss to understand how aspect ratio controls pitch sensitivty. I
can load a Grobe sail plane up so that it is so pitch sensitive that Duane
Cole couldn't fly it. at the other end of the scale I can load up a Dyke
Delta so that it couldn't land or take off under 100 MPH. (very low pitch
sensitivity).
Thats no design change, just altering the distance between the avarege center
of pressure and the CG.
Lynn E. Hanover

It also has to do with the rate of change of the lift coef with angle of
attack. That is shown in the chart I uploaded. The term pitch sensitivity is imprecise
and ill defined and not a term you see in the stability and control text books.
Pitching moment coef is the more precise term. There is elevator authority
as well and perhaps that is what you are referring to.


Paul Lamar
 
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