The certification requirements. They do not mention in any way a specific
aoa.
They define stall by how the aircraft acts. Like reaching a stick limit, or
responding in a
direction other than that of a control input. Or, on bigger aircraft, when
the computers
say that the plane is stalled. Back to little planes. The stall varies
widely, mostly
depending on weight and cg position. For example at forward cg, the stall is
often
determined by running out of elevator travel. The airplane isn't really
stalled, but the
certification requirements say it is. Reaching a control limit is a limit.
At aft cg, the
airplane nose may stop rising and may even start dropping with increased
elevator
position. This is a limit, because the aircraft is not responding in the
direction of input.
The same things apply to aileron action. The airplane must respond in the
direction of
control input at conditions above stall speed. Stall characteristics get
into this at the
same time. Even though the aircraft may respond in the proper direction, if
the angle
of bank exceeds a rather small number (15 degrees, as I recall) the stall
characteristics
are deemed unacceptable. Addressing all these problems results in
compromises.

I'm sure that I have not covered the issue well at all. It would be a good
exercise pull
up the certification requirements for light aircraft and read them. After a
month or two
of full time study, a person could come up with a lot of questions on just
how the heck
can you certify any plane.

One other thing. Stall speeds vary considerably with entry rate. The regs
specify a 1
knot per second entry rate. At slower entry rates, the stall speed is
higher. At higher
entry rates, the stall speed is lower. Very, very few instructors do 1 knot
per second
entry rate stalls. It's much more difficult to do than the "bring the nose
up and recover
when it breaks" type. This is my most favorite pet peeve. Many instructors
are avoiding
one of the most insidious parts of the envelope. "There I was, turning final
above stall speed and the plane dove into the ground." Turning flight. Slow
speed
decline. It adds up.


Ron Natalie wrote in message
.. .
wrote:
That's a key statement. The definition of stalled, as the FAA and the
pilot
see it, is not an aerodynamic definition. It is a definition based on
aircraft
handling and controllability.

Says who?