In my experience, a stall break while straight and level or in a 60 degree
bank if perfectly coordinated will drop the nose straight down.
The kicker is that 98% of the pilots have lazy feet and don't really keep
the aircraft coordinated. If power is ON, the aircraft will need more
rudder to control yaw and that amount of rudder will increase as speed is
decreased approaching the stall. Some airplanes may not have enough rudder
to stay coordinated to the stall, most pilots will not use the rudder that
is available.
Some airplanes will not spin, even wit yaw supplied by maximum rudder input
at the stall in a pro-spin direction. The Beech Skipper [BE77] requires
that the stall be entered, just before the stall, full pro-spin rudder is
applied to induce a roll. At a 90 degree bank angle, sudden and full
aileron in the opposite direction as the rudder is necessary to stall the
wing crisply at the outer half. That will cause the airplane to roll
rapidly and enter a spin. If not timed or done correctly, the aircraft will
enter a spiral.

In the accidental spin, the pilot is likely to do exactly the same thing,
just not with thought and skill. The plane is stalled while yawing
[uncoordinated] and when the break happens, the poorly trained and
non-current pilot's reaction will often be to try to pick-up the wing that
is falling and the nose with aileron and up elevator. The natural reaction,
which training and experience correct, is to "fight" the falling nose, the
falling wing, with normal control input.

IF the aircraft is coordinated perfectly, the difference in lift vector is
due slightly to the radial airspeed difference between the L&R wings, but
more my the dihedral built in the airplane. The problem is that flight is
very dynamic, control forces are changing, humans have reaction times, and
the control authority created by the aerodynamic surfaces rapidly falls with
a small decrease in airspeed [lift equation] and the other forces, such as
P-factor and engine torque involve inertia and mass.



"Todd W. Deckard" wrote in message
...
|
| "Dudley Henriques" wrote in message
| ...
| There is only one thing you have to know about spins. To enter one you
| need 2 things to be present; stall and a yaw rate.
|
| So to corner your answer to my question: you cannot? spin from
coordinated
| flight.
| The airplane must be yawed during the stall break (thus the inclinometer
| ball slips or skids
| to one side).
|
| My question is not to seek out practical advice in spins, or recoveries.
It
| is to explore two
| academic debates: Can a certificated airplane depart if the ball is
| precisely in the middle
| and is there something telling in the emphasis from the foreign sources
| cited that exposes a
| gap in our US training practices and material.
|
| Thank you for your response.
|
| I'll be making a new years resolution to try it out in the neighboorhood
| Decathalon (with an appropriate
| chaperone) but as it is cold and snowy I thought I would put it to the
| uunet.
|
| Best regards,
| Todd
|
|