A dumb doubt on stalls
I don't care what you believe. Maybe I just wanted a heated
discussion to start, or maybe there is another reason.
Factors to consider...
CG range approved
Actual operational CG
condition of the airfoils
pilot technique
Let see what this logic shows...
aircraft is slowed to near stalling speed by the application
of back pressure on the elevator which increases the down
force on the aircraft tail cone which levers the nose upward
by dynamically shifting the CG to a point behind the CP
which is the moment arm of the tail times the force produced
by the tail in an algebraic balance with the arm of the CG
and CP.
If the tail does not stall, to some degree, what tail down
force ceases to exist to maintain the nose up attitude? If
the wing is stalled does the lift not decrease and thus the
CP force decrease? Would that not reduce the moment needed
to rotate the nose downward to regain flying speed reduce
the angle of attack)?
FAR 23 has design limits for control degradation, the rudder
must be able to yaw the aircraft at a speed less than
lift-off speed, the elevator must be able to apply forces
and even the ailerons have limits. But when the aircraft is
stalled, out of ground effect, what force or forces change
that cause the nose to pitch downward? The wing is
producing less lift which means that the moment produced by
wing lift also decreases, reducing the nose down force. The
tail was supplying the force needed to establish the
attitude and what would cause THAT forced to be reduced if
it is not at least a stall (partial or complete) of the
elevator?
If the aircraft is held in a stalled condition, with the
elevator full back and the aircraft has a stall break, the
nose drops and then the nose pitches back up and the stall
break happens again and again in a cycle, the pilot keeping
the elevator full back and the wings level with rudder and
some aileron if the ailerons still function, what change in
forces on the aircraft is causing the cycle? Did the wing
regain lift or did the tail regain down-force?
--
James H. Macklin
ATP,CFI,A&P
"Matt Whiting" wrote in message
...
| Jim Macklin wrote:
| No, do I need a credible reference?
|
| Only if you want us to believe you as what you are saying
goes against
| everything most of us have seen published in the
literature.
|
| Matt
|