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 
 
 
 
		
	
		
		
		
		
		
	
		 
			
 
			
			
			
				 
            
			
			
            
            
                
			
			
		 
		
	
	
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