The Aerodynamics of a Stall
The wings of your aircraft are simply an airfoil, which creates lift when air is pushed past it at the propper angle.  The best way to demonstrate this (believe it or not) is by driving down the road with your hand out the window of your car!  With your fingers held together and your palm  facing towards the ground and your thumb at the leading edge, your hand (the airfoil) hits the wind with an angle of attack of 0 degrees.  This doesn't create any lift, but if you increase the angle of attack (rotating the thumb upward), then your hand is pushed upwards (Diagram 1).
      The force pushing your hand upwards is called LIFT, and the force pushing your hand backwards is called DRAG.   The Angle between the oncoming airflow and the airfoil (your hand) is called the ANGLE OF ATTACK (AOA).  Note that if we have a low angle of attack, we produce a small ammount of lift and a small ammount of drag.  If we increase the angle of attack, we produce more lift, but also produce more drag (Diagram 2).
Diagram 1              Diagram 2 
 Say you are travelling at 60 kmph and keep the same angle of attack , but increase speed to 100 kmph, what happens?  Well more airspeed creates more lift, and your hand gets pushed upwards with even more force, but you also produce more drag.    Similarly if you slow down and maintain AOA, lift decreases, and so does drag..  If the airspeed is too slow, the ammount of lift produced is less than the force of gravity pushing your hand down, and so your hand falls.  This is not a stall - it is a similar situation to when you are on the runway a bit short of the required speed for takeoff.  From this we learn that the more speed you have, the more lift you can produce.
    What happens if we increase the AOA and keep the speed constant?  More AOA creates even more lift, but as you increase the AOA of your hand, it gets to a point where you cease creating lift, your hand drops down, and is pushed back by the force of the oncoming airstream. (Diagram 3) At this point you are creating no lift, but a lot of drag.  This situation is what we call a "STALL".  Note that if you maintain this angle and increase speed, you cannot re-establish lift, because the AOA is too extreme.
    A stall situation simply means that the airflow past the airfoil has become very turbulent (Diagram 4) instead of streaming past  and smoothly re-joining at the trailing edge  .  The only way to re-establish the correct airflow and subsequently lift, is to decrease the AOA- it's really that simple.   When the airflow is right on the edge of stalling for that particular speed, the airfoil is at it's CRITICAL Angle of attack.  If for example your hand has exceeded this critical AOA as in the top of diagram 3, doubling your speed will not create any lift, it will just create extra drag.
     It is important to realise that your aircraft can stall at any speed.   At very high speeds you are more likely to black out before you encounter a stall.   (You do have the Blackout/Redout option on, don't you??!!!)
Diagram 3            Diagram 4 
    A simple stall can be encountered by flying along slowly (160 kmph or 100 mph), keeping the wings level, and then pulling the nose up 20-30 degrees and holding it.  As the airspeed bleeds off, the lift generated decreases, and more back stick pressure is required to hold the nose up.  It gets to a point where the wings exceed the critical AOA, and bingo - you have stalled the airflow.  If the wings are level, gravity takes over and helps recover the stall for you.  With no lift, the weight of the aircraft forces you to lose altitude, the airflow over the tail section pushes the tail up and the nose down, and you dive, thus regaining airspeed again.  This type of stall is a piece of cake to get out of - you just point the nose downwards (Decrease AOA), open up the throttle  and build up some speed, then slowly pull out of the dive.  Where you get into trouble, is if the wings aren't quite level, and then it is more likely that you  will enter a Spin.

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