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I think the turbulence you felt was just turbulence... unless you flew in a complete circle and passed through your airplane's own "wake".
  Everyone here is happy to help, and most of us know what we're talking about, but if you're paying an instructor to teach you about flying, ask him these questions.
If he's being vague with his answers or dismissive about your newbie questions, get another instructor. Otherwise, you'll just waste your time and money.

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Good advice. It'll be much easier for him/her to explain sitting in front of you...

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Quite so & theory is all very well but you only fully understand it once you've actually done it. If you have a good instructor they will demonstrate all you need to know. I've had a good practical understanding of aerodynamics from a very early age when I first started building & flying model aeroplanes. I'm no scientist & if you'd asked me to explain it in technical terms I couldn't. I feel that I've always known & some of these drawings & explanations only confuse me. I sometimes wonder if the people attempting to explain these things in textbooks actually know what they're talking about.

I look on it in much the same way as driving a car. You play it by the book until you've passed your test but only really start leaming how to drive once you've passed it & thrown the book out of the window. Please note that I'm not suggesting that anyone actually does that where flying is concerned but it's the best comparison I can think of.

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And he's being paid to teach this stuff- a little theory is needed just to comprehend what's going on in flight. Were I the instructor, I'd try to explain it first, then say: "Go look it up later".
But whatever.I guess as long as a student learns to recognize an incipient stall, it doesn't matter too much if they fully grasp the physics involved.

Wow, this really exploded into some interesting arguments... well, I don't know that they're really arguments per-say... but still stimulating to the mind nonetheless. lol

As I said in my original post... everyone's point can still be true given the whole "critical angle of attack" statement earlier. 

Hagar wrote, "it's perfectly possible for an aircraft to fly under control & without stalling when the the wing is way beyond what would nomally be regarded as a critical angle of attack. "

Well, I wouldn't really say that the airplanes are not stalled... in fact, even in snap rolls they are in a stalled condition.  As for vertical maneuvers... to be super-picky the wing isn't stalled as (at least with vertical lines) the wings have nearly 0 AoA.  Now, the airplanes you mentioned like the Extra have a symmetrical airfoil, so it isn't creating any lift... but airflow is still pretty much laminar.  And when you do hang on the prop, then accelerate vertically... the wings are still un-stalled.  A stalled condition refers to disrupted/seperated airflow over the wing.  Vertical lines are done on nearly 0-degree AoA.  No seperation, just SLOW.

If you're familiar with Remote Control airplanes maneuvers such as the Harrier are performed with a fully stalled wing.  Now, the majority of the "lift" is from the fan up front, but those wings are still helping out.  In fact, this maneuver is the perfect example as to what happens when an airplane gets behind the power curve.  At the RPM required for this maneuver... the airplane can still fly just great S&L... to recover from Harrier you just lower the nose, no power adjustment even needed.  More on that later.

Now, when it comes to converting this "critical AoA" to an airspeed is a completly different storry and that seems to be the true culprit to your conversation, not the critical AoA itself. lol 



The original question was only about the stall itself... not control.  And, regardless of what any engineer tells you the actual critical AoA is... there is still a definate point when the airflow over the top of the wing becomes turbulent and seperates... thus your stall.  As I remember it, this critical AoA remains constant within the configuration of the airfoil with regard to speed. 


The problem you get into with jets and thrust, though, is the whole issue of being behind the power curve.   I'm sure many of you like myself have experienced this very problem in flight sim...  you find yourself too slow and stalling, then cram on full power and find that you're STILL DESCENDING even when everything is spool'd up at max RPM.  There is a certain AoA range of the wing when it's screaming for attention... may not even be in a stall... but is getting close.  When this happen, something has got to give... and the easiest thing to change is your AoA... lower the nose, reduce the drag, and the engines will help you out more. 

Try it up at altitude in something like a Hornet... the greater the thrust/weight ratio, the shorter this period of being behind the curve will last.  If you're doing that in a heavy 747 you may as well kiss your butt good-bye unless you've got 4,000 feet to spare!




Also, if you want to understand aerodynamics more, and really visualize it... I recommend buying some cheap RC plane (electric) that's ready to fly and play around with the wing and some smoke.  Heck, even a small plastic model and an incense stick works wonders for actually visualizing the airflow over the wing.  It's great to actually SEE the stall and see where the laminar flow starts to transition to turbulent and seperate from the airfoil. 

Now, take all this with a grain of salt as I haven't taken an aerodynamics classes in 2 years! haha  So if you know I'm saying something Bss Ackwards, slap me upside the head!  :p

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Velocity isn't the same as speed. Speed is a scalar quantity, velocity is a vector. For example, in straight and level flight, you move the throttle from idle to full power, and the speed will increase. However, if on the other hand you put in a control input you change the aircraft direction of movement, which is its velocity (effectively an acceleration).

(Wikipedia does a good explanation = http://en.wikipedia.org/wiki/Velocity

For example in a full power, steep turn at around 5G, I can stall my normal aircraft (into the heavy buffet) at about 135kts, yet in a similar configuration in straight and level flight the aircraft full stalls around 60 to 70kts...

Power can also change the stall speed on some aircraft (ie props) as the prop provides an increase in the airflow over the wing. Its not something we practice so I can't really give an example of how much of a difference it makes (not very much)...


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Very much the same now. We are taught 3 stalls: Clean, the finals turn stall (configured, low power, overbanked and pulling round the corner), and the approach (configured, simulating trying to extend the approach with too little power set). These are all taught before first solo, which is all in the circuit, and if you entered a spin you'd be 1) being a buffoon, and 2) pulling the Handle to vacate the aircraft! We are then taught spinning (erect and inverted) before going solo outside the circuit.

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That might be so in the RAF Charlie & I wouild expect nothing less. What about normal civil training to PPL standard that I was referring to? I can't see that being anywhere near as comprehensive & not sure you would even have to do stall recovery before being sent solo now.

I still think this is purely academic & not helping spirit1flyer who asked a simple question. My advice on that would be to ask his instructor & take no notice of us lot trying to prove how clever we all are.