Engine quit late downwind at Bankstown 6/6/09
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but you would really be better off manning up and admitting your error.
a stall is a function of AOA, and can be identified in the aircraft by stick position.. it has nothing to do with sink rate. or anything else.
as for my deleted post, i realised i had written a pretty detailed explanation on stalls, to the point where i thought it was almost a briefing, something that, as a professional, i get paid for.
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Stalling hmmm 
My memory always remembered it as a relationship to a reynolds number of the apparent flow. But maybe my memory is falling. Don't have my copy of andersons on me but I vaguely remember seeing Coefficient of Lift vs aoa graphs that vary depending on the reynolds number of the flow. Mind you that i know is predominadetly a sizing issue but does take into account the energy of the flow. It did change the point that the aerofoil stalled.
hmmmm As einstein says things are just all relative. Is light a particle or wave. Depends on the reference frame. I think the reference frame is in this situation who cares whether the pilot stalled it, had a high sink rate, out come was positive and yes probably even may choose other things if in the same situation. The real lesson here is I think just continue to fly the aircraft all the way to the ground. Even in a stall or high sink rate the pilot continued to fly the plane to the ground. It might not have looked pretty but was accurate in achieving the ultimate goal. Survival!!! So maybe individuals who label criticism here that is not constructive I would suggest stick to your navel and wonder how the fluff gets their
My memory always remembered it as a relationship to a reynolds number of the apparent flow. But maybe my memory is falling. Don't have my copy of andersons on me but I vaguely remember seeing Coefficient of Lift vs aoa graphs that vary depending on the reynolds number of the flow. Mind you that i know is predominadetly a sizing issue but does take into account the energy of the flow. It did change the point that the aerofoil stalled. hmmmm As einstein says things are just all relative. Is light a particle or wave. Depends on the reference frame. I think the reference frame is in this situation who cares whether the pilot stalled it, had a high sink rate, out come was positive and yes probably even may choose other things if in the same situation. The real lesson here is I think just continue to fly the aircraft all the way to the ground. Even in a stall or high sink rate the pilot continued to fly the plane to the ground. It might not have looked pretty but was accurate in achieving the ultimate goal. Survival!!! So maybe individuals who label criticism here that is not constructive I would suggest stick to your navel and wonder how the fluff gets their
Last edited by redleader78; 25th Jun 2009 at 08:38. Reason: Distinction and being pedantic between coefficient and real lift
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My memory always remembered it as a relationship to a reynolds number of the apparent flow
Reynolds Number simply refers to the scale speed regime used when testing the airfoil in a wind tunnel (ie proportionality). Interestingly, the calculation of the Reynolds Number also brings up the issue of inertia, another factor ignored in the discussion so far (as it relates to energy, critical angles and stalling).
If you get into that stuff, you soon realise that most of the explanations of stalling given here are simplistic in the extreme.
For example, my notes on aerodynamics show that a stall is defined as the point at which Cl starts to decrease, in other words being on the "back" of the drag curve is to be technically stalled. That would imply that a high RoD caused by being at a high AoA at low airspeed (ie low energy) is simply a stall without the associated symptoms that pilots are taught to watch for.
It is also true that the critical AoA varies with differences in aerofoil thickness (with the same camber), and the symmetry of the airfoil (symmetrical airfoils having a lower critical AoA), and so on.
So yes our friend in Bankstown was technically stalled, not that this is the point of the discussion...
Everyone's a fecking genius when it comes to an aircraft incident, aren't they
But no, you are right, we shouldn't discuss this stuff. Heaven forbid that anyone might actually learn something... can't have that, can we... after all, the only thing that really matters is whether the guy walked away from it, right???
Grumpy
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remoak
You will learn something from this by speaking to the pilot and listening - not showing off that you know the formula for the coefficient of lift or some other complex mathematical application.
These types of incidents are human factor events not entirely mechanical. I know we can't change the laws of physics but we can change the way in which we apply them during a high stress situation.
You will learn something from this by speaking to the pilot and listening - not showing off that you know the formula for the coefficient of lift or some other complex mathematical application.
These types of incidents are human factor events not entirely mechanical. I know we can't change the laws of physics but we can change the way in which we apply them during a high stress situation.
With ya so far on this one remoak, except
Drag might increase dramatically beyond Cl max, but 'back of the drag curve' refers to the situation where a decrease of speed results in an increase in drag (for S+L flight), does it not?
Thus, in the case of a glide, the 'back of the drag curve' is anywhere slower than the best glide speed, I would have thought.
The video is a near perfect demonstration of this, and how it leads to a stall.
in other words being on the "back" of the drag curve is to be technically stalled
Thus, in the case of a glide, the 'back of the drag curve' is anywhere slower than the best glide speed, I would have thought.
The video is a near perfect demonstration of this, and how it leads to a stall.
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Barkly1992
You really are grumpy, aren't you?I obviously can't speak to the pilot, much as I would like to. And I never mentioned any formulae at all. We were discussing stalling, and since most of what was said was barely accurate, it is worth being a little more precise with our terms.
Speaking of which...
glekichi
Quite right. I was having a grey moment! 
It also raises the question of whether the pilot was stretching the glide to get to the field, which it would appear he clearly was.
You really are grumpy, aren't you?I obviously can't speak to the pilot, much as I would like to. And I never mentioned any formulae at all. We were discussing stalling, and since most of what was said was barely accurate, it is worth being a little more precise with our terms.
Speaking of which...
glekichi
Thus, in the case of a glide, the 'back of the drag curve' is anywhere slower than the best glide speed, I would have thought.
It also raises the question of whether the pilot was stretching the glide to get to the field, which it would appear he clearly was.
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remoak thanks for reminding of all that stuff.. I think you got my point and thanks for saying it an elegant and concise way.
B_sta you still have some form of control in a developed stall.. Otherwise how do you recover when you practice stalls? I stand by my statement the lesson is continue to fly the aircraft all the way to the ground. Whether the pilot flopped it on or not. There was an amount of control that allowed them to survive. Like i said would the pilot take something out of this flight yes. Could i have done a better job.. Don't know.. as I don't know the condition of the aircraft. I would hope I would survive from my efforts. Who cares whether it wasn't a greaser that the romanian judge scores a 9 point 5 and the small minded individual scores a 3. The lesson is as i think more about this. Is be mindful of the energy in the glide at all times. Control it through what ever might happen.
B_sta you still have some form of control in a developed stall.. Otherwise how do you recover when you practice stalls? I stand by my statement the lesson is continue to fly the aircraft all the way to the ground. Whether the pilot flopped it on or not. There was an amount of control that allowed them to survive. Like i said would the pilot take something out of this flight yes. Could i have done a better job.. Don't know.. as I don't know the condition of the aircraft. I would hope I would survive from my efforts. Who cares whether it wasn't a greaser that the romanian judge scores a 9 point 5 and the small minded individual scores a 3. The lesson is as i think more about this. Is be mindful of the energy in the glide at all times. Control it through what ever might happen.
