Originally Posted by Wizofoz
[PBL: One of the "variables" which I suggest you regard is speed. Stall AoA at, say, 0.8M is rather different from stall AoA at, say, 170 kts CAS, in almost any airplane capable of that performance variation.]
Can you back that statement up?
Just for an indication, stall at 0.8M on contemporary commercial jets will happen at AoA of less than about 10°; on most significantly lower. Exactly where "stall" is defined, though, is another matter. It will mostly be defined by uncomfortable buffet (see the certification criteria) rather than by the point at which C_L starts to drop off radically. There can indeed be a degree or two between the two. In other words, at "defined stall" C_L may still be increasing.
In contrast, stall at 170kts on contemporary commercial jets will be somewhere in the higher 'teens of degrees.
Originally Posted by Wizofoz
It was always my understanding that critical AofA was a fixed value for a given airframe.
Yes, well, you are not alone.
PBL