Originally Posted by gums #122
The modern commercial heavies have really great aero characteristics that can make a stall insidious. And the stall is not like the Airbus manuals depict on the lift versus AoA curve. There is no sharp break in the curve at "x" AoA. It's a very gentle curve and one can fly at fairly extreme AoA's without the sharp pitch excursion we all saw when checking out in a Chipmunk or Cessna or T-28 or......
Gums' point is illustrated in this graph:
cLalphaM06.gif
It should be noted that only the blue data points are 'fact'. The extrapolation of the trend line beyond the last datapoint should be treated as a 'guess'.
Originally Posted by takata
PS: onset of buffet... buffet may be expected close to stall speed, but gums was also certainly talking about a completely developped stall, where 1 g stall is fully achieved, that may be quiet in such a large and basically very stable aircraft.
You will note in the graph that there is a substantial margin between the onset of buffet (alpha-max) and the 1 g stall. BEA says in its interim report no.2 that the stall is identified by 'vibrations' which is french for buffet, and I think they mean heavy buffet.