1. Thank you,Henra for that link to old documents (1930')
2. Do you know or does anybody knows where Prandtl's closed curves can be found on the web : lift and drag on the two axis as mesured with dynamometers, for the whole range of angle of attack (-180,+180°) at constant speed ?
I had these precious books for all the studied profiles, but they have been stolen...
On these curves it is easy to understand that stall is not so wild, but aircraft stability and changing speed may do (or not do ) it wild.
3. We often read posts opposing flying speed and flying gee, or Cl max and deplacement of center of lift, as coming from different paradigms. Thanks to Gums who is reminding or teaching us how gravity feeling, hence gee is an accurate mean to pilot speed, stall,aso for well taught pilots with aerobatics :Nz is the derivate of the speed, so it tells us the speed tendance, it previews speed modification, so the best way to pilot speed uses gee !
Similar math reading of cl max does not emphasizes the fact that cl is maximum at that point, but that left of that point lift increases with attitude, and starts to decrease with attitude passing at the right size of that point.
It is mandatory to the airline pilot to understand the tendance (mathematic derivation) to preview the flight. Hiding how FBW ( in normal law) elevator is a math integration of the side stick position or pressure, and Airbus THS is a math integration of elevator are pedagogic holes, with heavy issues for flight safety. The requested level of math is elementary math. Piloting anticipates the plane 's movement, you need to know the tendance.