@ simfly:
To answer your question, if very high AoA could lead to an engine stall in a SU-27:
Look at the "Cobra" Maneuvre, if you have seen one at TV or in real life at an airshow. I have only seen this maneuvre performed by SU 27 and MiG 29 aircraft. (F 16s are not able to do this...)
The airplane arrives at 800kph, idles the engines, pulls up very sharply, but doesnt leave a horizontal flightpath, which means AoA is going to 100 deg. The airplane decelerates in horizontal flight with the nose pointing straight up - even a little backwards to 200kph, tilts back forward and engages thrust again to continue slow flight.
So I think, high AoA on a SU 27 has never been a problem.
Russian aerodynamics is far advanced against westerly planes of the same age!