O.K. students, the lesson for today is "stall angle of an aircraft wing". There will be a test to follow. :-)
I'm guessing our KR is "typical of many airfoils" as mentioned in the first paragraph. Larry Flesner ******************************************************************** From Wikipedia: The airspeed at which the aircraft stalls varies with the weight of the aircraft, the <http://en.wikipedia.org/wiki/Load_factor>load factor, bank angle, the center of gravity of the aircraft and other factors. However the aircraft always stalls at the same critical angle of attack. The critical or stalling angle of attack is typically around 15° for many airfoils. Also from Wikipedia: A stall is a condition in <http://en.wikipedia.org/wiki/Aerodynamics>aerodynamics and <http://en.wikipedia.org/wiki/Aviation>aviation where the <http://en.wikipedia.org/wiki/Angle_of_attack>angle of attack increases beyond a certain point such that the lift begins to decrease. The angle at which this occurs is called the <http://en.wikipedia.org/wiki/Angle_of_attack#Critical_angle_of_attack>critical angle of attack. This critical angle is dependent upon the <http://en.wikipedia.org/wiki/Profile_%28engineering%29>profile of the wing, its <http://en.wikipedia.org/wiki/Planform>planform, its <http://en.wikipedia.org/wiki/Aspect_ratio>aspect ratio, and other factors, but is typically in the range of 8 to 20 degrees relative to the incoming wind for most subsonic airfoils. The critical angle of attack is the angle of attack on the <http://en.wikipedia.org/wiki/Lift_coefficient>lift coefficient versus angle-of-attack curve at which the maximum lift coefficient occurs. And from an FAA written test: The angle of attack at which an airplane wing stalls will ANSWER: remain the same regardless of gross weight. A given airplane wing will always stall at the same angle of attack regardless of airspeed, weight, load factor, or density altitude. Each wing has a particular angle of attack (the critical angle of attack) at which the airflow separates from the upper surface of the wing and the stall occurs.
