CFIS REPEAT IT LIKE A MANTRA: An airplane can stall at any airspeed, in any pitch attitude. Your trainer’s wing always stalls when it exceeds its critical angle of attack—and that can happen even if the airplane is pointed straight down and approaching VNE. So what do the stall speeds published in the pilot’s operating handbook mean? These only apply for the stated conditions: often level flight, maximum gross weight, and most forward center of gravity, with flaps retracted (VS1) or in the landing configuration (VS0). Factors such as total weight, load factor, power, and center of gravity location affect stall speed—sometimes significantly.
Stall speed increases as weight increases, since wings need to fly at a higher angle of attack to generate enough lift for a given airspeed. The increase in load factor in a turn also increases stall speed; in a level, 60-degree-bank turn, for instance, the effective weight on the wings doubles and stall speed increases by about 40 percent. And wing contamination such as frost or ice can reduce the amount of lift produced by the wing, also raising the stall speed. Changes to the airfoil geometry from high-lift devices such as flaps or leading-edge slats increase the maximum coefficient of lift and thus lower stall speeds. Here, we look at two lesser- known factors affecting stall speeds: center of gravity location and thrust produced.
Flight Training Magazine (AOPA)
Daidzic, N. E. (2020). Nothing but a number: A closer look at stall speed. Flight Training, 32(2), 54-55.
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