Below is an example of a stall speed chart, taken from the performance section of an airplane's operating handbook. It shows the approximate stall speed of the airplane for which it was issued. Stall speeds will vary with bank angle and flap deflection.
It can be seen that in a level turn, bank angle significantly increases stalling speed, while flap extension slightly reduces stall speed.
Since flap extension lowers stalling speed, two stalling speeds will be published...
VSO – the stalling speed of the airplane in the landing configuration (stuff out).
VS1 – the stalling speed of the airplane in a specific configuration, often specified as clean (stuff in).
