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Principles of flight

5.4.1.3 The relationship between bank angle, G-forces and stall speed

The figure below shows the relationship between G-forces and stall speed.

At 1G, the stall speed is as specified in the aircraft manual.

You can calculate the stall speed when you know how many G’s you will pull.

The formula is:

”new stall speed” = GVs
(Vs is the stall speed)

Example: If you pull 4G, the stall speed will increase by the square root of 4, i.e.,

2. This means that in this case, the stall speed is doubled!

The stall speed increases with the square root of the number of G’s pulled.

You can also calculate G: G = 1/cos for heel angle

The next page shows the relationship between bank angle in degrees and the

increase in stall speed in percentage.

For example, at 60° of bank, the stall speed increases to 140% of the original

value. You pull 2 G’s in a 60° bank turn.

You can see that the stall speed is doubled at a bank angle of about 75°.

At higher bank angles, the aircraft stalls at a higher speed.

Flight Theory PPL(A)(UL)/LAPL Henning Andersen, Midtjysk Flyveskole© 2025 465