By approximately what percentage will stall speed increase in a horizontal coordinated turn at a bank angle of 45°?

In a horizontal coordinated turn, the stall speed of an aircraft increases due to the additional load factor experienced at bank angles. When flying at a high bank angle, like 45 degrees, the load factor increases, leading to a higher stall speed.

At a bank angle of 45 degrees, the load factor is approximately √2 (or about 1.414). This means that the aircraft is subject to 1.414 times the weight, which, in turn, increases the stall speed calculated for level flight. Stall speed is related to the square root of the load factor, so the increase can be derived from the formula, which states that stall speed in a turn is proportional to the square root of the load factor.

By calculating this, the increase in stall speed at a 45-degree bank is about 19%. Therefore, the percentage increase in stall speed is around 19%, making the most appropriate answer for the increase at that bank angle.

Understanding this concept is crucial for pilots to maintain safe flight operations, especially in maneuvering flight conditions where the aircraft may approach stall limits due to the increased load factor.