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A light aeroplane is in steady, straight and level fight at a low subsonic speed, with no flaps. On reaching a turning point the pilot at a constant speed, uses a load factor of 1.15 to maintain level flight. Due to the turn, the coefficient of lift:
• A
Increases by 32%.
• B
Remains constant.
• C
Increases by 15%.
• D
Increases by 7%.
The load factor (n) can be defined as the ratio of the actual lift of an aircraft to its weight (n = Lift / Weight).

In level flight, lift equals weight. However, if the aircraft maneuvers (i.e. turn), load factor n will be higher than 1. To have a general formula, lift has to be equal to weight, multiplied by the load factor.

L = W n
CL p/2 V2 S = W n
CL = (2W n) / (p V2 S)

• W, p, V and S remain constant.
CL is proportional to n, therefore coefficient of lift increases by 15%.

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