The airplane's weight could be different from the total weight supported by the wings during maneuvers; this leads to which concept?

• A. Wing loading
• B. Stability margin
• C. Load factor
• D. Center of pressure

Answer: (C)

Load factor is the ratio of the total lift produced by the wings to the airplane’s weight. During maneuvers the wings must not only support gravity but also provide the extra lift needed for turning or accelerating the airplane; this means the lift can be greater than the weight. The load factor n is defined as L/W, so it can be greater than 1 in turns or pull-ups. For a level coordinated turn, the lift equals weight divided by the cosine of the bank angle, making n = 1/cos(bank angle); as the bank increases, the load factor rises, increasing the stress on the wings. This concept is fundamental for understanding why airframes are built to withstand higher g loads during maneuvers. Wing loading, which is weight per unit wing area, and center of pressure, the point where lift effectively acts, describe different aspects and are not the same idea as the load factor.