Wing Bending Relief
In fixed-wing aircraft, fuel is usually carried in the wings. Weight in the wings does not contribute as significantly to the bending moment in the wing as does weight in the fuselage. This is because the lift on the wings and the weight of the fuselage bend the wing tips upwards and the wing roots downwards; but the weight of the wing, including the weight of fuel in the wing, bend the wing tips downwards, providing relief to the bending effect on the wing.
When an airplane is being loaded, the capacity for extra weight in the wing is greater than the capacity for extra weight in the fuselage. Designers of airplanes can optimise the maximum takeoff weight and prevent overloading in the fuselage by specifying a MZFW. This is usually done for large airplanes.
Most small airplanes do not have a MZFW specified among their limitations. For these airplanes, the loading case that must be considered when determining the maximum takeoff weight is the airplane with zero fuel and all disposable load in the fuselage. With zero fuel in the wing the only wing bending relief is due to the weight of the wing.
Read more about this topic: Zero-fuel Weight
Famous quotes containing the words wing, bending and/or relief:
“The broken pillar of the wing jags from the clotted shoulder,
The wing trails like a banner in defeat,”
—Robinson Jeffers (1887–1962)
“‘Tis this desire of bending all things to our own purposes which turns them into confusion and is the chief source of every error in our lives.”
—Sarah Fielding (1710–1768)
“Known commonly as the jackass, this long-eared little creature is respected throughout the southwest—roundly cursed yet respected—and here he is usually referred to by his Spanish name, burro. Because of his extraordinary bray, he is sometimes ironically called the “Arizona Nightingale.””
—Administration in the State of Ariz, U.S. public relief program (1935-1943)