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:
“How soon hath Time, the subtle thief of youth,
Stolen on his wing my three-and-twentieth year!”
—John Milton (1608–1674)
“Sometimes we sailed as gently and steadily as the clouds overhead, watching the receding shores and the motions of our sail; the play of its pulse so like our own lives, so thin and yet so full of life, so noiseless when it labored hardest, so noisy and impatient when least effective; now bending to some generous impulse of the breeze, and then fluttering and flapping with a kind of human suspense.”
—Henry David Thoreau (1817–1862)
“It is told that some divorcees, elated by their freedom, pause on leaving the courthouse to kiss a front pillar, or even walk to the Truckee to hurl their wedding rings into the river; but boys who recover the rings declare they are of the dime-store variety, and accuse the throwers of fraudulent practices.”
—Administration in the State of Neva, U.S. public relief program. Nevada: A Guide to the Silver State (The WPA Guide to Nevada)