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 uncomfortable angels that rot
On the slabs, a wing chipped here, an arm there:
The brute curiosity of an angel’s stare
Turns you, like them, to stone....”
—Allen Tate (1899–1979)
“This Great God,
Like a mammy bending over her baby,
Kneeled down in the dust
Toiling over a lump of clay
Till He shaped it in His own image;”
—James Weldon Johnson (1871–1938)
“What do we want with this vast and worthless area, of this region of savages and wild beasts, of deserts, of shifting sands and whirlwinds, of dust, of cactus and prairie dogs; to what use could we ever hope to put these great deserts, or those endless mountain ranges, impenetrable and covered to their very base with eternal snow? What can we ever hope to do with the western coast, a coast of 3,000 miles, rockbound, cheerless, uninviting and not a harbor in it?”
—For the State of Kansas, U.S. public relief program (1935-1943)