elastic axis

elastic axis

[i′las·tik ′ak·səs] (mechanics) The lengthwise line of a beam along which transverse loads must be applied in order to produce bending only, with no torsion of the beam at any section.

elastic axis

If an up-gust strikes the wing an increase on angle of attack results. Increased lift acts through the aerodynamic center. The wing twists nose upward about its elastic axis located some distance behind the aerodynamic center. This increases the angle of attack and lift even more and the self-perpetuation continues.A span-wise line along the cantilever wing. Along this line, a load will produce bending but not torsion. The illustration shows an example of an elastic axis of a wing when it encounters gust. See also aileron reversal.