The Problem of Wing Oscillation

Abstract

THE steady increase in speed and use of thin aerofoils compels a deeper consideration of the problem of oscillation. In recent years there has been a tendency to the building of large aeroplanes. This is closely connected with the problem of oscillation. The author in a first approximation tries to solve, from a proportionality point of view, the question of influence of kind of material and size of aeroplane on wing flexural and torsional natural frequencies. Following the idea of solving this problem from a qualitative and not from a quantitative point of view, the conception of proportionality instead of equality is introduced. The idea of “wing torsional rigidity” is created, being inversely proportional to the angle of twist at the end of wing. Applying Newton's Law, at first the flexural and torsional natural frequency of an oscillating rod is found. Afterwards the method is used in the case of an oscillating tubular member. The results are checked by Rayleigh's Method. Lastly, the influence of size of wings having similar shape is taken into consideration.