Flutter and divergence of swept-back and swept-forward wings

Abstract

In this note, the equations of the flexural-torsional flutter of a swept wing are established, assuming the wing to be semi-rigid and fixed at the root. The general effects of sweep-back, wing stiffness and position of the inertia axis are determined. The critical speeds for flutter and for wing divergence are determined (i) for incompressible flow (ii) for compressible flow, applying the Glauert correction. The critical flutter speed is in general higher for a swept-back wing having the same wing stiffness as the unswept wing; for a swept-forward wing, divergence will occur before flutter.