Wind-Tunnel Tests on the Effect of a Localised Mass on the Flutter of a Swept-back Wing with Fixed Root

Abstract

Wind-tunnel tests to determine the flutter characteristics of a model wing, carrying a localised mass, are described. The investigation covers the effects of wing sweepback, and of the magnitude and position of the localised mass. Consideration is also given to the effects of pitching radius of gyration and aerodynamic shape. The mass values. used vary from 0.13 to 1.17 times the wing mass. The test results indicate that the parameters that have the greatest effect on critical flutter speed are mass value, spanwise and chordwise position of the localised mass, and wing sweepback. Radius of gyration and aerodynamic shape of the localised mass are found to be secondary in their effects. It was found that the flutter speed of a wing could be considerably increased or decreased by attaching a localised mass; under certain conditions the flutter speed could be more than doubled. A number of different forms of flutter were obtained in the tests, and the values of the parameters at the transition from one form of flutter to another provide the main guide to the flutter characteristics of a wing carrying a localised mass.