Flutter of an all-moving tailplane

Abstract

Tailplane flutter is investigated theoretically for the following semi-rigid modes : (i) tailplane bending, frequency ω1; (ii) tailplane torsion, frequency ω2; (iii) tailplane rotation, frequency ω3; (iv) fuselage bending or torsion (according to symmetry), frequency ω4. The frequency ratios ω2/ω1 ; ω3/ω1 ; ω4/ω1, are varied and graphs of flutter speed against ω3/ω1 are given. The flutter speed drops sharply at low values of ω3/ω1 but it is probably the ratio ω3/ω4 that determines the position of the drop in flutter speed. Symmetric and antisymmetric results are included both for swept-back and unswept tailplanes. The effects of compressibility are excluded, apart from one isolated calculation, but this omission is not considered to have an important effect on the conclusions.