Calculation of stability derivatives for tapered wings of hexagonal planform oscillating in a supersonic stream

Abstract

The aerodynamic loading is formulated for a family of symmetrically tapered wings describing simple harmonic pitching oscillations of low frequency in supersonic flow. The planforms have supersonic leading and trailing edges of constant sweep, the variable parameters being the angle of rake of the side edges and the ratio of span to root chord. For Mach numbers -/2 < M -< 2.4, the investigation covers supersonic and subsonic side edges which act as leading edges, streamwise tips or trailing edges. The lift and moment are evaluated to first order in frequency on the basis of linearized thin-wing theory. In the case of subsonic trailing side edges, it is more convenient to obtain the total forces by use of the reverse-flow theorem. The theoretical values of the pitching-moment derivatives are compared with experimental results obtained on half-wing models with alternative pitching axes and a basic 5% double-wedge section. An estimate of thickness effect is calculated by applying two-dimensional aerofoil theory on a strip-theory basis. When corrected for thickness the theoretical values are in good agreement with the experimental derivatives for Mach numbers greater than 1.6.