The mathematical model of aerodynamic forces and moments is described, based on results from various wind-tunnel experiments with the RAE High Incidence Research Model (HIRM). Simulations of the responses due to longitudinal and lateral control inputs at high angles of attack are compared with the responses measured on free-flight models of the configuration. It is shown that the main features of the flight behaviour are reproduced, in particular such phenomena as roll-off, wing rock and nose slice.

In Part II*, an inviscid model using a panel method has been formulated to solve separated flow past a steady aerofoil/spoiler configuration in a low speed stream. In this note, an investigation has been carried out to formulate an incremental model to solve the steady incremental problem when the aerofoil/spoiler changes its geometry by a small mount (eg for a small angular change of the spoiler).

It has been found that to satisfy the incremental boundary conditions on the initial aerofoil/spoiler geometry, incremental changes in the influence coefficients have to be included for the small change in aerofoil/spoiler geometry and the change in separation streamline geometry. A first order procedure is satisfactory; a second order procedure is also presented.

A numerical panel method has been developed for the calculation of the two-dimensional potential flow about an aerofoil-spoiler configuration undergoing periodic motions. The cases investigated include a spoiler oscillating in simple harmonic motion on a steady aerofoil, and an aerofoil-spoiler configuration oscillating in overall pitch and normal translation.

The method is a perturbation method about the steady in viscid flow model of an aerofoil-spoiler configuration.

Elements of linear piecewise vorticity are placed on the aerofoil and spoiler surfaces, while the separation streamlines are replaced by elements of uniform vorticity. Time varying vorticities are shed from the spoiler tip and aerofoil trailing edge, along the upper and lower separation streamlines respectively, through the wake closure region, combining in a planar wake downstream of the wake region.

Predicted forces and moments are broadly in agreement with trends of experimental results available in the literature.

Large deflection problem of a spring loaded hinged nonuniform cantilever beam subjected to a rotational distributed loading is formulated by means of a second-order non-linear integro-differential equation. The problem is examined by considering the beam of rectangular cross-section with linear depth taper subjected to a uniform rotational distributed load. The elastic curves of a beam for this special case are presented.