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.