ESDU 90013 gives a semi-empirical method for thin uncambered and untwisted wings with streamwise or pointed tips and sharp leading-edges and unswept sharp trailing-edges. It applies for angles of attack up to 60 degrees and for Mach numbers from 1.2 to 5. The method requires only the aspect and taper ratios@ together with values at zero angle of attack of normal-force-curve slope and aerodynamic centre position which may be obtained from ESDU 70012. The method was developed from a correlation of published and unpublished experimental data for taper ratios less than 0.5 and aspect ratios of 0.5 to 4 while for taper ratios exceeding 0.5 the aspect ratios were from 0.5 to 2; however@ for angles of attack less than 20 degrees@ the aspect ratio went down to 0.2. It predicted the normal-force coefficient to within 10 per cent except at low angles of attack where the accuracy was determined by ESDU 70012 and was within 15 per cent@ and gave aerodynamic centre position as a fraction of aerodynamic mean chord to within 0.05 which yielded a pitching moment coefficient@ based on root chord@ within 0.03. Although all the data are for monoplane wings@ it is suggested the results will apply to a cruciform configuration in symmetric flight with one wing in the plane of symmetry. The use of the method is illustrated with a worked example.