THE distribution of pressure over an aerofoil is often required for rib tests and for obtaining the loadings for flaps and ailerons. The experimental data on the subject is scanty and for some of the newer sections no tests have as yet been published. A method of obtaining the pressure distribution over an aerofoil analytically is described in N.A.C.A. Report No. 452, “General Potential Theory of Arbitrary Wing Sections” by T. Theodorsen and I. E. Garrick; this method gives the pressure distribution on upper and lower surfaces and is applicable to both thin and thick sections. Earlier methods advanced by Munk and Glauert were only applicable to thin sections and as they worked in terms of the mean camber, only gave the mean pressure.