The theory of the design of aerofoils with an analysis of the experimental results for the aerofoils R.A.F. 25, 26, 30 to 33

Abstract

Recently a number of aerofoils have been designed with the object of obtaining (1) a good thick wing, and (2) a racing wing. Experimental results for these aerofoils are contained in reports R.&M. 915, R.&M. 928, and R.&M. 943. (b) Range of Investigation.-An account is given of the theory on which the aerofoils were designed, the essential feature being to curve the centre line of a good symmetrical section into a circular arc of suitable camber. In the case of high camber, a cubic curve was also tried for the centre line in order to reduce the movement of the centre of pressure. The experimental results are analysed for comparison with the theoretical predictions, and curves are drawn showing the relative merits of the aerofoils. (c) The theoretical basis of the method of design has been fully confirmed by the experimental results. In addition, it appears that the method leads to aerofoil shapes which compare very favourably with previous aerofoils. (d) Further progress may be obtained by seeking for the best possible symmetrical sections of suitable thickness, and further experimental investigation is also required on the effect of reflex curvature in thin and in thick aerofoils.