A technical discussion on the use of the wind channel to aircraft designers was held in the Library on Thursday, January 8th, 1925, when the following were present:—Wing Commander T. R. Cave-Browne-Cave (in the chair), O. T. Gnosspelius, Griffith Brewer, W. O. Manning, C. C. Walker, H. N. Wylie, G. T. R. Hill, A. P. Rowe, A. A. Hammond, B. W. Townshend, R. Reynolds, G. P. Douglas, J. S. L. Oswald, W. H. Sayers, T. M. Barlow, R. McKinnon Wood, N. A. V. Piercy, V. Gaunt, R. K. Pierson, F. L. Richards, A. H. Tiltman, S. H. Evans, N. S. Norway and A. V. Roe.

In opening the discussion, Mr. C. C. Walker said that the wind channel should be a means of supplying a mass of systematic data which will indicate the direction in which promising full-scale experiments may be made.

At the request of the Council the following notes on the subject have been prepared, with special reference to the Flettner “rotor ship” and to possible applications in aeronautics.

While it is necessarily somewhat provisional, the data available are pretty full, and it is hoped that no serious modifications will be required as a result of further experimental investigations.

In the now well-known Joukowsky transformation from a circle to a wing profile, maintaining the circulation G and the steady flow at a distance U, unaltered, the diameter of the cylinder 2a, its angular velocity ω, the chord of the profile 4a. (subject to a small correction of about – 5 per cent) and the effective incidence (β are connected by the relations G = 2πa2ω = 4πa sin βU so that aω/2U = sin β.