This document is a supplement to Air Service Information Circular, Vol. 1, No. 49, Report of wind tunnel test on U.S.A. aerofoils 25, 26, 27, 28, 29. A check run on the U.S.A. 27 airfoil was made at M.I.T., November, 1920, for the purpose of checking the characteristics obtained in a test on March 8, 1920. Old and new values are plotted, and the new characteristics tabulated. It is felt that the discrepancies are not of any great practical moment, and that designers need not, in most cases, correct previous computations based on the older results.