The reaction on a wing whose angle of incidence is changing rapidly. wind tunnel experiments with a short period recording balance

Abstract

A balance has been developed in the Aeronautics Laboratory at Cambridge by which the reaction on a wing whose angle of incidence is increasing or decreasing rapidly can be recorded. The reactions have been measured on eight aerofoils, including those used in R. & M. 1588. Large hysteresis effects at and above the stall have been found in two-dimensional conditions. It is considered that these form a basis for accounting for certain full scale observations which have not hitherto been satisfactorily explained. It is proposed to extend the work to three-dimensional conditions. The work is partly the outcome of that described in R. & M. 1561. It also forms part of the investigation of stalling described in R. & M. 1588, and in Professor Jones Wilbur Wright Lecture, 1934. A short account of the results was given by the author at the Fourth International Congress for Applied Mechanics, Cambridge, July, 1934.