Abstract:
This report gives the results of cascade tests on blades of aspect ratio varying from 3.0 to 1.5, with particular reference to stalling flutter. It is concluded that the influence of aspect ratio on stalling flutter cannot be simply formulated but depends largely on the particular blade design. The effect on the magnitude of the flutter stresses is not critical although the curves do show a tendency to flattening at an aspect ratio about 2.0 (height/thickness: ratio of 20), indicating that the advantages of further reduction in aspect ratio are relatively small. The 'critical flutter velocity' is more complex. For the 'low' to 'moderate' stress levels the increase of critical flutter velocity, with decreasing aspect ratio, occurs quite gradually, while for the high stress levels the increase is very much greater, and is in fact itself quite critical.
