Effect of tip vanes on the performance and flow field of a rotor in hover
Tests run with a single bladed model rotor with a vane located at the tip of the blade indicated significantly increased performance under certain test conditions. Data reveal that a figure of merit increase of over one third occurred in hover. Flow visualization using smoke revealed that a pair of vortices sprung from the blade tip and the vane tip. The vane tip vortex tended to roll up and over the primary vortex. The vortices in the wake became much less well defined with the tip vane configurations.
Velkoff, H. R.↗