The vortex ring state (VRS) is an aerodynamic condition for helicopters normally generated in nearly vertical or vertical descent when the relative upward air velocity equals the downward induced main rotor flow rate. This research should provide a better understanding of the VRS phenomenon on different kinds of helicopters, the analytical and simulation prediction methods, and flight test methods for its determination. It should further provide an indication of the effectiveness of alternative recovery maneuvers such as the one proposed by Capt. Vuichard.
The following outcome will be required with this experimental research:
1) To experimentally determine the flight conditions at which the vortex ring state (VRS) starts to develop for at least three different types of helicopters to support and evaluate the correctness of theoretical methods for prediction of the vortex ring boundaries;
2) To experimentally evaluate the effectiveness of the Vuichard recovery technique for at least three different types of helicopters.
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