IMPORTANT CONSIDERATIONS CONCERNING AUTOROTATION HANDLING CHARACTERISTICS
Charles M. Seibel · 1961
An instrumented flight test development program was conducted by the Cessna Aircraft Company with the purpose of evaluating those considerations which benefit the power-off characteristics of helicopters. The comments presented herein are based on the results of this program. The ease with which helicopter power-off landings can be executed is discussed with consideration for the effects of proper control coupling, trim changes, and available control rate application. It is shown that these effects can assist the pilot to a degree comparable to sizeable increments in rotor inertia and disc loading. Hovering autorotation handling characteristics are improved by minimizing most trim changes associated with power variation. However, a reduction in collective pitch associated with power reduction is quite beneficial. Improvement in rotor rpm decay under cruise conditions is improved also by a collective pitch reduction with power reduction, and by a nose-up trim change associated with power reduction. Control coupling between collective and cyclic is beneficial during normal flare landing, providing forward cyclic introduces a decrease in collective pitch. Availability of sufficient collective pitch to effect rotor blade stall is beneficial.