Parametric Study Of The Aeroelastic Stability Of A Bearingless Rotor

A trade study has been conducted to illustrate the sensitivity of the aeroelastic stability of a bearing less main rotor to the rotor hub coupling parameters that are available for the designer. The r esults are presented over the complete range of rotor speed and collective pitch available and the effects on air resonance of the 6 beam installation angles are compared together with the results of offsetting the cuff snubber attachment. The major part of the study was conducted using the FLAIR analysis which incorporates a uniform representation of the flexbeam. Results are also shown for a modified version of FLAIR in which the uniform beam is replaced by a member having the geometric tailoring resulting from structural optimization.