MODELING AND ANALYSIS OF TILT-ROTOR AEROMECHANICAL PHENOMENA

The paper presents a recent effort to explore tilt-rotor aeromechanica l phenomena with an emphasize on aeroelastic stability in forward flig ht (airplane mode). A general tilt-rotor model has been developed and implemented using a numerical technique that preserves symbolic exactn ess of the equations of motion. The stability study is based on an eig envalue analysis about a nonlinear periodic trim solution. The present method enables both high resolution periodic response, and clear trac ing of the instability drivers by providing the exact partial derivati ves of the involved degrees of freedom in each one of the associated e quations of motion. In addition to the common way of identifying trend s and sensitivities by parametric study, the present approach supplies information about the effectiveness of possible mechanisms that are n ot included in the baseline model. The present results demonstrate the ability of the method to provide such unique insight into the aeromec hanical phenomena in forward flight. illustrative indications regardin g required tilt-rotor design features that will postpone the instabili ty phenomena are discussed. (C) 1998 Elsevier Science Ltd. All rights reserved.