Abstract:
In order to reveal the influence of rotor design on the aeroelastic characteristics and explore the ways to enhance the whirl-flutter stability through blade tip improving of a tilt-rotor aircraft, an analytical model including tiltrotor/nacelle/wing system is formulated. Moreover, the corresponding methods for trim and eigenvalue solution are developed. Byusing XV-15 as an example, the wing modal characteristics under the windmill condition are calculated. The results show that the wing's bending modes get into an unstable state when the advance ratio exceeds 0.9. These results are in good agreement with the data in references. The influence of the rotor blade tip sweep, droop and taper on the whirl-flutter stability is studied. It is indicated that the modal damping of the wing is enhanced significantly due to the swept angle and drooped angle of the blade tip. The method of improving the whirl-flutter stability is obtained through comparative analysis.