Whirl Flutter Stability of A Foldable Propeller on Flexible Nacelle using Multibody Dynamics Analysis

Abstract

This paper invesitgates the whirl flutter stability of a foldable propeller with flexible nacelle that are a part of the distributed electric propulsion (DEP) on the NASA X-57 Maxwell. This propeller, named high-lift propeller will accelerate flow over the wing and improve low speed performance by generating induced airflow over the wing. The high-lift propeller blades are designed to fold against the nacelle when not in use during cruise to reduce drag. Blade folding motion on this propeller is akin to blade flapping motion on an articulated helicopter rotor. A flexible nacelle added to a multibody-dynamics model of a high-lift propeller, and the whirl flutter stability, is studied. The stability of propeller blade folding motion is also studied with the isolated rotor and with the flexible nacelle. Whirl flutter stability is investigated at various propeller RPMs and flight speeds for the folded propeller on the flexible nacelle.