TY  - JOUR
A1  - Böhnisch, Nils
A1  - Braun, Carsten
A1  - Muscarello, Vincenzo
A1  - Marzocca, Pier
T1  - About the wing and whirl flutter of a slender wing–propeller system
JF  - Journal of Aircraft
N2  - Next-generation aircraft designs often incorporate multiple large propellers attached along the wingspan (distributed electric propulsion), leading to highly flexible dynamic systems that can exhibit aeroelastic instabilities. This paper introduces a validated methodology to investigate the aeroelastic instabilities of wing–propeller systems and to understand the dynamic mechanism leading to wing and whirl flutter and transition from one to the other. Factors such as nacelle positions along the wing span and chord and its propulsion system mounting stiffness are considered. Additionally, preliminary design guidelines are proposed for flutter-free wing–propeller systems applicable to novel aircraft designs. The study demonstrates how the critical speed of the wing–propeller systems is influenced by the mounting stiffness and propeller position. Weak mounting stiffnesses result in whirl flutter, while hard mounting stiffnesses lead to wing flutter. For the latter, the position of the propeller along the wing span may change the wing mode shapes and thus the flutter mechanism. Propeller positions closer to the wing tip enhance stability, but pusher configurations are more critical due to the mass distribution behind the elastic axis.
Y1  - 2024
U6  - http://dx.doi.org/10.2514/1.C037542
SN  - 1533-3868
SP  - 1
EP  - 14
PB  - American Institute of Aeronautics and Astronautics
ER  - 
TY  - JOUR
A1  - Böhnisch, Nils
A1  - Braun, Carsten
A1  - Muscarello, Vincenzo
A1  - Marzocca, Pier
T1  - A sensitivity study on aeroelastic instabilities of slender wings with a large propeller
JF  - AIAA SCITECH 2023 Forum
N2  - Next-generation aircraft designs often incorporate multiple large propellers attached along the wingspan. These highly flexible dynamic systems can exhibit uncommon aeroelastic instabilities, which should be carefully investigated to ensure safe operation. The interaction between the propeller and the wing is of particular importance. It is known that whirl flutter is stabilized by wing motion and wing aerodynamics. This paper investigates the effect of a propeller onto wing flutter as a function of span position and mounting stiffness between the propeller and wing. The analysis of a comparison between a tractor and pusher configuration has shown that the coupled system is more stable than the standalone wing for propeller positions near the wing tip for both configurations. The wing fluttermechanism is mostly affected by the mass of the propeller and the resulting change in eigenfrequencies of the wing. For very weak mounting stiffnesses, whirl flutter occurs, which was shown to be stabilized compared to a standalone propeller due to wing motion. On the other hand, the pusher configuration is, as to be expected, the more critical configuration due to the attached mass behind the elastic axis.
Y1  - 2023
U6  - http://dx.doi.org/10.2514/6.2023-1893
N1  - AIAA SCITECH 2023 Forum, 23-27 January 2023, National Harbor, MD & Online
SP  - 1
EP  - 14
PB  - AIAA
ER  -