Analysis of Twin Turboprop Aircraft Whirl-Flutter Stability Boundaries

Cecrdle, Jiri

doi:10.2514/1.c031390

Cited by 15 publications

(7 citation statements)

References 1 publication

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The model was used for preliminary analytical studies. First, the bulk of parametric calculations by optimisation-based approach 21 to find the stability margins and to predict the flutter behaviour of the system during the wind tunnel tests were performed. The station of both hinges and balance weight were kept at the centre of their ranges, while both vertical and lateral stiffness as well as the propeller revolutions became parameters.…”

Section: Discussionmentioning

confidence: 99%

Mechanical concept of W-WING whirl flutter aeroelastic demonstrator

Cecrdle

Malecek

2014

Proceedings of the Institution of Mechanical Engineers, Part G:

View full text Add to dashboard Cite

This paper deals with the mechanical concept of a whirl flutter aeroelastic demonstrator. It works out the previous study on the W-WING demonstrator design and summarises the new achievements. The paper gives a theoretical background of the subjected whirl flutter phenomenon and summarises the whirl flutter occurrence in aerospace practice. The second part is focused on the experimental research of whirl flutter. At first, a brief summary of past main developments in this field is provided. The main part deals with the new aeroelastic demonstrator 'W-WING', designed and developed at the VZLU. The demonstrator represents wing and engine of a twin turboprop commuter aircraft. Contrary to the most of past demonstrators, it includes thrusting propeller. The demonstrator allows changes of the main structural parameters influencing whirl flutter stability characteristics. The demonstrator is intended for experimental investigations at the VZLU 3m-diameter low-speed wind tunnel. The results will be used for validation of analytical methods and software tools as well as in the frame of research projects.

show abstract

Section: Discussionmentioning

confidence: 99%

Mechanical concept of W-WING whirl flutter aeroelastic demonstrator

Cecrdle

Malecek

2014

Proceedings of the Institution of Mechanical Engineers, Part G:

View full text Add to dashboard Cite

show abstract

“…Later, in 1989, Rodden and Rose [9] demonstrated the inclusion of such derivatives (based on the Houbolt/Reed method) into flutter analysis using MSC Nastran, paving the way for its inclusion into the flutter assessment of full propeller aircraft configurations. Since then, the method has found application in certification [4], design and optimization [10,11], as well as parameter studies [12][13][14], due to its computational efficiency.…”

Section: Introductionmentioning

confidence: 99%

Comparison of Unsteady Low- and Mid-Fidelity Propeller Aerodynamic Methods for Whirl Flutter Applications

Koch,

Böhnisch,

Verdonck

et al. 2024

Applied Sciences

View full text Add to dashboard Cite

Aircraft configurations with propellers have been drawing more attention in recent times, partly due to new propulsion concepts based on hydrogen fuel cells and electric motors. These configurations are prone to whirl flutter, which is an aeroelastic instability affecting airframes with elastically supported propellers. It commonly needs to be mitigated already during the design phase of such configurations, requiring, among other things, unsteady aerodynamic transfer functions for the propeller. However, no comprehensive assessment of unsteady propeller aerodynamics for aeroelastic analysis is available in the literature. This paper provides a detailed comparison of nine different low- to mid-fidelity aerodynamic methods, demonstrating their impact on linear, unsteady aerodynamics, as well as whirl flutter stability prediction. Quasi-steady and unsteady methods for blade lift with or without coupling to blade element momentum theory are evaluated and compared to mid-fidelity potential flow solvers (UPM and DUST) and classical, derivative-based methods. Time-domain identification of frequency-domain transfer functions for the unsteady propeller hub loads is used to compare the different methods. Predictions of the minimum required pylon stiffness for stability show good agreement among the mid-fidelity methods. The differences in the stability predictions for the low-fidelity methods are higher. Most methods studied yield a more unstable system than classical, derivative-based whirl flutter analysis, indicating that the use of more sophisticated aerodynamic modeling techniques might be required for accurate whirl flutter prediction.

show abstract

“…Rodden [21] refined them for the use in conjunction with the simulation code NASTRAN and therefore with arbitrary structural models. Cecrdle later applied them [3] to the analysis of full aircraft models and demonstrated their application to aircraft certification [2]. He uses an optimisation procedure [1] to find the stability boundary with respect to propeller pitch and yaw frequencies and highlights the importance of such modes for the whirl flutter stability of turboprop aircraft.…”

Section: Introductionmentioning

confidence: 99%

Parametric whirl flutter study using different modelling approaches

Koch

2021

CEAS Aeronaut J

View full text Add to dashboard Cite

This paper demonstrates the importance of assessing the whirl flutter stability of propeller configurations with a detailed aeroelastic model instead of local pylon models. Especially with the growing use of electric motors for propulsion in air taxis and commuter aircraft whirl flutter becomes an important mode of instability. These configurations often include propeller which are powered by lightweight electric motors and located at remote locations, e.g. the wing tip. This gives rise to an aeroelastic instability called whirl flutter, involving the gyroscopic whirl modes of the engine. The driving parameters for this instability are the dynamics of the mounting structure. Using a generic whirl flutter model of a propeller at the tip of a lifting surface, parameter studies on the flutter stability are carried out. The aeroelastic model consists of a dynamic MSC.Nastran beam model coupled with the unsteady ZAERO ZONA6 aerodynamic model and strip theory for the propeller aerodynamics. The parameter studies focus on the influence of different substructures (ranging from local engine mount stiffness to global aircraft dynamics) on the aeroelastic stability of the propeller. The results show a strong influence of the level of detail of the aeroelastic model on the flutter behaviour. The coupling with the lifting surface is of major importance, as it can stabilise the whirl flutter mode. Including wing unsteady aerodynamics into the analysis can also change the whirl flutter behaviour. This stresses the importance of including whirl flutter in the aeroelastic stability analysis on aircraft level.

show abstract

Analysis of Twin Turboprop Aircraft Whirl-Flutter Stability Boundaries

Cited by 15 publications

References 1 publication

Mechanical concept of W-WING whirl flutter aeroelastic demonstrator

Mechanical concept of W-WING whirl flutter aeroelastic demonstrator

Comparison of Unsteady Low- and Mid-Fidelity Propeller Aerodynamic Methods for Whirl Flutter Applications

Parametric whirl flutter study using different modelling approaches

Contact Info

Product

Resources

About