Whirl Tower Demonstration of an SMA Blade Twist System

Salvatore Ameduri*, Monica Ciminello, Antonio Concilio, Ignazio Dimino, Bernardino Galasso, Mariano Guida, Marco Fabi Miceli, Johannes Riemenschneider, Steffen Kalow, Jannis Luebker, Ben K S Woods

*Corresponding author for this work

Research output: Contribution to journalArticle (Academic Journal)peer-review

7 Citations (Scopus)
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This paper focuses on the development and demonstration of a novel blade morphing system within a whirl tower facility. The scope is to investigate the behavior of the proposed architecture under representative loads, demonstrating its capability to alter the blade original shape in operation under centrifugal, aerodynamic, and internal forces. The morphing concept was developed inside the European project “Shape Adaptive Blades for Rotorcraft Efficiency”, SABRE, and consists of a shape memory alloy system able to change the original twist law and, in this way, enhance rotor performance at certain specific regimes, such as hover and vertical flight. These phases, indeed, are generally penalized with respect to other more extended flight regimes (cruise). The work starts with an overview of the research in the field of morphing, with specific reference to the researches envisaging rotary wing demonstrations. Then, an overview of the morphing twist concept is provided, with particular attention paid to those features particularly suited for the whirl tower representative test environment. The laboratory characterization and commissioning operations are illustrated. Then, the task of the installation of the prototype on the whirl tower facility is described together with the testing modality adopted. Finally, the results of the test campaign are illustrated and critically discussed, providing the reader with insights and possible future steps to be taken in further research. The impact on the morphing capability of the following different parameters was investigated: the number of the prototype segments switched on, the speed and thus the centrifugal actions, and the angles of attack. The stiffening effect due to centrifugal actions was quantified through the measurement of the actual twist and the internal deformation. The link between speed, angle of attack at root, and twist and flap angles was also tracked, building a database useful for the comprehension of the phenomenon, and for the assessment of numerical predictive models. The achieved results highlighted the capability of the system to produce a twist angle matching the target of 8° per blade radius; this figure is related to a potential power saving of 10% in hover and vertical flight and an improvement of about 1% on the over-all efficiency of the rotorcraft.
Original languageEnglish
Article number141
Number of pages25
Issue number6
Publication statusPublished - 25 May 2022

Bibliographical note

Funding Information:
This work was carried out as part of the Horizon 2020 funded research program known as Shape Adaptive Blades for Rotorcraft Efficiency (SABRE). This project is framed within a scenario that testifies the growing interest of the research community into approaches and technologies targeting a reduced environmental impact. In line with this, at the European level, among the others one may recall the projects of: GENESIS (H2020 Program), targeting the transition to electric and hybrid aircraft [30]; ARTEM (H2020 Program), focusing on innovative technologies for the reduction of aircraft noise at the source [31]; CHANGE (FP7 Program), evaluating technologies enabling morphing [32]; AFLONEXT (FP7 Program), targeting the maturation and the demonstration of flow control concepts [33]; AIRGREEN2 (Clean Sky 2 program), focusing on the development of wings of new generation [34], and SARISTU (FP7 Program), enabling the physical integration of several morphing technologies [35]. At the international level, one recalls the projects of: MAS, promoted by Defense Advanced Research Projects Agency, focusing on the integration of different innovative morphing technologies [36]; MADCAT, promoted by NASA to develop and demonstrate flexible wing technologies [37], and VCAN, funded by the National Natural Science Foundation of China, for the development of variable camber wings [38].

Funding Information:
Funding: The research was funded by the European Research Council (ERC) under the European Union’s Horizon 2020 Research and Innovation Programme, as part of the Shape Adaptive Blades for Rotorcraft Efficiency (SABRE) project (Grant Agreement No. 723491).

Publisher Copyright:
© 2022 by the authors. Licensee MDPI, Basel, Switzerland.


  • SMA blade twist
  • Morphing
  • Adaptive rotor


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    Woods, B. K. S.


    Project: Research, Parent

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