Luca Marchetti, Sergio Ricci, Luca Riccobene, Donato Grassi, Paolo Mantegazza, Stephan Adden, Huaiyuan Gu, Jonathan Cooper

DOI Number: N/A

Conference number: IFASD-2024-192

Increasing the aspect ratio is one way to improve aircraft aerodynamic efficiency. This reduces the induced drag term but, at the same time, produces an increment of the wing loads, hence an increase of the structural weight. This paper reports the results obtained during a dedicated experimental campaign inside the large wind tunnel at Politecnico di Milano exploring the gust load alleviation capability of a folding wing tip device. This activity has been done under the umbrella of CS2-U-HARWARD project. The high aspect ratio wing equipped with this device was mounted on a half aircraft lying on its side. The model could freely rotate around its pitching axis and a sledge allowed the entire model to plunge. An electromagnetic actuator allowed the application of a dummy weight force to the aircraft counteracting the lifting force, hence permitting the trim of the aircraft. The gusts were produced by deflecting six vanes in front of the model, with different gust lengths produced to excite different frequencies of the wing. A pneumatic actuator
was used to keep the wing tip in its standard configuration and release the mechanism allowing it to fold at will. Several delays between the triggering of the gust and the release of the hinge mechanism were tested, to assess the coupling between the dynamics induced by the gust and the one induced by the release of the mechanism. Three strain gauge bridges were installed on the spar of the wing to measure the bending moment at three different sections corresponding to the root, the engine and as near as possible to the hinge. In addition, a camera tracking system composed of six infrared cameras allowed the reconstruction of the 3D motion of the wing hit by the gust and the complex dynamics of the folding wingtip. The measured wing root bending moment shows that the amount of load alleviation depends on the time when the gust hits the folding wing tip. The wing tip needs to be free to float when the gust hits it for the alleviation to be effective, but the transient of the unlocking of the hinge seems to be beneficial to the goal.

Read the full paper here

Email
Print
LinkedIn
The paper above was part of  proceedings of a CEAS event and as such the author has signed a publication agreement to have their paper published in the repository. In the case this paper is found somewhere else CEAS always links to the other source.  CEAS takes great care in making the correct content available to the reader. If any mistakes are found  in the listings please contact us directly at papers@aerospacerepository.org and we will correct the listing promptly.  CEAS cannot be held liable either for mistakes in editorial or technical aspects, nor for omissions, nor for the correctness of the content. In particular, CEAS does not guarantee completeness or correctness of information contained in external websites which can be accessed via links from CEAS’s websites. Despite accurate research on the content of such linked external websites, CEAS cannot be held liable for their content. Only the content providers of such external sites are liable for their content. Should you notice any mistake in technical or editorial aspects of the CEAS site, please do not hesitate to inform us.