Development of a Span-Extending Blade Tip System for a Reconfigurable Helicopter Rotor

Vocke, Robert D.; Kothera, Curt S.; Wereley, Norman M.

doi:10.2514/6.2012-1664

Cited by 5 publications

(4 citation statements)

References 18 publications

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“…Variable-camber wings have been designed using several types of auxetic structures, including reentrant hexagonal honeycombs (Dong and Sun, 2011; Heo et al, 2013; Vigliotti and Pasini, 2015), chiral honeycombs (Airoldi et al, 2012; Bornengo et al, 2005; Martin et al, 2008; Spadoni and Ruzzene, 2007), and cross-shaped honeycombs (Zhang et al, 2012, 2014). Zero-Poisson’s-ratio honeycombs have been used in variable-span morphing wings (Ajaj et al, 2012; Bubert et al, 2010; Chen et al, 2015; Gong et al, 2015; Liu et al, 2013; Olympio and Gandhi, 2010; Vocke et al, 2012, 2015). Figure 12 shows a variable-span morphing wing with a 100% extension (Vocke et al, 2011).…”

Section: Structuresmentioning

confidence: 99%

Morphing aircraft based on smart materials and structures: A state-of-the-art review

Sun

Guan

Liu

et al. 2016

Journal of Intelligent Material Systems and Structures

284

137

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A traditional aircraft is optimized for only one or two flight conditions, not for the entire flight envelope. In contrast, the wings of a bird can be reshaped to provide optimal performance at all flight conditions. Any change in an aircraft’s configuration, in particular the wings, affects the aerodynamic performance, and optimal configurations can be obtained for each flight condition. Morphing technologies offer aerodynamic benefits for an aircraft over a wide range of flight conditions. The advantages of a morphing aircraft are based on an assumption that the additional weight of the morphing components is acceptable. Traditional mechanical and hydraulic systems are not considered good choices for morphing aircraft. “Smart” materials and structures have the advantages of high energy density, ease of control, variable stiffness, and the ability to tolerate large amounts of strain. These characteristics offer researchers and designers new possibilities for designing morphing aircraft. In this article, recent developments in the application of smart materials and structures to morphing aircraft are reviewed. Specifically, four categories of applications are discussed: actuators, sensors, controllers, and structures.

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Section: Structuresmentioning

confidence: 99%

Morphing aircraft based on smart materials and structures: A state-of-the-art review

Sun

Guan

Liu

et al. 2016

Journal of Intelligent Material Systems and Structures

284

137

View full text Add to dashboard Cite

show abstract

“…Much less attention was paid to concepts of quasi-static shape changes according to the flight state. Among the most successful works on this are the EU project FRIENDCOPTER (SMA based quasi-static twist) and the DARPA Mission Adaptive Rotor programs (not fully disclosed, but from what is published, includes, among others, span extension [8], deformable airfoils [9], etc.). Chord extension was intensively studied by Gandhi [10][11][12]), showing discrete technology bricks for both rigid body extraction as well as compliant chord extension.…”

Section: Introductionmentioning

confidence: 99%

Manufacturing and Testing of a Variable Chord Extension for Helicopter Rotor Blades

et al. 2022

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Helicopters are still an indispensable addition to aviation in this day and age. They are characterized by their ability to master both forward flight and hover. These characteristics result in a wide range of possible operations. Key for the design of the rotor blades is a blade design that always represents a compromise between the different flight conditions, which enables safe and efficient flight in the various flight conditions. In order to operate the rotor blade even more efficiently in all flight conditions, a new morphing concept, the so-called linear variable chord extension, has been developed. Here, the blade chord length in the root area is changed with the help of an elastic skin to adapt it to the respective flight condition. The simulations performed for this concept showed a promising increase in overall helicopter performance. The fabrication of the resulting demonstrator as well as the tests in the whirl-tower and wind tunnel are presented in this paper. The results of the tests show that the concept of linear variable chord extension has a positive influence and a great potential for hovering flight.

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“…Honeycombs have been extensively used in wingbox and skin design [21][22][23][24] because of high bending stiffness per unit weight and specific transverse shear stiffness. Cellular structures such as zero Poisson's Ratio honeycomb [25] can also provide large in-plane morphing configurations when applied to wind turbine blades [26], span-wise [27][28][29] and chord-wise morphing [30,31], as well as variable camber wing configurations [32]. Active actuation is a relatively novel new feature in cellular structures.…”

Section: Introductionmentioning

confidence: 99%

Morphing wingtip structure based on active inflatable honeycomb and shape memory polymer composite skin: A conceptual work

Sun

Scarpa

et al. 2021

Aerospace Science and Technology

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Development of a Span-Extending Blade Tip System for a Reconfigurable Helicopter Rotor

Cited by 5 publications

References 18 publications

Morphing aircraft based on smart materials and structures: A state-of-the-art review

Morphing aircraft based on smart materials and structures: A state-of-the-art review

Manufacturing and Testing of a Variable Chord Extension for Helicopter Rotor Blades

Morphing wingtip structure based on active inflatable honeycomb and shape memory polymer composite skin: A conceptual work

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