Aircraft Sizing with Morphing as an Independent Variable: Motivation, Strategies and Investigations

Abstract

Recent developments in smart materials and adaptive structures have renewed interest in the possibility of bird-like flight. While the length scale and flight regime of most aircraft preclude the mimicking of birds, much can be gained by learning from nature's principles. Of particular interest is birds' ability to adapt to multiple flight regimes. Such capability in aircraft would enable truly multi-role missions with a high level of efficiency throughout all mission segments. Considerable effort has been focused on the development of smart materials and adaptive structures. Such technologies have the potential to provide substantial improvements in aircraft efficiency, particularly for multi-role aircraft. System-level analysis is key to utilizing these technologies to full advantage. Such analysis will identify high-impact applications and will provide focus for future device development and integration. This paper presents an approach to aircraft sizing that incorporates the effects of as independent variables in the process, so that aircraft performance, size, and weight are functions of morphing. Motivation for a system-level study of is discussed. Strategies are developed for affecting shape change and measuring the empty weight impacts of shape change. Investigations provide an initial view of system-level benefits possible from and identify key issues that must be addressed in the development and integration of devices. The objective of the morphing as an independent approach is to provide a technology pull. This will be accomplished by identifying high-impact uses of and setting target requirements for further development of devices, actuators and effectors. This ability to adapt is often termed 'morphing' and is defined as an in-flight shape change to efficiently perform multiple tasks. Smart materials and adaptive structures, which form the foundation for morphing, have been the topic of extensive research during recent years. Specific devices and strategies have been developed, which enable such capabilities as hinge-less control surfaces, variable wing twist, and seamless variable camber. 1,2 NASA's Aircraft Morphing program 3,4 and DARPA's recently announced Morphing Aircraft Structures program 5 are examples of larger coordinated efforts to develop aircraft. However, device development alone is not sufficient to ensure that is used to its fullest potential. A key element in the success of these programs will be the ability to identify those technologies that can provide the greatest improvements in aircraft performance.