Aerospace Systems Directorate, RQ/Aerospace Structures, Aerodynamics, and Flight Controls
||Wright-Patterson AFB, OH 454337542
Conventional wings using a discrete control surface system (e.g., ailerons or flaps) suffer from aerodynamic inefficiency due to non-smooth outer mold lines and gaps/holes that can create unwanted vortices and flow separations, which increase drag. The discrete nature of these systems also creates structural inefficiency due to limited ability to control induced stresses during the performance of maneuvers. Competing economic and flight performance requirements drive aircraft design to consider aeroservoelastic solutions to balance these requirements, and in some instances attain performance beyond traditional capabilities. Enhanced maneuverability decreased structural weight, reduced drag, reduced noise, and maximized mission range are benefits that may result from replacement of traditional control surfaces with camber morphing and continuously reconfigurable wing designs.
AFRL recently developed a Variable Camber Compliant Wing (VCCW) and tested it in the vertical wind tunnel at Wright-Patterson AFB. This demonstrated that a wing with a single continuous and non-stretchable composite skin can be designed, fabricated, and tested to achieve a large, predefined camber change using a compliant mechanism. This achievement of shape reconfiguration with minimum actuation was possible due to an inherently flexible substructure that is strong enough to withstand aerodynamic loads while meeting acceptable deformation constraints.
The VCCW design team in Aerospace Systems Directorate is interested in exploring Camber Morphing and Continuously Reconfigurable Wing Structure technologies that enable maneuvering without using a discrete control surface system (e.g., ailerons or flaps) in terms of the aerodynamic benefits and developing advanced enabling technologies such as control laws, planforms that are more inherently synergistic with VCCW, hybrid system, engineered material, and fabrication. The research focus includes but is not limited to (1) understanding the 2D/3D aerodynamics of a camber morphing and continuously reconfigurable wing structure; (2) evaluating the benefit of the conformal wing system compared to a conventional wing system with a discrete control surface system (e.g., ailerons or flaps) in terms of efficiency, flight control effectiveness, fuel consumption, and so on; (3) increasing vehicle range and/or flight performance by modifying wing characteristics in flight, such as continuous camber shape optimization at different flight conditions during flight; (4) novel hybrid morphing multi-functional structure design combining compliant mechanism, smart structures, traditional mechanism design and actuation inspired by bio-flight; (5) aeroelastic behavior of a camber morphing and continuously reconfigurable wing structure; (6) control allocation for optimization or balance of sub objectives, such as aerodynamic efficiency, structural loading, and maneuverability; (7) flexible/corrugated skin; (8) novel actuation system; (9) novel wing mechanism/structure design methodologies such as topology optimization; (10) advanced fabrication and bonding; and (11) verifying the benefits and performance using wind tunnel test; and more.
Joo JJ, et al: “Variable Camber Compliant Wing – Design,” 23rd AIAA/ASME/AHS Adaptive Structures Conference, Kissimmee, FL, 5-9 January 2015
Marks CR, et al: “Variable Camber Compliant Wing – Wind Tunnel Testing,” 23rd AIAA/ASME/AHS Adaptive Structures Conference, Kissimmee, FL, 5-9 January 2015
Morphing structures; Reconfigurable structures; Hybrid-structure; Compliant mechanisms; Camber morphing; Bio-Inspired; Aerodynamics; Aeroelasticity; Control; Actuator;