NASA KY EPSCoR: Development and Testing of Enabling Technologies for Morphing Airfoils in Low Density Environments

The development of enabling technologies for morphing airfoils for low density atmospheres (low Reynolds number) is proposed. Conventional airfoils have lift coefficients which typically range from 1.0- 1.5. Such lift coefficients will be inadequate in low density atmospheres, such as high altitude flight in Earth's atmosphere or any altitude in the atmosphere of Mars. Propulsion costs and reasonable relative ground speeds of aircraft in such low density environments will drive the available dynamic pressures down substantially requiring a corresponding increase in lift coefficient. With current common static airfoils the necessary lift coefficients are unattainable, particularly since at low densities the Reynolds numbers are driven to values at which the assumptions underlying conventional wing theories do not hold. The effects of viscosity do not remain confined to a thin boundary layer, and large separation regions occur destroying the performance of conventional airfoils. We propose the development of low Reynolds morphing airfoils which have the ability to alter their shape in situ to maximize their lift or some other aerodynamic parameter. One technology that shows promise in meeting these goals is inflatable wing sections with embedded actuators that can rapidly alter wing shape. We have thus far demonstrated the effectiveness of particular techniques of the latter in reducing the degree of separation over low speed airfoils. This proposal will explore the optimization of the shape controlling parameters and shape tailoring processes of morphing airfoils through both modeling and experimental investigation, namely prediction and measurement of aircraft performance variations during morphing maneuvers, as well as morphing strategies that achieve maximum performance enhancement with minimal shape changes.