The X-66 is an X-plane being developed by NASA and Boeing through NASA's Sustainable Flight Demonstrator project. The demonstrator aircraft will work to shape the future of aviation by testing new technologies, aircraft configurations, and materials to help reach our goal of net zero aviation emissions by 2050. The aircraft will incorporate extra-long, thin wings stabilized by diagonal struts, known as a Transonic Truss-Braced Wing concept

Original Model by Nasa: 

https://nasa3d.arc.nasa.gov/detail/x-66-x-plane