Prandtl-D, Preliminary Research Aerodynamic Design to Lower Drag, Resembling a boomerang, complex aircraft. 外形酷似迴旋鏢, 複雜的飛機

NASA's Armstrong Flight Research Center engineers are working on an increasingly complex aircraft called the Preliminary Research Aerodynamic Design to Lower Drag, or Prandtl-D. Resembling a boomerang, the aircraft features a new method for determining the shape of the wing with a twist that could lead to an 11-percent reduction in fuel consumption. In this photograph, the Prandtl-D No. 2, which had a 12.5-foot wingspan, lands following a test flight.
November 5, 2015
http://www.voanews.com/media/photogallery/november-5-2015-day-in-photos/3038516.html