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 flight test.
NASA/Ken Ulbrich
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