!function(d,s,id){var js,fjs=d.getElementsByTagName(s)[0],p=/^http:/.test(d.location)?'http':'https';if(!d.getElementById(id)){js=d.createElement(s);js.id=id;js.src=p+'://platform.twitter.com/widgets.js';fjs.parentNode.insertBefore(js,fjs);}}(document, 'script', 'twitter-wjs');

var addthis_config = {"data_track_clickback":true};

Future aircraft fuel efficiency could be dramatically increased thanks to ideas validated with increasingly complex subscale, experimental, remotely piloted aircraft at NASA's Armstrong Flight Research Center in California. Flights are scheduled to resume this summer on the flying wing-shaped Primary Research Aerodynamic Design to Lower Drag, or Prandtl-D No.3. The project features a new wing design method and a twist. If the concept continues to prove its value, it could forward NASA's research goals to prove technologies leading to significant fuel economy and emissions reduction.

Jay Levine NASA Armstrong Flight Research Center 3-28-16

The NASA Aeronautics Research Mission Directorate has provided funds for student assistance with the flight research that has been ongoing for more than three years at Armstrong. The Prandtl-D No. 3 is undergoing the addition of instrumentation in preparation for the upcoming flights, said Al Bowers, NASA Armstrong chief scientist and Prandtl-D project manager.

Through a series of remotely controlled-subscale Prandtl-D models in 2013, 2014 and 2015, several with sensors that validated aerodynamic design merits and control expectations of the concept, Bowers, colleagues and students recorded more than three hours of flight data. That research confirms that the bell-shaped spanloading method generates proverse yaw. Proverse yaw is thrust, rather than drag, at the wingtips and makes the aircraft's tail unnecessary because of the design and not because of the need for electronic controls. The result is greater efficiency and the potential to reimagine airplane design.

Researchers, industry and academia can learn how wing twist and a radically different bell-shaped spanloading – the load distribution over the wing's span – could lead to a substantial reduction in drag detailed in a technical paper released in March. [...]
Read more »