Fly Flexible, Fly Safe

摘要

Long-span wings generate less drag, but design rules limit their slenderness to avoid the potentially catastrophic aero-elastic instability known as flutter. Now, as part of the search for fuel efficiency and long endurance, flexible-wing control technology is being flight-tested to overcome those limits. Set to fly to the edge of the envelope and beyond to show flutter can be tamed, Lockheed Martin's X-56A unmanned aircraft made its first flight from NASA Dryden Flight Research Center at Edwards AFB, Calif.,in late July (top photo). Nose-gear issues delayed a second flight, but the aircraft is intended to demonstrate active flutter-suppression and gust-load alleviation to enable lower-drag, more flexible wings for future transport and unmanned aircraft.