Lockheed Martin X-56

The Lockheed Martin X-56 is an American modular unmanned research aircraft designed by Lockheed Martin's Advanced Development Programs, the group informally known as the Skunk Works. It was built to explore High-Altitude Long Endurance flight technologies for future unmanned reconnaissance aircraft, and in particular to test active flutter suppression and gust-load alleviation on long, flexible wings. The X-56A is a small testbed with a wingspan of 8.4 metres and two Jetcat P400 turbojets, and four interchangeable sets of wings were built so that stiff and flexible configurations could be flown. It first flew on 26 July 2013 from Edwards Air Force Base for the Air Force Research Laboratory, and was later operated by NASA. The first aircraft was badly damaged in a crash in November 2015, the second made its first flexible-wing flight in August 2017 and showed that body freedom flutter could be suppressed by the digital flight control system, and the X-56B was destroyed in a crash on 9 July 2021.