|The X-56A on its first flight|
|National origin||United States|
|Manufacturer||Lockheed Martin Skunk Works|
|First flight||26 July 2013|
Air Force Research Laboratory
The Lockheed Martin X-56 is an American modular unmanned aerial vehicle that is being designed to explore High-Altitude Long Endurance (HALE) flight technologies for use in future military unmanned reconnaissance aircraft.
Design and development
Designed by Lockheed Martin's Advanced Development Programs, known informally as the Skunk Works, the aircraft was first revealed by Aviation Week, and is intended to research active flutter suppression and gust-load alleviation technologies. The X-56A is based on Lockheed's earlier UAV work, showing influence from the Polecat, Sentinel and DarkStar UAVs. The program calls for the construction of two 7.5 feet (2.3 m)-long fuselages and a wingspan of 27.5 ft, with four sets of wings being constructed for flight testing.
The X-56A first flew on 26 July 2013, flying from Edwards Air Force Base; twenty flights were to be flown on behalf of the Air Force Research Laboratory before the aircraft would be handed over to NASA for further testing.
The first X-56A unmanned aircraft was severely damaged in a crash shortly after takeoff from the dry lakebed at Edwards AFB, California, on 19 November 2015, on its first flexible-wing flight to test active flutter suppression. The aircraft had previously made 16 flights with stiff wings to prove its operating envelope.
The second X-56A unmanned aircraft flew for the first time on 9 April 2015 while under operation by NASA. The aircraft flew eight flights with the stiff wings to clear its operating envelope. The vehicle then completed its first flight with the highly flexible wings on 31 August 2017.
One instability mode, body freedom flutter, was shown to be actively suppressed by the digital flight control at 110 kn (200 km/h), within its normal flight envelope. Slender, flexible and lighter low-drag wings would be enabled by flutter suppression.
Data from 
- Crew: 1 (flown by remote control from ground-based console)
- Length: 7.5 ft (2.3 m)
- Wingspan: 27.5 ft (8.4 m)
- Powerplant: 2 × Jetcat P400 turbojets, 88.7 lbf (0.395 kN) thrust each
- Maximum speed: 138.1 mph (222.3 km/h, 120.0 kn)
- "Introducing the X-56A MUTT: Who Let the Dog Out?". NASA. Retrieved 15 September 2012.
- Norris, Guy. "USAF Reveals Skunk Works-Designed X-56A As Latest X-Plane". aviationweek. Retrieved 15 September 2012.
- "Lockheed Martin X-56A Multi-utility Aeroelastic Demonstrator". www.hitechweb.genezis.eu. Retrieved 15 September 2012.
- X-56A Testbed Arrives At NASA Armstrong Flight Research Center 17 April 2014.
- Jordan, Holly (31 July 2013). "X-56A technology demonstrator achieves first flight". Wright-Patterson Air Force Base: Air Force Research Laboratory. Archived from the original on 5 October 2013. Retrieved 9 October 2013.
- Warwick, Graham (6 August 2013). "Skunk Works' X-56A - Taming Flutter". Aviation Week & Space Technology. Retrieved 9 October 2013.
- The Week In Technology 23-27 November, Aviation Week & Space Technology
- Conner, Monroe (2015-04-14). "Second MUTT takes to the sky". NASA. Retrieved 2017-09-20.
- Conner, Monroe (2015-04-02). "X-56A Multi-Use Technology Testbed". NASA. Retrieved 2017-09-20.
- "Highly Flexible Wings Tested". nasa.gov. Retrieved 2018-03-26.
- Graham Warwick (Nov 1, 2018). "NASA's X-56 Demos Flutter Suppression Flexible Wing". Aviation Week & Space Technology.
- Lockheed Martin X-56 page
- Lockheed Martin X-56 (2012): Active Flutter Suppression Aviation Week I& Space Technology