Northrop Grumman X-47A Pegasus

The Northrop Grumman X-47A Pegasus is an unmanned combat aerial vehicle built to demonstrate key technologies. It originated within DARPA’s J-UCAS project and later fed into the U.S. Navy’s UCAS-D initiative, which aims to field a carrier-capable drone. Unlike the competing Boeing X-45, Northrop Grumman funded the Pegasus’s early development itself.

The U.S. Navy did not commit to practical unmanned combat air vehicle efforts until mid-2000, when it awarded $2 million contracts to both Boeing and Northrop Grumman for a 15-month concept-exploration phase. Design challenges for a naval UCAV included resisting saltwater corrosion, handling on deck for launch and recovery, integrating with command-and-control systems, and operating in the high electromagnetic interference environment of a carrier. The Navy also wanted its UCAVs to perform reconnaissance, penetrating defended airspace to locate targets for strike aircraft.

In early 2001, the Navy gave Northrop Grumman a contract for a naval UCAV demonstrator designated X-47A Pegasus. Burt Rutan’s Scaled Composites built the proof-of-concept vehicle at the Mojave Spaceport.

The Pegasus resembles a simple black arrowhead, lacking a vertical tail. Its leading edge sweeps back 55 degrees, and its trailing edge sweeps 35 degrees. It has retractable tricycle landing gear—a single wheel on the nose and dual wheels on the main gear—and six control surfaces: two elevons and four “inlaids,” which are small flaps mounted on the top and bottom of the wing ahead of the wingtips.

A single Pratt & Whitney Canada JT15D-5C high-bypass turbofan engine powers the X-47A, producing 3,190 pounds of thrust. This engine also powers operational aircraft like the Aermacchi S-211 trainer. The engine sits on the demonstrator’s back, with its inlet atop the fuselage behind the nose. The inlet duct uses a serpentine diffuser to hide the engine fan from radar, but to keep costs low, the exhaust is a simple cylindrical tailpipe with no special measures to reduce radar or infrared signature.

The airframe is built from composite materials, with construction subcontracted to Scaled Composites, which had the expertise and tooling to do the work inexpensively. The airframe consists of four main assemblies, split down the middle—two on top and two on bottom.