Northrop Grumman X-47A Pegasus
Company-funded UCAV demonstrator for carrier-based unmanned operations.
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.
Quick Facts
- Manufacturer
- Northrop Grumman
- First Flight
- 23 February 2003
- Primary User
- United States Navy
- Developed Into
- Northrop Grumman X-47B
Facts from the source article.
Lore & Background
The X-47A Pegasus was built under contract by Burt Rutan's Scaled Composites at the Mojave Spaceport. The demonstrator looks like a simple black arrowhead with no vertical tailplane, featuring a leading edge sweep of 55 degrees and a trailing edge sweep of 35 degrees. It has retractable tricycle landing gear, with a one-wheel nose gear and dual-wheel main gear, and six control surfaces including two elevons and four 'inlaids'—small flap structures mounted on the top and bottom of the wing forward of the wingtips.
The X-47A is powered by a single Pratt & Whitney Canada JT15D-5C small high-bypass turbofan engine with 3,190 lbf thrust, mounted on the demonstrator's back with the inlet on top behind the nose. The inlet duct has a serpentine diffuser to prevent radar reflections off the engine fan, but to keep costs low, the engine exhaust is a simple cylindrical tailpipe with no provisions for reducing radar or infrared signature. The airframe is built of composite materials, consisting of four main assemblies split down the middle with two on top and two on bottom.
The X-47A was rolled out on 30 July 2001 and performed its first flight on 23 February 2003 at the Naval Air Warfare Center at China Lake, California. The flight test program did not involve weapons delivery, but Pegasus has two weapons bays, one on each side of the engine, that may each be loaded with a single 500-pound dummy bomb to simulate operational flight loads. The demonstrator was also used to evaluate technologies for carrier deck landings, though it did not have a tailhook.
Reader's Guide
The X-47A Pegasus served as a proof-of-concept vehicle for the US Navy's efforts to develop a carrier-based unmanned combat aerial vehicle. Its development was initially company-funded, distinguishing it from the Boeing X-45. The Navy awarded Northrop Grumman a contract for the X-47A in early 2001 following a 15-month concept-exploration program that began in mid-2000 with contracts of US$2 million each to Boeing and Northrop Grumman. Design considerations for a naval UCAV included dealing with the corrosive salt-water environment, deck handling for launch and recovery, integration with command and control systems, and operation in a carrier's high electromagnetic interference environment. The Navy was also interested in using UCAVs for reconnaissance missions, penetrating protected airspace to identify targets for attack waves. The J-UCAS program was terminated in February 2006 following the US military's Quadrennial Defense Review, after which the US Navy selected Northrop Grumman's X-47B as its Unmanned Combat Air System Demonstrator (UCAS-D) program. The X-47A's legacy lies in demonstrating key technologies for carrier-based unmanned operations, including deck handling and stealth design, leading to the larger X-47B and proposed X-47C variant with a 10,000 lb payload and 172 ft wingspan.
Did You Know?
- It has no vertical tailplane and uses six control surfaces including two elevons and four 'inlaids'.
- The engine exhaust is a simple cylindrical tailpipe with no stealth provisions to keep costs low.
- The X-47A has two weapons bays that could each carry a single 500-pound dummy bomb for flight load simulation.
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