Guy Norris/LOS ANGELES

Northrop Grumman is expected to unveil its mock-up of an unmanned combat air vehicle (UCAV) demonstrator, dubbed "Pegasus", on 26 February at its El Segundo site in California.

Although the company remains coy about the configuration and performance of its concept demonstrator, Flight International understands the UCAV is due to make its first flight in the fourth quarter of this year.

The vehicle is likely to perform simulated aircraft carrier operations at the US Naval Weapons Center, China Lake, where "traps and shots" will be conducted on a simulated carrier deck.

Images of the Pegasus reveal a low-observable, sharply swept flying-wing design reminiscent of the B-2 bomber and YF-23 advanced tactical fighter.

The single-engined UCAV is arrowhead-shaped in plan view, with split elevons on the trailing edge for directional control.

The Pegasus is equipped with conformal antennas and a slightly bulbous sensor or satcom housing in the area of the forward fuselage normally reserved for the cockpit.

The vehicle has widely spaced, double-wheeled main undercarriage legs for carrier operations, as well as a single-wheeled nosegear and an arrester hook beneath the aft fuselage. Two conformal, and low-observable engine air inlets are located on the main spine of the aircraft just aft of the sensor bulge.

Northrop Grumman says the Pegasus is not necessarily a dedicated naval UCAV, but is amore generic design tailored to demonstrating the carrier-based utility of the concept.

The company is one of two contractors working on the Defense Advanced Research Projects Agency (DARPA)/US Navy UCAV-N programme. The other is Boeing, which is also working on a DARPA/US Air Force UCAV demonstration effort with its recently unveiled X-45.

Unlike the USAF programme, for which DARPA and the air force have now downselected to a single UCAV design for demonstration, the UCAV-N programme is not leading directly to a single design.

Instead, at the end of the demonstration there is what DARPA describes as a "clean break", and the programme will be handed over to the navy with two contractors. The navy also has the option of proceeding with its own flight demonstration, or joining the DARPA/USAF progamme.

The Pegasus mock-up is being unveiled as part of an open-house event at the company's recently completed Advanced Systems Development Center. The site also houses an advanced simulation center which has been used extensively during the development effort. The actual flying concept demonstrator variant of Pegasus is believed to be under construction at Scaled Composites' site in Mojave, California where assembly is expected to be completed in the third quarter. The involvement of Scaled suggests Pegasus is largely made up of composites.

Source: Flight International