Northrop Grumman marked the beginning of a three-year flight test programme for the X-47B with a 29min flight over Edwards AFB, California, on 4 February.

After take-off at 14:09, the unmanned, tailless demonstrator climbed to 5,000ft and validated navigation software and aerodynamic control by flying several racetrack patterns over the base's vast test range.

"Designing a tailless, fighter-sized unmanned aircraft from a clean sheet is no small feat," says Janis Pamiljans, Northrop's vice president and programme manager.

 X47B close-up 445
 © Northrop Grumman
The X-47B will move to Patuxent River Naval Air Station, Maryland, later this year after completing a series of tests at Edwards to expand the aircraft's aerodynamic envelope, Northrop says. Meanwhile, a second X-47B test aircraft is scheduled to join the flight test programme.

Both aircraft are designed to demonstrate that an unmanned aircraft with a tailless planform can safely operate aboard in the complex operational environment of an aircraft carrier. Carrier trials for the unmanned combat air system-demonstrator (UCAS-D) programme are scheduled to begin in 2013.

The first flight event for the X-47B comes ahead of a similar event scheduled for one of its potential rivals, which is also based at Edwards.

X47B takeoff 445
 © Northrop Grumman
Boeing plans to launch a 10-flight test series with the Phantom Ray, a company-funded derivative of the X-45 developed by the US Air Force and the Defense Advanced Research Projects Agency (DARPA).

Previous versions of the X-47 and X-45 flew a series of test flights from 2001 to 2004 before the Department of Defense cancelled the joint unmanned combat air systems (J-UCAS) programme.

Northrop Grumman X-47B 
Overall Length: 11.6m (38.2ft)
Wingspan:18.9m (62.1ft)
Height: 3.2m (10.4ft)
Aircraft Carrier Takeoff Gross Weight: About 20,412kg (44,500lb)
Speed:High subsonic
Power Plant: Pratt & Whitney F100-220U
Payload Provisions: 2,041kg (4500 pounds), plus electronics

In 2005, the Quadrennial Defense Review required the USN to restart the programme to demonstrate that such an aircraft could operate on an aircraft carrier. After awarding the UCAS-D contract to Northrop in 2007, the programme survived a cancellation threat in 2008.


X-47B lands - Northrop Grumman 
© Northrop Grumman
Since the US Navy recommitted to the programme, the service has added an autonomous refuelling demonstration to the UCAS-D schedule. In addition, the US Air Force has joined the programme as an observer, but has not financially invested in the X-47B's development.

[Click here to watch a Northrop Grumman video showing the X-47B's first flight.]   

Source: Flight International