Second X-47B takes to the air

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Northrop Grumman’s second X-47B unmanned aerial vehicle has taken to the air for the first time, increasing the pace of flight testing for the US Navy’s Unmanned Combat Air System Carrier Demonstration (UCAS-D) programme.

The tailless, autonomous aircraft known as Air Vehicle 2 (AV-2) took off from Edwards Air Force Base on November 22. It climbed rapidly to an altitude of 5 000 feet and flew several racetrack patterns over Rogers Dry Lake before landing safely.
“The successful addition of AV-2 to the fleet of X-47B test aircraft provides a critical inflection point for the UCAS-D program,” said Carl Johnson, vice president and UCAS-D program manager for Northrop Grumman’s Aerospace Systems sector. “With two aircraft now available, we can increase the amount of aircraft performance data we gather, which will allow us to meet our required aircraft capability demonstration goals in a timely manner.”

The availability of two test aircraft is particularly important, added Johnson, for helping the program maintain a satisfactory flight test rhythm as it begins transitioning X-47B aircraft to Naval Air Station Patuxent River, Md., (Pax River) for shore-based carrier suitability testing. While one aircraft is being moved to Pax River – expected to occur by the end of 2011 – the other one will continue envelope expansion flight testing at Edwards.

The second X-47B incorporates design improvements to the engine nozzle structure in order to rectify issues with the acoustics that arose from the X-47B’s Pratt & Whitney F100-220U engine that contributed to delays to AV-1.

The testing at Pax River is scheduled to begin early next year. It will include testing the X-47B’s ability to conduct precision approaches to the carrier, and to perform arrested landings and “roll-out” catapult launches at land-based test facilities. The testing will also include flight testing precision navigation computers and new guidance, navigation and control software recently installed on both aircraft. The new suite of hardware and software will enable the X-47B to make precision landings on a moving carrier deck.

The X-47B is a computer-controlled unmanned aircraft system that takes off, flies a preprogrammed mission, and then returns to base – all in response to mouse clicks from a mission operator. The operator actively monitors the X-47B air vehicle’s operation using simple situational awareness displays, but does not fly it via remote control, as some unmanned systems are operated.

The Navy awarded the UCAS-D prime contract to Northrop Grumman in August 2007. The contract calls for the development and flight testing of two strike-fighter-sized X-47B unmanned aircraft. In 2013, rather than late 2011 as originally planned, the program is scheduled to demonstrate the first carrier launches and recoveries by a tailless, unmanned, low-observable-relevant aircraft. Autonomous aerial refuelling demonstrations are planned for 2014.

The X-47 is the US Navy’s first dedicated stealth aircraft since the General Dynamics/McDonnell Douglas A-12, which was cancelled in 1991.

The X-47 project started out under the Defence Advanced Research Projects Agency’s (DARPA) Joint Unmanned Combat Air Systems (J-UCAS) programme, and first flew in February 2003. In February 2006 the J-UCAS programme was cancelled but in August 2007 the US Navy selected the X-47B with Pratt & Whitney F100-PW-229 engine for its Unmanned Combat Air Systems Demonstration (UCAS-D) project to create a carrier-based unmanned aircraft.



The first X-47B, Air Vehicle 1 (AV-1), was rolled out in December 2008 but the start of flight tests was delayed by engine-related acoustic and starting problems and software complexity. The X-47B was originally due to fly in November 2009 but Northrop Grumman and the US Navy only passed the aircraft for taxi tests at a flight readiness review in early November 2010. The X-47B took to the air for the first time on February 4 this year.