Northrop Grumman X-47B

The Northrop Grumman X-47B is a demonstration unmanned combat air vehicle (UCAV) designed for carrier-based operations. Developed by the American defense technology company Northrop Grumman, the X-47 project began as part of DARPA's J-UCAS program, and is now part of the United States Navy's Unmanned Combat Air System Demonstration (UCAS-D) program. The X-47B first flew in 2011, and, it is undergoing flight testing, having successfully performed a series of land- and carrier-based demonstrations. Northrop Grumman intends to develop the prototype X-47B into a battlefield-ready aircraft, the Unmanned Carrier-Launched Surveillance and Strike (UCLASS) system, which will enter service by 2019.

Origins
The US Navy did not commit to practical UCAS efforts until 2000, when the service awarded contracts of US$2 million each to Boeing and Northrop Grumman for a 15-month concept-exploration program. Design considerations for a naval UCAV included dealing with the corrosive saltwater environment, deck handling for launch and recovery, integration with command and control systems, and operation in an aircraft carrier's high-electromagnetic-interference environment. The Navy was also interested in procuring UCAVs for reconnaissance missions, penetrating protected airspace to identify targets for following attack waves.

The J-UCAS program was terminated in February 2006 following the US military's Quadrennial Defense Review. The US Air Force and Navy proceeded with their own UAV programs. The Navy selected Northrop Grumman's X-47B as its unmanned combat air system demonstrator (UCAS-D) program. A new weapon system will not be developed for the X-47B, but it will be able to carry existing weapons, and has a full-sized weapons bay. To provide realistic testing, the demonstration vehicle is the same size and weight as the projected operational craft.

The X-47B prototype rolled out from Air Force Plant 42 in Palmdale, California, on 16 December 2008. Its first flight was planned for November 2009, but the flight was delayed as the project fell behind schedule. On 29 December 2009, Northrop Grumman oversaw towed taxi tests of the aircraft at the Palmdale facility, with the aircraft taxiing under its own power for the first time in January 2010.

Flight testing


The first flight of the X-47B demonstrator, designated Air Vehicle 1 (AV-1), took place at Edwards Air Force Base, California, on 4 February 2011. The aircraft first flew in cruise configuration with its landing gear retracted on 30 September 2011. A second X-47B demonstrator, designated AV-2, conducted its maiden flight at Edwards Air Force Base on 22 November 2011.

The two X-47B demonstrators were planned to have a three-year test program with 50 tests at Edwards AFB and NAS Patuxent River, Maryland, culminating in sea trials in 2013. However, the aircraft performed so consistently that the preliminary tests stopped after 16 flights. The aircraft will be used to demonstrate carrier launches and recoveries, as well as autonomous inflight refueling with a probe and drogue. The X-47B has a maximum unrefueled range of over 2100 NM, and an endurance of more than six hours. In November 2011, the Navy announced that aerial refuelling equipment and software would be added to one of the prototype aircraft in 2014 for testing. The demonstrator aircraft will never be armed.

In 2012, Northrop Grumman tested a wearable remote control system, designed to allow ground crews to steer the X-47B while on the carrier deck. In May 2012, AV-1 began high-intensity electromagnetic interference testing at Patuxent River, to test its compatibility with planned electronic warfare systems. In June 2012, AV-2 arrived at Patuxent River to begin a series of tests, including arrested landings and catapult launches, to validate the ability of the aircraft to conduct precision approaches to an aircraft carrier. The drone's first land-based catapult launch was conducted successfully on 29 November 2012.

On 26 November 2012, the X-47B began its carrier-based evaluation aboard the USS Harry S. Truman (CVN-75) at Naval Station Norfolk, Virginia. On 18 December 2012, the X-47B completed its first at-sea test phase. The system was remarked to have performed "outstandingly", having proved that it was compatible with the flight deck, hangar bays, and communication systems of an aircraft carrier. With deck testing completed, the X-47B demonstrator returned to NAS Patuxent River for further tests. On 4 May 2013, the demonstrator successfully performed an arrested landing on a simulated carrier deck at Patuxent River. The Navy launched the X-47B from the USS George H.W. Bush (CVN-77) on the morning of 14 May 2013 in the Atlantic Ocean, marking the first time that an unmanned drone was catapulted off an aircraft carrier. On 17 May 2013, another first was achieved when the X-47B performed touch-and-go landings and take-offs on the flight deck of the USS George H.W. Bush while underway in the Atlantic Ocean.

On 10 July 2013, the X-47B launched from Patuxent River and landed on the deck of the George H.W. Bush, conducting the first ever arrested landing of a UAV on an aircraft carrier at sea. The drone subsequently completed a second successful arrested landing on the Bush, but it was diverted to the Wallops Flight Facility in Virginia after a technical problem was detected, requiring that a planned third landing be aborted. One of the drone's three navigational sub-systems failed, which was identified by the other two sub-systems. The anomaly was indicated to the mission operator, who followed test plan procedures to abort the landing. The Navy stated that the aircraft's detection of a problem demonstrated its reliability and ability to operate autonomously. In a test attempt on 15 July 2013, a different X-47B demonstrator, designated 501, failed to make a successful flight deck landing on the Bush due to technical issues. Officials asserted that only one successful at-sea landing was required for the program, though testers were aiming for three, and only two out of four were achieved. The Navy will continue flying the two X-47B demonstrators through 2014 due to criticism saying the service prematurely retired the testbeds. They plan to deploy the aircraft to carriers three more times over two years. The first deployment is to occur in late 2013, and the second in 2014. The last is to be from late 2014 to early 2015 and demonstrate that unmanned aircraft can seamlessly work with the 70-plane carrier air wing.

The Navy is using software from the X-47B to demonstrate unmanned refueling capabilities. On 28 August 2013, a contractor-flown Learjet 25 refueled from a Boeing 707 tanker. A pilot was on board the Learjet, but it flew autonomously as a surrogate aircraft uploaded with the X-47B's technology. Surrogates are often used as stand-ins for unmanned aircraft. The test was to demonstrate that unmanned and optionally-manned aircraft can have an automated aerial refueling capability, significantly increasing their range, persistence, and flexibility.

On 18 September 2013, the X-47B flew the 100th flight for the UCAS-D program. Objectives of the program were completed in July, which included a total of 16 precision approaches to the carrier flight deck, including five planned tests of X-47B wave-off functions, nine touch-and-go landings, two arrested landings, and three catapult launches.

On 10 November 2013, flight testing for the X-47B continued on board the USS Theodore Roosevelt (CVN-71). During this phase, the X-47B's digitized carrier-controlled environment was tested which involved the interface between the unmanned aircraft and carrier personnel during launching, recovering, and flight operations. Such a digital environment offered increased flexibility and enhanced safety for carrier operations.

Costs
The project was initially funded under a US$635.8-million contract awarded by the Navy in 2007. However, by January 2012, the X-47B's total program cost had grown to an estimated $813 million. Government funding for the X-47B UCAS-D program will run out at the end of September 2013, with the close of the fiscal year.

Variants
Original proof-of-concept prototype with a 27.8 ft wingspan, first flown in 2003.
 * X-47A

Current demonstrator aircraft with a 62 ft wingspan, first flown in 2011.
 * X-47B

Proposed larger version with a payload of 10000 lb and a wingspan of 172 ft.
 * X-47C