http://www.defensenews.com/story.php?i=5252142&c=AME&s=SEA The first unmanned aircraft designed as a carrier-based strike jet is almost ready to take to the air for the first time, U.S. Navy officials have confirmed. The U.S. Navy's X-47B unmanned strike aircraft, as shown in Palmdale, Calif. (Northrop Grumman) Northrop Grumman's X-47B Unmanned Combat Air System Demonstration (UCAS-D) drone has been performing taxi tests for several weeks at Edwards Air Force Base, Calif., as engineers run the aircraft through a long series of pre-flight tests and checks. Program officials had hoped for a flight by mid-December, but weather and other factors have delayed the event. Officials were reluctant to specify an exact date, but are hopeful the flight will take place before the end of the year. Two X-47Bs have been built by Northrop's Integrated Systems sector under a 2007 development contract. The stealthy aircraft, which resembles a miniature B-2 bomber - also built by Northrop - is intended to test the concept of operating a small, unmanned, combat jet from aircraft carriers. Although numerous technical and command-and-control issues need to be addressed to bring the concept to maturity, war planners have routinely been using X-47s in war games as part of a carrier strike group. In some cases, they have even swapped out the manned air wing for an all-UCAS wing, with, reportedly, great success. Northrop's work on the program includes the design and development of airborne precision-guided positioning system algorithms to help navigate the aircraft, and autonomous aerial refueling technology to keep the planes aloft - perhaps for several days at a time. The first plane was to have taken to the air in late 2009 under the original contract, with the first at-sea tests on a carrier to have been in 2011, but those dates have been pushed back. Initial seagoing tests now are scheduled for early 2013. The single-engine, tailless X-47B has a wingspan of 62 feet and is 38 feet long. It is designed to carry 4,500 pounds of weapons in its payload bay, reach high subsonic speeds, and fly to altitudes of about 40,000 feet. Without refueling, it should be able to operate at ranges up to 2,100 nautical miles and stay in the air for more than six hours.