PAUL LEWIS /WASHINGTON DC
DARPA contract for yet-to-be unveiled follow-on naval vehicle also expected
Northrop Grumman is anticipating a contract shortly from the US Navy and Defense Advanced Research Projects Agency (DARPA) to begin developing the X-47B naval unmanned combat air vehicle (UCAV-N) demonstrator. It follows a successful autonomously controlled first flight of the company-funded X-47A Pegasus experimental vehicle.
DARPA and the USN are expected to finally kickstart the critical Phase IIB of the UCAV-N programme, possibly next month, with a request for proposals for Boeing and Northrop Grumman to each build and flight test demonstrators by 2006. The goal will be to show that it is technically feasible and affordable to operate a tailless, low-observable UCAV-N design from an aircraft carrier.
The USN's demand for extended range and endurance means the UCAV-N's aerodynamic shape will differ from the X-47A's relatively compact kite design. While Boeing has released early images of its proposed X-46, Northrop Grumman has yet to unveil its X-47B concept. It is understood to have a swept wing with a jagged trailing edge. While the X-47A is powered by a 3,200lb-thrust (14kN) Pratt & Whitney JT15D, the UCAV-N demonstrator will need a 10,000-14,000lb-thrust engine.
Northrop Grumman has spent more than $40 million on Pegasus over the past 31 months, with DARPA and the USN contributing $5.6 million. The company now has a core engineering team to transition to the X-47B. Key technology to carry over from Pegasus will include design architecture and system redundancy, along with a common system integration laboratory and flight test data.
For this reason, says X-47A programme manager Dave Mazur, Northrop Grumman is planning a limited Pegasus test programme of no more than 30 flights. During the initial 12min flight at China Lake, California, a small amount of pitch and roll oscillation was detected at 130kt (240km/h).
The main goals of Pegasus are to demonstrate flying qualities equivalent to a small manned aircraft and make 110kt precision approaches at descent angles up to 4° and using a shipboard-relative GPS system. On the vehicle's first landing, it achieved a dispersion of 2.4m (18ft) long and 4.9m to the side of the predesignated runway aimpoint.
Source: Flight International
