(New throughout, adds comment from BAE, analyst, paragraphs)
By Andrea Shalal
WASHINGTON, Feb 6 (Reuters) - Northrop Grumman Corp said on Friday it is designing and already building a new aircraft for the upcoming U.S. Air Force T-X competition to build 350 new training planes, an $11 billion program that analysts say could double in value in coming years.
Northrop, which built the B-2 stealth bomber and makes the center fuselage of the F-35 fighter jet, said it planned to fly a prototype of the new trainer for the first time this year. That represents a switch from its initial plan to offer an existing aircraft.
The Air Force aims to launch a competition in 2017 to replace its aging fleet of T-38 planes. Analysts say it could eventually buy up to 600 of the new training planes.
Northrop, anxious to score its first prime contract for a big military aircraft program in years, is also vying with a team of Boeing Co and Lockheed Martin Corp for a $50-billion plus contract to build a new long-range bomber.
The company launched a national ad campaign last year to tout its work on some of the world's most advanced aircraft, and even bought air time during the Super Bowl.
Northrop teamed up with Britain's BAE Systems Plc in 2011, aiming to offer the Air Force BAE's proven Hawk plane and the associated training system, which is already in use in Britain and has been sold to Saudi Arabia, Oman and India.
The companies switched to work on a "clean sheet" design about two years ago, betting that emerging manufacturing technologies would help meet evolving Air Force requirements.
BAE and Northrop are still finalizing an agreement on using just the Hawk training system, not the aircraft, said Chris Addison, with BAE Systems Military Air & Information division.
Other companies on the team include L-3 Communications Holdings and German robotics giant Kuka AG.
Another key player is Scaled Composites, a Northrop unit that builds experimental aircraft like the X-47B, a drone that Northrop successfully tested on an aircraft carrier. General Electric will supply the engine for the prototype.
The competition will be fierce: Boeing has teamed with Sweden's Saab AG to develop a new design, and Textron Inc will also offer a new airplane. Lockheed and a separate team made up of General Dynamics and Italy's Finmeccanica Spa plan bids based on existing planes.
"Failure to win a new contract will force Northrop Grumman out of its historical role as prime contractor for military aircraft," said Loren Thompson with the Lexington Instiute.
Marc Lindsley, director and head of Northrop's T-X "capture team," gave no details about the new airplane, but said every company on the team was investing heavily in the project. It will include ground-based training equipment, advanced simulators and an open architecture to allow continual upgrades.
He said a new design would allow the team to benefit from new technologies and advanced manufacturing techniques, which would help keep down the cost of the new planes.
"We want to give the Air Force what they want," he said. "We're designing in affordability from the start." (Reporting by Andrea Shalal; Editing by Eric Beech and David Gregorio)