The Air Force and Northrop Corp. lifted the B-2 stealth bomber secrecy curtain another notch Tuesday, allowing reporters a peek at the sprawling factory where the radar-dodging planes are built. The 800,000-square-foot plant where Northrop performs final assembly from parts provided by itself, Boeing, LTV and other subcontractors was far quieter than a normal aerospace plant. Part of the technology that hides the B-2 from radar is the plane's smooth surface, which is achieved by using a minimum of rivets, nuts and bolts. That in turn makes for an eerily quiet manufacturing process. The second through fifth of the flying wings _ their graphite skins covering a honeycomb composite structure _ could be seen on their assembly lines in the plant in the desert city north of Los Angeles. Flanking them were terminals to a computer system whose sophistication Northrop says far exceeds any ever used to build a plane. Company officials predicted it will find wide use in civilian manufacturing. The first B-2 is performing beyond expectations in initial flight testing, completing stability control, in-flight refueling, landings and other tests with few problems, said Bruce Hinds, Northrop's chief test pilot. ``The airplane is maturing and we're able to operate efficiently much earlier than we thought,'' he said. The plane, which Hinds said can turn sharply _ more like a fighter than a bomber _ has been taken up to 35,000 feet and flown at 373 mph. It has won praise from all the pilots who have flown it, Hinds said. The tour came amid continuing efforts in Congress to kill the B-2, which critics contend is far too expensive, especially as the Cold War is ending. If the program were stopped with the construction of 15 planes, as some favor, construction costs would be $35.4 billion. Air Force Maj. Gen. Richard M. Scofield, the B-2 program director, said 15 planes would not be enough to provide a significant military deterrent. Defense Secretary Dick Cheney has suggested building 75 B-2s, which would bring the total cost of the bombers to $62.4 billion. Ron Fraser, an analyst for the dovish Center for Defense Information in Washington, said the real cost of building 75 planes would be more than $110 billion, including $48 billion to operate and support the bombers. ``So cutting it off now, the savings are huge,'' Fraser said. ``It's a bomber we don't need at any price and the price is pretty darn stiff.'' Northrop Chief Executive Kent Kresa and Scofield said such concerns were shortsighted and that the United States should not give up on a plane that will be useful decades into the 21st century. They also argued that the manned bomber provides a needed complement to a U.S. defense system that includes nuclear armed submarines and land-based nuclear missiles. Kresa and Scofield disputed reports that stealth technology could be counteracted by some radar systems. One of those systems, reportedly in Australia, was among 40 supposed stealth-busting techniques that the bomber was tested against, Scofield said. He said the test showed the system had as much chance of locating a stealth bomber as an individual equipped with a flashlight would have of finding one person among a crowd of thousands in the Rose Bowl at night. Marion McHugh, vice president of operations for Northrop's B-2 division, said 11 of the bombers are now 50 percent or more complete. The 10th and 11th will take about 1.2 million worker hours to construct. That's compared to 3.5 million for the first bomber, which McHugh acknowledged took substantially longer to build than anticipated. But he said officials are happy with the progress being made.