Northrop had to undertake a massive effort to redesign the wings of the top-secret Stealth bomber several years ago, costing the government roughly $1 billion and causing the current delays in the bomber program, the Air Force chief of staff disclosed Friday.
The effort to redesign the wing started about five years ago when the Air Force changed its assumptions about how low the bomber would have to fly, requiring that the plane have a stronger structure, Gen. Larry D. Welch said in Los Angeles.
“That is the primary reason for the delay of the program,” Welch said. The comments marked the first time that a top Air Force official has publicly discussed problems in developing the revolutionary bomber, which has wings without a fuselage and is commonly referred to as a “flying wing.”
Ultimately, the redesign of the wings led to a series of top-secret decisions about 18 months ago to restructure and stretch out the entire program, congressional sources said.
The bomber was originally scheduled to fly more than a year ago, but it is now unlikely to fly before early next year. It will be rolled out of its hangar in Palmdale for the first time in ceremonies Nov. 22.
Estimated Cost Skyrockets
The restructuring had broad ramifications on congressional funding, and the delays in the program ultimately led Northrop to write off $200 million against its profits on the program, the sources said.
Welch said he could not provide an accurate estimate of the cost of the controversial bomber program, other than to cite the longstanding figure of $36.5 billion.
“It’s the only official number at the moment, and it’s wrong,” he acknowledged. A recent congressional study put the cost at about $68 billion. Welch told reporters at a breakfast meeting Friday that the wing was redesigned before production started, indicating that even more costly modifications were avoided.
Nonetheless, the decision to change the wing was significant because Northrop had already started to build production tooling for the bomber, and the tooling had to be changed, sources said.
The problems may have been exacerbated by a unique Northrop method of building airplanes. Normally, prototype planes are built with preliminary tools and jigs called “soft tools.” However, to avoid the expense of building those soft tools for just a few airplanes, Northrop builds prototypes with the same tools that are later used to mass produce the aircraft.
As a result, the costly production tools on the Stealth bomber program had to be modified once the wing was redesigned.
Welch said the redesign of the wing involved modifications to its “carry-through structure,” a reference to the area where the two wings mate in the center of the aircraft and distribute the aerodynamic load to the rest of the air frame.
The changes affected the wing both internally and in terms of its external shape, Welch said. The new wing is both lighter and stronger and has an even-smaller radar visibility than the original design, Welch said.
“It was a brilliant effort,” he added.
New Altitude Requirements
But congressional sources said they were concerned that the Air Force attempted to rush into the redesign with the intention of sticking to the original schedule. Eventually, Congress demanded that the program be slowed down until the wing design could be completed, thereby reducing the risk that even more changes would be needed later.
Welch disclosed that the Stealth bomber is intended to ordinarily cruise at “high altitudes,” similar to the 60,000-foot ceiling common to other combat aircraft. It would rely on its unique shape and composite materials to escape detection by enemy radar.
But an assessment by the Strategic Air Command led to a decision that the Stealth may someday have to fly at very low levels, similar to the B-1 bomber, to penetrate Soviet Union air space if that country improves its defenses.
“We decided it needed an all-altitude capability,” Welch said. “Nobody can project the type of threats we are going to face over the next 30 years.”
Since aircraft experience far greater aerodynamic stresses at low altitudes, the wing had to be strengthened if it were to withstand that type of use and not wear out prematurely. “When all of the analysis was done, we didn’t like some of the load paths--some were too stressing,” Welch said.
The disclosures, along with other recent news released about the bomber, mark a significant relaxation of the secrecy surrounding the aircraft. Welch said that full budgetary details about the Stealth will be disclosed by early next year.